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: Denon DCD-600NE CD player

 (image from the Denon website)

I still remember the first time I heard a CD player - this was at some teenage party back in the mid-1980s and I was rather impressed how loud it played.  Hey this was before I knew what being an audiophile was.  It was a year later when my dad bought a Magnavox player for his system.  I spent a mighty chunk of change - $22 - buying a Misfits compilation that, sadly, ended up sounding very bright, thin, and irritating to the point where a headache soon came on.  Later, in college, when I got into tube gear, I owned a Theta Basic DAC.   However I still thought my Thorens TD-166 turntable with a $20 Grado Black cartridge served the soul of music much better.

Years later there was a time that I was into digital.  By then vinyl was getting harder to get a hold of and the CD re-issues were pumping out some excellent compilations of rarer groups.  I started experimenting with several DIY modifications and designs.  For example, the transformer-coupled RAKK DAC was one of the better iterations of digital I have ever heard.  But in the end it was analog that won my heart.  Over the years my CD collection continued to shrink while my passion for vinyl increased and became the focal point of my system.

Time marched on - CDs are now ridiculously cheap.  From a purely music lovers point-of-view, they are an easy way to build a music collection, especially compared to the now high price of vinyl.  I decided once again to buy a CD player, hoping that technology has improved the Red Book standard.

But what to get?  I searched through Ebay and Audiogon, looking at several vintage models.  Ideally I wanted something with a digital out so I could experiment with DACs in the future.  Accessories 4 Less came to the rescue with a refurbished Denon DCD-600NE player that featured a 32 bit DAC and AL32 processing that - to quote their website - "expands audio data to 32 bits and uses a proprietary algorithm to interpolate the data and perform up-conversion and sampling, achieving a playback sound that is close to the original source."  So, as my friend likes to joke, "Perfect Sound Forever just got MORE perfect."

The Denon DCD-600NE is a stripped down player and - shockingly - has a metal enclosure.  If you want to use the full functions - random play, direct mode, track programming, etc, - this is where the rather large remote comes into play.  Digital out is via Optical - not ideal - but this may point to a future Schiit Bifrost 2 DAC upgrade.

So how does this little beast sound?  Initial impressions weren't the best.  There was a forwardness to the sound that was tiring, along with a sense that, compared to even my lowly Dual CS5000 turntable, that 20% of the musical information was just missing.  What I mean are the spatial cues were gone, rendering the voice and instruments as very two-dimensional.  A good reproduction system should have depth along with breadth, transporting the listener to the mind of the producer, or with some classical recordings, to the venue itself.  Instead the Denon reminded me once again why I prefer vinyl for home listening.

After a few days of break-in I decided it was time for some comparisons against two different turntables along with some general impressions.

The forwardness was reduced but there is no other way to say this - this budget Denon still sounds like digital.  Compared to the same LP, the CD is missing reverb cues; either the room or artificial.  An example of this is Willie Nelson's Stardust.  The body of the acoustic guitar is gone, leaving just the top layer of the guitar notes.  The "black background" sounds uncanny but not in a good way.  It's like a black hole of information - nothing is there! - compared to the warmth and fullness of analog which captures the space of the room and the size of the instruments.  It feels as if the music has gone through some kind of horrible clinical ward, stripping off the flesh of the music and leaving only the bones.

Now that does sound like a harsh review.  To be fair some CDs were better than others, like a few Chet Baker albums in my collection that sounded quite good.  Jazz is usually well-recorded but I still preferred my LP versions - even with my second turntable, a budget Dual CS5000.  At least with analog my brain connects to the music and I can relax.  With digital I am still gritting my teeth and feel uncomfortable with the overall presentation.

Maybe a DAC will bring some improvements.  We shall see!

System:

• Audio Research SP8
• modified Eico ST70 with 6AR6 tubes
• Cardas Neutral Reference interconnects
• KEF R500 speakers
• Dual CS5000 turntable with an Ortofon OM20 cart, aftermarket Shibata Stylus
• Thorens TD309 with Ortofon 2M Bronze
  

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
  

Project: Building a Pass Aleph J Amplifier

After the success of the ACA amplifiers, I decided to tackle something a little more difficult: the Aleph J, which is yet another Nelson Pass design that he released to the community at DIY Audio. Like the ACA, the Aleph J is single-ended design but instead uses two output devices in parallel, along with a current source. Power output is in the 25W range, which is good enough for my small listening area, even with 86dB efficient speakers. Except for the input capacitor on the negative leg of the input, the entire amplifier is also DC coupled which means the output offset must be nulled out.

Nelson Pass has a manual on the Aleph J here.

DIY Audio Build - with better pictures than mine - is here. Also includes a schematic.

I first stuffed the circuit boards, including the power supply PCB, with the passive parts:

And next was the installation of the Jfets and FETS, along with the placement of the circuit board on the heatsink. I ran into some problems that the DIY Audio community graciously helped me with. Turns out that I have too much of a soft touch with the soldering iron and had a few cold solder joints. It's that fear of burning up those rare 2SJ74 jfets that make me nervous. Also note the Keratherm output transistor insulators which are a lot easier to install than the old "white goop" thermal grease, and also make removing the board easier for troubleshooting. 

  

I'm obviously skipping a lot of the build steps - power transformer installation, power switch, and the wiring. So with the magic of my time machine, here is the end result of most of my labor: some magic glowing blue LEDs. I do have to say that the DIY Audio Store supplied chassis and circuit boards made this project a lot easier - everything, with the exception of the power transformer, just fits without having to drill holes or battle with placement.

Here is a picture of the completed amplifier :

Note on playing the Aleph for the first time in the main system: I'm quite impressed - lots of little detail on records that I hadn't heard before, super fast but delicate sounding - ie, not aggressive. Excellent bass control. Some actual depth and wide imaging. They would make excellent mastering/studio monitoring amps.

The sound is a tad "clean" - lacking some of that bloom that I hear with the best tube amps. So like digital television versus 70mm film. Perhaps not the best analogy but the only one I can think of. It does need some more break-in time so I'll be patient. But - at least in this system - it is the best solids state amplification I've heard. I think a really good SE tube amp would be preferable but at half the cost, the Aleph is certainly in the running.​

01/04/19 Update: The Aleph J is one of the more interesting amplifiers that I've ever experienced.  It has such a lack of apparent "character" that it just blends into the background.  I'm not trying to say it is boring, quite the contrary; you can hear the differences between recordings.  That is to say every record sounds different, as to be expected.  And, for a solid-state amplifier, it has some of the best body and definition I've heard.  I'm really beginning to hear the limitations of my front end now!  The bottom end is also tightly controlled too, giving quite a bit of boogie factor even with the small woofers of the Denton speakers.

Now the Aleph still doesn't sound like a tube amp - but it also doesn't have that upper-midrange glare or treble edginess I hear with lesser solid-state amps.  Highly recommended for its neutral character and dynamic ability.  This amp will be running in my system for a long time while I start to explore different turntable and speaker upgrades.  Stay tuned!

Tube Review: The Mullard XF2 EL34 pentode

Introduction:
The Mullard EL34 - though perhaps not the best sounding of this family of tubes - is famous for a big and rich sound favored by guitarists and hi-fi nuts.  The XF2 version, like many early tubes, has welded plates, along with that thick, dark getter that is a trademark of the valves that rolled out from the Blackburn factory.  Later ones have similar construction but used crimped plates - I've never sat down and compared the different XF models, but needless to say they're all pretty good.

 The Mullard "sound", for whatever reason, has always been on the darker scale than neutrality.  Perhaps there is some secret mojo in the cathode chemistry or the metal quality, but this sound difference is easily noticeable in comparison to an original Philips EL34 or even any modern EL34.  This romantic sound, in the wrong amplifier, can lead to a syrupy sound - I'm thinking of something like a stock Dynaco 70 or any vintage amplifier with weak power supply capacitors and/or oil coupling capacitors.  So, like anything else, system balance is important.

The pair of Mullard XF2 EL34s I'm reviewing here are high mileage units pulled from my Eico HF-60 monoblocks.  Though they have plenty of hours on them, they still test almost as new - longevity is something that vintage tubes seem to do well and is needed, especially when running in something as abusive as the HF-60.  For this amplifier with a plate voltage of 400VDC and a screen of 250VDC, 60mA was chosen as a nice cruising speed.

Listening Tests:
The Immortal Otis Redding has a nice and punchy sound, albeit a tad stripped down.  The Mullards conveyed this simple recording with excellent clarity, depth, and dynamics.  Otis's voice sounded very natural as did the instrumentation.  The sound never became harsh or strident with this output tube.  There was also a nice projection to the vocals, pushing the sound beyond the speakers.  This seems to be a trait of vintage tubes - an enveloping sound with a 3-D effect: layered depth, wide and stable imaging, and a sense of being tangibly involved in the music.

Frank Sinatra - Sinatra at the Sands appears to be a three channel recording with instrumentation on the left and right with Frank right in the middle of the action.  The dynamics - on the right system - are truly breathtaking.  The Mullard EL34 excelled here, sounding almost as big as the Tung Sol 6550.  On the quieter songs like Don't Worry 'bout Me, all the emotion came through with the sensitivity that only Sinatra could surprisingly pull from that playboy act.

The last record in this listening test was Steely Dan - Aja which is a modern recording with deep bass, shifting dynamics, and crafty compositions.  The Mullard EL34 wonderfully captured the trailing edges of the reverberation and gave a soundstage that was big and organic.  The instruments floated nicely in space too.  There was a touch of darkness to the music, giving a not quite neutral sound compared to a Tung Sol 6550 or the ultra-vividness of the Philips metal base.

Conclusion:
The Mullard EL34, compared to the new production tubes I've heard, has a real magic.  The music flows with more ease - a naturalness that is hard to describe, but the sound that is reproduced is cut from the same cloth in a grain-free way that makes me forget that I'm listening to a stereo.  Even the Shuguang GEKT88 - which is very good - doesn't capture this ability of convey the real soul of the recording.

However, the Mullard is not the most hyper-detailed and bends the signal to a darker, more romantic spectrum.  But this is a nice place to be - especially in the world of hot digital recordings and aggressive moving-coils.  If you're searching for the most transparent or an abundance of detail, then this may not be the tube for you.  But - and this varies from listener to listener - any sins are easy to forgive.  This is a tube for the music lover, not the nitpicker. 

Review: Monoprice MHP-839 headphones

(image from Google)

Having never spent more than a $79 on a pair, I'm a admitted headphone cheapskate.  For work, I'm a longtime user of the budget Sennheiser HD-201, while for home use, the Grado SR60s get the nod.  At heart I will remain a speaker guy since the visceral gut impact of something like the UREI 813As just can't be matched even by the finest headphones.  But for listening to MP3s at my desk or while doing late night mixdowns of my amateur synth music, it's hard to beat the sonic solitude of a pair of headphones.

When I finally decided to give up the Sennheiser HD-201s, a good audiophile friend recommended the Monoprice MHP-839s.  He's a longtime Sennheiser HD-600 user, but commented that the Monoprice headphones were quite enjoyable with a nice overall sound for the price.  I ordered my pair from Amazon - hey, free shipping! - and got them a few days later.

After a few hours of break-in, I found the Monoprice headphones to be quite decent.  The lowest bass goes quite deep with more impact and slam than the old HD-201s.  They also have a richer midrange, making the Sennheisers sound a bit nasal and hollow.  Perhaps the Monoprices are a tad congested - for example, sounding like a doped paper woofer than something like Kevlar.  Their biggest failing is in the treble.  My middle-aged ears don't quite hear the higher frequencies like they used to, but even I could hear a steep roll-off here.  This isn't a big deal for MP3 sources or anything that was recorded a little on the hot side - like many Synth or Dance mixes, but could be a deal breaker for the serious audiophile.  With their open back design, I prefer the Grado SR60s - they have a clarity that is hard to beat for the price - but such a design wouldn't work for my workplace.

As far as design, the Monoprice headphones aren't quite as comfortable as the Sennheisers.  I notice my ears getting hotter quicker.  I have a fairly large noggin though, so perhaps I'm stretching the band pretty hard.  Compared to the HD-201s, the background noise of a busy office is muted more with the Monoprices.  This is good if you require noise suppression like I do - programming takes concentration.

Construction quality is good - these headphones are built with heavy-duty plastic.  The two different lengths of supplied cords are a nice touch.