Glitterati/BB preamp more low end and more gradual gain control

[gitaar0]

This is a very nice sounding pedal.

I would like to ad more low end to the Glitterati/BBpreamp. Only adjusting the input cap is not enough. Any suggestions?

I would also like to change the gain control. As it is it goes from clean to quit a fair amount of gain. Would it be possible to make that more gradually?

Thanks, Marc

[oldhousescott]

Change the gain pot to a 1M audio taper. That should bring the gain up more gradually in the first bit of rotation. You could change the volume pot to an audio taper as well if the volume is coming up too quickly.

Can you not get the amount of bass you desire by cranking up the bass control? Have you double-checked all the component values in the tone network? You should get plenty of both boost and cut with those controls. If you add to too much bass too early in the circuit, it'll start to sound flubby and splatty. If you want to try something though, increasing the value of C4 will get you more bottom. Try 68n or 100n or even higher.

[gitaar0]

The audio taper did help to make it more smoothly. Maybe even too much now


I can dial in that low end but only when I crank up the bass almost too the end.

I tried changing C4 to 100n (did not have 68n) but it did not give me the same low end that I have in bypass.
This pedal really can give a very nice clean sound as well and having that bit of extra low end would be nice.

I tried changing R9 (to 2k2) as well in changing C4  but not the right result yet.

any other ideas?

Marc

[oldhousescott]

You can also increase C8. Try 220n or 470n. That should help get back the very bottom of the frequency response. If that still doesn't get you there, you could replace C9 with a combination of a 47k resistor and a 22n cap in series. That will give you an apparent boost of 6dB below 150Hz, but will also cut your overall output by 6dB so you will have to crank the output higher to match the same levels as before.

[gitaar0]

You can also increase C8. Try 220n or 470n. That should help get back the very bottom of the frequency response. If that still doesn't get you there, you could replace C9 with a combination of a 47k resistor and a 22n cap in series. That will give you an apparent boost of 6dB below 150Hz, but will also cut your overall output by 6dB so you will have to crank the output higher to match the same levels as before.

I increased C8 to 470 which helped.

Now I have C1 47n, C4 at 68n and C8 at 470n. Gain is 1Ma.
I am almost back at the same frequency range as in bypass.
I still have to experiment a bit on the effect of this on the overdrive sound, but as it is now I can change from clean to overdrive very well.

Thanks for helping.

Marc