Yup. Did a little circuit evaluation and the Luxman is essentially a monster a-b push pull amp that is biased so that both transistors think they are operating in small signal mode (where all a-b amps use both halves). So, essentially, you could probably drop the bias way down and you would convert the amp to a standard complimentary pair a-b amp. In fact, I did that on the good channel and the heat went away but the amp still cranked out the power with very little distortion (according to my distortion checks at 1kHZ) . So, if I owned one, I might install a switch that converts it back and forth. Kind of A to heat the room and a-b for standard listening. (Snarky, I know, but it bugs me people are spending big bucks for what is really just a modified a-b amp).
But in class A mode crossover distortion is no more. The first watt becomes the best watt. A lot of what you listen to is at quite low power levels (unless you only listen to ACDC!) and that's where a lot of the detail in music is. I've had class A/B amps of various sorts but I much prefer the sound of a good class A amp. Most class A/B amps have their distortion measurements done at near full power. Measure them at 1 watt and it's a very different story.
Hi whsh93a,
You are off topic in a thread specifically about the Luxman M-05 power amplifier. The comment made by analog_sa was a reminder to you that threadjacking (what you are doing) isn't allowed.
Should you wish to discuss your point of view, feel free to begin a thread on the topic. For now I will clean this thread up a little.
-Chris
It is a pretty amp. I said that in the off topic p.a. comment whwn comparing them. I happen to like vintage stuff a lot - including Luxman. Apparently some members here don't ever want to see "A" in the same sentence as "B". The Norwegian boards seem to relish it (they point out that the M05 will normally go into "B" mode when driven hard). Doesn't seem to matter to them. This whole thing started because I was asking how it's a pure "A" amp. I got a snarky answer and only got a nice answer on a European board. I passed that along and people had their feelings hurt, I guess.
Hi whsh93a,
Well, it's class A for most of any signal it is likely to see. It runs stinking hot and eats several components inside. I happen to disagree with running things so darned hot. That's one reason I bought the M-02 / C-02 combination instead. I also have a C-05, but it doesn't sound as nice as a few others. It is well designed. Mine was severely abused before I rescued it from the trash pile.
-Chris
Well, it's class A for most of any signal it is likely to see. It runs stinking hot and eats several components inside. I happen to disagree with running things so darned hot. That's one reason I bought the M-02 / C-02 combination instead. I also have a C-05, but it doesn't sound as nice as a few others. It is well designed. Mine was severely abused before I rescued it from the trash pile.
-Chris
All true. That's why I suggested turning the bias down some to allow it to switch to "AB" mode at maybe 40 or 50 watts. It would save wear by running much cooler and almost everything listened to would be class A (except maybe electrostatics or other inefficient types). But, they seemed to hate the idea.
Hi whsh93a,
The entire idea about the M-05 is the Class"A" thing. A cool running M-05 is basically broken until it is biased properly again. Note that although I disagree with running stuff really hot, this equipment is what it is and is designed to run like that. You can't and shouldn't try to make it into something else. Not unless you are the owner of course. I haven't bothered to take distortion readings from one at normal bias and turned down. Maybe after receiving my RTX-6001 and setting it up I'll give that a whirl.
-Chris
The entire idea about the M-05 is the Class"A" thing. A cool running M-05 is basically broken until it is biased properly again. Note that although I disagree with running stuff really hot, this equipment is what it is and is designed to run like that. You can't and shouldn't try to make it into something else. Not unless you are the owner of course. I haven't bothered to take distortion readings from one at normal bias and turned down. Maybe after receiving my RTX-6001 and setting it up I'll give that a whirl.
-Chris
Totally agree.
Been working on this M-05 for the past few days (it is really trashed by some other tech) Both sides were bad and one meter was not working.
Anyhow, Now both amp boards and the meters are OK but the right side power supply board - apparently - is not.
I read someplace that some of the connectors are mis-labeled. ie., 311 should actually be 312 or similar. Does anyone know which ones should be switched?? Which PS board are connectors switched on??
The schematic is so full of errors that I don't trust it to be labeled correctly - and since it was worked on previously, I don't trust where the connectors are now inserted (311 is in 312 and vice versa). I'm suspicious that the connectors are the only problem
(The NPN outputs heat badly when using the right PS and PNP no heat at all. It's not the amp board since it works fine using the left power supply).
Thanks!
Been working on this M-05 for the past few days (it is really trashed by some other tech) Both sides were bad and one meter was not working.
Anyhow, Now both amp boards and the meters are OK but the right side power supply board - apparently - is not.
I read someplace that some of the connectors are mis-labeled. ie., 311 should actually be 312 or similar. Does anyone know which ones should be switched?? Which PS board are connectors switched on??
The schematic is so full of errors that I don't trust it to be labeled correctly - and since it was worked on previously, I don't trust where the connectors are now inserted (311 is in 312 and vice versa). I'm suspicious that the connectors are the only problem
(The NPN outputs heat badly when using the right PS and PNP no heat at all. It's not the amp board since it works fine using the left power supply).
Thanks!
Right Channel Power Supply - switch connectors A312 and A310
==================
Thanks-
It's all repaired. The mis-labeled connectors on the right side power supply board are the plugs going to A312 and A310. They should be reversed so 312 plugs into header 310 and visa versa.
I discovered some interesting things about the amp while repairing it. I may sum some of that in a later posting.
==================
Thanks-
It's all repaired. The mis-labeled connectors on the right side power supply board are the plugs going to A312 and A310. They should be reversed so 312 plugs into header 310 and visa versa.
I discovered some interesting things about the amp while repairing it. I may sum some of that in a later posting.
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