This review page is supported in part by the sponsors whose ad banners are displayed below

Lab JC

When we say JC is back, what exactly does that mean? After all, we’re talking about someone who even before he left was never conspicuously in the hifi mainstream in the first place. To put it mildly. I’ll let JC speak for himself from the Lab JC website: "Design, consultation and repair of certain older recording and playback equipment and musical gadgets (sound effects) can all be accomplished under one roof. Commissioned designs for audiophiles and recording engineers are a specialty…"
In a very general sense, if it has tubes and makes music and you want it built or fixed, JC may very well be your man. As I’ve said before, JC Morrison is the go-to guy for tube guys with questions. I know more than one tube amp manufacturer who relied on JC when they had questions no one else could answer. His knowledge of tube technology, circuit design and audio history is vast. As important, he understands how to put this knowledge into the service of music. JC is also currently working as design consultant to Korea’s Silbatone who, rumor has it, amassed an incredibly large stash of classic audio gear from the likes of Western Electric. 

Check out JC's website, his Sound Practices articles and search the web for a fuller picture. II’ve enjoyed reading a number of his articles and posts online including his introduction to tube circuits The Fi Primer pamphlet which includes details and schematics for preamps, single-ended and push/pull amps using the 6L6, 2A3, 300B, 211, 6CK4, 6B4-G, 807 and 845 power tubes. But don’t let this list limit your imagination. JC has built many custom designs for professional and home use. I own a pair of JC amps which are the “Mullard-style push-pull 6B4-G bass amps” mentioned in the Sound Practices article Tuned In above.

Here are a few more quotes from various JC articles and posts worth sharing: "I cannot encourage you enough to try your hand at making your own hifi equipment. Besides the obvious delights of vacuum tube audio, there is nothing quite like the moment your construction starts to make music. This is something that those 'little black boxes' can never do, no matter whose name is on it. In addition, careful implementation of vacuum tube technology does sound better than most of what the consumer electronics industry likes to call 'high-end'. The last notion I'd like to leave you with is that almost anyone can build tube audio equipment. The only prerequisites are patience and the desire to learn. Please respect that this takes time and effort, don't bombard me with dumb nonsense about tranny/resistor/capacitor types or other weird tweaky bullshit that will never make or break any approach."

And here are the categories from one of the NY Noise show competitions:
• Most Byzantine
• Most Fabulous
• Cheapest and Ugliest (one category)
• Most Absurd
• Most Self-Righteous
• Most Alluring
• Least Offensive
• Most Philosophical
• Most Aggressive
• Most Rebellious

The Lab JC 211 PP Amplifier
I asked JC for a description of his 211 PP amplifier and here’s his response in its entirety: "This amp is a test bed for an idea hatched about a decade ago. It was following a conversation with John Curl about another conversation I had with Ed Oxner. It was about the predictability and consistency of nonlinearity in a transistor’s transfer characteristic; that it was much more predictable than the actual slope or variation of tolerances in any device – and that clever thinking about this can lead to circuit design. Both of these guys specialize in this sort of 'backwards' thinking. I think Barry Gilbert of Tektronix was probably the master of this…?

"Tubes are a little different but not enormously so. Triodes behave and are applied much like variable resistors and feedback (error correction) can be applied to make them really behave like linear variable resistors with a slope relating to sensitivity/gain. For a varying voltage in, you get a varying current out related to the plate resistance (this is Ohm's law). But pentodes are another beast altogether. In fact, they have a lot in common with FETs in transfer function. They are fundamentally not linear in terms of Ohm’s law or simple math functions like adding, dividing, squaring etc. For a varying voltage in, you still get a varying current out, the slope of which is related to the screen voltage. What’s interesting is that the plate voltage has very little effect on the current. It’s like a programmable current source. For a wide range of plate voltages, there is almost no change in plate current. It doesn’t naturally behave like a resistor. You can add feedback and make it behave any way you like. But what if you didn’t?

"This amp uses a novel voltage-to-current converter circuit (all tube circuits do this) that relies on the predictability of the pentode’s nonlinearity (that’s not so typical). I will post schematics for this [on the JC Labs website] as soon as I figure out how to do it. The current difference generated by the input signal works against a fixed resistor and you end up with an Oh's law relationship: i*r = e. What a mouthful. Sounds like some of Bob Carver’s marketing, doesn’t it? It's not really as complicated as it sounds, which is true of most things human. The point is to get high voltage amplification with good linearity without any feedback (error correction). The circuit will work great with feedback but I wanted to prove to myself that I could get 240v peak to peak out of the driver circuit without any tricks, with wide bandwidth and a simple 1st-order decay.

"The output stage is completely ordinary and biased AB1-ish so that the tubes go a long way. There aren’t that many 211s anymore and I don’t want to repair these amps anytime soon. I use an input tranny for a phase splitter, two mirror image driver circuits and the push/pull output is cap coupled to the 211s. The output transformer is a Peerless SQ-275s (12k : 6ohm) wound in Philadelphia 10 years ago. The tube compliment is 2 x E80CF (6BL8), 2 x 5703WB sub mini (under the hood), 1 x 6CG7 and 2 x 211. The power supply has a regulator for the driver stage and this allowed me to have one transformer winding supply all the B+ voltages (in other words, laziness). The regulator uses any 6L6 type tube and a 12AX7 and 0D3 gas tube. B+ is 1400 VDC and the driver stage uses 400 VDC. The amp makes 50 watts into 10 ohms at 3% THD measured with an HP334a. 20 watts is 0.3% THD. No local or global feedback is used to correct the driver stage."

Musical Practices
The experience of listening to music on a hifi can be many things -nostalgic, emotional, thought provoking and more. During our listening time at Monkeyhaus VIII: Return of JC I got to experience a bit of everything, a buffet of hifi’s musical delights. From the emotionally eviscerating Machine Gun by the Peter Brötzmann Octet—a live recoding from 1968 that came up in conversation the first and last time I met JC a few years ago—to the Rev. Charlie Jackson’s Wraped [sic or maybe not] Up In Jesus ,an impeccably soul-stirring slam of a 45RPM 7”; the truly wrenching Threnody for the Victims of Hiroshima (for 52 strings) by Kristoff Penderecki performed by the Rome Symphony Orchestra under Bruno Maderna; the creepy-funky-full-fathom-five jive of Syclops' I've Got My Eye On You; Ratatat’s LP3 and the new song-pop-ing Fiery Furnaces’ I’m Going Away to name but a few.

At some point Herb Reichert turned to John and said "your speakers change their voice to suit the music" or something very similar (I take mental notes) and I was reminded of how succinctly right Herb can be. While we’re on the Reichert/DeVore theme, here’s Herb from his Listener Magazine HE 2002 Show Coverage report: "And the DeVore Gibbon 8 loudspeaker had this unmistakable natural tone and presence that reminded me of all the good qualities I associate with vintage Altec/JBL/Tannoy speakers." And to fill in our historical Monkeyhaus overlaps, the 2001 NY Noise Show saw two early pairs of DeVore speakers, one paired with a Komuro class-A PP 845 amp and another pair driven by a JC Morrison 2A3 amp.

A brief aside - Herb’s writing was a huge influence and inspiration for me both in terms of learning about what’s important in hifi and how to write about it. I’d imagine this is the case for many enthusiasts who were fortunate enough to be reading about hifi when Herb was writing about it. While his return to a public hifi forum at Monkeyhaus VIII is deserving of its own separate telling, I’ll hope that some smart publication has the sense to hire him so he can tell us with his own words what he’s been up to. As John DeVore said in a post-event email, "it's nice to see that he still has a love for it". For those unfamiliar with Herb Reichert’s love of hifi, I’d suggest reading anything you can get your hands on (see Sound Practices, Listener magazine and Enjoy The Music).