Treble cap/caps and mid boost question

[Tdale]

Do you guys use two caps for the treble pot, with the mid boost switch bypassing one of them? Or do you just use a 500 pF cap?

If I want the mid boost, what values should I go for, for the two caps?


Tommy

[Darkbluemurder]

I use a 330pf in normal mode and bypass it with an 820pf as a treble shift/mid boost.

[Tdale]

Do you wire them in parallell?

[Bob-I]

I played quite a bit with this ckt and in a moment of brain damage, paralleled a .005uF with the 330pF. It lowered the freqency of the treble control to below the mid's range, and added a ton of gain. I love it and I use it almost all the time with the ODS side.

[llemtt]

The original circuit claims for a 2000pf in series with a 390pf, you bypass the latter with a front panel switch to engage mid-boost but this is a very huge boost, many find it not so useful.

teo

[Tdale]

OK. I'll experiment with values I think.

I'm also thinking about making the mid caps switchable, between a 0.01 and a 0.047.

Tommy

[Darkbluemurder]

Do you wire them in parallell?

Yes, that makes it 1150pf in boost mode. I may try the series combination. The advantage is that if you pass the second cap in series you should not have any DC on the switch contacts (unless the first cap in series gets leaky).

[Tdale]

if you put a 500pF and a 100pF in series....do you calculate the total value the same way you do with resistors in paralell?

EDIT: Yes..a quick google search helped me with that.

tommy

[Bob-I]

The advantage is that if you pass the second cap in series you should not have any DC on the switch contacts (unless the first cap in series gets leaky).

There's no DC on the parallel caps, you simply switch on the non-DC side only.