ha! hi ed, good to see you. good old days, right?
axeman, i actually had registered here last year but never posted. thanks for the invite!
yes, RG's article is good however dated and overworked. he researched it, posted it and moved on. a lot of things have been invented and discovered since he wrote it.
at gus smalley's urging, i delved into modeling wha circs in spice last year. we found , to our delight that the program predicts what the circuit will do very accurately. it has become a staple of my designing and building.
couple notes:
1.sharp peaks sound good. broad flat peaks make a boring wah.
2. inductor mh is not that big a deal ( can deal with mh by changing sweep cap ), inductor R is more critical to Q in actual use. 35 to 50 ohm is a nice target. you can add series R to a low R inductor, not so good to try and lower a high R inductor.
3. everything affects everything else. trying to tune a wah is like playing 5 games of chess at the same time. there is no free lunch, easy to move the sweep up or down but is very hard to widen it.
4. i like low gain trans better than high gains. my faves are 160 - 200 for Q1, 200 - 240 for Q2. simply altering gain of high gain trans by the normal biasing tricks has a different sound than low gain trans.
5.the old internet trick of using a .33 in place of one of the .22s going to the pot to simulate icar taper does not work in spice, and hasn't ever done anything i could discern in real life either. to get any kind of taper altering 'effect', the wiper cap needs to become 3 to five times larger than the other .22. at this point, other things get messed up ( see note #3 ).
6. pot taper is important not just for player feel but i think there is actually a tonal effect in how the cap to ground off inductor charges/discharges depending on the R going to either half of the pot at a given point in time. my theory is that 'fast' tapers may not ever get the cap fully charged as it goes by too quick.
Clyde Mccoy Wah Circuit Board
Moderators: VelvetGeorge, BUG
-
- New Member
- Posts: 8
- Joined: Mon Jul 23, 2012 10:58 am
- Just the numbers in order: 7
-
- New Member
- Posts: 8
- Joined: Mon Jul 23, 2012 10:58 am
- Just the numbers in order: 7
Re: Clyde Mccoy Wah Circuit Board
regarding # 3 above^
one of the major components to widening the sweep is all the parts in balance. it is a finicky filter.
this is what makes the boomerang so special. they have a really wide sweep when they have the correct pot in there. the engineers really knew what they were doing, and the gains of the trans had to be within 5-7% of spec in hfe to pull it off since they weren't trimmers to dial in each wah.
one of the major components to widening the sweep is all the parts in balance. it is a finicky filter.
this is what makes the boomerang so special. they have a really wide sweep when they have the correct pot in there. the engineers really knew what they were doing, and the gains of the trans had to be within 5-7% of spec in hfe to pull it off since they weren't trimmers to dial in each wah.
-
- Senior Member
- Posts: 1035
- Joined: Wed Jul 07, 2010 11:55 pm
- Just the numbers in order: 7
Re: Clyde Mccoy Wah Circuit Board
It's great seeing Joe here. He really had some innovative fuzz designs a while back so ifj he applied that to wah I'm curious about what he found. Might get me to open up my mod-wah again and start tinkering...axeman wrote:I actually invited him over here stedyeddie so he could be an active member.
-
- Senior Member
- Posts: 147
- Joined: Thu Jan 14, 2010 6:23 pm
- Just the numbers in order: 7
Re: Clyde Mccoy Wah Circuit Board
I have a few of those NOS polystyrene caps and a few of the Halo inductors that Dunlop uses in the Bonamassa wah. These are a great combination in my home built wahs.
- axeman
- Senior Member
- Posts: 2464
- Joined: Wed Apr 02, 2008 1:21 pm
- Just the numbers in order: 7
- Location: Los Angeles
- Contact:
Re: Clyde Mccoy Wah Circuit Board
I would like to buy some, post some pictures.projectx102 wrote:I have a few of those NOS polystyrene caps and a few of the Halo inductors that Dunlop uses in the Bonamassa wah. These are a great combination in my home built wahs.
-
- Senior Member
- Posts: 1035
- Joined: Wed Jul 07, 2010 11:55 pm
- Just the numbers in order: 7
Re: Clyde Mccoy Wah Circuit Board
Do the NOS polystyrenes sound any different than, say, the ones you get at Mouser?
-
- Senior Member
- Posts: 147
- Joined: Thu Jan 14, 2010 6:23 pm
- Just the numbers in order: 7
Re: Clyde Mccoy Wah Circuit Board
For those inquiring about the styrene caps, I used what I had in my personal builds and I sent the rest out to another pedal builder. As far as the tone of NOS vs newer, it' s kinda like NOS Iskra resistors vs newer types. They are somewhat warmer with less of a harsh top end. They sound less "plasticky" if that makes any sense.