Germanium transistors on a tonepad wah?

[TryingToDo613]

Hi all. I have a ton of germanium trannies I'm in the process of testing with RG's tester. Is there an advantage to using them on the tonepad wah? Would I have to modify the circuit? -ph

[jrc4558]

what trannies are they? would you care to sell some? as for your question, just bias the Q1 correctly.

[Fret Wire]

Zero advantage. It's not one of those ckts where germ characteristics/mojo would help one bit. Stay with silicon's, germs will also make it harder to voice the wah to your own taste. No need to add inconsistant trannys to the mix. Besides, remember that germs are heat sensitive. Do you want your wah to change it's sweep and voice with every temp change, then crap out completely when the room/outdoor temp gets too hot?

[TryingToDo613]

Thanks Fretwire. I suspected as much.  Yes, the temp effect is something else. As for where to buy them, I got some very nice AC128s on ebay from a guy in england, like over a hundred, and I got about a hundred from another guy on ebay who sells some fairly high gain GE ones for about a buck and a half. Small bear has tested sets. -ph

[Joe Kramer]

Zero advantage. It's not one of those ckts where germ characteristics/mojo would help one bit.

Hi!

With all due respect Fret Wire, I beg to differ.  I put 2N1308's in my Thomas Crybaby and the slightly brighter Ge's added a nice sweetness to the high end that wasn't there with the original 5117's.

The only dictatorial advice I would ever give anyone is "Never take the advice of someone who tells you not to experiment."  If you have the parts and the time, why not try it?  You have only to gain, whether it be in sound quality or in knowledge via hand's-on experience.  

BTW, Constantin, what Ge's are you looking for?

Regards,
Joe

[Fret Wire]

The only dictatorial advice I would ever give anyone is "Never take the advice of someone who tells you not to experiment."  

With all due respect Fret Wire, I beg to differ

Make up your mind Joe, are you trying to be respectful, or a dick? Dick is what you are if you're trying to put words in my mouth. I made that statement out of both experience and experimenting. Even after RG had once stated it was not worth it to try germs. I still tried it myself, and felt it wasn't worth the effort. Even if yours sounds good (ge's with more high end than si's?) as you claim, you still can't do much about the temp effects on the gain and leakage. The ge diode trick goes only so far in controlling that.

My "dictatorial" advice to you Joe, is to save the punk mentality and insulting insinuations for the kids on the forum. :wink:

[Fret Wire]

Thanks Fretwire. I suspected as much.  Yes, the temp effect is something else. As for where to buy them, I got some very nice AC128s on ebay from a guy in england, like over a hundred, and I got about a hundred from another guy on ebay who sells some fairly high gain GE ones for about a buck and a half. Small bear has tested sets. -ph

Sounds like a nice score.  With over 200 trannys, you're sure to get some really nice matched up pairs. Of course some will be unstable, some will have too much leakage regardless of their gain. And some will have good leakage, but the gain will be either too low or too high for most of the fx ckts.

The rest of the good gain and low leakage can be used for Tonebenders, Dallas Fuzz's, Rangemasters...whatever.

Here's something to think about. You'll have some that are low leakage but too high or low gain. Some people use those for clipping diodes. I think that's a waste of a transistor that's perfectly good, but just doesn't have the gain you're looking for.

Someday, we''ll run out of ge transistors, there will be no more. There are other uses for Ge's besides fx. Resoration of radio's and other older electronics use ge's too. Take the good trannys with high or low gain, and sell them on Ebay as tested lots. List their gain and leakage. Someone can still use them. You'll probably sell ten for much more than ten untested Ge's go for. And you've passed them on to someone who can use them.

[Joe Kramer]

The only dictatorial advice I would ever give anyone is "Never take the advice of someone who tells you not to experiment."  

With all due respect Fret Wire, I beg to differ

Make up your mind Joe, are you trying to be respectful, or a dick? Dick is what you are if you're trying to put words in my mouth. I made that statement out of both experience and experimenting. Even after RG had once stated it was not worth it to try germs. I still tried it myself, and felt it wasn't worth the effort. Even if yours sounds good (ge's with more high end than si's?) as you claim, you still can't do much about the temp effects on the gain and leakage. The ge diode trick goes only so far in controlling that.

My "dictatorial" advice to you Joe, is to save the punk mentality and insulting insinuations for the kids on the forum. :wink:

Dear Fret Wire,

My bad!  Although I said what I said in good will, I'm very sorry it was misunderstood.  I admit the word "dictatorial" has strong connotations, but I didn't mean anything personal by it--how could I without even knowing you? Besides, I have too much to be thankful for in my life to waste time insulting strangers on an internet forum.

However, I do think there's a tinge of "dictatoriality" emerging on this forum, which should in fact be a place of encouragement for experimentation.  There are no shortage of people in the world who'll be happy to tell you something's "not worth a try."  I reject their advice with all my heart and without apology.  I am entirely self-taught in electronics, and although my knowlegde is full of gaps at best,  what I do know I managed to learn without the help of those who told me "that's not worth a try."  

At any rate, I hope to be clearer in what I say in order not to be misunderstood or to offend.  I offer you a hand of reconcilliation.  Shake on it?

Regards,
Joe

[Fret Wire]

Joe, consider it a handshake.  We sound the same, both electronically and personality wise (A-type). "Zero advantage" does sound final, I should have added "IMHO". I do agree there is some limiting advice here now and then. But I'm not always qualified to know if comes from closed mindedness or from personal experience meant to save someone else time. But I usually try to speak from experience, that's where my advice came from. I've put plenty of time in on the wah ckt, and still don't have all the angles figured yet. I never found ge's to be repeatedly worth it. Too many disadvantages to me. In this case, he has AC128's, PNP...definately not worth it. Plus, the 300 ma or less leakage standard doesn't apply to every ckt. Some ckts won't tolerate half that leakage, and AC's are not known for having real low leakage. To me, the various Si's work so well in the wah, that the Ge's might as well be saved for ckts where they really matter.

Just my opinion.

[Joe Kramer]

Joe, consider it a handshake.

We sound the same, both electronically and personality wise (A-type). "Zero advantage" does sound final, I should have added "IMHO".  I do agree there is some limiting advice here now and then. But I'm not always qualified to know if comes from closed mindedness or from personal experience meant to save someone else time. But I usually try to speak from experience, that's where my advice came from. I've put plenty of time in on the wah ckt, and still don't have all the angles figured yet. I never found ge's to be repeatedly worth it. Too many disadvantages to me. In this case, he has AC128's, PNP...definately not worth it. Plus, the 300 ma or less leakage standard doesn't apply to every ckt. Some ckts won't tolerate half that leakage, and AC's are not known for having real low leakage. To me, the various Si's work so well in the wah, that the Ge's might as well be saved for ckts where they really matter.

FW,

Time-saving hints can be a great help, but then again, anyone who wanted to save time wouldn't be tinkering around building his own wah pedal!   :wink:   As far as trying to dial-in that circuit, I know what you mean.  I've never stopped fiddling with the thing since I got it way back in 1978.   FWIW, I will stand by that 2N1308 mod.  There's a certain hi-freq zing those xstrs have that works well with clean circuits, although they tend to sound ragged for distortion.  If you'd like, drop me an address and I'll send you a couple to try out.

BTW, have you ever tried messing with the taper of the wah pot?  Right now I'm using a 50K reverse-log taper that was a lucky find, and that taper really improves the "quackiness" of the wah.  The next best thing to an oddball pot would be a tapering resistor.   For a 100K pot, try a 22k resistor from the middle lug to I believe the lug that connects to ground.  (If not, it's obviously the other one.  Sorry, brain drain.)  Anyway, if you haven't tried this yet, you might want to.

Regards,
Joe

[Fret Wire]

BTW, have you ever tried messing with the taper of the wah pot?  Right now I'm using a 50K reverse-log taper that was a lucky find, and that taper really improves the "quackiness" of the wah.  The next best thing to an oddball pot would be a tapering resistor.   For a 100K pot, try a 22k resistor from the middle lug to I believe the lug that connects to ground.  (If not, it's obviously the other one.  Sorry, brain drain.)  Anyway, if you haven't tried this yet, you might want to.
Joe

Pots?  I've spent the most time with the wah ckt experimenting with both pot tapers and pot/gear adjustment.  Somewhere buried in my 2300 useless posts, I'm blathering on and on about tapers/adjustment in a few threads. A taper that works well in the Crybaby with it's short throw, doesn't always translate to the Vox with it's long throw, and visa versa. One adjustment setting doesn't work for every inductor, sweep cap, or overall voicing. I've got written notes of pot adjustments in both gear teeth and ohms, and taper graphs of most of the pots. When I finally get all the info together in a manner that's consise and makes sense, it will be a true time saver. But that's a whole other thread.

[Joe Kramer]

I've got written notes of pot adjustments in both gear teeth and ohms, and taper graphs of most of the pots.

In that case, I should be asking you for tips!   :oops:   What's your favorite/best/recommended pot taper/value/set-up for the Cry Baby?

[Fret Wire]

Like I was saying, it depends on the inductor, sweep cap, and voicing. And depends alot on which particular wah sound you're looking for. Do you like the quick sweep or long? Generally, for the Crybaby with it's shorter throw, the quicker tapers sweep the best for me. The ICAR types can sound like there's flat spots in the sweep sometimes. It's hard to get the long Colorsound sweep in a Crybaby with most pots. If the taper is too slow, it sounds like a flat spot. Believe it or not, the Hot PotzII with it's quick taper works well with the Crybaby. And you can easily get its full range (approx. 12ohm-95k). It ramps up quick, then hits full value around 2-3 o'clock, and holds it. Not knowing about the rest of voicing and components, I'd say start with full travel, then back off one gear at a time. Measure with the DMM. It jumps up from ohms to kohms pretty quick. Use both your DMM and mark the gear teeth on the pot, and set the basline (full travel). Then shorten it from there being mindfull of the mechanical stops in the pot. Record each change by tooth number and ohm reading. I'm hesitant to recommend a specific number of teeth on your wah because each tooth does not change the value equally. Changing the sweep r (33k) is interdependant with the pot sweep and adjustment.

Me, with a Yellow Fasel, 56k on sweep, mid gain trannys, and stock or one value lower sweep cap, I usually go around 10k/15k - 95k. Nice even sweep. If I have to use a HotpotzII with a Vox, I always adjust for full value. Very even and expressive with the voicing I use. Requires a well oiled heel for quick quacking though. It's not my favorite for the 847 though.

The interdependant relationship of all this started to all make sense and click some time ago.... in my head, that is. When I try to articulate it, I sound like someone who's talking underwater. Where my charting/recording of tapers, settings, and tooth changes of specific pots will come in handy, is when I can simulate the ckt with the different pots (and their specific taper characteristics), plus various inductors and other tweaks. Then I envision a plug n' play type calculator similar to what Joe Davisson has (EMH). Enter in your shell and wah sound desired, plus any components that you may already have decided on, and it will spit out a specific list of parts, values, and pot setting to come as close as possible to the desired sound. The less you limit it and pre-select your parts, the more accurate it gets. You plug in nothing but a Vox shell and hit "Colorsound", and it tells you which inductor, trannys, pot (and it's adjustment range) to use, plus gives you all resistor & cap values.

Well, the cat's part way out of the bag.  That's what I hope to present to the forum as a decent contribution others can really find helpfull. For as much as I've already done on it, there's still a long way to go.

[jrc4558]

to Joe Kramer,
well, anything except the SA/SB/SC/SD japaneese transistors line, i have a plenty of those germanium. Specifically I'm interested in AC128, NKT275(?), the originals of the fuzz-face i guess...

[Joe Kramer]

FW,

Thanks for the info.  You've obviously been very scientific and methodical.  Your idea of a sort of "wah tone calculator" would be valuable to a lot of people I think.

By contrast, I doubt I could ever duplicate the sound of my wah with its haphazard ingredients--Ge xstrs, a 50K reverse log Allen-Bradley pot, and an inductor I cannibalized from an old Realistic 5-Band EQ from the 70's.  Not to mention every cap and resistor replaced or tweaked in some way.  But it sounds pretty "authentic"--there's almost a phasey tone to the sweep, similar to some old Italian wha's I've tried.   Probably won't be long before I'm back to tweaking it some more though. . . .

To Constantin:  Sorry, no AC128's here.  I do have some other AC numbers though.  If you're interested email me.

musetrap@earthlink.net


Joe

[petemoore]

Ge's that sit on the edge of a barrier or parameter can exhibit 'unusual' behaviour.
 When I'm writing up a schematic using them, I know I'm only submitting info I found in a Ge subject in a subject circuit, both the component and the circuit may have enough tolerance difference to exhibit a change in behaviour, writing up a circuit, especially one that depends on the transistor being pushed near barriers is at least somewhat sketchy at best IMHO.
 Many have built the exact same circuit and put in the same exact Ge transistors and noted differences. Changing transistors or duplicating the whole thing even moreso.
 The wah highs probably seemed to sound different, I probably won't be messing with Ge wahs, BCxxx's or BCxxx/MPSA18 seems to work well.
 Sometimes to finding where the exact edge, or whether there is one to be found [considering weather influence etc.] depends on walking over it numerous times.