It is an excellent design. Upgrading the coupling capacitors, feedback loop capacitors and the resistors (plate, cathode, grid stopper and feedback) brings them up to the level of anything you can buy today in that poower range.
I had two pairs of them around 1981. The only thing I hated about them was the old fashioned screw strip for speaker wires. I even bought some new ones but the guy I took it to insisted there wasn't room to install them. I am not sure in retrospect that he knew what he was doing. The old Lux units like the CL 35 and CL 32 were good and can be made better with new parts, but you knew that.
The Luxman 3045B is outstanding. Aside from the usual periodic maintenance (re-caps, resistors, etc.) the circuit is sound. I used these for a couple of decades with a stash of the original high power triode tube.
With this amp, you're pretty much at the limit of push-pull sound. The transformers are beyond reproach. Instead of trying to make the Luxmans something they aren't (you're already a half-step back by the conversion to KT88s), accept your amps are sensational and consider your next step moving to an 845 SET or P-SET 300B amplification.
I had eight of these in the late 70s. Aside from the output tube becoming unavailable, by biggest problem was setting the bias. Each night all eight had to be biased and this needed to be repeated during an evening of listening. I did not have them or the Fulton Premieres for very long, largely because of this, but I did like the sound of these amps.
Thanks all. I do not have any technical experience with amps although I can and have replaced components. Can anyone explain to me how to find the items you mention: feedback loop resistors and capacitors; plate, grid, cathode, feedback resistors, and others. I have the circuit diagram with all labels and voltages, but I don't know which components are the above mentioned items. Many thanks again, I would love to keep these amps!
I believe you have a better chance of getting specific technical advice if you post on one of the tube DIY forums.
I had the factory KT88 conversion procedure manual mailed to me from Luxman. I can mail you a copy, email or snail mail. I converted my amps some fifteen (20?) years ago, and have been quite happy. The old design had the tubes right on the hairy edge of the operating envelope, that's why they went through output tubes and needed frequent bias adjustment. With KT88, you set the bias once (check after a few hours of break-in) then forget it. I have rechecked the bias after five years, and it remained rock solid. I have since upgraded the caps and resistors, and true to what Shussbliss says, I heard noticeable improvement.
Stevenm, having had six of these amps and having to bias them perhaps twice an evening, I wish I had known of the KT88 conversion. Did they sound as good as the original tubes? I had them on Fulton Premiers.
Fortunately, I acquired a pair of these last week. It has the KT88 mod above.
What preamps are you recommending please.
Steelyjoe, if you are asking me, I used a Treavor Lee modified PAS3.
I use a Spectral DMC 20 Version 2, (solid state) to great advantage !
Hello, Can anyone either provide me with good directions for upgrading the Luxman MB3045 tube amp, or perhaps let me know where I can get the directions? Please help!!??!! Gene. Cell 860-608-8502
Why not get a CL32, 34, etc? They are nice sounding preamps. But I would guess you would want to get the caps replaced on whatever you buy. They are very rich and organic sounding. A classic 12AX7 sound. So the system will be a little laid-back.
I have two pair of MB3045. One with original tubes, one with KT88's. I don't use them. They're in my office museum. I just bought a pair of Dahlquist DQ-M9 that are mint, and I'm going to have a retro system from 1979 I can play with here and there.
I was really excited to get the Dahlquist here. But I plugged them in, and they are nothing near my Sonus faber Guarneris. Not even close. I was shocked and a little bummed.
These amps look pretty, but its sound does not match its look, IMHO. I owned 2 pairs with the original 8045 tubes, a pair with KT88 mod and a pair with 8417 mod and liked the KT88 version the least.