Monday, August 24, 2020

The Quick and Dirty 300B tube shoot-out

Introduction

The 300B vacuum tube must be one of the most talked-about vacuum tube models, especially in Asia. Critics like to pan it as hyped-up, before introducing their own favourite directly heated triode tube. Others on the other hand revere it as the lighted path to sonic bliss.

The 300B tube was introduced in 1938 by Western Electric to amplify telephone signals. It is a large directly heated triode tube, with a typical power of 8-9 watts for a single-ended design, and about double the power for a push-pull or paralleled design. I recall that it's popularity was at its peak in the 1990s and 2000s, coinciding with the surge in popularity of single-ended triode amplifiers. 

The Shoot-Out

One of my audiophile pals recently bought an Elekit 8600R integrated amplifier and loves it to bits. His set has the works, including upgraded resistors, premium coupling caps (V-Cap CuTF), Lundahl output transformers and a TKD potentiometer. He recently bought a pair of Elrog 300B tubes and I offered to "help" (more like push him down the slippery slope) with some tube rolling activities.

The Elekit 8600R is an affordable 300B integrated tube amplifier, with a single 12AX7 and two 12AU7 tubes used in the input and driver stages. It uses solid state rectification and is available with a variety of upgrade options. The catch ? You have to build it yourself. The circuit is laid out on PCBs, but there are a lot of parts to solder, and some of the solder pads are small and very close together. This is definitely not a kit for a beginner and you should have a bit of soldering experience and good soldering equipment before tackling this. Your reward is a great sounding amplifier at a fraction of the cost of a completed product.

















Here is a group picture of our contestants :-

(Clockwise from top left) - Shuguang Treasure 300B-Z, Elrog, Takatsuki, Genalex, Sophia Electric Royal Princess.

As a disclaimer, none of these tubes have considerable time on them, with about 25-50 hours of playtime except for the Sophia Electric which is used and has at least a few hundred hours on them. Some claim that these premium tubes may need about 500 hours of burn-in time to sound their best. Secondly, the logistics and timing of this get-together only permitted us to warm up the tubes for about 10 minutes before playing 3-4 tracks. There were three other participants besides myself (one person left after the Elrog and Takatsuki comparison - he was too deeply traumatised to continue having sold off his Takatsukis during a moment of foolishness !).

Elrog ER-300B

There were reports of unreliability in the early days, but things are said to have improved significantly after Thomas Mayer took over. The Elrog stands tall and proud. The taller than usual height meant that the Elekit tube cage could not fit and had to be removed. 

The Elrog retails for EUR 1,240 per pair including VAT and shipping within Europe. These tubes have a maximum plate voltage of 600V and 40W dissipation ! The re-issue Western Electric 300B in comparison has a maximum plate voltage of 450V.

I really liked this tube. It has a Teutonic precision to it, with very tight and controlled bass and a linear sound throughout the frequency range. Among all the tubes tested, I found it to have the best dynamics and speed. The soundstaging is laidback and the tonality is slightly dark. 

Here are the comments from the other participants :-

"Neutral, dynamic, tight bass, good extension of highs and lows. Suitable for fast music and rock."

"Open sounding. Linear and muscular. Detailed sounding as well."

".... pushed the vocals and focus "in front", towards the listener. The soundstage was more intimate, but may actually be more transparent- it had a precise and narrow focus to the sound made the ANJ's sound more like other ANJs I've heard ..."

Takatsuki TA-300B 

Kyoto isn't just great for sight seeing and eating Japanese sweets and snacks. It is also home to Takatsuki Electric Industry Co Ltd. Currently they only produce two models of vacuum tubes, the 300B and the 274B rectifier. 

Like any high-end Japanese product, the Takatsuki comes in exquisite packaging with the tubes packed securely in a wooden box, full literature on the product including individual test results from their Amplitrex tube tester. A pair of Takatsukis will set you back about USD 1,500-2000 per pair.

This was definitely a crowd favourite and elicited plenty of excited superlatives. The Takatsuki is a very clear and open tube with the widest and deepest soundstage. The top end has incredible amounts of air, which created the most realistic acoustic space among the tubes on test here. I found the staging to be slightly forward, with noticeable midrange projection, contrary to the findings of one of the participants who felt that it had recessed soundstaging.

It had less tonal density and heft compared to the Elrog, and careful matching is required to avoid excessive brightness. Otherwise, it was the clear leader in terms of detail retrieval, imaging and soundstage precision. The crowd begged for the Valvo Heerlen 12AX7 to be put in place of the Telefunken (more details below), but I politely declined to maintain a consistent test base for our shootout. 

Here are the comments from the other participants :-       

"Big soundstage, airy, good extension of highs and lows, slightly colored compared to elrog. Suitable for vocals and recitals."

"Open, lit, detailed. Excellent soundstage and so holographic sounding"

"Voicing "behind" the speakers, incredible microdetail and filled out the space. Extremely holographic, clean, and refined. the Takatsuki opened up the sound and removed the ANJ flavouring."

Sophia Electric Royal Princess

This tube was generously on loan from TC. Although he did not participate, he had very high hopes for his tube. 

This tube had two big problems, the Elrog and the Takatsuki. While the Royal Princess was more open sounding that the Genalex, this came with a subtle grit at high-frequencies. There is also more midrange glow compared to the rest of the tubes here. Objectively, this is a decent tube but viewed against the very high price it commands, it was underwhelming. According to the Sophia Electric website, these tubes cost USD 1,200 per pair. 

"Shuguang Treasure/Sophia Princess-both are good tubes. Good details. But a bit of sibilance can be heard."

"Sophia was noticeably less open, but still detailed sounding. As mentioned by Eric, the sibilant treble was a minus. Still quite holographic"

"Good soundstage, falling behind the Takatsukis, clear warmer focus and more bassy than the other two. However lack of refinement compared to both the Takatsuki and Elrog."

Shuguang 300B-Z Black Treasure

Shuguang of China makes tubes, a lot of them ! Their tubes are supplied as stock by many equipment manufacturers. In recent years, they launched their premium offering - the Treasure Series. 

Apart from differences in construction and materials, only senior technicians are deployed to assemble these. The most visually striking part of Treasure Tubes are their polymer carbon coating with gives the glass their characteristic blacked appearance.

I have previously used Black Treasure tubes, their KT88s and the CV-181. I lost one KT88 after about 500 hours, but otherwise they have held up reasonably well.

These tubes sit squarely in the middle price wise between standard and premium offerings. They typically sell for about USD 300-400 per pair. 

I found these tubes to be very good value for money. They did everything the Genalex did, with a slight but noticeable improvement. Tonally, they are warmer and denser than the Genalex, while maintaining good levels of detail retrieval. There was a bit of midrange harshness in the beginning, but this was missing by the time we reached the last test track. I suspect this tube may be a dark horse as my previous Black Treasure tubes sounded their best after more than 500 hours of burn-in.

Here are the comments from the other participants :-     

"Good tube. Good details. But a bit of sibilance can be heard."

"Shuguang was Genalex level up. Meaty and full sounding while retaining an acceptable amount of details. More refined than the Genalex."

Genalex Gold Lion PX-300B

These Russian tubes are made in the old Reflektor plan in Saratov, but under foreign ownership. New Sensor Corporation now owns the rights to a lot of the big trade names of the past and churns out an impressive line of tubes under various labels. Locally, they cost about USD 300 per pair. 

These tubes are to me perfectly listenable and very good all-round performers. You are unlikely to get any sonic wows, but there are no nasty surprises either. Tonally, they are slightly on the warm side of neutral. I thought that they had good staging and projection, but the Takatsuki showed how much was being left on the table. 

I would rate their field reliability to be similar to the Shuguang Treasure. I lost a KT-88 years ago, so that makes one death count each. Alternatively, maybe I just have bad luck with KT-88 tubes ?

Here are the comments from the other participants :-     

"Perfectly listenable if I didn't hear the rest. But after hearing the rest, it was meaty but flat sounding."  

"Good all rounder. Value-for-money."

The Unsung Heroes

We also took some time to roll the 12AX7 tube. Our host had Telefunken smooth plates installed. Changing this tube had as much effect as the 300B tubes. We tried a JJ ECC83S, and two vintage Valvo tubes, one produced in Heerlen, and another from the Hamburg plant. All three tubes had a warmer and denser tone compared to the Telefunken (no surprise really), and the host liked the Valvo Heerlen tube the best. The above shoot-out was carried out with the Telefunken tubes installed.

Conclusion

Your mileage will vary. Each tube will sound different when deployed in another system, due to circuit differences, as well as system synergy. 

Also to be clear, none of these tubes made the system unlistenable or objectionable in any way. As one participant pointed out, we could have had a happy outing with the Genalex if we did not hear the rest of the tubes. So please experiment for yourself and happy rolling ! 

Don't forget to let us know your favourite 300B by leaving a comment. 


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