Treble Boost

[Polar Bear]

Hey folks, our good man Rocky has built me a Top Boost treble booster. Lovely sounding pedal, however compared with the Treble Booster that's housed in my Vox Brian May Special it's lacking a whole heap of gain. Rocky has been back and forward with me with this pedal trying to sort it for me, and has done a stellar job, but we've now hit a bit of a wall. Here's a link to the project that was used. Looking at this, is there an obvious way to get more boost from the little beast?

http://www.tonepad.com/project.asp?id=40

[rocklander]

just as an FYI. I changed the 10K trim pot for 20K... hasn't had the desired effect

[ash]

Find a transistor with a higher hfe (gain).

Also find a schematic of the Vox to be sure that it really is the same circuit and not a "special" edition.

[NZRS_Matt]

Modern treble boosts begin and end with the Analogman Beano Boost IMHO. It's AWESOME!!!!!

[borge]

decrease the emitter resistor (R6).

Whats the voltage at the collector? probably easiest to test at lug 3 of the pot.

[rocklander]

I tried a bunch of xistors in there ash, but not measured.. just tried different ones and the 2n5087 had the most gain audibly)
can ya recommend an alternative?

just occurred to me PB.. we could have tried the may queen?
http://www.runoffgroove.com/mayqueen.html
(audio clips are there)
it has a jfet (the j201) in for more of a boost... looks pretty simple to bang together


and Matt.."how do I get more gain from this pedal?" "get a different pedal".. really..? ..really?

[Gelato]

and Matt.."how do I get more gain from this pedal?" "get a different pedal".. really..? ..really?

That Matt, always trying to pedal his wares. Yeah, I'll get my coat

[rocklander]

decrease the emitter resistor (R6).

Whats the voltage at the collector? probably easiest to test at lug 3 of the pot.

thanks borge.. I have another of the same board here so can measure that up.
wont be able to till tomorrow though..

[borge]

and Matt.."how do I get more gain from this pedal?" "get a different pedal".. really..? ..really?

Well the beano boost is just a few values changes and a switch away from what you have so it could be helpful

[Polar Bear]

I tried a bunch of xistors in there ash, but not measured.. just tried different ones and the 2n5087 had the most gain audibly)
can ya recommend an alternative?

just occurred to me PB.. we could have tried the may queen?
http://www.runoffgroove.com/mayqueen.html
(audio clips are there)
it has a jfet (the j201) in for more of a boost... looks pretty simple to bang together


and Matt.."how do I get more gain from this pedal?" "get a different pedal".. really..? ..really?

We sure could have, still only has the 10k trim pot too. Interesting.

[NZRS_Matt]

and Matt.."how do I get more gain from this pedal?" "get a different pedal".. really..? ..really?

LOL - just me showing my complete non-understanding of the internal works of a pedal.

"Doesn't sound right?, buy a new one" sounds like my life indeed.....

[BG]

I think I have dibs on your SLO, for when you decide it just doesn't sound right

[alf]

I tried a bunch of xistors in there ash, but not measured.. just tried different ones and the 2n5087 had the most gain audibly)
can ya recommend an alternative?

I ended up using an AC128(?) xistor in the one I built which had noticeably more gain than whatever the ones I got from jaycar were (5087 substitute) - freely admit to not really knowing much about how this all works though.

Also, changing the cap at C2 moves the boost frequency around which might be worth playing with (I added a toggle switch to change between 2 values) - smaller value gives more treble

[rocklander]

the ac128 might be the go cos that's what the rangemaster had I think.. defo a Ge xistor rather than Si.. but (and I'm no expert) aren't the Ge ones somewhat more prone to wilder variances? .. as in a Ge could be heaps more gainy, or heaps less? not sure. Easy swap for PB though cos it's a socketed xistor there right now.

[alf]

Yeah, the Ge ones seem to be the dogs knob judging by the comments on the tonepad site - I happened to have an AC128 lying around in a box of bits and just whacked it in to try. Mind you, at bedroom volumes the difference isn't that noticeable to be fair