Tone Bender MKII Help Part 2

[Wagster]

Hey guys,
I just built a PNP positive ground MKII using the GGG PCB board and layout.I used match transistors from small bear.The transistors are mounted in with sockets.I measured each resistor before I soldered them in.The pedal is way too saturated.I had this same problem with the old GGG MKII that I scrapped.It sounded good for a while and then started sounding saturated.I built another GGG MKII using all news parts other than the transistor.Here are my transistor readings.

Q1) E 0.00 B 0.08 C 7.51

Q2) E 0.00 B 0.11 C 0.58

Q3) E 0.44 B 0.57 C 4.58

I also notice that GGG MKII Pro has the LED hookup in the wrong spot.Anyone else notice this?
http://www.generalguitargadgets.com/diagrams/tonebender_m2p_lo_pp.gif
Shouldn't it be to the upper right of C1?

[John Lyons]

The MKII is a very aggressive and saturated pedal. The Tonebender boutique and or 2 knobs tonebenders are smoother land a less gain.
You can always use a lower gain transistor or put some small resistance between the emitter and ground of the first transistor.
Also putting resistance between the base and R1 would tame the gain down. 50Kor so pot wired as a variable resistor.
Take a look at the fulltone version of the tonebender. 

[Wagster]

It's not a normal amount of gain.Even on zero it won't clean up.The 1st one I built worked fine for a few days.On full the gain is just plain crazy.It's like 3 FF hooked up in series.

[John Lyons]

Oh, ok...Hmmm...
There must be a problem somewhere.

[yeeshkul]

I built one MKII recently. When i turned the attack knob all the way down, it sounded like Ge FF almost all the way up. I'd say that is the way it is supposed to work.
I used 50/60/100 Ge, PNP trannies.

[Wagster]

 I just listened to the Brit Bender clips on the MJM site  http://www.mjmguitarfx.com/mjm_soundsamples.html
If you do a mouse over the play button in Explorer they give the settings.Mine sounds like that at those settings so I guess it's working right.I tried a different Transistor in Q1 and it spits and sputters just like the clips.It's more gained out than I thought it would be.It's very gnarly but in a cool way.

Do you think there would be any tonal differences using mustard caps in place of the poly film caps?

Billy

[mac]

I think Q1 collector voltage is to low and so more gainy. Try increasing to 8v - 8.5v.
Also the gain pot won't clean up at min since Q1 isn't clean at all.

mac

[Wagster]

I think Q1 collector voltage is to low and so more gainy. Try increasing to 8v - 8.5v.
Also the gain pot won't clean up at min since Q1 isn't clean at all.

mac

Mac,
I found a old Japanese transistor and put it in Q1.It reads 9.6v on the collector.Is this too high?It's cleaner sounding than the other.I have a 25k trimpot wired as a variable resistor in place of the 8.k resistor for Q3.So I need to install a trimpot wired as a variable resistor between the Q1 collector to ground?All I have around at the moment is a 2k trimpot.Would this work?

Here's are my new readings
Q1
C = 9.60
B = 0.04
E = 0.00
Q2
C = 0.60
B = 0.11
E = 0.00
Q1
C = 4.53
B = 0.57
E = 0.44

Thank,
Billy

[yeeshkul]

Emitter of Q1 and ground.  Use really a small one (500 ohms trim pot).

But first of all - 9.6V on Q1c is full voltage of your battery, there should be a voltage drop on 10k collector (Q1) - check the resistor it looks that collector goes straight to battery for some reason.

[Wagster]

I get 7.51 reading a Q1C with the transistor I got from Small Bear .It sounds too gained out.The one reading 9.6v sounds cleaner.I checked to make sure the resistor was 10k and and it reads 9.88k.

[yeeshkul]

did you measure the mighty suspicious tranzistor? 

[yeeshkul]

i mean there must be difference in voltage between the voltage joint itself and the joint between Q1c and 10k res ....

[mac]

i mean there must be difference in voltage between the voltage joint itself and the joint between Q1c and 10k res ....

If the transistor has very low leakage, as a silicon, it wont bias since there is no current through the base and therefore no collector current.
For example, I have some Toshiba Ge leaking less than 20uA, or 0.02mA, they need a resistor from B to C, or B to -Vcc.

mac

[Wagster]

I think Q1 collector voltage is to low and so more gainy. Try increasing to 8v - 8.5v.
Also the gain pot won't clean up at min since Q1 isn't clean at all.

mac

Mac,
I found a old Japanese transistor and put it in Q1.It reads 9.6v on the collector.Is this too high?It's cleaner sounding than the other.I have a 25k trimpot wired as a variable resistor in place of the 8.k resistor for Q3.So I need to install a trimpot wired as a variable resistor between the Q1 collector to ground?All I have around at the moment is a 2k trimpot.Would this work?

Here's are my new readings
Q1
C = 9.60
B = 0.04
E = 0.00
Q2
C = 0.60
B = 0.11
E = 0.00
Q3
C = 4.53
B = 0.57
E = 0.44

Thank,
Billy

I just noticed I listed Q3 as Q1    

[yeeshkul]

i mean there must be difference in voltage between the voltage joint itself and the joint between Q1c and 10k res ....

If the transistor has very low leakage, as a silicon, it wont bias since there is no current through the base and therefore no collector current.
For example, I have some Toshiba Ge leaking less than 20uA, or 0.02mA, they need a resistor from B to C, or B to -Vcc.

mac

so the Q1 biases only due to its own leakage? That's what i needed to know, i was thinking about it and wasn't sure ,  good one.

[mac]

The funny thing about leakage bias is that in a NPN Ge current "flows" out of the base via the 100k to gnd.
Q3 in a TB 3-knob is another example.

mac