Feedback (The good kind ) !

Thanks for the great work on the Fisher 400cx2.  It has brought new definition to the Zu Definitions IV.  Following the power supply rebuild, ground scheme improvements, recapping with Super Caps, and flawless build of the Gold Point attenuator/power switch this is one of the finest vintage preamps I have ever heard.  I try to shy away from the audiophile adjectives because I have a hard time finding much meaning in them, but this baby is musical with explicit definition.  Midrange expression is phenomenal and nothing is lost at the extremes.  I would put it up against just about anything (within reason of course) and am confident it could hold its own, particularly the phono stage.  Great job, money well spent.


I really enjoy improving the performance of the classics

Dr. Tubeology


Recent feedback from a customer

Pat, I’ve spent the last week listening to the Marantz 5’s every day.  Paired with the Model 7 pre, 10 tuner, Garrard 301 and Altec Carmel speakers, this system sounds better than any I’ve heard till now.  I’m extremely impressed with the tone and clarity from the amps and just fantastic presence in vocals and instruments.  I love the vintage sound (tone) with clarity I’ve come to expect from high end equipment.  I actually think I may prefer this sound to the more modern SET Shindo and Thoress I have in my main system.  Thank you for all the work that you did on these amps and you have one very happy customer for life.

David A


IMG_2050 IMG_2053

Milestone with our Lab Beta Ultimate 2A3 amplifier, “Truth”

A milestone has been achieved in one of our two Lab amplifiers for the long term durability QC testing. Note (in the photo) the lower left hour meter, It’s close to turning 2000 run hours on the lab unit. This is one we are set up for both long term listening in the lab and other testing processes, so pardon the missing features and controls, its not pretty. Not only have we achieved a true 2000 hours of run time this has been a durability test as to power cycling, many hundreds of times long, short , in-between.

We have purposely tried to kill it. No issues nada, zilch!. how’s that for a world class tested audiophile component!. We pulled the tubes and did a full curve and test of emissions in all parameters and no detectable loss of emission or other anomalies was found.

So in summation not only do you have the worlds best sounding 2A3 amplifier (TRUE DC Coupled, No Capacitors) with the best components and engineering that exists, it can take a beating and keep on ticking!.. you deserve as the customer nothing less. It really does sound like a million bucks. We will put it up in comparison with anything we are that confident!

Head “Whammer”

for more about the most amazing 2A3 amplifier on the planet see:



Check out the progress on our ultimate 2A3 tube amplifier!


Many years of work have come to fruition. We debuted at THE Show Newport and just showed with Zu Audio at The CAS Show in San Francisco CA. The press is taking note we have a world class performer. The “Truth” amplifier  has lived up to all of our expectations and beyond. It is the “Ultimate” 2A3 tube amplifier

Dr. Tubeology

“Truth in Audio”



MC30 Rebuild Project Part 3

Well, here we are – the 9pin sockets are installed into the chassis and the circuit board is also attached, now to figure out where all those wires need to go.

notice how the heater wires are attached to the 9pin sockets – very good idea I think that I may use that on one of my custom builds.

stay tuned for part 4

McIntosh MC30 Tag Board install

9 pin sockets and board installed on the custom McIntosh MC30 rebuild project

MC30 Rebuild Project Part 2

So far we have the new McIntosh Mc30 chassis re-chromed, the MC30 transformers and base plates painted with gloss black automotive paint and now we have the first of 2 stuffed circuit boards all ready for final installation.

I have used Teflon coated silver aircraft wire which is a much higher quality than the original. All the resistors are hand picked to be less than 1% of tolerance and in most cases they measure exactly as the schematic says they should.

The black cap’s you see on the board are Solen’s made in France.

McIntosh Main Board Old and New

McIntosh MC30 Main Board old and new