a tube amplifier repair technician

Well, I've had my BAT VK-75SE amp back from Bob for one week now, and only have about 14 hours on it, so I guess I should chime in here. I did just get off the phone with Bob, and I'll pretty much just sum up what I told him here. The most immediate difference that I noticed was in the bass, which went deeper and was better defined. Very impressive for a tube amp....or any amp really. The second impression that comes to mind is the speed/resolution/articulation improvement. Details that were before glossed over are now open for all to hear. Very exciting indeed.

The one nit that I had is that the amp seemed to lose a slight bit of warmth, or musicality. Bob said that this should return with another 75-150 hours of burn in for the caps/wires.

Overall I am very pleased with the modifications at this point in time, keep in mind that I only have 14 hours on the amp at the moment. The added bass and resolution are very amazing at this point in time. I look forward to letting the amp burn in more. At this point I would still highly recommend Bob's services.

For those interested, Bob did a mod on the input/driver tubes that supposedly takes the strain off of them and allows them to run in a more linear fashion. He also replaced the stock Belden input wire with gold plated silver wire, and replaced the coupling caps with V-Caps.
Total time, 23 days, total cost $1457.00, including taxes.

Cheers,
John

The truth is that V-Caps can take up to 200hrs to burn in(Teflon's like that). They are the most transparent caps out there after that. You can speed the process by playing a pink/brown/white noise signal(or plain old music) through the system(on "repeat"). Hook one speaker out of phase with the other and place them closely together, facing one another. That way most of the sound cancels out, and you're less likely to go nuts from the monotony. The sound will go through some strange changes before then, but the music will be there in spades afterward. Happy listening!

It is "28 Days Later" and the sound is truely scary.
The only problem is that "Bug" is still alive & kicking.

I have talked to Bob about my options & his recommendation are as follow:
- modding those build-in amps in my Quatros might not be the best/performance/economical idea.
- my new Granite Audio preamp could be a good candidate for mods but I need more time with it to be sure that it is the only option. Its build in phono section might also need a face lift. Or, I could mod the Ref 40 but that one is up for sell right now (to support my other moves). If it won't sell, I will keep it as my reference phono and work with Bob to bring the best out of it. Too bad I have not even tried it in my system. But who know....maybe I will.

So, you got it back and it seems that you like what you hear....great.
I am glad that you do since I was somewhat guilty of it too (among others).
But since everything is peachy...that is all that matters.

Now ............................let's hope you are "Bug" free.
( but " 28 Months Later" is right around the corrner......so, watch out .....at the end there is always that last little bug.)

Rodman99999, Bob actually advises against the playing pink/white noise on repeat. He says that the components will break in faster using standard turn on/off cycle methods....FWIW. I don't know, I used to use the constant pink/white noise method for breaking in cables, but Bob says the caps need to fully cycle...charge....discharge....we'll see.

Cheers,
John

PS: As for Mrjstark, I'm sorry, there is no hope for you. I can only hope that I can escape the elusive "Bug".....

You can run but you can not hide.
I will be watching you ........