Wah pedal Nirvana finally found!

[powerplayj]

I socketed my GCB95 transistors last night and experimented with a few as well.  I found that Q1 is primarily associated with the gain while Q2 affects the sweep and tone of the pedal and the gain as well to a much lesser extent.  Substitutions for Q1 only affected the gain and any of the cheap high gain NPN's worked equally as well as the stock transistor.  My medium gain BC108's/109's were much too weak for Q1.  The medium gain BC109 was perfect for Q2.  It seemed to hit a sweet spot with the sweep and had slightly less gain than the stock transistor.  The BC108 was very similar but maybe  softened the gain a bit too much.  

All transistors I tried were dead quiet and my pedal has been modded for true bypass.  My BC transistors were all medium gain and ordered from Small Bear.

Anyone tried a Ge NPN tranny yet?

[petemoore]

My 1rst 847 with BC109's is sounding just wonderful...toe down it's funkmaster Z chord heaven, sweep is nice, apparent and even enough  sweep, very even...it has a 100k alpha pot 'spring-strung' to the treadle
 My Other 847 unit came with a different inductor than the one typed of above, I put every mod [except inductor] on in, the 33k mod makes no difference [because of the inductor IU], it has BC109's in it's sockets, it sees no use as it has a serious 'Wanky' at 2/3rds toe down, a large sweep range is in 1/4'' at that 2/3rds toe down range...
 I have some 4401's...It could be the light usage on the newer pot has caused a scritch to appear, but treadling slowly I didn't notice any, I think it's just that the sweep is so fast at that point in the range that it causes a midrange 'whomp'...

[Manolo Dudes]

I used two BC109B in my "Clyded" Crybaby. Both trannies had about 325 of hFE and sound awesome. Details here.

[hilbi]

my red fasel and bc109B trannies arrived today, gonna put them in my V847. I will let you know my findings.

[petemoore]

2nd' 847 edit and mod done.
 I was mistaken thinking I'd put the sockets in this one, so I just did so.
 It had the Mpsa18's.
 For the gain transistor [the one that cuts signal totally when you pull it out], I'm using the original Mpsa18, because it's low noise, has enough gain, and smaller transistors just seemed to make the unit a bit weaker mostly...or didn't really seem to influence tone....some of the lower gain transistors tried in this position caused an oscillating squeal...from what I had on hand [BCxxx's, 3904's, 2n2369's, 4401's, 5088's]...I decided good performance is probably had with the Mpsa's.
 The Q2 transistor [to make LSS] is a BC109 now, although the 3904 did ok, I noticed noise that was eliminated when it was swapped out.
 I'm about certain I can hear the tone of the BC109, slightly gainier sounding or something, I like it, and the Wah effect is wayy Smoothed Out...for the first time...
 It surprized me that I'd done mods for Q control, unity+ gain, buffer added to output etc., but hadn't socketted the Q's...which is what makes this wah workable, great sounding [different of course to my 847#1 modded one].
 Seems that would be the first place I'd suggest to start on a stock unit to make the sweep more 'usable'.
 The toe down position is way less 'quanky', gone are the nasty high end distortions [unless I play hard on certain note/combination of notes]...
 So thanks for all the info, I'm sure glad this thread accumulated responses like this.

[Fret Wire]

It's always good to make sure the pot is adjusted right before you make any other sweep adjustments. Sometimes, they can be way off from the factory. One or two teeth on the pinion can make a noticeable difference. Many sweep problems can be adjusted out with the pot. Also, keep in mind that the Crybaby has a shorter pedal throw than the Vox. And the Hotpotz has a pretty quick taper, too. What works for the Crybaby sweep wise, doesn't always work for the Vox. And visa versa.

[deke99]

Interesting point about the pot.  I have messed around with my Pot fairly extensively also.  Right now I'm using the pro-pot which is a 250K pot instead of the standard 100K.  I adjusted it down to max out at 100K and it sounded very bassy.  I use a Dunlop shell.  What is the general consensus on wah pots?  Is the Fulltone pot worth the price?  Is there a better replacement pot?

[Joe Kramer]

My 1rst 847 with BC109's is sounding just wonderful...toe down it's funkmaster Z chord heaven, sweep is nice, apparent and even enough  sweep, very even...it has a 100k alpha pot 'spring-strung' to the treadle.  

Hey Pete!

What's "spring strung?"  Sounds cool.  Please describe?

BTW, speaking of transistors, anyone ever try germaniums in their wah?  I put in some 2N1308 and mine spanks like Lafawnduh in a leather catsuit.

(Apologies girls. . . .)

Joe

[petemoore]

Spring strung wah pot is what I end up with when I re-invent the wah case.
 I mount a pot in an L bracket, mount that to the box, so that the string angles will be right.
 The toe of the pedal pulls on the string to pull the pot across to full CW position, a spring does the couterpulling on the string to pull the pot to full CCW position [if I do well...and have enough travel, not too hard...I start with a Homemade long throw pedal, then adjust the travel so to spring or CCW pull bottoms the pot a CCW.
 Basically I start with a round, flat sided knob [about 3/4'' from side to side 'around]. I drill a hole through the knob to feed the string to [this keeps the string from slipping around the knob], and wrap around the knob one time [so the string has enough wrap on the knob that it is always coming off the knob at the same angle]...
 Basically [my favorite word] the string is attached to the toe, goes into the pedal through a hole in the top of the box, wraps around the knob, has a little slack [length left after the knob wrapping] and connects to a spring...the spring is taught and must provide tension over about a 2'' length [or the length of string that comes off the knob as it's turned from fully CCW to Fully CW]...
 I have a Splitter Blend in a DIY Treadle box, it uses a clock spring for string takeup/potstring tensioner.
 This is quite similar to the Ernie Ball Volume Pedal arrangement, except for a knob where there'd be a pulley...
 Adjusting it isn't too tricky, just pull some of the string through the knob's string hole you drilled, using fine' needle nose pliers, and releiveing tension from the other side.
 #1 and #2 are both working very good [haven't tried any Fasels...] in the wah mode, #2 though now needs badly to be true bypass, the tone sucker switch 1/2 died this morning...somtimes goes to bypass mode...lol...

[petemoore]

I put half of an old Rat's DPDT in for non true bypass.
 It was too easy for me to do this, the switch and DMM in hand, I figured out what the old Vox Non TB Switch is, a SpDt.
 The old Rats switch had one side still good [SPDT}, so I decided to make easy use of it right there.
 This way I can try the tone suck mojo a little longer...and figured out exactly what's going on with SPDT Bypassing.
 Some circuits don't need DPDT TBypass I understand, I'll get to see how much this one could use the TB.

[Doug_H]

This is good news.  I have the exact same problem with my wah. Tone to die for but the sweep is so narrow it almost gives me a foot cramp to try to control it.  Deke99, Jered, Ed: what is the hfe of the transistors you are using? I wonder if that could have something to do with it?

I'm going to try some bc109's and 2n4401's and see what happens myself.

Thanks for the report, Deke99!

Doug

[hilbi]

I Put in the BC109b's tonight (Q1 hfe 394, Q2 hfe 380) and the Red Fasel.

I already modded the paralel inductor resistor wich is now 56k, i also did the 2k2 resistor and the 390 resistor. The sweep cap is now 12,7nF.

I didn't replace the other caps. I think i'm quite there now. I nice smooth wah, no shrill highs and a very decent quack.

[Joe Kramer]

 This is quite similar to the Ernie Ball Volume Pedal arrangement, except for a knob where there'd be a pulley...

Ah, I get it.  Nice smooth treadle action I bet.  Thanks for the rundown, Pete!

[Fret Wire]

Interesting point about the pot.  I have messed around with my Pot fairly extensively also.  Right now I'm using the pro-pot which is a 250K pot instead of the standard 100K.  I adjusted it down to max out at 100K and it sounded very bassy.  I use a Dunlop shell.  What is the general consensus on wah pots?  Is the Fulltone pot worth the price?  Is there a better replacement pot?

The Hotpotz I & II have pretty quick tapers. They are very reliable and give good service. The Fulltone has a more gradual taper very close to the original Icar taper. I've haven't had any problems with them, but more than a few here said they have had problems, both with sweep and longevity. I've got the feeling that many of the complaints, sweep wise, might have been due to improper/lack of  adjustment. Who knows? If something doesn't work for you, it doesn't work for you. Once again, the Crybaby has a shorter throw than the Vox. For price, BG Micro has been selling the Hotpotz II for $6.95 for quite awhile, and Antique Electronics has the Fulltone for $16.95, as well as other wah parts.

The pot adjustment should always be the first. I always find the physical limit of adjustment, where the toe-down position will hit the internal stop's on the pot. Then I go back a tooth at a time, until I find the  optimum sweep. I record each setting by tooth, and by DMM reading. The Hotpotz are pretty consistant, and eventually you can rely on either a tooth or a dmm setting alone. You can mark the limit on the gear with nail polish or whatever.

Since the pot adjustment is inter-dependant with other mods like the trannys, inductor, sweep resistor (Q), etc., you should check the pot sweep after each of these mods. Sometimes, a mod won't seem to do much until you re-adjust the pot to take advantage of it. That goes especially for the sweep cap. If you take the time to record the settings, you won't get lost if later adjustment doesn't do anything.

Adjust the pot on the stock pedal for best sounding sweep. Record the setting. Do your next mod. Check the sound. Try adjusting the pot. If it sounds even better, record the pot setting, if there is no improvement..return to last recorded good setting. And so on with each mod. It's not that much work once you get into it. And it gives you a real good feel for the pedal and it's nuance's...your head really gets inside what each mod does, sound wise, pretty fast.

No one would dream of building a pedal such as Ed's BSIAB II to specs, and then reach into a box, and grab three pots of unknown taper and value and stick them in. By not adjusting the wah pot, or ckecking it's taper on a DMM, it's almost the same thing. An important adjustment that is often overlooked or not explored to it's potential.

[Manolo Dudes]

...what is the hfe of the transistors you are using?

I experimented with a bunch of BC109B. I found that the best sounding to my ears were those with hFE around 325. I used an arielfx halo replica and fulltone pot.

[ocelot]

Where to buy in OZ ?? is there a different part number for these trannys ?