Zvex SHO Master DIY

[jwri9790]

Is it possible to put a master pot on a SHO. I have a Twin Reverb RI and I want to use the SHO as an overdrive and a boost, but it just won't push the Twin into overdrive. Is there a DIY mod that I could do? I know there is the Super Duper, but I have the SHO now and I just thought it could be done.

[jamiefbolton]

so you're saying that turning the SHO all the way up won't overdrive the Twin? wow.
i don't think another pot will get you more out of the circuit. its pretty hot as it is. i'd suggest getting a transparent overdrive instead.

[jwri9790]

It will eventually make the Twin break up, but the volume is insane.

[phector2004]

Huh?

SHO isn't really an overdrive... it's a booster. It should be plenty "transparent" as it's only making your signal bigger...

What I would do, if I were you, is breadboard one to screw around with the values. I don't know if this is a big no-no, but maybe you can play with bypass capacitors (in parallel with the 5k pot). You'll get a bigger signal but the FET might start clipping or something.

EDIT: Yeah... Based on your last comment it's working just fine. I'd suggest earplugs  

And jamie B's right. If you want less volume, get an OD!

[HOTTUBES]

The SHO will add gain at around half way etc , and then as you continue it begins to add more gain !!
below half it stays pretty much clean , just strait volume boost !!
I love it infront of my Marshall !!

[jwri9790]

Could I add a pot on the input stage which would control the volume and gain level of the pedal alongside the crackle. So when I crank the crackle okay pot and put a master low the Twin has a nice subtle overdrive and reasonable volumes?

[phector2004]

Technically, yes, but I don't know if that'll get you what you're after.

For your amp to distort, you need to push it with a big signal.

The SHO is a booster, not an "overdrive"*. It turns your wimpy guitar signal into something much greater in amplitude causing the tubes in the amp to distort.
Wild analogy: accidentally dropping a bowling ball onto your foot versus an angry ex of yours hurling a bowling ball out of a 2nd storey window onto your foot. In which case will you need a visit to the hospital?

Now if you add a master volume pot to the SHO, it brings the signal back down to normal. Conversely, if you add an input pot, you'll be boosting a smaller signal back up to normal. So it won't be overdriving your tubes. You might get some light distortion from the MOSFET, but it's not doing what it's meant to do (and presumably the sound you're trying to get??)

That'd be like the furious woman strapping a parachute to her projectile... What's the point?



*I.e. Blues Driver, Tubescreamer, anything that adds "crunch"

[Ben N]

It will eventually make the Twin break up, but the volume is insane.

Probably not just the volume, but also, and especially, the highs.

Where you need a master volume (if anywhere) is in the Twin. Have you thought about an attenuator?

People have been complaining about this in Twins forever. But, hey--loud and clean is what a Twin is made for. The solution is either (a) get your distortion off-board with an overdrive, as suggested above, (b) an attenuator, or (c) a smaller amp. That's why Fender made Deluxes, Supers, etc. Trying to overdrive a Twin in any normal enclosed space is an activity incompatible with hearing retention, or, for that matter, with bandmates.

[Renegadrian]

I think nobody saw the easiest solution - to put a regular volume pot at the end of the ckt!!! simple mod, just try it and I think you'll be able to get what you want! (maybe you should remove the 100k res at the output)

[yeeshkul]

Guys what may have been the reason for not including the bypass cap across the gain pot? I can't find any apart from a little extra money ...

[StereoKills]

You could always check out Frequency Central's "Super Heated SHO/Red Dwarf Drive".

[Mich P]

I think give a try to something like a BOR that can give you gain and, (or) boost.
Mich P.

[DougH]

Why do people think that adding volume controls will increase distortion? 

If you think that, you don't understand basically how a booster works or how it creates distortion. It creates distortion by driving the amp into distortion. It may internally break up too when turned up past a certain point- but that's usually not very impressive on its own. It's all about driving the amp into distortion. If your amp is too loud when it is distorting, that's a separate issue. As Ben mentioned, your amp is what needs the master volume, not the pedal.

In all honesty, a Twin is the wrong tool for the job for doing this sort of thing. Twins are loud & clean by definition. You need a lower wattage tweed, marshall or vox or something with less headroom, if you want to do this at a sane volume level without using an attenuator.

[Renegadrian]

ehm maybe I misread the original question - I was thinking about the sho giving out distorted sound when pushed hard (and yes it gives distortion), but the volume is high, so a volume pot is a good choice to have it pushed hard all the way but with controllable volume. Obviously a pot won't give extra gain!

[DougH]

It does distort somewhat when turned up. But that in and of itself is not a big deal. It's not an overdrive. Boosters get their "distortion" sound by driving an amp, and in some cases that sound combined with internal distortion. My Rangemaster sounds beautiful, but in front of a clean high-headroom amp? Not that impressive.

If you want the same volume as bypass, use an overdrive. Or build a booster into an overdrive circuit. IOW, use a SHO/Rangemaster/etc as a first stage to drive another pedal stage into distortion. Lots of DIY examples of that sort of thing. And yeah, that's sort of what the Box of Rock does, in a way, as someone else implied. It's a SHO driving a multi-stage "mimicked amp" circuit.

[bipedal]

Does the OP just want more of a clipped signal tone coming out the SHO?  How about a pair of clipping diodes (red LEDs, perhaps?) at the end of the SHO?

[fpaul]

I agree with Doug.  I used a borrowed twin reverb a couple of times and could never get it to distort much at all.  Just got really LOUD.  Kind of frustrating. ThinK I was using a D+ at the time.  Great clean sound though.

[darron]

I think give a try to something like a BOR that can give you gain and, (or) boost.
Mich P.

Boost is gain... Now you are just confusing people...

[Hides-His-Eyes]

Why do people think that adding volume controls will increase distortion? 

If you think that, you don't understand basically how a booster works or how it creates distortion.

The SHO will absolutely clip brutally when driven hard. Zach makes an SHO with a master volume. Put four in a row and you get chugga chugga.