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.

Short Review: Dynaco A-25 VW loudspeakers

 

The Dynaco A-25 is a 2-way bass-reflex loaded speaker sporting a 10" woofer and a soft dome tweeter.  I picked up this pair at a half-off day estate sale.  I wasn't, however, expecting much since my experience with vintage speakers has been mixed.

To my surprise, the A-25s really capture the midrange in a nice and pleasing manner.  Yes my (larger) KEF R500s can pump out more bass & treble, do dynamics better, and throw a deeper soundstage; but still these old Dynacos have a certain magic that is hard for me to put my finger on.  Perhaps it is the nice all tubed front end I have, but these vintage speakers are just relaxing to listen to.  They do jazz really, really well; hard rock not as nicely due to their dynamic limitations.

So if you see a pair of A-25s for a good price, check them out.  They would be great in a small system with a low-powered tube or Class A solid-state amp; along with a suitable preamplifier.  They don't do all of the hi-fi tricks of something more exotic, but, like the Dynaco PAS and Stereo 70, capture the midrange depth and bloom a lot better than many, many modern budget components.

Short Review: the Musical Fidelity A1 integrated amplifier

Musical Fidelity A1

This is one of those little amplifiers that I've always wanted to hear for years but didn't get a chance until today.  You probably know the history: designed by Tim de Paravicini, may he rest in peace, this integrated was very popular in the mid-80s and very hot running, but providing that Class A magic for a relative bargain.  It was apparently Musical Fidelity's biggest seller.  It wasn't without its well-documented issues with noisy volume controls and switching, but this particular unit seemed to have held up quite well over the years.

How does it sound?  Like my Aleph J clone, very Class A.  But also very British polite.  I would say the phono stage doesn't quite stack up to my (much more expensive) tubed Audio Research SP8, but the amplification portion was a real surprise.  In my small/medium sized listening room it had no problem driving the 88dB efficinet KEF R500 towers.  Lower bass, like on my UK pressing of the Bee Gees - Trafalgar - was deep and controlled.  The midrange is quite magical, but the sense of dynamics work better with Chet Baker jazz albums then say something like AC/DC.  There is a distinct lack of glare and edge in the treble, the overall sound hewing further to the warmer side than neutral.

So overall a nice little integrated - that runs so hot that after an hour of use I can only hold my hand on top for a half a second before I fear getting burned.  Not a good napping place for those with cats, or children with curious hands!  Nonetheless, back in the past I would have been very happy with this amplifier since it images quite well and does a very good job with vocals.  And it is the sort of sound that makes me search through my stack of records and pull out some old favorites.  Very much a music lover's amp than audiophile-extremis.

This is one of those little amplifiers that I've always wanted to hear for years but didn't get a chance until today.  You probably know the history: designed by Tim de Paravicini, may he rest in peace, this integrated was very popular in the mid-80s and very hot running, but providing that Class A magic for a relative bargain.  It was apparently Musical Fidelity's biggest seller.  It wasn't without its well-documented issues with noisy volume controls and switching, but this particular unit seemed to have held up quite well over the years.

How does it sound?  Like my Aleph J clone, very Class A.  But also very British polite.  I would say the phono stage doesn't quite stack up to my (much more expensive) tubed Audio Research SP8, but the amplification portion was a real surprise.  In my small/medium sized listening room it had no problem driving the 88dB efficinet KEF R500 towers.  Lower bass, like on my UK pressing of the Bee Gees - Trafalgar - was deep and controlled.  The midrange is quite magical, but the sense of dynamics work better with Chet Baker jazz albums then say something like AC/DC.  There is a distinct lack of glare and edge in the treble, the overall sound hewing further to the warmer side than neutral.

So overall a nice little integrated - that runs so hot that after an hour of use I can only hold my hand on top for a half a second before I fear getting burned.  Not a good napping place for those with cats, or children with curious hands!  Nonetheless, back in the past I would have been very happy with this amplifier since it images quite well and does a very good job with vocals.  And it is the sort of sound that makes me search through my stack of records and pull out some old favorites.  Very much a music lover's amp than audiophile-extremis.

 

This is one of those little amplifiers that I've always wanted to hear for years but didn't get a chance until today. You probably know the history: designed by Tim de Paravicini, may he rest in peace, this integrated was very popular in the mid-80s and very hot running, but providing that Class A magic for a relative bargain. It was apparently Musical Fidelity's biggest seller. It wasn't without its well-documented issues with noisy volume controls and switching, but this particular unit seemed to have held up quite well over the years.

How does it sound? Like my Aleph J clone, very Class A. But also very British polite. I would say the phono stage doesn't quite stack up to my (much more expensive) tubed Audio Research SP8, but the amplification portion was a real surprise. In my small/medium sized listening room it had no problem driving the 88dB efficient KEF R500 towers. Lower bass, like on my UK pressing of the Bee Gees - Trafalgar - was deep and controlled. The midrange is quite magical, but the sense of dynamics work better with Chet Baker jazz albums then say something like AC/DC. There is a distinct lack of glare and edge in the treble, the overall sound hewing further to the warmer side than neutral.

So overall a nice little integrated - that runs so hot that after an hour of use I can only hold my hand on top for a half a second before I fear getting burned. Not a good napping place for those with cats, or children with curious hands! Nonetheless, back in the past I would have been very happy with this amplifier since it images quite well and does a very good job with vocals. And it is the sort of sound that makes me search through my stack of records and pull out some old favorites. Very much a music lover's amp than audiophile-extremis.

Review System:
Thorens TD-309 turntable with Ortofon 2M Bronze
Cardas Iridium interconnects
KEF R500 speakers with Cardas Twinlink speaker cable

Project: Restoring a Audio Research SP-8 preamplifier

 A recent purchase was this Audio Research preamplifier that sadly is in need of repair.  All original early 80s, it will need a cap job, a new volume control, and a solid-state regulator supply fix.  More later!

Short Take: the Adcom 545

(picture from Google Images)

My old McIntosh MC2100 is in desperate need of a rebuild.  This poor amplifier, after all, is knocking on forty or more years of usage, which means capacitors, resistors, and other bits are due for replacement.  This age has shown up as "vintage" warmth, but also a rolled-off top, plummy bass, and some signal degradation.  To put it bluntly, this amp sounds old and tired.

With that in mind I decided to replace the Mac with a partner to the Adcom GFP-555, the venerable GFA-545.  Of course the 545 is no youngster either, but it is inexpensive and can also be stacked on top of the preamplifier.  Given my tight listening space this was the biggest reason to go this route.

The Adcom GFP-545 is a conservatively rated 2-channel power amplifier making 100WPC.  5-way binding posts, RCA inputs, captive power cord, etc.  Very basic and no frills with only the mentioned connections, an on-off switch and indicators if either channel is clipping.  Designed by Nelson Pass, it sits between two other models, the 60WPC GFA-535 and the 200WPC GFA-545.

In the 80s and even up to the 90s, Adcom amplifiers were mainstays in many, many systems,  My father still has an original 555 running in his downstairs home theater system, so that speaks of some good reliability.  But, like my McIntosh 2100, they are getting to the point where some maintenance is due.

How does it sound?  At least in my budget system, very good.  With the fresh power supply and direct coupling, the Adcom had much better and tighter bass than the McIntosh.  It does lack some of the warmth, but the clarity and detail is higher along with a less grainy presentation.  Top end is extended, perhaps a little etchy compared to the best tube amps, but nothing that will drive the listener out of the room.  So a good basic power amp that can be used in a variety of systems.

Ultimate fidelity?  In a word: no.  But my current system is a whole bunch of compromise, and with the soft presentation of the Shure M97xe / Dual CS5000 combination and the nature of the Adcom GFP-555 preamplifier, it somehow all works, even blunting the forward character of the B&W 805s,

So for now the Adcom 545 delivers music and does it in a way that I find inoffensive.  But with tube amps coming soon it's time in my system is short.

Review: Adcom GFP-555 preamplifier

 (Image from Google)

Note:  This review is of the original incarnation of this model, not the latter Series II model.  The "Series 1", for lack of a better term, features a moving-coil head-amp that can be turned on via a switch on the back.

History: Adcom.  There's a company that brings memories of the late 80s and early 90s, back when their gear seemed to be everywhere.  The famed GFA-555 amplifier drove a lot of high-end speakers, and as proof of their longevity, one of these amplifiers has been in continuous service at my father's house for over twenty years.  My very first "high-end" preamplifier was the Adcom GFP-565 which was once on Stereophile's Class B list.  I never liked the unit, or, to be fair, I never liked the sound I got out of it when matched with a Harman Kardon Citation V.  I've also owned the GTP-400 tuner-preamplifier; not exactly a stellar performer but good for mid-fi duty.

So how did I end up with a GFP-555 in my system?  It was mostly a matter of need since I recently bought a McIntosh 2100 amplifer.  For now I decided to wait until a good McIntosh preamplifier comes along but I required something serviceable until then.  For $129 via Ebay, the Adcom GFP-555 is certainly affordable, and, as I was to find out, is actually quite listenable.

Ins & Outs: A rather boring, er, conservative black metal case.  The tone controls that are defeatable.  A Mono button.  Two outputs - one with capacitors on the output and a "Lab" output that is DC coupled.  Switchable MC (with a 100ohm load) head amp, and a regular ol' MM phono stage.  Dual tape outs - hey, you remember cassette tapes! - and, more important for the McIntosh 2100, switchable two-prong AC jacks.  No video switching or subwoofer outs.

The Sound: Paired with the McIntosh 2100 - a rather strange combination in terms of years - the sound is actually quite good.  Fairly warm without that upper midrange/lower treble grit that I normally associate with solid-state gear.  The bass goes down low with nice control and the treble is fairly clean too, at least not intrusive with the transparent B&W tweeters.  Not bad for a bunch of op-amps.  However, compared to the departed Quicksilver tube preamplifier, the Adcom suffers from less detail, a flatter, more 2-D sound, and, for lack of a better word, some greying of the musical palette.  But such weaknesses are only obvious with active "between the speakers" listening, and does not normally interfere with my current listening habits.

For us vinylphiles, the phono stage is very good - quiet is the first word that comes to mind.  Perhaps I'm too used to tube gear, but with the Adcom the music comes out of the speakers from a black background.  There is no tube hiss or rush anymore.

Conclusion: The Adcom GFP-555 is a sensible - but perhaps a touch boring - option for any entry-level system.  Where it fails - definition, detail, and dimensionality - will only be noticeable as the quality of the front-end and speakers begin to outpace this classic piece.  So this preamplifier does get a recommendation, but only within the confines of the partnering gear.  For example I certainly wouldn't use the GFP-555 to drive a pair of Eico HF-60s into the UREI loudspeakers because only then would I start to hear the deficiencies of this budget piece.  But partnered up with an Adcom amplifier, or any other budget solid-state powerhouse, and some decent speakers, this preamplifier is a good starting point. 

System:

Dual CS5000 turntable with Nagaoka MP-110

Pioneer DVD-V7400

McIntosh MC2100

B&W Matrix 805s on stands

Wire: Various brands

Refurbishing a vintage Sony TA-3120A solid-state amplifier

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The original Sony TA-3120 is quite the ancient (solid-state-wise) piece of gear.  As far as I can tell, the original TA-3120 amplifier was released in 1966, the start of the decline of vacuum tube technology.   It was this model, along with many others, that was also the beginning of the end for American stereo manufacturers.  Thanks to truly portable radios, the Japanese had a leg up on making solid-state gear that didn't blow up and could provide countless hours of trouble-free operation.

(right click to see larger image - or check out the service manual)
Note: this is the 3120 schematic, the 3120A appears to be slightly different.

The TA-3120 and the latter TA-3120A features very simple circuitry, looking quite valve-like in operation.  A quick look at the schematic reveals a very simple single voltage power supply, a single transistor gain / and single transistor phase-splitter, two pairs of output transistors per channel, and a large capacitor coupling the transistors to the speaker.  My own interest in these types of amplifiers are purely historical.  Though I believe a good tube or a modern circuit will lay waste to these early units, I also have an interest on hearing just how good these things could potentially sound.  Those vintage electrolytic capacitors, especially back then, weren't particularly well-made, not compared to the tightly wound models of today.

These stand-alone "one third" amplifiers seemed to have been rarely used with a preamplifier - instead they were supposed to be mated with integrateds, powering the back channel in early Quad / primitive surround sound systems.  Making a decent - for the time - 50 watts per channel this amplifier will have enough moxy to drive most speakers, provided the they don't dip below 4-ohms impedance.  The capacitor coupling will also save woofers if the output transistors decided to go south.  I also like adjustable gain knobs in back, perfect for matching up with any number of different preamplifiers.  With that in mind, along with the handsome chrome shoebox looks and potted power transformer, I decided to buy one for a paltry $129 and see how it sounded.

  

Initial listening results through the UREI 813A speakers were unfortunately short-lived.  However, before the problem came to light, I heard an amplifier that sounded pretty good but a tad "confused" with not very good control over imaging and soundstage placement.  There was a "blur" to the sound, along with a recessed midrange and a slightly tizzy treble.  Bass response was half-decent though definitely not approaching the uber-depth and control of my old Threshold S/500 or even my Eico HF-60 tube amplifiers.  But still, I would rate these higher than stock Dynaco ST-80/120s or even many vintage receivers I've heard.  I could tell the fine fellows at Sony had put some serious thought into these amplifiers but were hampered by the technology of the time.

A few minutes of listening and the sound suddenly cut off.  And then mysteriously it came back.  Only to be cut off again.  At first I thought some speaker protection relay - as seen in the TA-3120 schematic - was clicking off and on.  However, an examination of the 3120A innards showed no such circuit.  A quick check of the multimeter showed that the power supply was undulating from 62 to 82Vs roughly every two seconds.  As the voltage dropped, so would the sound.  This pointed to a potential capacitor problem - a device that stores and releases voltage.  To the Digikey site I went - it was time to replace every capacitor on the circuit board.  Like the original amplifier, I went with Elna (mostly Silmic) capacitors where possible.  I also discovered that the TA-1320A is quite different than the original 3120, with different values and some there not at all.  So if you need to do this job, record the capacitors needed from the components on the circuit board, not the schematic.

Yikes!  This was a nightmare.  Even though Sony had thoughtfully made it easy to pop off the three circuit boards in question, I still opted to keep the multiple leads intact.  This left me a few inches between the back of the PCB and the heatsink.  The solder traces are also extremely fragile and appear to be made of very thin copper - use caution!  When I was done, I had a nice pile of used capacitors and a much more modern looking board.

 

When I finally finished, I hooked up my Pioneer test speakers and took the output directly from the SACD player.   I turned the amplifier on ... and hurrah!... there was music!  I let it play and tested this power supply voltage.  This time it was a rock steady 86 volts, higher than the initial value.  Since I hadn't replaced the main bucket capacitor which I thought was the source of the original problem (and the most expensive fix) I was happy to hear undistorted sound.  The Pioneer speakers, however, aren't the highest in fidelity, but still good enough for some initial thoughts and component break-in time. 

Hmm... good bass response and a bouncy engaging rhythm.  A very pleasant background sound as I help my fellow marines hammer through the defense of Iwo Jima - courtesy of the virtual world of Rising Storm, a Red Orchestra 2 upgrade pack.  However, the old saw "all amplifiers sound the same" really does hold true, but only if the speakers in question can't resolve the differences.  It was time for a true sonic torture test, the venerable UREI 813A monitors with their compression horn tweeters, a speaker that has broken many an amplifier.

Hooking up the Sony amplifier was easy as pie - the back connectors work great with the mid-sized spades of the Cardas Hexlink speaker wire.  Large spades and banana plugs please do not apply.

The first cut was my original U.S. pressing of Tom Waits - Closing Time.  This recording is a tad dark and it showed.  The upper midrange / lower treble grit I normally associate with solid-state gear was pretty suppressed - you had to really listen for it to hear it.  Only a few non-tubed amplifiers truly get rid of it - at least according to my experience.  The next recording was the 180g re-issue of Ray Charles - Genius + Sould = Jazz.  I was taken aback by the sheer musicality of the sound.  I began to feel a tad suspicious, wondering if I was hearing one of the better amplifiers of my life.  Seriously.  The dynamic swings worked well and the spaciousness of the recording was evident; this sort of depth is something I normally associate with tube amps.  Hmmm....

Next up was a first pressing of Donald Fagan - The Nightfly.  Ah, now I could hear the limitations of this early digital recording.  The treble was noticeably splashy and forward.  The very deepest bass was not exactly missing, but not as low as I remember with other, more powerful amplifiers.  The separation of the vocals were not as defined as other amplifiers caused by a slight blurring and loss of detail.

Now it was time for something really dynamic - The Classic Records re-issue of The Who's - Tommy and my original pressing of Frank Sinatra - Sinatra At the Sands.  With these two recordings, everything was there and the music was still emotional as ever, but the lowest bass registers were just slightly underdamped and lacking - perhaps an effect of the music going through such a large electrolytic output capacitor.  The very top could get hard and uncontrolled when listening too loudly, the sign of an amplifier running out of steam - obviously 50Ws can only do so much.

Conclusions?  This is a very nice amplifier, especially with a bevy of new Elna capacitor replacements.  Perhaps it is the simple circuitry or the effects of the (fairly) non-linear output capacitor, but the Sony TA-3120A lacks much of the grit and harshness I associated with solid-state gear.  Sure I've heard better - notably a large number of tube amplifiers, but if I didn't know any better, I could really live with this piece of vintage amplifier.  What it lacks is the ultimate finesse of the best gear I've heard - detail retrieval, bass control, and soundstage depth.  However, it does - much like the B&K ST-140 but not quite as warm - convey the music in an enjoyable way.  Of course much of this may come from my VPI table and Quicksilver preamplifier; the flaws of the Sony diminished by the strength of the other audio gear.  Nonetheless, recommended for vintage junkies who want to try something different.

Review System:

VPI Aries with JMW 10.5i tonearm and SDS Power Supply
Dynavector 10X5
Cardas Cross 1M interconnects
Quicksilver preamplifier with Mullard short-plate 12AX7s, RCA 12FQ7s, Amperex 12AU7s

Cardas Quadlink 5C 1M interconnects

EICO HF-60 monoblocks with Mullard XF2 EL34s & 5AR4s, GEC CV4085s, and GE 6SN7GTAs.
Cardas Hexlink speaker cable
UREI 813A monitor speakers
VTI BL503 equipment rack