Swapping transistors in my Wah

[kevn]

I've done most of the mods I know about to my 1990 crybaby & thought I'd try different transistors as some people have reported dramatic improvements here. I ordered a bunch (5) NTE123A's from Mouser and found two fairly close in hfe (130 & 117) and swapped them out with the stock transistors (hfe 248 & 208) & noticed perhaps a slightly smoother sweep but nothing very significant. Next I tried from the new ones a  189/130 pair and thought this was a slight improvement  over the 130/117 pair. I believe the hfe range on these is supposed to be within 100-300 so I guess I got a bunch on the low end. What I'm looking for is anyone with experience who could offer insight into the following:

- How much does the absolute value of transistors in either position matter (would I see more improvement by getting up into the 3,4 or 500 hfe range)?

- How much does the type of transistor matter?

- How much does the difference in hfe matter across positions (Q1 & Q2)

[cmat]

Since we are talking about transitor tone changes... I would like to know what everyone thinks about the diffrence between mpsa18, 2n5088's and BC109's.  I am building one now with BC109's but I am waiting on my inductor. BTW there is a guy with FullTone pots for $15.99 www.danalectroid.com check it out he has pro pots for $12.99.

[kevn]

There was one other question I had. When changing transistors is it necassary to check/reset the bias on them? Dont know too much about this myself, but I seem to remember discussions where bias adjustments were mentioned when using different transistors.

[jimbob]

"Since we are talking about transitor tone changes... I would like to know what everyone thinks about the diffrence between mpsa18, 2n5088's and BC109's.  I am building one now with BC109's but I am waiting on my inductor. BTW there is a guy with FullTone pots for $15.99"
I tried what seems like a million different transistors and found that it depends on what circuit your using. I actually like the mpsa18 in my mod wah from GGG, and bc109's and bc108c and 2n2222's for my Vox wah.

[no one ever]

Since we are talking about transitor tone changes... I would like to know what everyone thinks about the diffrence between mpsa18, 2n5088's and BC109's.  I am building one now with BC109's but I am waiting on my inductor. BTW there is a guy with FullTone pots for $15.99 www.danalectroid.com check it out he has pro pots for $12.99.

404..


i liked bc109c's over the mpsa18's in my old crybaby, yet to try those expensive bc109b's or 108c's.

[cmat]

I finished the wah tonight with the BC109's and I did not like them in the GGG board.  I have a given set of mods I do to a wah and when I was finished is sounded really weak and had slightly lower volume than the original signal.  I poped in some MPSA18's and there was my tone and extra volume and slightly more gain than the BC109's.  I guess it goes to show you to stick with what you know you like!   I have a VOX comeing and I will try the BC109's in it and compare it to MPSA18's and 2n5088's and let you know what I think.  What is everyones opinion on pots in a vox and crybaby?  What are your favorites in each?  I prefer the FullTone pot in each but I havent tried the propot just stock pots and HP2's.  How about inductors, I like the yellow Fasel.

[kevn]

CMAT - Do you know what the hfe was of the BC109's you tried? If you read my earlier post youll see that I found improvement when I used the same model transistors (NTE123A's - Mousers substitute for BC109) but used  2 with higher gain (went from 130/117 hfe pair to a 189/130 hfe pair). Besides increasing the gain of each transistor it also increased the difference in hfe between the two. I dont know if the difference matters or not, but I dont want to discount it until some one who knows what theyre doing can telll me either way.

[formerMember1]

i just built a Vox Clyde McCoy wah this past week, and i don't like it, but i am still tweaking it,  I thought my pair of transistors was low, let alone yours, mine are around 330 and 298, they are BC109B's.  I am gonna order BC109C's, BC108C's, BC109's, and BC108's from someone to try. 

I am looking for the early jimi wah tone,

I tried the dunlop pots, fulltone pots, propots, and also tried to tweak the pedal for each pot, the best pot to me is the propot, i didn't like the fulltone, or dunlop pot,   

The fulltone pot, does sound ok in my other wah i have lying around(crybaby classic), the fulltone was more vocal, and sounded more like Cream's tale os brave ulyssess's song, the propot has a longer feel to it,  only problem seems to be that the propot has everything  bunched up at the end of the travel, when the fulltone's didn't,  the propot sounds more authentic to an ICAR pot though,...

oh well, like i said, i am still tweaking,.....