My SHO clone is to dark sounding. Any ideas whats gone wrong?

[zambo]

its a new build with irf510 from ratshak. plenty loud just sounds like my guitar tone knob is rolled off. ( ichecked that. its not...  )

[Toney]

 Check all cap and resistor values, check pot wiring and layout for soldering
SHO is a bright sounding boost but very few parts, if you have it running there are only a few possibilities.

[darron]

Check all cap and resistor values, check pot wiring and layout for soldering
SHO is a bright sounding boost but very few parts, if you have it running there are only a few possibilities.

going from this schematic it doesn't look like it could be a cap issue:

http://analogguru.an.ohost.de/193/schematics/Zvex_SHO.gif

both the caps should let full bass response through so if the values were wrong it would only make the tone thinner, not darker.

there's no high bleed off caps either.

i can't imagine any of those resistor values making the tone dark also...




something else? but yeah, like Toney said check wiring/soldering. Something's not doing what it should.

[zambo]

i am a little dense sometimes so here goes. I used clips for the caps so I could swap between bigger and smaller to attenuate bass response. Would the less then soldered connection make it darker by adding capacitance or just being a crappy conection or something?

[Toney]

 
If the connection is solid not likely. Is the out put level normal? Full boost range?

[zambo]

i think so. never built one but its slamming the input pretty dang good. just kind of dark. I will solder in the caps and report back if that fixes it
.

[LucifersTrip]

...you first need to compare the transistor voltages to ones from a working SHO.

there was a thread earlier where I posted the voltages of mine, but can't quickly find it now....


edit:
just noticed this after I posted. your SHO's probably cursed so probably best to incinerate it fast. "dark sounding" makes perfect sense now.

[darron]

where the capacitors are only used for coupling, they will conduct or not. even if they had some sort of dodgy connection that only passed SOME sound, it would be the higher frequencies that came through loudest. not the lower darker sounds. sometimes 1 in 100 i get this with a bad 3pdt switch where the signal is just getting through on minimal capacitance and not making good continuity.


ermm... maybe some photos? or...? like you said, it's passing a solid signal and not gating or anything so there's no point in telling you to check the pinout i guess? tried another tranny? just pulling at strings now.


do a proper "debug" report i guess with voltages first.

[LucifersTrip]

Here're the voltages of my working one

GDS

Power: 9.59v
Min: 2.82,  7.36, 2.48
Max: 1.49, 2.98, .13

[davent]

All else being equal, would the choice of Mosfet be a factor? I've only ever used the BS170 or 2N7000 and never had issue with multiple samples of either of those.

[zambo]

Thanks guys. After doing a little voodoo and soldering the caps in instead of clipping them in it seems to be fine. I also put the first two resistors at 10M instead of 1M to brighten it up. It really does have a lot of boost! Thanks again for the help. Will post the pedal when im done!