Need more boost

[Kræn]

Hi.
Buddy of mine has a Carl Martin Hydra Boost. He'd like it to have a couple of extra dB's to boost. Is it doable to mod the pedal into do this? How? Only thing is, he want's it to remain clean. Imortant!

Thanks
Christian

[Mark Hammer]

It may be, but there are limits to how much clean boost you can have with 9v.  The Manual for the Hydra notes that " Performance and headroom can be improved by using 12 & 18V power supply".  So, whatever additional boost may be attainable, it may be wise to follow their power-supply advice.

Note that gain is always multiplicative.  So, if pedal A has a gain of 20, and pedal B has a gain of 3, the pair combined have a gain of 60.  What this means is that if your friend was able to add a simple clean boost circuit in the same chassis, or in a separate chassis, that gain would multiple with the existing 15db gain from the Hydra and get the overall boost he wants.

[Kræn]

So it would ok safe to try it with a 12v power supply?

[Mark Hammer]

Quite probably.  Most op-amps, and transistor circuits are quite happy to work from 12v, 15v, and sometimes 18v supplies.  They get *designed* to run from 9v because that's a standard battery size, and buying pairs of 9v batteries at a time can get expensive).  Increasing the supply voltage will not add more gain.  However, it will make more of the booster's potential gain clean, insetad of having, say, everything up to 3:00 clean and everything after that kind of gritty.

[Kræn]

Great! Thanks Mark

[Kræn]

Could I just change the 1K output resistor to a lower value?? If so, which value?

[Kræn]

bump

[Mark Hammer]

The picture isn't very legible, which probably explains the lack of response.  Is the 1k the last resistor in series?  If so, the answer to the question is likely "no".  The circuit shown (though *seen* is another thing, eh?) looks very Fuzz Face like.

[Kræn]

The picture isn't very legible, which probably explains the lack of response.  Is the 1k the last resistor in series?  If so, the answer to the question is likely "no".  The circuit shown (though *seen* is another thing, eh?) looks very Fuzz Face like.

Sorry about the pic. I have a larger pic. But photobucket automatically resized it to this scale. Anyone know a good place to upload pictures?

Christian

[Steben]

yes fuzz face indeed, but with added positive feedback from collector 2 to emitter 1.
Looks like medium-high input since there is no decoupling cap on emitter Q1. This lowers gain, but lifts up the input impedance. Silicon NPN and 1,5 kohms resistor? Lets say 300kohms input impedance. Not bad.

The positive feedback should increase gain I guess, but I don't know how much.

[squidsquad]

And also.....adding a Fetzer Valve from runoffgroove.com is another simple easy way to boost an anemic effect.  And the output cap can tweak the tone (bigger=more bass gets out).

[Kræn]

Here is a bigger schem.