-=Germania=-
Headphoneus Supremus
- Joined
- Sep 25, 2005
- Posts
- 3,008
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- 12
Hey Smeggy,
I did find it pretty useful to add the cathode bypass caps, but something to decide how you want to "tune" the amp is to throw a pot place of the cathode resistor and play with what you like. For my personal amp, I used 470uf Panasonic with 20k ohm resistor because basically I had only 100uf Muse or 470uf Panasonics in resonable voltages and the muse wasn't large enough to get a really nice and full sound. With my PSU, it goves me breathing room. In the others I have built 220uf is plenty, but I bumped the cathode resistor up to 5k or 10k. IMO without upping the value of the cathode resistor the sound can get too bassy.
A small gain switch for the input is uber useful. I have mine so that I can choose between 100ohm and 100k ohm with the high gain meant more for extreme case and the 100k as my normal with 32ohm headphones and because I don't listen very loud (even still listening right around of the middle of the pot).
In a two channel though, 20-40k is probably more in line depending on user preferences.
My personal amp is not the same as the BOM and uses a a higher current PSU which is modded and also used much larger power caps on the circuit to account for this, so YMMV and all that.
I will say that using a nicer PSU that can supply ample current not results in better sound, but the tubes "burn" less hot and with a bit less light. The fets also heat less. could possibly result in longer tube life, but I don't know.
I did find it pretty useful to add the cathode bypass caps, but something to decide how you want to "tune" the amp is to throw a pot place of the cathode resistor and play with what you like. For my personal amp, I used 470uf Panasonic with 20k ohm resistor because basically I had only 100uf Muse or 470uf Panasonics in resonable voltages and the muse wasn't large enough to get a really nice and full sound. With my PSU, it goves me breathing room. In the others I have built 220uf is plenty, but I bumped the cathode resistor up to 5k or 10k. IMO without upping the value of the cathode resistor the sound can get too bassy.
A small gain switch for the input is uber useful. I have mine so that I can choose between 100ohm and 100k ohm with the high gain meant more for extreme case and the 100k as my normal with 32ohm headphones and because I don't listen very loud (even still listening right around of the middle of the pot).
In a two channel though, 20-40k is probably more in line depending on user preferences.
My personal amp is not the same as the BOM and uses a a higher current PSU which is modded and also used much larger power caps on the circuit to account for this, so YMMV and all that.
I will say that using a nicer PSU that can supply ample current not results in better sound, but the tubes "burn" less hot and with a bit less light. The fets also heat less. could possibly result in longer tube life, but I don't know.