I posted some thoughts and photos on this amp on show and tell page. Overall pleased but, as I mentioned in that post, the gain is way to high for my source. Looking for suggestions to tame it.
The amp is a 300B design. The first section is a single 12AX7 split between channels feeding a pair of 12AU7s paralleled to each channel. My source is a Denafrips DAC with RCA output at 2.0Vrms, 625 Ω
1. Lower gain tube in V1. I tried a 5751 (which has 30% less gain than the 12AX7) in the front. Their was an almost indiscernible decrease in level. I also tried an 12AT7 with similar results but a slight loss of quality. No help.
2. Any thoughts on changing out resistors or caps to lower voltage/gain in pre section while keeping tubes in designed operating parameter?
Don’t know if it helps. Here’s the spec idle voltages from schematics: 12AX7: Cathode: 0.8V. Anode: 110V. Grid: ?? 12AU7: Cathode 8.7V. Anode 175V, Grid 0V. 300B: cathode???, anode 360V, grid -70V
3. Voltage divider in front of volume pot. Looking at something similar to Goldpoint website. They have tables with VERY specific values based on pot impedance. Is there a reason for this? If I step outside of these values will there be impedance matching issue? These are not common values and I do not want a gaggle of resistors. Any recommendations for about a 12 dB decrease? Current pot is 50 Kohm. Source output is RCA at 2.0Vrms, 625 Ω