"It Might Get Loud" Pages Tonebender?

[azrael]

I may have missed it, but what kind of transistor gains should I look for in the 2N3904s and the 5088 for optimal performance? I found some 2N2222's that are lower gain than the 3904s, and I'm wondering if I should use them....

[Brymus]

You should use sockets and try different ones,I tried the 2n2222 they sounded good too.
I tried several different kinds the 2n2222 being the lowest gain ones I have on hand.
You might like something else.
In the clips I posted I used  Q1,Q2> 2n3904 and Q3 2n5088
Look at Macś posts he recommends several different low gain types, that I will be trying when I get the chance.
Since I socketed almost everything...
I also got some Ge PNPs to try in another build of the TBMKII Pro so I can compare the two.
I have been working a BMP on my breadboard and I actually like my Si TBMKII better sound wise.
The BMP has more sustain and takes a booster pedal in front of it better though.
The TBMKII Pro Si  just has a better overall fuzz sound IMO.
Bryan

[seedseed]

I can not get q3 collector voltage to bias i have checked the circuit for correctness 1 thousand times i swear but q3 will only read 8.6 volts i can't get it down to 4.5 or 7 even with a pot or resistors. i have a 10k resistor coming from the collector of q2 do i need to change this to a 47k possibly. It has got me totally stuffed unless i need to change my transistors. Iam using 2 2n2396a and for the first two stages and a bd139 for q3 not sure what else i can change to make it work i don't really understand this leakage problem on the 100k resistor. any ideas thanks

[joelindsey]

You could always just get yourself one of these...



Shameless bragging, I know. But it nails the Zep tone!

[Quackzed]

  cheeky!
http://www.youtube.com/watch?v=s9X31x2SHzw

[Brymus]

I can not get q3 collector voltage to bias i have checked the circuit for correctness 1 thousand times i swear but q3 will only read 8.6 volts i can't get it down to 4.5 or 7 even with a pot or resistors. i have a 10k resistor coming from the collector of q2 do i need to change this to a 47k possibly. It has got me totally stuffed unless i need to change my transistors. Iam using 2 2n2396a and for the first two stages and a bd139 for q3 not sure what else i can change to make it work i don't really understand this leakage problem on the 100k resistor. any ideas thanks

With 9v battery and a 5K pot on the collector of Q3 I can get anywhere from 2.4V up to 7.7V ( I just checked again )
IDK about your transitors and I am not going to look up their data sheets thats your job.
I do know several people have built this using my schematic and common small signal NPNs and all of them reported they liked it alot.
If you post the voltages for all 3 transistors I will try to help you as best I can.
Bryan

[mac]

The BMP has more sustain and takes a booster pedal in front of it better though

The BMP has more input impedance than the TB. The input resistor of the BMP avoid boosters from saturating the input.
A 10k to 47k at the input might help, without sacrificing gain... TB has lots of it.

mac

[Brymus]

Hey Mac have you tried putting a buffer on the front of the TB ?
BTW I am going to eventually make and post a transfer for this, just havent got to it yet.

[mac]

Hey Mac have you tried putting a buffer on the front of the TB

Nop.

mac

[seedseed]

I fixed my problem YAY i checked everything in my build one billion times (little bit of an exageration) but when you have a fault in your unit this is how it goes what it ended up being was the pot that i had joined on for the gain the 1k on the earth lead on it the flux from the solder had managed to make it a high resistance joint. It wasn't until i fired it up and did some probing that i noticed the voltage drop when i connected a wire between the q3 emitter and ground! Low and behold the voltage dropped. I then checked the pot and found it to be 3meg resistance and then thought bingo there you are you little sucker. The thing is that to look at everything the solder's looked fine and you would think well must be a component or have i done something wrong on the board. But after all it ended up being the damn flux the unit now functions beautifully the only issue i found is that when the sustain switch is on it seems to feedback and sort of take of to much on me is that the same problem anyone else is getting when they give there amp a bit kick of juice. is there anyway the sustain can be kept and tame it back a bit? Thanks for your help bryan

[Brymus]

If I understand your question about the sustain switch right.
You could take R4 and split it into two different values in series and tie the cap at the point they meet.
Just like a fuzz/gain pot on a FF , (this would be degenerative emitter feedback (if I understand what I ve learned of late)
You could also try using a pot and connecting the cap to the middle wiper.
You can also try lowering the value of the cap (make it smaller) so only the higher frequencies are boosted more than the lower.
Glad you figuered it out 
Post some pics and sound clips here in this thread when its done.
Bryan

[keto]

Wondering what I did wrong on the sustain switch, possibly wrong switch?  On-On SPDT wired as you show it, outside leg to 1uF, outside leg to ground, mid leg empty.  Now, I did use an electrolytic there, pointed ground to ground and + to R4, so it could be a polarity issue as well.

Otherwise, it functions just as it should and sounds great.  Used 3904's and a 5088 just like you drew it up.

[Brymus]

Yes it sounds like you wired the switch wrong.
Try checking it with a continuity checker ,
I think (cant know with out having the switch to check )
That you want to use the middle and one outside lug.
So the (-) end of cap to the middle lug,and the outside lug to ground (either one should work),The (+) end of the cap would connect at the emitter R4 junction.

Something you could do with that switch is wire the emitter to the middle lug then have two different value caps each with the (+) terminal tied to an outside lug and the (-) terminals tied to ground.
I would try a 1uf or higher and a .47 or lower value.
This would give you two different kinds of boost.

[keto]

Thank you, you got it exactly right on the switch, just had to move 1 wire 1 lug over.  All I can say is  awesome.

[keto]

clamfest, compressed youtube sound and camera mic, but I think it gets the idea across    http://www.youtube.com/watch?v=gABsgZ_vLx0&feature=player_embedded

[Brymus]

I was lucky enough to get sent a few gold pin 2n2369 transistors from a VERY nice forum member 
They arrived in the mail today.
Five minutes later...
I put a 67 Hfe in Q1 and a 69 Hfe in Q2 and left the 2n5088 in Q3.
With the sustain/phat switch off this pedal is FN AWESOME !!!!   Less gain = smoother distortion
It is perfect now for the early Zep tones ,that I have been practicing lately.
I love this pedal even more than before !!!


This is yet another verification of what Mac said early on in this thread,you want LOW gain Q1 and Q2 for the most authentic TB MKII sound from Si transisters.
If any of you can get some of the low gain trannies Mac recomends (read earlier in this thread for his picks),please try em out.
You wont be dissapointed.

Major Thanks !!!! to the forum member who sent me these ,you are a prince among men. 

[mac]

Brymus,
I bet you have some leaky unused germs, try one at q3. Temperature is not going to be a problem and you could germanize the thing a little more.

mac

[Renegadrian]

I made this layout here. I ended up using 470k at q1 and 10k at q2. 3904 give too much gain I believe and sounds like sh.t!
Got some pn2369, low hfe, they work much better. q3 is not that important but I'd put a 2369 there too...

[Arcane Analog]

The problem with Ge is leakage. Get the right leakage and you´ll get a nice pedal, otherwise...
Q1 needs a moderate leakage to sit at around 8v. If too leaky then collector will drop too much and more siganl will hit the FF section which is not good IMHO.
How much leakage? 100uA or so.
Q2 has to be low leakage, below 50uA because a tiny amount of leakage across the 100k sends Q1 collector too close to gnd, making almost impossible to bias Q3.
We say all the time that Q3 needs to be at 4.5v, and never mention where Q2 must sit. I'd say that with a 100k, 0.3v - 0.4v is the sweet spot. In a FF this small gap is 0.4 - 0.6v.
Besides,  low leakage means less variations with temperature.
Q3 can be leaky.

mac

In my experience, low leakage is not preferable in Q2 and Q3 is certainly not looking to be 4.5V. You want 8+ volts at Q3.

[blackcorvo]

Anyone ever tried MPSA42's for these fuzz effects? They have pretty low Hfe and are really common out there.