Saturday, July 11, 2020

Musical Paradise MP-701 Mk II Tube Preamp

Introduction

Musical Paradise is a cheerful company that serves up tantalising components to audiophiles on a modest budget. According to their website, they state the following, "Our mission is to design and manufacture high quality audio equipment to fulfill critical audiophiles' demand with competitive prices." 

This is the first Musical Paradise product that I've owned and so far I have been impressed by their innovation, quality of build, sound quality and totally outrageous value-for-money. 

Description

Looking like a very tall oversized shoebox, the MP-701 Mk II measures 31 cm (W) x 39 cm (D) x 14.5 cm (H). Construction is really good, with a solid aluminium alloy faceplate and panels. Weight is a reassuring 12 kg. 

The MP-701 Mk II is said to be the product of two years of research and development. It is a three tube design with zero negative feedback. The power supply is tube rectified. There are plenty of conveniences, including XLR sockets in addition to the usual RCA sockets, as well as a remote control.

Parts quality is very good throughout, with a 150 W shielded toroidal transformer, Vishay resistors, Nichicon and Rubycon electrolytic capacitors, and Obbligato Gold film coupling capacitors. There is also an option to upgrade the coupling capacitors to Mundorf Silver Gold Oil capacitors for a premium.   

This is the point where the usual list ends and things really get interesting. 

Want to roll your own capacitors but don't know which end of the soldering iron to hold ? No problem, just undo the binding posts and change the capacitors yourself. 

Can't get the gain matched properly in your system ? No problem, just change the gain settings by flipping a DIP switch. 

Want to roll different tube types ? No problem, change your preamp or rectifier tube heater voltage settings by accessing a switch too.

Here is a list of rectifier and preamp tubes that can be used in the MP-701 Mk II :-

Rectifier tubes

6.3 V - 6Z5P, 6X5
5 V -  5R4, 5U4G, 5AR4, GZ33, GZ34, 274B, 5Y3, 5Z3P

Preamp tubes 

6.3 V - 6N11, 6N1P, E88CC, E188CC, CCA, 6922, 6H23, 6H6, 6H30, (6SN7 with 6SN7 to 6922 adapter).

12.6 V - 12AU7, 12BH7, E80CC, (12SN7 with 6SN7 to 6922 adapter).

Don't forget that as each rectifier type has a different voltage drop, the resulting plate voltage will also change. As this shifts the operating point of the tube, the rectifier choice will alter the sound. This means that the possibilities on tweaking the sound are endless ! Similarly, you can get a more classic tube tone with tubes like the 12AU7, or a more modern and linear sound with the 6N1P or 6H30 tube.

Both the two output coupling capacitors and two film capacitors that bypass the main electrolytic power supply capacitors are mounted on speaker binding posts that unscrew to allow easy replacement.

Impedance is specified at 100 Kohms (input) and 2 Kohms (output) with a recommended pairing with a power amp with a minimum 10 Kohms. I personally think that is a bit too liberal, and at least 47 kohms may be more appropriate.

To be continued ... 


3 comments:

Ram said...

Hi Eric

Thank you for your well written tasteful teaser. I value your well thought and rather detailed articles. Pretty insightful.

I have purchased this amp and it is due to arrive soon. Am quite excited about the prospects from what you have just shared, especially in terms of tube roll.

I wish to seek your opinion about tubes as I am new to tubes and even so a preamp. I understand the stock tubes may not be ideal though I must say I havent tried it yet.

May I know what would be recommended tubes as an upgrade that I can try out with this amp please ? I am allright with neutral or warm neutral but not too warm or mushy. Love dynamism, clarity, details and a tight bass punch as I have been using solid states and these attributes are something I appreciate. Am hoping these attributes would be retained with the tubes I eventually get; as the MP 701 MKII will be connected to my solid state Class D XTZ A2 300 stereo power amp and Klipsch RP 6000f speakers.

On the flipside, am also looking for a smooth texture, holograpohic feel and good soundstage; guess this is what is special about tubes and being a newbie to tubes, am looking forward to experience this enveloping feeling without compromising details as mentioned earlier. In short, am hoping for better musicality.

Being a seasoned audiophile, would you think 12AU7 be a better fit as compared to 6N1 6922 or E88C in this amp? I read your other blog on tubes and came across the Tung Sol reissued GTBs being reviewed favourably. Would this be a good set to get; say the 12AU7 version instead? Others with some good reviews seem to be Sylvania, Brimar, Mullord Nos and the Mullord replicate types. Wish to hear your opinions about these if it would suit my listening preference; and whether it would be a good match for the MP 701 MKII.

May I ask if it is also better to change the rectifier tube simulataneously to enhance audio quality? From my brief research, I found Martin Electronics and Well Audio Lab in Burlington Square as a place to get tubes. So am trying to shortlist some tubes to try out on this amp when it arrives. Sorry for the list of questions. Appreciate your help with your vast knowledge and experience in this area.

Thank you



Best regards
Ram

Eric Teh said...

Hi Ram,

Actually I don't have much affection for the 12AU7 tube. I much prefer the 6N1P, my favourite being the vintage Russian ones in special grade - the 6N1P-EB. This is of course a generalisation and in each tube type you have a whole spectrum of tone, e.g. a Telefunken would sound much brighter and open compared to a Mullard.

I would suggest you run the unit stock for a few hundred hours to get a handle on the sound before you start changing anything.

As for the supply of tubes in Singapore, Martin Electronics has very little vintage tubes left, and a modest selection of modern production tubes. Well Audio Lab has a larger variety. Pricing wise, both are similar.

I would also suggest that you go for a linear and transparent tube (the 6N1P as an example) and add any warmth or liquidity through the coupling capacitor.

Regards

Eric

Ram said...

Hi Eric

Thanks for your advise. Yes, I will try out the stocks first for a period of time before deciding what I may need. Will consider the 6N1P . The linearity and transparency which you mentioned appeal to me. Thanks for the suggestion. Also the approach of going linear with the tubes and then looking at caps to enhance liquid or warmth sonic signature. Appreciate you letting me know that Well Lab has a wider range. Will check them out. Really helpful as I start my journey with tubes.Thanks once again

Best regards
Ram