Could anybody enlighten me on ways to lower gain?
I've built a hybrid power amplifier with a Korg B1 pre and a Bottlehead quicksand amp. There's no potentiometer. Rather I have a voltage divider at the input. If I understand correctly, maybe I could lower gain by changing the values to attenuate the input signal further? The Quicksand is 20dB, that already is the lowest setting according to TPA3122 schematic. Then the Korg B1 has 16dB. I'd rather not lower that. Otherwise what's the point? I would be reducing the tube effect and it serves little purpose then.
So that's a total of 36dB. I am wondering if there's something I can do at the speaker posts. Ideally, something that would solve turn on and turn off thump too.
I've built a hybrid power amplifier with a Korg B1 pre and a Bottlehead quicksand amp. There's no potentiometer. Rather I have a voltage divider at the input. If I understand correctly, maybe I could lower gain by changing the values to attenuate the input signal further? The Quicksand is 20dB, that already is the lowest setting according to TPA3122 schematic. Then the Korg B1 has 16dB. I'd rather not lower that. Otherwise what's the point? I would be reducing the tube effect and it serves little purpose then.
So that's a total of 36dB. I am wondering if there's something I can do at the speaker posts. Ideally, something that would solve turn on and turn off thump too.
Turn ON thump is better reduced by delaying the time when the output is connected, usually with a relay.
The same relay can also disconnect the output before the rails collapse by monitoring the AC feed to the power supply.
Reducing the gain can be achieved by increasing the feedback if you know what you are doing but this may change the character of the amplifier. It is often better just to attenuate the input as you mentioned.
The same relay can also disconnect the output before the rails collapse by monitoring the AC feed to the power supply.
Reducing the gain can be achieved by increasing the feedback if you know what you are doing but this may change the character of the amplifier. It is often better just to attenuate the input as you mentioned.
What about one of these from eBay ‘HI-END DACT Type SMD Stepped Attenuator 21 step volume control 10K 20K 50K-250K’. I’ve got a similar one in my 3255 and ordered one of these to replace it as my one doesn’t turn the volume all the way down. What makes them perform so well is that the signal only ever goes through a single resister. The green one on eBay looks identical to one used in a hi end passive preamp that had amazing reviews. I’m a noob to all this so I might be talking ****.
After some experimentation, I have found my voltage divider values weren't incorrect per se. I connected my digital source directly to the amp and the levels are perfect. I think this is what I used when determining my values originally. The problem occurs when my Schiit Modi is involved. The Modi is bumping up the noise floor by, at least, 1/3 volume when in use; this compares the Modi to a laptop audio out (same source).