How would I increase output volume of this?

[steveyraff]

Hey all,

Another silly question which I am sure the more experienced members can help me out with. This circuits output seems to vary depending on not only the Volume control setting, but also the Fuzz and Blend setting.

What would be the best thing to experiment with for more over-all volume? I'd like unity gain to be found a lower settings in general. There seems to be a bit of a volume drop in general when the pedal is engaged.

Thanks!

[antonis]

You don't want us to trace the board to draw a schematic, do you.. 

[steveyraff]

You don't want us to trace the board to draw a schematic, do you.. 

Nope - of course not. That would be ridiculous. I thought others may be able to easily spot an output cap that can be changed, or a potentiometer value to try swapping with.

[antonis]

I thought others may be able to easily spot an output cap that can be changed, or a potentiometer value to try swapping with.

Others might have sharper eye than me and tell us that there is a single output cap which can alter signal level without altering tone or a pot which is set just in series with output but I can't see anything like that..

Output is taken from middle lug of Blend pot, which pot uper lug is fed from 2N3391 Emitter follower (also fed Fuzz Vol pot upper lug) and lower lug is fed from Fuzz Vol pot middle lug and so on..

To make any recomendation we need a schematic..
(at least, I do..)

[steveyraff]

I thought others may be able to easily spot an output cap that can be changed, or a potentiometer value to try swapping with.

To make any recomendation we need a schematic..
(at least, I do..)

Me too. Unfortunately, I do not have one. 

[MrStab]

Hi Steve,

as there's the whole blend thing going on, if you want to increase the overall volume without affecting the response of the rest of the circuit, all i can think of is a small amplifier stage added to the output. increasing the gain on the very bottom-left JFET at the bottom could affect what you like about the circuit or risk unwanted clipping and oscillation, whilst upping the one right next to that could unbalance the wet-dry, er, balance. If you don't ever use the Gain control maxxed, maybe you do have some leeway here, though.

i don't think it's healthy to have a naked blend pot on the output anyway, tbh. could cause all sorts of interactions further downstream. there would be a noise penalty for boosting the output, but the alternative is boosting the input with the aforementioned clipping & oscillation risks.

edit: just occurred to me that those FETs are acting as source-followers, so may take more surgery to get em to actually amplify beyond a gain of 1. would probably just be easier to stick an amplifier before all that. kudos to this person for making a layout with all-flat resistors, btw! nice and compact, too!

[steveyraff]

Hi Steve,

as there's the whole blend thing going on, if you want to increase the overall volume without affecting the response of the rest of the circuit, all i can think of is a small amplifier stage added to the output. increasing the gain on the very bottom-left JFET at the bottom could affect what you like about the circuit or risk unwanted clipping and oscillation, whilst upping the one right next to that could unbalance the wet-dry, er, balance. If you don't ever use the Gain control maxxed, maybe you do have some leeway here, though.

i don't think it's healthy to have a naked blend pot on the output anyway, tbh. could cause all sorts of interactions further downstream. there would be a noise penalty for boosting the output, but the alternative is boosting the input with the aforementioned clipping & oscillation risks.

http://tagboardeffects.blogspot.co.uk/2014/03/moosapotamus-acoustic-360-bass-fuzz.html
Thanks. I wonder would this alternative circuit be an improvement. I notice the output is not coming from the blend pot on this. Hmm, I might try it and compare the two. I am skeptical as to if they both sound similar due to different trans, but I am sure it should be pretty close.

Thanks for the help.

[Mark Hammer]

Q10 is a gain recovery stage.  Do whatever is required to increase the gain of that stage, such that the attenuation of its output cvan still achieve bypass level at low settings.

[MrStab]

i came across the schem Mark just posted, scratched my head a bit, and realised the original stripboard layout has had input buffers added for the clean blend purpose. you can probably get away with just increasing the fuzz recovery gain and not the clean signal. i'd still put at least a buffer on the output of that blend pot, though, or maybe even an inverting mixer with 2 volume pots (or a dual-gang pot wired like blend pots in guitars).

does cutting the Blend 3 wire have any major affect on volume btw? sorry if you end up cutting it for nothing! lol