I mentioned the input resistors in case you'd want to double check them with your multimeter just to ensure they
are the correct values.
If you have another 12AT7 tube try switching them.
Check your volume pot wiring. If you can get another volume pot even a cheaper one, install it to see if it fixes the problem.
are the correct values.
If you have another 12AT7 tube try switching them.
Check your volume pot wiring. If you can get another volume pot even a cheaper one, install it to see if it fixes the problem.
Can someone please tell me a switch manufacturers' name and and part number that can be used to build this?
Not that I'm going to try to do this on my SSE build...I would just like to incorporate this into a future amp possibly
Thanks...Blake
Not that I'm going to try to do this on my SSE build...I would just like to incorporate this into a future amp possibly
Thanks...Blake
YES, but......
I have seen two different implementations of switched cathode resistors.
One used a switch and separate 5 watt resistors with none installed in the board. This will work, but I DO NOT recommend this. There will be a momentary interruption of current when turning the switch which WILL make a big noise in the speakers, and will cause the output tube to try and get its current through the cathode bypass cap, possibly leading to an ugly mess of cap goo!
The method shown by Russ in post #2 of this thread works best and is what I had in my amp. In that case any generic non shorting (break before make) switch should work fine. It only eats 50 volts or so at under 100 mA. His resistor values should be fine, but I no longer have my big SSE amp, so I can't see what's in it.
Thanks! Just what I was hoping to hear.
Once I get my SSE up and running, I may want to add this feature as in post #2. Still in the process of gathering parts as I wait for transformers to arrive (early May?). Will add these components to the BOM just in case 😛
Once I get my SSE up and running, I may want to add this feature as in post #2. Still in the process of gathering parts as I wait for transformers to arrive (early May?). Will add these components to the BOM just in case 😛
One more question, hopefully...
In post #2 Russ seems to have all 10 select-able resistors soldered to a single black wire, which I presume is ground. Where did the other end of this wire terminate?
Did it terminate directly to the chassis somewhere, at just one of the two ground pins of R17 or R27, or across both ground pins of R17 and R27 (seems unlikely)?
If I hadn't noticed this, I would likely have thought to run separate wires for each channel. So a total of four additional connections; two each to pins R17 and R27.
In post #2 Russ seems to have all 10 select-able resistors soldered to a single black wire, which I presume is ground. Where did the other end of this wire terminate?
Did it terminate directly to the chassis somewhere, at just one of the two ground pins of R17 or R27, or across both ground pins of R17 and R27 (seems unlikely)?
If I hadn't noticed this, I would likely have thought to run separate wires for each channel. So a total of four additional connections; two each to pins R17 and R27.
In theory two separate ground wires are the best option. In practice the mili dB's of channel separation lost by running a single ground wire will not be noticed.
Connect two ground wires to the ground end of the appropriate cathode resistor.
Connect a single ground wire to the ground end of the most convenient cathode resistor, or to the negative end of the filter caps, since that's the star ground point on the board.
Connect two ground wires to the ground end of the appropriate cathode resistor.
Connect a single ground wire to the ground end of the most convenient cathode resistor, or to the negative end of the filter caps, since that's the star ground point on the board.
I honestly don't remember where I hooked it up exactly, but I vaguely remember adding one of those small terminal posts somewhere on the board. It was probably near the star ground point.
Russ
Russ
- Status
- Not open for further replies.