Review: Sovtek 12AX7WA

 I have a love and hate relationship with Russian tubes.  Some of them - like the ECC99 - rival some of the best vintage American and European tubes, while others, like much of the Electro-Harmonix line sounds like solid-state in a bottle.  Yes these tubes can be transparent but they are often lacking in detail or suffer from an aggressive treble and upper midrange.

The early Russian tubes, that first were available in the 1990s to the Western World, were godsend to the tube-o-phile community.  They were cheap and rugged.  An example of this is the 5881WXT which could take the current hungry bias of the Harmon-Kardon Citation V.  Even a RCA blackplate of the era would start to glow on the seams.  But not these Russian mil-spec tubes.

It's been my belief - shared by some friends too - that Russian tubes have good metallurgy but not the best cathode chemistry.  Yes they are rugged, but many of them have the already mentioned issues with the higher frequencies.

As for the Sovtek 12AX7WA, it has a pair of very small coated plates and what I would call a primitive looking spacer that should be made out of mica.  The pins ends are sharp but overall construction looks quite good.  I plugged it into my Frankenstein EICO ST70, which provides the initial gain before the 6SN7 phase-splitter.

The Sound:  Initially I was surprised how much I like the Sovtek.  The sound was very transparent and, at first listen, very modern sounding.  I was reminded of a really good JFET preamplifier or MOSFET amplifier - big, dynamic and smooth.  But, like the aforementioned solid-state gear, lacking in inner detail.  The soundstage was also smeared a bit, removing the space around individual instruments and the big front-to-back sound of a vintage Mullard.  Dynamics in the upper part of the spectrum became a little rough/forced sounding with the Sovtek.

What I'm really finding - at least so far - is that modern tubes often has a good tonal presentation but lack in inner detail and making a big soundstage.  I'm curious to the reason why this is true.  Is this linearity or an artificial presentation brought on by - an unknown variable?  We shall have to continue and have some vintage comparisons.  More later!

Review: JJ ECC83S short plate 12AX7

 

To be honest my expectations for this 12AX7 was low.  I haven't had a JJ tube in any of my gear for well over a decade.  Nothing personal, mind you, but back then I was all about more exotic tubes like the C3m, 5687s, EL156s, and whatnot.  JJ has been around since 1994, built on the ashes of Tesla and Ei.  Their small signal tubes aren't mentioned all that much on the forums I visit, or at least I missed the posts.

This particular version of the 12AX7 looks to be based on the famed Telefunken ECC803S, which also had a Tesla copy.  The architecture has small plates that are very similar to a 6DJ8.  This should translate to low microphonics.

As for the sound, at least as the gain tube for a power amplifier, the JJ ECC83S was better than I expected.  There is an overall darkness, making this a good match for some zingier MC cartridges or digital front ends.  This is a "chocolate" expression of the music, with solid and tuneful bass, warm mids, and a high end (to my older ears) that is even less detailed than a Mullard. 

Inner detail with the JJ is less than the long plate Mullard; a slight smearing of instrument and vocal space along with soundstage depth.  Nonetheless at least the JJ sounds like an vacuum tube unlike some of the inexpensive Russian offerings I've heard.  So, much like the TJ and the Psvane, a solid offering but, and your mileage will vary, not exceeding the better old stock versions of the 12AX7 I've heard.

Review: Psvane 12AX7

 

The Psvane T-12AX7, apparently the base version, is a Chinese design that looks much like a vintage one with gray ribbed plates, quality construction, and steel pins.  The triple-layed mica also looks good.  Bulb size, like so many other new tubes, is slightly larger than my collection of old stock, a mm or two difference in height and circumference..

Break-in was approximately fifty hours as the driver tube in my Frankenstein Eico ST70.  This is basically the classic Mullard 5-20 circuit.  It's been my general experience that the driver tube - before the phase splitter - has a high impact on the overall amplifier sound, more so than the phase-splitter or even the output tubes.

Listening was initially done while reading a book.  There were several times where I had to look up from the pages to truly appreciate what I was hearing.  Like the TJ FullMusic, the Psvane has a great almost vintage tone.  I was hearing little details - an example is Lonnie Liston Smith's Vision of a New World - that I thought weren't apparent to my standard vintage Mullard.  I was beginning to feel some really high hopes for this Psvane.

However some further, more detailed listening, some of it shared with an old audiophile friend with an extensive knowledge of 12AX7s both new and old, began to show some weaknesses.  Though the sound was never muffled, the Psvane, like the TJ, also lacked inner detail and bloom around the instruments.  But wait a minute, you say, where did that extra detail you mentioned go?  It is a strange effect of the Psvane: suppression of reverberation both artificial or natural, pushed some information forward.

Keep in mind this is still the best new production 12AX7 I've heard and I could see use for it in gear or speakers that aren't the most transparent.  The bass was excellent, there was a distinct lack of glare unlike some lesser "solid-state in a bottle" new production tubes.  The midrange was also even as was the treble.  It was just the lack of detail that stopped the Pvane running with the best of the vintage 12AX7s.

Disclaimers: No tube is 100% perfect for all gear.  The only way to be sure how a tube will sound in _your_ system is to hear it.  Also a tube in a phono stage, for example, may have different audio characteristics than say line, input, or phase-splitter use.

 Negative feedback - several dB in this circuit - also reduces the sonic signature of the tube.  An example of this came apparent to me when I built a triode-connected EF86 linestage.  The tube selection - GEC CV4085 and the Mullard "long mesh" were the best - played a big role in the sound quality.  However the EF86 in my Eico HF60 monoblocks were less important, most likely due to the loop negative feedback or perhaps the total number of tubes in play with a more complicated circuit.

 It should also be noted that I am not biased towards vintage tubes.  I really do want a new tube that can compete with the old.

So take this review as a general guideline, not as hard fact.

Review: TJ FullMusic 12AX7

 

 

The TJ Full Music 12AX7 is a box plate Chinese design that looks much like a vintage Mullard M8137 and completely unlike any other current new 12AX7 offering.  The gold pins are a nice touch, and it looks like actual mica (?) was used instead of the whatever the heck is used for the Shuguang small tubes.  Bulb size is slightly larger than my collection of old stock, a few mm difference in height and circumference..

Break-in was approximately fifty hours as the driver tube in my Frankenstein Eico ST70.  This is basically the classic Mullard 5-20 circuit.  It's been my experience that the driver tube - before the phase splitter - has a high impact on the overall amplifier sound, more so than the phase-splitter or even the output tubes.   

Tonally the TJ 12AX7 was one of the better new production tubes I've heard so far.  I was initially hard-pressed to hear any difference between it and a quality old tube like a 1950s Mullard.  Bass definition and instrumental shading of the TJ was particularly good, but, even as the hours piled on, I detected a slight muffled sound.  There was a lack - especially compared to the Mullard - of inner detail or instrumental/vocal bloom.  That is to say the TJ had a flatter and smaller presentation.  I'm reminded of an inexpensive cartridge or CD player; the magic "glow" or shimmer, whatever one prefers to call it, was pulled back on the soundstage.

The old Mullard, in comparison, sounded bigger and had better bloom.  The music was more "filled in" with depth and soundstage width.

Do the TJs need more break-in?  I really didn't hear large differences between hour zero and fifty so I remain skeptical.  Nonetheless I did like the TJ tonally, especially compared to some other new production valves I have heard, but I was ultimately disappointed.  I do want new tubes that can perform in the realm of the best of the old.  At least with this tube I'm not hearing it!

Disclaimers: No tube is 100% perfect for all gear.  The only way to be sure how a tube will sound in _your_ system is to hear it.  Also a tube in a phono stage, for example, may have different audio characteristics than say line, input, or phase-splitter use.

 Negative feedback - several dB in this circuit - also reduces the sonic signature of the tube.  An example of this came apparent to me when I built a triode-connected EF86 linestage.  The tube selection - GEC CV4085 and the Mullard "long mesh" were the best - played a big role in the sound quality.  However the EF86 in my Eico HF60 monoblocks were less important, most likely due to the loop negative feedback or perhaps the total number of tubes in play with a more complicated circuit.

So take this review as a general guideline, not as hard fact.

Review: A Tale of Two Schiits - Mani 1 vs Mani 2 phono preamp

(photo from Schiit)

I've been using the original Schiit Mani 1 phono preamplifier for some time.  Its sole purpose has been to provide the needed amplification and equalization for my second turntable, the Dual CS5000.  It has done well plugged into the line section of the Audio Research SP8, which has a phono section that is used for the primary turntable, a Thorens TD309.

To be fair, the Mani is a budget phono stage so I could put up with the slight graininess, mid-fi resolution, and the general lower fidelity.  For all the Mani 1's faults, it is still better than a lot of stock phono sections found in budget receivers, preamps, and integrateds.  And given the mostly background music it was used for I had no complaints.

A recent visit to the Schiit Audio site and I saw that a second version of the Mani has been released, this one using a different op-amp and it was also direct-coupled.  The case looks exactly the same but the dip switches on the bottom have changed, allowing more settings for MM and MC cartridges.

To cut to the chase, compared to the old version, the new Mani 2 is more detailed, faster, has better resolution, deeper bass, and higher overall fidelity.  It also images, left-to-right in a fashion that will be most pleasing.  It isn't perfect - nothing is! - but it does swing at a higher than the $149 (black face model) price point suggests.

Where the Mani 2 ultimately fails - compared to the Audio Research SP8 or the Classe Five - is inner detail and that certain "you are there" magic that I've heard with these more expensive units.  The soundstage of the former is also flatter without that depth I've come to expect.   However, to be fair. the Mani 2 does strike awfully close to better preamps making my budget Dual CS5000 sound a lot closer to the combination of Thorens TD309 and the ARC SP8 phono stage.  Depending on your front end, amps, and speakers, this difference may not matter at all.

 As always your mileage may vary depending on your front end, setup, and preferred listening habits.

System:

• Dual CS5000 with Ortofon OM20 and an aftermarket Shibata stylus
• Thorens TD309 with Ortofon 2M Bronze
• Audio Research SP8 with vintage Mullard 12AX7s 
• Eico ST70 "Frankenstein" amplifier with 6AR6 output tubes
• KEF R500 speakers
• MIT interconnects
• Cardas Twinlink speaker cables