Showing posts with label Amplifier. Show all posts
Showing posts with label Amplifier. Show all posts

Sunday, October 31, 2021

Devialet Expert 140 Pro Amplifier

Prologue

Mei impatiently twirled the ends of her long hair as she waited for Joe outside The Adelphi - Mecca of all audiophiles in Singapore. Minutes later, Joe appeared in a huff and drenched in perspiration - the humid tropical weather was especially unkind to office workers in their impractical attire.

"Took a leisurely walk here Joe ?" Mei commented sarcastically before defusing the sharp edge of her words with the sweetest smile ever.

Joe ignored her remark and quietly opened the door, heading straight for the shop that carried Devialet products. Mei had tasked him to find a suitable stereo system for her and he thought this fit the bill even though it was too much of a compromise by his exacting audiophile standards.

Mei and Joe were welcomed into the shop (Joe was a regular customer there) and after some refreshments, the salesperson ran them through the features of the Devialet Expert Pro amplifier. Mei sat down on the sofa with Joe standing behind her. She scrolled through the iPad lying on the sofa and within a minute, her favourite tunes were playing sweetly through the speakers in front of her. She twirled the knob of the remote control a few times and nodded approvingly. After a few tracks, she got up and walked over to the Devialet amplifier that was sitting on the top shelf of the component rack. She brushed her long slender fingers on the beautifully chromed chassis. It looked like a futuristic slab of metal, with just a single small circular window breaking the uniformity of the top panel.

"This is a very beautiful piece of art. Will you help me set it up ?" Mei smiled at the salesperson with her dimples barely showing.  

"Ah! Of course Miss. We will set up the whole system for you. If you have an existing music library your boyfriend can help you connect it - it's really easy." The salesperson could smell the scent of a pending sale and the soon-to-be-earned commission was already warming the cockles of his heart.

"Boyfriend? Please!" Mei dismissively replied while rolling her eyes disapprovingly. Joe blushed at both the salesperson's words and the sting of Mei's response.

"It's a digital amp and you are paying a premium for a lifestyle product!" Joe protested at Mei's impulsive decision. Mei ignored Joe and continued to stroke the Devialet lovingly.

Thankfully, the salesperson managed to close the deal and the Devialet was delivered promptly to Mei's home with other components to make up her minimal and very tasteful music system.

Introduction

Mei and Joe are fictional characters, but there are many music lovers like Mei. They want a beautiful and good-sounding amplifier that can fit nicely into a modern home. Too many audio components look like something from a mad scientist's laboratory, or the control panel of a nuclear reactor. 

My very first experience with Devialet dates back many years ago when the D-Premier was first launched. A fellow audiophile was very eager for me to listen to it, and he turned up at my doorstep with a large flat box under one arm (don't try this with conventional amplifiers!). It was an impressive experience, with a laidback and slightly warm sound that was more than powerful enough to power my speakers then - a pair of Focal Diablo Utopia bookshelf speakers. Positive impressions aside, there were some glaring omissions in my opinion, the prime ones being unstable wi-fi streaming and a lack of a USB port. 

Was the D-Premier equal to my stack of components which were of equivalent value? Like a directionless corporate meeting, we respectfully agreed to disagree. He preferred the D-Premier, while I preferred my clumsy stack of components. He mischievously reminded me that the D-Premier was cheaper by a significant margin once I took into account the many footers, cables, power cords and rack space involved with my traditional stack.

The D-Premier cost close to S$ 20,000 when it was first released in Singapore. Thankfully, Devialet has worked hard over the years and the entry-level model (the subject of this review), the Expert 140 Pro is much more affordable.

Description


The Expert 140 Pro retains the sleek lines of the D-Premier. It is sexy enough to elicit envious glances from the most jaded audiophile. It has a more than passing resemblance to a high-end bathroom scale, and can even be mounted on the wall if you so desire.

A small port window shows various information including volume, source, and the status of SAM, and network connections. A single button powers up and shuts down the unit, while a sleek remote control controls commonly used functions (or as customised by the user).

Beauty here is not merely skin-deep. The Expert 140 Pro packs impressive amounts of technology and integration. Apart from being a powerful integrated amplifier, it also contains a DAC, phono stage (both MM and MC) and streamer. 

The most controversial design point is that everything is handled in the digital domain. In the case of the phono stage, or analog input, the signal is converted to digital using a high quality A/D converter. Listening to your records after it has been digitised ? Sacre Bleu !  An optimist would of course focus on the benefits of having the signal in the digital domain, including the ability to process the signal using powerful DSP. Devialet is able to do this for both the partnering record cartridges (RAM) and speakers (SAM). The digital heavy lifting is carried out using a Quad-core 1 GHz CPU and 2 X SHARC 400 MHz DSP units.

Despite the compact form factor, the Expert 140 Pro packs a powerful punch. Power output is 140 W per channel into 6 ohms. Amplification is achieved with a hybrid design that combines a Class A amplifier (providing voltage amplification) with Class D modules (providing current). In a way, this concept is similar to the current-dumping design launched by Quad in 1975 which combined a Class A amplifier with "current-dumping" transistors to supply the necessary current. Class A designs are required to dissipate tremendous amounts of heat and a design that could deliver power equivalent to the Devialet would be massive and put out enough heat to warm a small room! 

RAM and SAM

Record Adaptive Matching (RAM) is available in the Expert 220 Pro upwards and the Expert 140 Pro only allows a choice between MM/MC and adjustment of sensitivity. RAM allows the user to choose more than 256 combinations of resistance and capacitance, as well as a choice of equalisation curve. 

Speaker Adaptive Matching (SAM) is a complex compensation model that attempts to correct sub-optimal speaker behaviour. Devialet measures the speaker in question to create a map of more than 60 parameters. The model is derived from measurement of the crossover network, speaker driver displacement, deformation, maximum displacement, speed and acceleration. Speaker models are continuously added to the SAM database, and the current database stands at more than 900 models. Conveniently, both my Vivid Giya G4 and Tannoy Kensington GR speakers are listed in the database. 

A worthy mention is that SAM allows extension of your low-frequency response, with sensible protection built-in to prevent you from blowing up your speakers. It can be switched in and out on the fly using the remote control. By configuring your remote, it is possible to adjust the level of SAM correction from 0 % to 100 %.

Configurator

An online configurator allows you to set up your Devialet according to your preferences. You can configure your inputs to be either digital or analog (either line-level or phono), and apply SAM, and phono settings too. 

This is just scratching the surface of what the configurator allows you to do. You can also (this is just a shortlist of features available) customise your remote control buttons, adjust the sampling rate of the ADC for analog inputs, set individual sensitivity levels, and adjust the maximum power output allowable from the unit.  

The configuration file is then saved onto an SD card which is inserted into a slot at the back of the amplifier. You could create multiple configuration files to be saved on different SD cards should you wish to show off your amplifier in another person's system. 

Operation and Ease of Use

Getting the Expert 140 Pro up and running was quite easy, save for the scare I got from the non-responsive remote. It turned out that the installed batteries were dead even though my unit was brand new. 





The compact dimensions do require you to use a power cord with a slim IEC and banana plug terminated speaker cables. In an all-time first, an entry level Audioquest power cord is supplied in the box. In case you insist on using your massively sized power cords, a removable rear plate allows you to do this, losing a bit of stylishness in the process.

I never got the Devialet to stream from a DLNA server source, and neither did I install Devialet Air (the companion streaming software) as this runs on a personal computer (which I do not use in my main system). Instead, I used the Devialet as a Roon endpoint where it worked seamlessly. You can also use Airplay and Spotify Connect if you want to.

I did have the odd occasion where the Devialet failed to detect the SD card upon start-up. However, powering the unit down and re-inserting the SD card solved this. I found it odd that Devialet used such a primitive method of configuring the unit when everything else about the unit is technologically light-years ahead of the competition. The configuration file is a text file that can actually be viewed and edited, which seems dated. It would have been nice to be able to configure the Devialet using an app instead. Instead, the free app works as a substitute for the remote control. 

My remote also had an issue with batteries, eating up fresh alkaline batteries every 2-3 months on average. No wonder, the factory-supplied batteries were flat on arrival! I've read of other users having similar issues, and this apparently can be fixed by the factory.  

Sound Quality

The Devialet appeals as a lifestyle product and brings with it the misconceptions of an overpriced and inferior product. Actual use (I've had my set for more than two years) proves that this is a highly versatile product that is a viable and attractive alternative to a stack of components with spaghetti cabling everywhere! I have brought the Devialet along to listening sessions in other setups where they have always acquitted themselves, even against very expensive equipment.

The Devialet does have a subtly sweet and rich tone that is pleasant and inviting. The Class D detractors would have to leave in disappointment at this juncture. The midrange in particular is sweet, smooth and laidback. The bass quality is good, with power and a full textured midbass. In fact, you could argue that the Devialet takes the polite path rather than a sharp, or hyper analytical route. The high frequencies are also cleanly reproduced, without any noticeable evidence of roll-off or anomalies from the low-pass filter required for Class D designs to filter out ultra-sonic noise.

I would rate the Devialet's performance as reasonable for the price. However, enabling SAM lifts it up significantly. Apart from the very obvious boost in bass extension and power, there is an increase in focus and coherency that makes it very hard to revert back to SAM-less listening. Play it again Sam!  

Conclusion

The Devialet is a superb all-in-one that demonstrates that convenience need not come at the expense of sound quality. It's a pity that traditionally-minded audiophiles may not give the Devialet due consideration. 

With shrinking living spaces in Asia, this is the perfect product that ticks all the boxes :- looks, convenience, quality and price. Some may disagree that the Devialet is an affordable product, but I am convinced based on the many boxes it replaces, and the outstanding sound quality it delivers - Highly Recommended.    

Epilogue

Mei sat gracefully on her sofa, listening to music from her new sound system. Joe had managed to convince her to install the Expert 140 Pro amplifier on top of her cantilevered TV rack. Discrete cabling ran to two very slim floorstanding speakers. The system was a perfect foil to Mei's character - graceful and elegant.  

Her music collection had been ripped and stored on a dedicated Intel NUC PC that functioned as a Roon server. Joe had also subscribed to Tidal in case Mei wanted to explore new music just like she did when she came over to his home.  

Standing up, Mei surveyed the very neat job that Joe had done in arranging everything. Her long flowing white dress showed off her slim waist and she glowed like an angel. Joe's heart skipped a beat and he bit his lower lip hard.


Devialet Expert Pro 140 Amplifier

Price : S$ 8,990 

  


        



Wednesday, May 26, 2021

Elekit TU-8600R Integrated Amplifier

Introduction

Problem Statement - You want a quality integrated tube amplifier, but no means to afford one. No problem, just build your own ! Assuming you have decent soldering skills, and are not instruction-intolerant (sadly, that rules out my teenage daughter), the Elekit TU-8600R lets you enjoy quality on the cheap. You will need about four full days to build one, but the effort is well worth it.

Description

The Elekit TU-8600R is a 300B single-ended integrated tube amplifier kit from the nice folks at Elekit of Japan. The TU-8600R is neither a basic kit nor design, and has parts quality and design features found in high-end models.

The power transformer is a high-quality R-core type, with low magnetic flux leakage. The solid state rectification uses Schottky fast recovery diodes. The power supply circuit includes ripple filters and plenty of regulation stages. An active automatic bias adjustment system means no fiddling with bias pots, and optimal sound quality at all times.

Parts quality is generous with plenty of Japanese branded resistors and capacitors. The PCB thoughtfully provides sufficient space for you to install large boutique coupling capacitors too. After all, isn't that the whole point of DIY, the freedom to express yourself ?

The TU-8600R's circuit is based on a single 12AX7 input tube, which then feeds dual 12AU7 tubes. The latter's two triode sections are wired in parallel to drive the 300B power tube. The output transformer has speaker taps for both low and high impedance speaker loads (selectable by a switch on the rear). A headphone socket allows you to enjoy your Elekit with your favourite pair of cans. Jumpers on the PCB allow you to adjust the headphone output level, and the colour of the power LED.

Although the TU-8600R is an integrated amplifier, there is only one set of RCA inputs. This could be a deal-breaker for some, although you could purchase or build an input switching box to get around this. 

Build Experience

Elekit gets first prize for having the best instructions I've ever received with an audio-oriented kit. The instructions rely on very clear diagrams and steps to guide you every step of the way. The PCB is marked clearly and even reminds you when components are required to be installed on to the reverse side of the board. Plenty of due care and consideration went into ensuring that the assembly is as painless as possible. 

The sheer parts count and complexity of the PCB makes this project highly unsuitable for a first-time build. The soldering of the transistors was the most delicate part of the build, as the solder pads are dangerously close. I would also highly recommend that a temperate controllable iron be used. 

In my case, I chose to upgrade the stock resistors to Takman Carbon film ones, and the coupling capacitors to Amtrans AMCY Golden Black. I also bypassed the volume pot and wired the input jacks directly to the main PCB. The input sensitivity will be high, but if you are able to adjust the output level on your source (e.g. a DAC with volume control), you should be fine. 

Starting off at the professional assembly area a.k.a. dining table.

The Takmans are too large to fit and the legs have to be bent in a curved fashion to fit the board.

Soldering of the resistors is complete.


Plenty of space for upgrading the coupling capacitors.

This is the top side of the board. The main circuit is on the underside.

Testing phase. I made a boo-boo here. 

Running-in phase. 

The only mishap suffered was when I wired the input wiring to the wrong solder pads. I happily soldered them to the input pads. They should have been wired to the output pads instead (Elekit refers to them as output pads in the sense that they receive the output from the potentiometer). 

The power and output transformer connect to the PCB via push-on Molex connectors. Since the stars were aligned, I decided to run in both the stock output transformers and the Lundahl ones which are optional. 

One criticism I have is with respect to the sheet metal covers. They have a fair amount of ring, and degrade the sound quality. This was very noticeable when I installed both after my run-in process was completed.

Sound Quality

Paired with Genalex 300B tubes and a variety of 12AX7 and 12AU7 tubes from my stockpile, I gave each set of output transformers about 10 hours of run-time before I did any critical listening. I used my Totaldac DAC (using digital volume control) and icOn4 Pro as preamplifier, and my Vivid Giya G4 speakers. 

The Elekit is highly detailed, fast and open. The tone is light and clear, so if you are seeking the vintage 300B tone (warm, full and midrange-centric) you should look elsewhere. Despite the low power on tap, vocals and smaller works were an absolute treat with the Vivid. While the midrange was not overly liquid, the presentation was clearly in the tube amp camp. 

Soundstaging and imaging was holographic with pinpoint placement and excellent depth and width. The bass control and dynamics were satisfactory, but this is not the reason why you choose a single-ended tube amp. I believe that given the right set of loudspeakers (i.e. high efficiency), the Elekit would have no problem bringing the house down.

Swapping in the Lundahl transformer is the point where the Elekit is transformed from competent to world-class. The gains in detail retrieval, control over both ends of the frequency spectrum and refinement make the Lundahl a solid investment proposition. Elekit supplies the stock transformer even if you opt for the Lundahl, so you could always upgrade in the future, only losing out on having additional shipping costs.

The Elekit is good enough to be your end-game amplifier unless you suffer from equipment polygamy (which Audiophile doesn't ?). I was heartened to find such high quality at an affordable price, knowing that many would be able to enjoy its fine musicality.  

Conclusion    

There is a sense of rightness to the Elekit, and there is the invaluable ability to dial it in precisely to your taste through judicious choice of parts. 

It comes in at an attractive price tag, so the only real downside is that you need to spend the time and effort to build it yourself. However, most Elekit dealers would offer a build service for a fee, or be able to refer you to someone who could. Best Buy and Highly Recommended.

Elekit TU-8600R Integrated Amplifier

Price - POA

Elekit kits are available from :-

Horizon Acoustics

1 Pemimpin Drive
#08-11, One Pemipin
Singapore 576151
http://www.horizonacoustics.com


Saturday, June 6, 2020

Pass Labs ACA Power Amplifier

Introduction

The Amp Camp Amplifier ("ACA") is a simple amplifier that was designed to be built in a single afternoon. It was created by Nelson Pass for an event called "Amp Camp" in which a small group of people turn up and by the end of the day, they would have built a small amplifier.

This means that the build has to be straightforward, even for the first-timer. Indeed, the build is quite easy, and the very detailed build guides on the internet will certainly ensure that you get this up and running in no time at all.

A complete kit with everything you need is available at the Diyaudio Store - just be quick, because they sell out really fast !

Description

The ACA is a low power Class A power amplifier which is able to deliver 8W per channel into an 8 ohm load (at 3 % distortion), or 15W if operated as a monoblock. It is built in a very compact chassis, with a separate power brick supplying 24V DC to the ACA. This is a great idea for a first-time project as you don't have to mess around with potentially lethal voltages.  

The current version of the kit at the time of this post is V 1.6, which was the version I built. Other important specifications :-

Input impedance - 10 Kohm
Gain                    - 14 db
Damping factor  - 10
Output noise       - 100 uV

For a detailed description of the circuit, you can read what Papa Pass (as he is affectionately called in the DIY audio scene) has to say here.

Build Experience

I highly recommend this for the beginner. Like any kit, it would be helpful if you practice your soldering on a practice or waste board first. Everything you need is in the kit, except for soldering iron, solder and a multi-meter. I assume of course that you have basic tools around the house, like screwdriver set, pliers and a cutters to snip of the component leads.

This is a PCB kit, and the very low parts count means that you really can finish this in half a day if you are minded to do so. 









The kit includes both blue and red LEDs - choose your favourite colour. I friction fit those LEDs for fun, and settled for red LEDs.




Like any Class A circuit, this runs quite hot. It settles down at about 18-20 degrees C above ambient temperature.


Like anything in life, things can go wrong if you do not take due care. This kit is straightforward enough that your possibility of messing things up are quite low. The most difficult part of assembly is likely to be affixing the transistors to the heatsinks (installing the insulation pads wrongly could either short out your transistors, or cause them to overheat. The second most difficult part (for a beginner) is biasing the transistors. Well, for me the most difficult part was aligning up the chassis as one of the rails arrived bent out of shape.

In operation, the ACA runs hot - it needs every square inch of those heatsinks ! After about two hours of operation, the faceplate is quite hot to the touch too. There is no anti-thump circuit, and the ACA will make rude sounds when powering off, and a loud thump when switched off. If you are using sensitive speakers, this is loud enough to scare both pets and probably their owner too.   

Sonic Quality

The limited power requires careful partnering. If you have typical speakers (e.g. 86-89 db sensitivity), you certainly can’t go very loud with the ACA. However, the few watts on tap will suffice for background music, and even reasonable listening levels if you are sit close to your speakers and listen to less complex music. To extract the most out of this amplifier, high-efficiency speakers are highly recommended.

The ACA has a very pleasant smooth and warm quality that makes listening very pleasurable. I spent more than a week during this lock-down, paired with my Vivid Giya G4 speakers (hardly the easiest load). Used within its power limitations, the ACA actually sounds very good for the money invested (Let's face it - pickings are slim for Class A amplifiers below USD 500).

Soundstaging is reasonably good, with good dimensionality. The ACA has a very nice grain-free and refined sound that eludes most solid state designs. The only obvious weakness was a lack of bass control with a flabby and loose low-end. Given the low damping factor of the ACA and the unsympathetic load, this was hardly surprising. Time to try out the ACA with more suitable speakers !

A pair of Tannoy Kensington GR speakers proved to be a better match although it was evident that more power was needed. Although they are rated at 93 db sensitivity, the Tannoys are not known to be an easy load either. They sound quite good at background music levels, with a usable limit at a volume in between my usual listening levels and that. Pushed harder, and the amp begins to harden in sound, as well as lose its limited grip on the woofers. Perhaps my very easy to drive Zu Dirty Weekend II speakers would be a perfect match ? I'll update this post once I've tried that.

Conclusion

The ACA is a pleasant amp that is easy to build and an excellent introduction to the wonderful world of DIY. If you have reasonable expectations and a suitable partnering pair of speakers, you could end up with sonic bliss at a very modest budget. If you are expecting something really special with a sound that rivals First Watt or Pass Lab's offerings, you are going to walk away disappointed. 

Pass Labs ACA Power Amplifier
Available direct from diyaudiostore.com
USD 327



Sunday, September 25, 2016

Merrill Audio Taranis Power Amplifier

Introduction


The Taranis is Merrill Audio's most affordable amplifier. I seldom mention price at the very beginning of a review, but I'll make an exception for this one. The Taranis retails for USD 2,500. It is based on a Hypex Ncore NC500 module, and puts out 400 watts of power into 8 ohms, and 600 watts into 4 ohms. Oh, and it is built in a chassis that does not look flimsy, cheap nor home made. Taranis is the Celtic god of thunder. It didn't bring loud fearsome noises into my system, so the thunder is probably Merrill Audio striking fear into hearts of competitors. At this level of performance for the silly budget money that Merrill Audio is asking for, they had better be running scared.

Description

The Taranis is rather striking in appearance. The black steel chassis used contrasts nicely with the mirror polished silver front panel. No, it's not some laser cut or massive aluminum panel with decorative finish fit for a master craftsmen from horology's finest in Switzerland, but it looks really nice and classy.


Picture courtesy of Merrill Audio. Apologies for not taking my own pictures this time - my review sample came well protected with plastic film on it's faceplate and made quite an unsightly photoshoot model !


The Taranis has a fully differential input stage with a high input impedance of 100k ohm and can swing up to 13.5V with 300 mA of current to the output stage. High input impedance is useful for users pairing the Taranis with source equipment (with a volume control), or preamps with highish output impedance, e.g. tube output stages, or passive preamps. Gain is specified at 26 db which should be more than enough for most users. Lastly, a peak current of 26A should allow the Taranis to keep unruly loads in check.

The power supply used is the same as Merrill Audio's flagship Veritas monoblock amps (according to their website, they use a Hypex SMPS1200A700 power supply). Internal wiring is Teflon insulated silver plated copper, while Cardas XLR input jacks and Furutech gold plated IEC are used. Speaker binding posts are made from pure copper with rhodium plating. The only thing cheap about the Taranis is it's price. 

Rather unusual for an audiophile product, is the power meter display on the front panel. A series of LEDs indicate output, with green, yellow and red LEDs corresponding to level (-60 to -21 db for green LEDs, -18 to -12 db for yellow LEDs, and -9 db to 0 db for red LEDs). Call me a wimp, but given my modest listening levels, I never saw the red LEDs light up in the time I had the Taranis.

The footers used in my review set were wooden cones. However, you can upgrade to Stillpoints Ultra Mini Risers for a premium. My review set came equipped with a Synergistic Reserach Red fuse. 

The Taranis does not really have a power switch. Plugging the Taranis into the mains supply puts it into standby mode. A small toggle switch on the bottom of the chassis, near the front panel, takes the Taranis out of standby mode. Another toggle switch allows you to switch off the front panel, while a small knob nearby controls the brightness of the LED indicators. 

Personally, I would have liked a more robust part for the standby toggle switch. It will see a lot of use over it's lifetime - not too sure how it would hold up over the long term.

In standby mode, the Taranis is slightly warm to the touch. From experience, the amplifier is always ready to go from standby mode - one or two tracks are good enough for the Taranis to sound good. 

Sound Quality

The Taranis made its rounds in both my bedroom and main system. As the Taranis only has balanced inputs, I opted to pair it with balanced sources and the only preamp in the house with balanced inputs / outputs - the VAC Signature IIa. My balanced sources, the Totaldac d1-dual DAC, and Antelope Zodiac Platinum both have volume controls which were run direct into the Taranis. The Totaldac uses a digital domain volume control, while the Antelope has a high quality relay-controlled resistor network volume control.

While direct drive sounded quite good, it was the pairing with the VAC that really allowed the Taranis to perform at it's best. No sane audiophile would pair the Taranis with a preamp that cost many multiples of it's own price tag though, but it was nice to see how well the Taranis could scale with equipment upgrades.

After some experimentation, the two best matches in my home were the Totaldac / Taranis pair powering the Vivid Giya G4, and the Antelope / VAC / Taranis matched with the Thiel CS 2.7. 

The Taranis is a powerful brute, and exhibited vice-like grip over the woofers of both speakers. Bass quality had both visceral impact and a nice level of articulation. In fact, while listening to my usual test tracks, some of the objects in the room started to rattle - I never had this problem previously ! Bass had a nice bloom to it, and apart from low end extension, there was a noticeable fullness in the mid-bass. This gave both my Vivid and Thiel speakers a warmer tone compared to usual. In the case of the Thiel, this was a very welcome development , as the Thiel can sometimes sound a little bit too lean otherwise.

Midrange presentation was slightly on the laidback side, with velvety smooth vocals albeit with reasonably good clarity. Some fine detail was smoothed over, but this also flattered sibilant recordings. 

The top-end was quite extended, but very well-behaved too. The treble had a airy, open and yet soft quality to it. Listeners are unlikely to find the Taranis harsh or bright. 

Listening to a variety of music, I found the Taranis to be adept at both large scale works that required dynamics, impact and scale, as well as delicate violin and piano solo pieces. It's richer tone and softer approach would mean that it sounded more comfortable and relaxed. Listeners that like their music with a bit more edge may not warm up to the Taranis.

Spatially, the Taranis cannot resolve to the extent of either my recently departed Gryphon Diablo (hopefully happy in it's new home), or my Conrad Johnson ART monoblocks. While staging and imaging were accurate, instruments and voices were reproduced in a flatter manner, with less sense of the acoustic space around them. Neither could it resolve low-level detail to the same ability as the aforesaid giants. Inserting a top-notch preamp like the VAC narrowed the gap considerably, but there was still a comfortable gap in performance, as well and even wider gap in terms of the price difference.

From a value perspective, I would be hard-pressed to find better performance at this price level. This makes the Taranis an absolute steal !

Conclusion


The Taranis is not about loud noises despite it's name. It makes beautiful music, has plenty of power on tap, and plenty of refinement - all for a silly price tag. Highly Recommended and Best Buy.

A big thanks goes to Merrill Wetasinghe of Merrill Audio for arranging for this review and K.M. Poon of Horizon Acoustics for providing the review sample.

Merrill Audio Taranis Power Amp 
Power at 8Ω: 400W
Power at 4Ω: 600W
Input Impedance: 100 kilohms
Output Impedance: 1.5 milliohms
Frequency Response: 0Hz to 50kHz, 0/-3db
Gain: 26dB
S/N: 130dB
Maximum output: +/- 80V
Maximum output: 26A
THD: 0.005% at 200W
Price : USD 2,500 or SGD 3,500 (Singapore)
Website : http://http://www.merrillaudio.net/

Horizon Acoustics
144 Upper Bukit Timah Road

#03-15 Beauty World Centre
Singapore 588177
Telephone : 91259149
Website : http://www.horizonacoustics.com



Sunday, March 20, 2016

Sony TA-A1ES Integrated Amplifier

Introduction

The Sony TA-A1ES (I will refer to this as the "A1ES") integrated amplifier arrived at my doorstep together with the HAP-Z1ES. There has not been much news or reviews of the A1ES which in my opinion, is a great pity - this is really something quite special.

A trickle of products in recent years suggests that Sony is quite serious about re-entering the high end audio arena, and judging from the quality of products I've evaluated (the A1ES included), they are certainly on-track.

Description

The A1ES is a compact unit, measuring 430 mm x 130 mm x 420 mm (W x H x D). The dimensions are quite deceptive, and lifting it out of the box required a fair amount of effort - I found out later that the unit weighs 17 kg.





This is a wide bandwith design (10 Hz to 100 KHz), with 60 watts per channel on tap. Some noteworthy design features include a discrete component preamp circuit, a smart bias system, and a separate headamp circuit also utilising discrete components. To maintain sonic purity, the A1ES utilises a single pair of transistors per channel. I was reminded of a very interesting conversation I had with another leading manufacturer that believed strongly in the merits of this approach versus multiple transistors in parallel. 

The smart bias system varies bias according to volume position in order to reduce excessive heat while maintaining transistor linearity. Conventional class A operation amplifiers are highly inefficient, with high power consumption and heat when idle. Varying the bias across the output devices is not a new idea, with various approaches in the past, e.g. varying bias with the signal level and/or output current, or having multiple bias steps. These approaches have the advantage of reducing bias at low signal / load levels, which reduces heat levels considerably. I found the Sony to run quite hot - you wonder how much hotter it would run without any form of bias management ! 

A knob next to the headphone jack selects the impedance range of the headphone used. The low impedance headphone setting selects low gain, and correspondingly, medium and high gain for the mid and high impedance settings. This helps address the problem of high levels of noise, and excessively "hot" volume control for low impedance headphones / IEMs, and insufficiently volume into high impedance headphones. The headamp circuit puts out a very healthy 500 mw per channel, into 8 ohm or 150 ohm loads, and 250 mw into 300 ohm loads. This should allow it to drive most headphones on the market, except some very unfriendly loads like some of the magnetic planar headphone models out there. 

A speaker impedance setting on the rear panel toggles between two positions, 4 ohms and 8 ohms. The manual does not explain why this is required, but a wild guess is that it alters the smart bias curve based on a rudimentary estimation of current draw.

Feature wise, five line level inputs are provided, one of which are balanced. An auto standby switch allows the amplifier to switch off when no signal is sensed for a while. The unit comes with a remote control. The over-sized speaker binding posts had the most smooth operation I've come across regardless of price. 

Sound

Paired with my Monitor Audio GX100 speakers, the A1ES struck me as having a supremely confident and effortless sound. I was pleasantly surprised at the amount of grip and control the Sony had over the speakers. This turned out to be the forte of the Sony - it had a punchy and fast bottom end that is really quite uncommon for a product in it's price range. 

The midrange had a slightly laidback quality, with a subtle sweetness. Female vocals were reproduced with a silky tone that was natural and free from grain. I found the A1ES to be very easy on the ear over long listening sessions - perfect for unwinding but maybe not if you like a more forward and incisive tone. 

High frequencies were clean and detailed, with a good "sparkle" and sense of air. I found the balance to be just right, with good behaviour and "bite" when required. One point worth noting is that both high and low frequencies would best be described as slightly dry - make sure this is paired with sympathetic equipment. 

I also found the A1ES to be highly resolving, with very good detail retrieval and precise imaging and staging. Image sizes were on the smaller side though, and flatter in perspective compared to my reference equipment (my Gryphon Diablo - let's not forget that the Diablo's price tag is many times a multiple of the Sony)

I tried hooking up a pair Thiel CS 2.7 speakers next (with the speaker switch set to 4 ohms) - results were quite good, but somehow the Thiels did not sound as effortless and spacious as the Monitor Audios. Possibly, the Sony should be paired with easier loads.

I also took the headamp stage for a spin - very nice indeed. I am sure it would be good enough to replace a mid-range headphone amp. Much of my observations above apply to the headamp stage when paired with my Beyer DT880 headphones (250 ohm version). 

Conclusion

The drawbacks noted above are very minor in the context of the price level of the Sony. In fact, I found the A1ES to be way off the charts in the value-for-money stakes. Audiophiles exasperated at the ever rising cost of equipment really should look at the A1ES. 

It keeps your system as simple as possible and delivers a glimpse into high-end performance, at a cheerful price that puts this within the reach of most audiophiles. For the money, it really doesn't get any better than this !

Highly Recommended and Best Buy

A big thanks goes to Sony Singapore for supplying the review set, and it's media partner Waggener Edstrom for making all necessary arrangements.

Recommended Consumer Price - S$ 2,499.


Saturday, June 28, 2014

Pop Pulse T-AMP180 integrated amplifier

Introduction

Pop Pulse is a small Hong Kong based company that offers a small but interesting offering of audio products.

The T-AMP180 ("T-180") is a nicely sized integrated amplifier. Based on Tripath chips, the T-180 joins a plethora of similarly equipped electronics available in the market. Bearing in mind that many of such examples are available very cheaply off the internet, the T-180 would need to distinguish itself to stand out to attract audiophile attention.

Features and Specifications

The T-180 is neatly packaged, measuring just 41.2 cm wide, 34 cm in depth and 17.7 cm in depth, and weighing in at 8 kgs.



The black aluminium face plate sports two identical knobs, one for selecting input (via a spring loaded knob), and the other for controlling the volume. A small plastic remote control is provided.

Turning to the rear panel reveals 3 pairs of line level inputs (one of which is 3 pin XLR balanced inputs), WBT style binding posts, an IEC mains inlet, and a rocker mains switch.



The T-180 is based on 2 x Tripath TA2022 chips, which have been bridged to deliver higher output power. Claimed power output is 120 watts into 8 ohm loads, and 180 watts into 4 ohm loads (specified at 0.1 % THD). There is no free lunch in this world, and bridged operation will result in the amplifier seeing half the actual load. Although the Tripath datasheets do not advise outright against low impedance loads, they do warn that amplifier efficiency will be reduced and that the current limiting may be prematurely triggered under such conditions.

Parts quality is good with a 4 channel motorised Alps pot controlling volume, LME 49720 op amps in the preamp section, and Philips,  Panasonic FC and Nichicon Fine Gold electrolytic capacitors spotted throughout the circuit. The circuit design is claimed to be fully balanced, which would explain the 4 channel pot. Lastly, a large toroidal transformer is used in the power supply.

I am guessing that the four large inductors between the heatsink fins are the the output inductors. 

A close-up view of the mains filter, which utilises inductors, capacitors and a single varistor.


Switch both SS1 and SS2 to the right to disable the 12db gain from the preamplifier circuit
Relay controlled inputs.
One interesting feature is the ability to "bypass" the preamplifier section by moving two switches internally. The volume control remains in the signal path and you are supposed to turn the volume control to maximum. This allows you to pair the T-180 with an external preamp, or DAC with volume control.

The LME 49720 chips are mounted onto sockets, so you could tune the T-180 to taste by using other compatible opamps.

Ergonomically, I think the location of the power switch is less than desirable. Apart from the rocker switch being quite small and difficult to feel for, it was blocked by my left speaker cables that were connected to the binding posts via spade terminations.

I also found the gain quite high, with very little range for adjustment on the volume knob, especially when using the balanced input.

Other than that, operation is quite hassle free. The T-180 thoughtfully remembers your last input, and resets the motorised volume back to zero each time you switch on the machine. Yes, it is a hassle if you are using the T-180 as a power amp, but it sure beats blasting your system to bits.

The T-180 ran slightly warm after extended periods of operations. Partnering equipment was the following :-

Oppo 103D (as a transport via coaxial)
Mac Mini with Pure Music 1.88 (as a transport via USB)
Antelope Zodiac Gold with Paul Hynes power supply
KEF LS50 speakers on Partington Dreadnought Broadside speaker stands

Sound Quality

Most of my prior experience with Class-T equipped amps have been with the TA2024 chip which is a low powered design. My memories of it - nice, smooth and warm sounding.

The T-180 was therefore quite a shock during listening tests. It has a neutral balance with a very clean and open mid-band. If you are looking for a euphonic and cuddly amp, this is certainly not one of them.

(Via balanced inputs)

Bass authority was very good, with a tight grip. There was really nice speed here which contributed to a fast and tuneful presentation. A relatively moderate amount of mid-bass bloom meant that the T-180 had a slightly full bass with good weight.

Midrange had good clarity and a slight sweetness. Vocals were grain-free and easy to listen to for extended periods of time.

Treble is good and evenly balanced compared to the rest of the frequencies.

Resolution is well above average, with good retrieval of microdetails. However, a slight reduction of air  made percussion work a little bit more closed-in than I am used to, with some diminishing of cymbal decay.

On the staging front, the T-180 had reasonable depth and width, but presentation had less three dimensionality by absolute standards. Compared to the Job 225 which I own, the T-180 had flatter perspectives.

Control over busy mixes was also good with adequate separation between instrument lines.

In use, I never found the T-180 lacking in power or drive - the moderate efficiency KEF LS50 didn't even make it sweat one bit.

(via single ended inputs)

The T-180 sounds much brighter through it's single ended inputs. You get a livelier sound, with a trade-off in separation, microdetail and a flatter soundstage. I ended up listening to the T-180 during most of the evaluation period through it's balanced inputs, which I preferred.

(with an external preamp)

I also tried driving the T-180 directly through the volume control of my Antelope Zodiac Gold DAC. The Antelope has a very high quality volume control, with attenuation controlled via a relay activated resistor network. I preferred using the the T-180's internal preamp circuit for better soundstage depth and more dynamics and drive. You could say that this is a testament  to the quality of the T-180's line stage. Although the result was not as expected, it is a nice option to have.

Conclusion

I was very impressed with the T-180 in the one month I had it with me. You get very competent performance and generous amounts of power - all for a modest price tag.

I would exercise some caution in matching the T-180 with bright sounding equipment. Apart from that, the T-180 is highly recommended.

The T-180 is available in Singapore from

Horizon Acoustics
144 Upper Bukit Timah Road
#03-15 Beauty World Centre
Singapore 588177


http://www.horizonacoustics.com/

Horizon Acoustics is offering the T-180 for an introductory price of S$ 650 at the time of writing.

A word of thanks to Mr. K.M. Poon of Horizon Acoustics for supplying the review unit.

Sunday, February 2, 2014

Job 225 Power Amp

Introduction




I've just got a new Job.

A Job 225 that is. After looking at all the positive information on audio forums out there, I placed an order last week. For those unfamiliar with Job Electronics Inc, it is an affiliated company of Goldmund and shares technology used in Goldmund products. Without sounding too condescending and dismissive, you could consider Job products as Goldmund derived products on the cheap for the average man in the street.

The Job 225 can be ordered directly online at www.jobsys.com. I previously failed to secure a unit when the batch sold out and I jumped on the opportunity last month when it was available again. Ordering the Job was a simple process, and 4 days later, the Job was sitting on my living room floor - delivered from Switzerland to Singapore within record time.

What makes the Job 225 compelling ? It is a high quality, powerful, compact and affordable amplifier.


Description

According to Job, the 225 delivers 125 watts per channel into 8 ohms, or 210 watts per channel into 8 ohms measured according to Goldmund's FPP standard (whatever that means). It is a high bandwith design, with a +/- 3db frequency response of 2 Hz to 900 kHz. Input impedance is a moderate 51 kohms which should make matching with passive preamps or tube preamps which usually have high-ish output impedance relatively easy. Full power is obtained at 0.75 volts, which makes the Job a high gain design. Looking at Goldmund's white paper available on its website also suggests that the Job is a high damping factor design.

Physically, the Job 225 is very compact, with dimensions of 36 cm x 24.5 cm x 8.8. cm, and a weight of 7kg.

The Job only has single ended inputs, and a power switch rocker on the front panel. A single yellow pilot light indicates operation. The rear panel is a bit crowded, with a fairly large heatsink dominating most of the rear. I did not like the fact that each RCA socket was directly under its respective channel's binding post.




The Job runs quite warm, and it's heatsinks are quite hot to the touch. The unit seems to reach a stable temperature after about 90 minutes of operation.



Set-up

Setting up the Job required a bit more care than usual due to it's high gain design. An old passive pre-amp that I happened to have lying around sounded quite good. Based on a 100K Ohm Alps Black Beauty pot, the combination had decent dynamics and drive, without high-frequency roll-off.

Switching out the passive pre-amp for a Conrad Johnson ET-3 SE preamp yielded even better drive and dynamics, but with far too much gain and tube-noise. The ET-3 SE being also a high-gain design was obviously not an ideal match.

Driving the Job directly from the volume control of either a B.M.C. PureDAC or Antelope Zodiac Gold sounded best. It is worth mentioning though that the Antelope had problems of setting ideal volumes. The Antelope adjusts the volume in 4 db steps up to -36 db, and thereafter in 1 db steps. -40 db was too soft, while -36 db was too loud for some tracks. The B.M.C. had no such problems. As life would have it, the Antelope suited my taste better.

Later into the review, I acquired an Amtrans APCG-01S passive controller. This is essentially a discrete resistor 10K Ohm potentiometer, preceded by a Lundahl transformer to provide 6 db of gain. This offered usefully low output impedance and ended up sounding the best of all the preamps on trial here.

Sound Quality

The Job was evaluated after 60 hours of burn-in time.

Initial impressions were quite promising - this is definitely a special amplifier for it's modest price tag. Sweet, and slightly rich, this is an organic and musical amp - not likely to appeal to those who like razor sharp focus and laser-like precision.

Bass is the most striking quality of the Job - very tight grip, coupled with excellent articulation quality and bloom. Bass notes are tuneful, tight and very fast. On this single aspect, the Job is capable of embarrassing much of the competition out there.

Other outstanding qualities are quietness and an absolute lack of grain. The Job has a very black background and very low noise floor. Even with your ear right up against the tweeter, there is almost no hiss.

I have always preferred tube equipment over solid state equivalents. Despite power limitations and more maintenance issues, I have almost always found tube equipment to excel in depth and height perception, freedom from grain and overall liquidity of sound. This is of course a generalization, and I have heard excellent solid state designs (Soulution, Vitus and Technical Brain come to mind), and some horrid tube equipment (which shall remain nameless).

The Job has been in my main setup, powering my Focal Diablo Utopia speakers for close to a week, and I must confess to not miss my Conrad Johnson equipment as much as I expected. The Job had an edge over my usual gear in the areas of power and bass control. It avoided the flat paper cut-out effect I've heard from lesser solid state gear and had sufficient image density and size to fool me into forgetting that I was not listening to my tube equipment.

However, I found the Job (paired with a stock power cord and placed directly on my TAOC ASR-4 equipment rack) a bit too mellow and lacking in high frequency extension. After some experimentation, I changed the stock power cord to an Acrolink 7N-4030II terminated with Oyaide P/C-004 plugs. The Job was placed on a set of Franc Audio Ceramic Disc Classic footers. Finally, the stock fuse was changed to a Telos QBT-18. This helped to open up the soundstage and top-end. The rest of the review proceeded with these tweaks in place.

Bass control is an outstanding point for the Job. Tight grip with just the right amount of "wetness" , bloom with great articulation. The bass has good rhythm and you could listen to this amp for hours on end just for this.

In the midrange, the Job presents the human voice with a warm and smooth tone. There is a slightly laidback feel to this, which suits slow and sultry pieces.

On the top end, the Job struck a fine balance between sparkle and warmth. I find some amplifiers too etched and dry in that regard, while others too dark and shut-in.

Resolving power is quite good, and aided by its low noise floor, fine detail is easily discernible, even at low listening levels.

I also tried the Job with my KEF LS50 and Thiel CS 2.7. The KEFs in particular were a good match. Although the Thiels sounded fine, I found the Job to be not as effortless as compared to my 500 watt per channel Virtue Audio ICEBlock M5001 amplifiers. I would stick with easier loads with the Job.

Well after I wrote most of this review, I continued to try the Job with other aftermarket powercords including the Crystalpower Ultra Reference and the Siltech SPX-800. The Job is actually very sensitive to power cords. Both the Crystal and Siltech elevated the Job to very serious equipment territory, with a wide open soundstage and clear tone. I do not expect a typical user to use power cords of that level, but it was an interest experience nonetheless.

Conclusions

The Job 225 may be likely overlooked by some audiophiles on the basis of its affordable price tag. This is a pity - the Job 225 is serious design that quite simply sounds better than any other amplifier I have heard in the price range.

Paired with the KEF LS50 and the B.M.C. PureDAC, you end up with a very serious setup that is affordable yet capable of very high performance.