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In the Forum: Melquiades Amplifier
In the Thread: Planning my DSET
Post Subject: Play It Again, SamPosted by Romy the Cat on: 7/26/2020
Anthony, I would recommend
you go other direction. I very much assure that with over 7V on fist stage bias
the channel is dead, it should be around 4V. Let see how to fix it. I would certainly do not change neither 12.1kR
resistor nor 402k resistor. Both of them form loading impedance for the filter
and it you change it then you need to move the value of the cap to ground (it forms
subtracting low-pass filter at 500Hz). It is not a big deal to do and it might
be that you want to move the crossover pose to one or another direction. It is your
room and your sound, you can do whatever you want. Still, remembering how much
time and efforts I spent to find the configuration that I published I would recommend
you to try it once as is and then move to whatever configuration works in your
room and for your ears. So, instead to changing the values let think why you
have wrong voltages if the PS voltages are as they should be. I am sure that
you tried to change the tube but I think it is not the case. I think you out in
there a wrong resistor accidently. It is easy to confuse them, and particularly
is you use my Dales who mark the values by a position of a dot. If instead of 402k
resistor you put in there 40.2k resistor then you will end up with what you
have. If you do not want to take the resistors out and to measure them you can measure
the resistance by measuring the voltage drop before and after resistor. I am sure
that wrong resistor in bias cha is the problem. Even if you do have access to
the resistor and can read the proper value on it then take it out and measure,
it might be faulty.Rerurn to Romy the Cat's Site