Adding a booster circuit inside a Boss DS1

[Xavier]

Since I'm using a Boss DS1 with an LPB1 boosting it, I actually attempted building it inside the DS1, basically inserting it right before C2.

If I plug the guitar into the LPB1 and then into the DS1 it sounds good.

But if I insert the LPB1 inside the DS1 as described, it sounds terrible. Not sure if it's an impedance issue or C2 is not the best location.

Would anyone have any suggestion ? I might try with a TS in case it fits.....

[GibsonGM]

Hi Xavier, can you post a schematic?

[Xavier]

https://goo.gl/images/JgVB2W

[GibsonGM]

Can you simply use it in front of the DS-1, from its input jack, just as if if was a separate pedal?  There are a couple of things going on at C2 that may be interacting with the LPB, I think.

[thermionix]

To bypass the LPB-1 together with the DS1, wouldn't you have to go in at C3?  But like Mike says, won't sound the same as going in at R1.  Maybe convert to TB?  I haven't tried to do that with a Boss pedal, might not be so easy.

[Xavier]

Damn you're right. C3 should be the right location..... I will try again then...

[GibsonGM]

Between Q6 and C3 may work.  You will need to keep the 1M pulldown resistor there.   Make sure no DC can 'escape' from the LPB...you will need coupling caps to prevent bias voltage from affecting the other stuff there. 

[Steben]

Do you want to use them together all the time? Modding the ds-1 might be a solution.
You can modify the first stage to LPB-1 style and make the opamp stage higher gain.

[Xavier]

Thanks all for your replies !

I tried C3 right after the pulldown resistor and it sounded better but not much....

OK let me try to explain what I want to achieve.

I am using the DS1 as a stand alone distortion for classic metal, over a clean channel, so I already did a few mods to it , mainly to:

- Reduce the pre-clipping gain as it sounds way too congested for me with humbuckers, therefore R7 goes from 470K to 180K.
- Clipping diodes changed to a pair of LED's so it sounds a bit more open
- R13 from 4K7 to 1K to raise the clipping gain to compensate for the pregain loss
- (most important to me), C3 from 0.047 to 0.022 in order to have much tighter palm mutes (this also kills the little fuzz in the DS1)
- And last one, C10 from 0.01 to 0.022 to tame the high end.

So now I have the DS1 where I want soundwise, but it's still a pretty raw distortion and it lacks that "liquidness" for soloing, which I only able seem to be able to achieve when I boost it with another device like your ordinary tubescreamer or an LPB1. Since I seem to be using it like this most of the time, I wanted to built it in so I have only one pedal.

These were the options

- LPB1, since it's a small circuit and fits in right away. But for whatever reason (impedance?), doesn't sound the same when I insert it between Q6 and C3 as if I use it externally

- I was looking for something like a "one knob tube screamer" with your usual maxxed volume / low gain setting. I believe Mark Hammer designed a circuit called "The crank" for this. This would be actually my preferred option. So a circuit that cuts lows and highs and adds some grit. I like mids

Ideally, I guess the best would be modding the pre clipping booster stage around Q2 to do this, but I am a bit lost

Many thanks for your help in advance ! My knowledge of electronics is very poor, I am just a tweaker (thanks to this forum )

[Steben]

Do you want it switchable inside the same DS-1 enclosure?

I'll try to use intuitive words.
If you add a boost before Q2, chances are high, you'ld drive mainly this transistor into higher saturation, rather getting "mushier" than "creamier". If you change the gain of the opamp, you'll have a "more of the same" tone with more sustain. A possible "creamy high gain boost" might be a switchable parralel  R + C  trace next to R13/C8 with more gain and higher freq treble boost.

I see you made more of a high pass change to Q2 stage AND did the same in the opamp stage changing the 3db freq point from 72Hz to 338Hz [f ~= 1/(R*C*2*3.14)]. You might lower C8 or R13 even more to get into tube screamer or marshall territory.

[Xavier]

Thanks for your replies Steben !.

No I don't need it switchable.

Most of what I did was to reduce the pre-gain bass to avoid the mushy tone ,but I am missing the additional "compression" and "easiness" that a pre booster adds to the equation.

I'll keep on testing different options see what I get