BSIAB bass cut

[MmmPedals]

Recently boxed up a BSIAB from here http://gaussmarkov.net/layouts/bsiab2/bsiab2-project.pdf
I left it stock. I have the resistor for the contour mod socketed  because i considered it but i liked it just the way it is. Great sounding pedal and very responsive. But the low end is just way to big for me. How would you suggest i cut the base. I am thinking to lower c8. what would you suggest? it is all built so i want to minimize desoldering.

[paulyy]

Recently boxed up a BSIAB from here http://gaussmarkov.net/layouts/bsiab2/bsiab2-project.pdf
I left it stock. I have the resistor for the contour mod socketed  because i considered it but i liked it just the way it is. Great sounding pedal and very responsive. But the low end is just way to big for me. How would you suggest i cut the base. I am thinking to lower c8. what would you suggest? it is all built so i want to minimize desoldering.

Try lowering C4 (.068) to .056 or lower. This should cut some of the bass out. If i remember correctly. Removing the cap completely will turn it to a overdrive. Hope that helps.

[amptramp]

I think C8 would be the best place to do this.  Any low-frequency noise originating in earlier stages would be cut out by making the bandwidth reduction happen as late as possible in the signal chain.  120 Hz hum could be reduced although there are cases where the effect of power supply ripple in one stage may be mitigated by the opposite ripple in a subsequent stage, C8 would be the best place in this unit since there are two stages ahead of it.  But 60 Hz comes from outside of the unit, so it would be reduced.  The effect of changing C8 is easy to calculate.  The effect of C4 is somewhat different.  The "upper" transistor in the amplifier stages (Q1 and Q2) appear to be set up as quasi-current sources with a fixed value at high frequencies but with the capability to operate at variable bias at low frequencies once the gate is at a frequency where the gate does not follow the source.  It is difficult to predict what eh effect would be with the normal variation in JFET bias.