The power transformer wiring looks correct too. The quickest way to find the problem is first check there is 6.3Vac from pin 9 to pin 4 and from pin 9 to pin 5 on the 12AT7's. If those voltages are good, somewhere between 6V and 6.6Vac, then measure the voltages on pins 1, 2, 3, 6, 7 and 8 on each 12AT7, these will be DC voltages and some will be very high so take care. Best if you can measure all these voltages with the tubes in place. If you can't, then we'll have to think of Plan B.
What I meant with have you tried a different source is, do you have another CD player or tuner you can use to feed some sound to the amp?
What I meant with have you tried a different source is, do you have another CD player or tuner you can use to feed some sound to the amp?
All those voltages look fine. Its likely there is nothing wrong with your amp, assuming the output tubes are new or known good, and your speakers are good.
A few people have had problems driving this amp with an ipod or a DAC. The reason is that ipods and DACS often don't put out enough voltage or current to drive the amp properly. It is not a fault of the amp design, it works fine with a standard line level input such as that from a tuner or CD player. I also run music from my PC through a DAC into a SPP amp, but use a line level preamp before the amp, no matter what amp I am running at that time. And from my wife's PC, the output of the soundcard is boosted before being fed to any amplifier. My guess is this is your problem. Do you have a DVD player or CD player to play some audio into the SPP to test this?
A few people have had problems driving this amp with an ipod or a DAC. The reason is that ipods and DACS often don't put out enough voltage or current to drive the amp properly. It is not a fault of the amp design, it works fine with a standard line level input such as that from a tuner or CD player. I also run music from my PC through a DAC into a SPP amp, but use a line level preamp before the amp, no matter what amp I am running at that time. And from my wife's PC, the output of the soundcard is boosted before being fed to any amplifier. My guess is this is your problem. Do you have a DVD player or CD player to play some audio into the SPP to test this?
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If you want to check the output section of the amp, you could measure pins 2 and 3 of each EL84 output tube, with all the tubes in place. You would expect to get 0V at pin 2, and around 11V DC at pin3.
Then, with the output tubes still in place, measure the voltages at L-PRI_1-2, L-PRI_1-3, L-PRI_2-2, L-PRI_2-1 and same for the right-hand channel, expect around 310 to 330V DC. You should be able to put the red probe on top of the screw of each terminal block to measure these voltages. Be careful.
Then, with the output tubes still in place, measure the voltages at L-PRI_1-2, L-PRI_1-3, L-PRI_2-2, L-PRI_2-1 and same for the right-hand channel, expect around 310 to 330V DC. You should be able to put the red probe on top of the screw of each terminal block to measure these voltages. Be careful.
i check those oput tube and terminals they same to be fine.I'll order the resistors and replace them. I hope it'll fix the problem. thanks for yoir help
nate
I was just referring to the diode configuration. He shows exactly what to use and how to place them.
It sounds like you might have a short somewhere past R1. R1 is pushed pretty hard in this design. Mine gets toasty and is a little burned-looking. That's because it's dissipating over 5W. It's probably time to take some measurements of B+ at various points, such as before and after R1 and, the OPTs, at the input plate resistors, and also the plates of the output tubes.
It sounds like you might have a short somewhere past R1. R1 is pushed pretty hard in this design. Mine gets toasty and is a little burned-looking. That's because it's dissipating over 5W. It's probably time to take some measurements of B+ at various points, such as before and after R1 and, the OPTs, at the input plate resistors, and also the plates of the output tubes.
You need to learn how to measure AC and DC voltages. B+ 366V is way too hot, yet you said, voltages fine, when I said 310 to 330V.