5600p on vol I

[VelvetGeorge]

I'm all for the switchable bright cap! It makes the 12 series so much more versatile. Not to mention fantastic for pedals with the cap out.
My old amp has 5,000pf ceramic and it does get really bright at lower volume settings. I usually have to back off the presence to compensate.

Keep in mind that as you raise the bright cap value you are allowing more frequencies to pass unattenuated. So the 5,000 is passing lots of mids also. Making the volume control basically an ajustable high pass filter.
The corner frequency is determined by the cap value and R of the volume pot setting.

It's interesting that you can hear the cap when the pot is dimed. In theory you shouldn't. But the cap adds another path, especially for high freqs, through that part of the circuit.

Another cool trick to mellow out harsh bright caps is to add a resistor in series. Try something in the 47k to 470k range.

George

[rgalpin]

My old amp has 5,000pf ceramic and it does get really bright at lower volume settings. I usually have to back off the presence to compensate.

Another cool trick to mellow out harsh bright caps is to add a resistor in series. Try something in the 47k to 470k range.

George

Thanks George - I'll try that resistor in series. I suppose that resists some of the highs that are passing without changing the corner fq. Cool. I cheat by lowering the highs on my Weber Mass 150 when it gets too much at the lower settings - nice to have all those variables to work with.

[Strat78]

The 5600p looked absurd to me till I realized that that was what I had in my amp which is sounding so good these days. Having the volume pot act like a "high pas filter" and gain control has been nice. Try the 2.7k at V1B as another angle of attack to work with the 5600p, it retains the diamond in the rough quality while polishing the highs.

[SteadyEddie]

The 5600p looked absurd to me till I realized that that was what I had in my amp which is sounding so good these days. Having the volume pot act like a "high pas filter" and gain control has been nice. Try the 2.7k at V1B as another angle of attack to work with the 5600p, it retains the diamond in the rough quality while polishing the highs.

2.7k cathode resistor? I was thinking of trying that myself. Should tighten up the sound.