It seems to me that everything is grounded, the RCA CD AUX1 and AUX2 give me continuity with the tester, as far as the relays are concerned, they have only one position, they shouldn't be wrong.
Only AUX2 are connected, with the tester it gives me both positive and negative continuity.
Lp is connected but there is no continuity between them
Lp is connected but there is no continuity between them
I did the same and didn't notice any issues with mines. Still an issue with the voltage for you?
the bridges shown on the pictures are for the tube heaters (lower, closer connections) and the high voltage supply (upper, further away) if I am not mistaken. That is fine, for the reasons mentioned earlier: If you turn on and off the heaters of the phono section all the time, they will break prematurely. Better to leave them on all the time I think.
This is not what is shorting the RCAs.... I will check with my unit now......
This is not what is shorting the RCAs.... I will check with my unit now......
I have used my M77 for a while now and I'm very pleased with it. The only issue left is that there is a bit of noise when switching between inputs. Do any of you have this problem? And perhaps a solution?
Hi Erman, my apologies it took some time. My unit is also shorting the unused inputs as well - didnt know that.... But it seems that all sources I ever connected handled this gracefully 😀
Hi tbaashus, this may come from some DC offset that one of your sources may have, does it always happen? does it move when you connect your sources at different inputs? One idea could be to add a 10k resistor across each RCA connector, to drain any remaining DC offset should there be some......
Hello hesener, you don't have to apologize to me, it's me who has to thank you for your advice and your presence. So there is no danger if other electronic components are connected, for example CD player, turntable, dac, etc.. Is there no danger of exposure?😁
I was wondering what could be the voltage difference problem I encountered in the 12.6v test point.
I have 13.3v on the line and 11.8v on the phono.
Is it possible that he inserted the MJ3000 transistor backwards?
I don't know where to find the solution.
Thank you.
I was wondering what could be the voltage difference problem I encountered in the 12.6v test point.
I have 13.3v on the line and 11.8v on the phono.
Is it possible that he inserted the MJ3000 transistor backwards?
I don't know where to find the solution.
Thank you.
I think the danger is very small, most sources have no problem with short-circuit on the output especially when there is no signal. Different story for power amplifiers 😀
Yes, that voltage difference is strange.... The MJ3000 and the 2N3055 (used before) have the same pinout, so you cannot really insert it the wrong way. The emitter of that transistor is the heater supply for all tubes, so they should all have identical heater voltage.
Maybe you could measure the resistance between the same points on the tubes (heater connection), to see if the traces are low-ohmic? (pin4 of each tube to pin 4 of the other tubes, same for pin5 to pin5). Just to see if there maybe is a problem with the PCB traces.....
Also, you could try and swap the tubes between phono and line section, just to see if one of the tubes has a problem....
Yes, that voltage difference is strange.... The MJ3000 and the 2N3055 (used before) have the same pinout, so you cannot really insert it the wrong way. The emitter of that transistor is the heater supply for all tubes, so they should all have identical heater voltage.
Maybe you could measure the resistance between the same points on the tubes (heater connection), to see if the traces are low-ohmic? (pin4 of each tube to pin 4 of the other tubes, same for pin5 to pin5). Just to see if there maybe is a problem with the PCB traces.....
Also, you could try and swap the tubes between phono and line section, just to see if one of the tubes has a problem....
I thank you for the answer.
The only thing I noticed is that when I soldered the MJ 3000 transistor some thermal paste got into the pinout of the transistor.
Is that a problem?
Can I measure voltage across sockets without tubes?
The only thing I noticed is that when I soldered the MJ 3000 transistor some thermal paste got into the pinout of the transistor.
Is that a problem?
Can I measure voltage across sockets without tubes?
Shouldn't be any problems with thermal paste on the pinout, I would clean it out though. You should be able to pull up voltage readings without tubes installed, I took the 6x4 rectifier tube out also, just so the voltages didn't climb wit no tubes installed.
As a matter of fact, I'm about to start on a 2nd build for a friend, who really enjoyed the one I had put together.
As a matter of fact, I'm about to start on a 2nd build for a friend, who really enjoyed the one I had put together.
Best of luck, can't wait to see your finished build, I recall you had a really nice-looking custom chassis for it. How's that coming along?