Blackstar HT-5R Mods to overdrive channel

[eschertron]

In the feedback loop there are 2 diodes in series with a 100R resistor. Can I reduce the amount of distortion produced by the 2 diodes by changing the resistor to a higher value?

Also, replacing one of the anti-parallel diodes with an LED might give you an asymmetric clipping that sounds more 'overdrive-y'. If the diodes and the resistor that you mentioned are the heart of the distortion circuit, then experiment away! You may find just what you're looking for.

If that would work, I could temporarily connect a, say 100k pot across the 100R resistor and adjust till I find the sweet spot. Then I can work out the required resistance by measuring the resistance of the value achieved by the pot including the 100R in parallel. That's how easy I want it to be.....he said wryly.

Any value pot across (in parallel with) the 100R resistor will only reduce the effective resistance. lift one leg and put the pot in series, if that hasn't already been mentioned

[BuzzardPie]

hi, thanks for reply.
With the overdrive channel gain on 0, no signal comes thru, even with the overdrive channel level at max. When you just crack the gain control up the distortion is too much. It's an overdrive channel, and should behave like one, but it's just behaving like an almost full-on distortion channel. If you look at the gain stage schematic in jazz p bass's post above, you can see the distortion circuit around ic3a which is a tl 072 op-amp. In the feedback loop there are 2 diodes in series with a 100r resistor. Can i reduce the amount of distortion produced by the 2 diodes by changing the resistor to a higher value?
If that would work, i could temporarily connect a, say 100k pot across the 100r resistor and adjust till i find the sweet spot. Then i can work out the required resistance by measuring the resistance of the value achieved by the pot including the 100r in parallel. That's how easy i want it to be.....he said wryly.

turn down your guitar volume.