Help with Boss OC-2 volume boost mod

[bassleigh]

Hey guys

I'm new to the diy pedal game and need some help modding a Boss OC-2 octave pedal. I have already modded the power supply to psa with success. I have noticed the 100% wet -1 octave (no dry signal) is lower in volume compared to the bypassed bass guitar tone and it makes the pedal quite unusable in a live situation. Can anyone help me with information on how to mod the pedal to remedy this problem? A global volume boost would be fine with each octave having a separate volume control. 

Cheers
Leigh

[Rob Strand]

Least intrusive method:

                                   Boost
         Normal      +1.7dB   +3.2dB
R43   27k              33k       39k
R49   100k            150k     270k

Note: boosting oct 1 will boost oct 2 as well         

Forgot to mention,  the oct1 output doesn't produce much output above 300Hz that means the perceived level difference between the wet and the oct 1 output is strongly dependent on the bass response of the speakers.

[bassleigh]

Thanks Rob

Shall give it a try   I'm aware of the perceived volume issue which is very apparent when using the -2octave (as to be expected). The 100% wet -1octave is too quiet even when playing quite high up the neck, seems to be a reasonably common problem with other users.

Is there a chance the mod will change the tonality of the effect?

Cheers
Leigh  

[Skrogh]

You are more likely to clip the signal (overdrive it). You are boosting the signal in the flip-flop stage, my experience with the oc-2 is that it easily clips here (On my active bass I have to turn down the volume, if i play on the E string) Since the clipping is only noticeable on oct-1 and oct-2, but not dry I assume it is in the clipping stage.

It is possible to modify the circuit to boost in the filter section, but this would require a lot of parts to be changed.

[Rob Strand]

@bassleigh
> Is there a chance the mod will change the tonality of the effect?
I have tried to keep the same behavior of the stage and just increase the stage gain.
I can't guarantee it is *exactly* the same without A/B testing.

@Skrogh
Actually I had problems with the OC-2 clipping on Bass too.  I found that in effect mode the *dry signal clipped* so I increased the value of R6 from 2k7 to 3k9 (about a 2.4dB overall drop).  I don't recall any clipping on oct1 and oct2.  Also I'd expect the filters should hide small amounts of clipping.

The bottom line is you just have to try it.  The next step would be to reduce the gain of the input stage and replace the passive mixing stage with an active mixing stage - that's going to a far more intrusive mod.