MK-II Wiring or 3x Si Problem?!

[niggez]

I built my first effect pedal (MK-II) according to this schematic:
http://fuzzcentral.ssguitar.com/mkII/mkIIlayout.gif
http://fuzzcentral.ssguitar.com/mkII.php
But i just dont seem to get the battery hooked up correctly. I have the - pole wired to the pcb - spot. I have the + pole wired to the shield section of the input jack, on which i connected another cable leading to ground (marked 6 on the pcb). Also, in and output jack shields are connected to this shield section, leading to ground.
In the tonepad-wiring faq diagram theres a third type of connection on the jacks called ring. I dont seem to understand what this is supposed to be?
There are 3 connections on my in/output jacks, but 2 of them get bridged together when you plug in the cable. The third one is the tip.
I use mono cable, and i have 2 stereo jacks one for input and one for output. I looked at the tonepad diagrams, but there still seems to be some kind of problem. Im only wiring a battery, no switch. The effect is supposed to be on as soon as you plug in the cable.
HELP! anyone!

[niggez]

I just found a thread describing an mk-2 will not work with 3 silicium transistors. Can anyone verify this problem? I built it with silicium transistors bc558c. I checked for the correct pin lineup. Maybe this is the reason why i wont get it to work? My wiring seems to be ok.
Edit: I measure 6.6V at the first transistor (to base), but very low voltages on the other 2. Its only 0.5 and 0.6V  on them.
Edit2: I figured out what the problem is. Its the si-transistors. Apparently they have to be biased. Argh

[slacker]

Yeah, using a silicon transistor for Q1 in a Mk2 won't work, unless you modify it slightly. The first transistor is biased using leakage from the base which works for germaniums but silicon transistors don't normally leak enough for this to work.
The easiest way to make it work is to remove the 100k resistor from the base of Q1 to ground and replace it with a larger resistor 300K - 1M going from the base of the collector of Q1. That will bias Q1 and the pedal should work.

[frankclarke]

http://www.home-wrecker.com/tbmkX.html

[Gus]

Frank

  check the date
http://www.diystompboxes.com/pedals/3tran.JPG

this is from the same time I need to find the original
http://www.diystompboxes.com/pedals/gusFuzzFace.gif

this one
http://www.diystompboxes.com/pedals/gusRitefuzz.gif

What happened to Doug's Hot Silicon?

[frankclarke]

Gus,
I saved http://www.diystompboxes.com/pedals/gusFuzzFace.gif and http://www.diystompboxes.com/pedals/gusRitefuzz.gif to my hard drive on 15/03/1999 (I save everything). The images are the same. Time flies .

[niggez]

Awsome! Im gonna look through this stuff and see if i get it to work...Thanks. Ill give an uptdate soon.

The easiest way to make it work is to remove the 100k resistor from the base of Q1 to ground and replace it with a larger resistor 300K - 1M going from the base of the collector of Q1. That will bias Q1 and the pedal should work.

So the 300k - 1M resistor, i have to attach it to the base of the collector of q1 going to ground? or from the base of q1 to ground? or from the collector of q1 to ground? im confused! ah i think from the base To the collector of q1?? Trying that out now

Edit:
Ive tried out all sorts of connections with a 1M Reistor (Base-Ground, Collector-Base, Collector-Ground) for Q1 but it wont solve my problem. Still very low voltages on Q2 and Q3


WOHOOOOOOOOOOOOOO GOT IT WORKING! Duuuuuude Thanks for the Tip...i finally got it. Problem was: all the transistors were soldered in the wrong way. Got confused by the little "tip" on the pcb layout i used!

Its a very crude, harsh fuzz, but lets see where i can take it

[niggez]

Ok some more issues here:

Im overall pleased with the fuzz type. BUT: as soon as i turn the volume knob down a bit on my guitar, the tone gets extremely muddy, and the sound sort of wavers from quiet to loud. It sounds as though someone was putting their foot up and down a volume pedal. This is already the case at 8 of 10. If i put my guitar to 6 i hardly hear anything, really dark muddy tone.

Second, the attack poti doesnt do anything, or hardly anything at all. Plus, the output volume of the thing is huge. I think i should lower that a bit, so that im more flexible with my amp settings? Otherwise my volume control (amp) is very touchy...

Any advice concerning those issues?

[niggez]

I drew the schematic of my version. Maybe this can help solve some things!
R1 is 1000k , its hard to read.
http://picasaweb.google.com/julius.nick/Schematics/photo#5146120641247787058

[DougH]

What happened to Doug's Hot Silicon?

It's right here http://www.aronnelson.com/gallery/v/DougH/  with a soundclip too.

[niggez]

it seems like my attack pot doesnt do anything at all? what could be a reason for this? The tone is very ragged...i think theres still a problem with the transistors not being optimized. I will install a trimpot at q1 to see if i can adjust it to a level where the overall sound improves!
Could this be a reason for the "attack" knob not doing anything?

[frankclarke]

The volume control on your schematic is drawn incorrectly, maybe your pots are wrong.

[niggez]

Thank you! But i think its just an error in my drawing. The middle terminal of the volume pot is attached to the output. The volume pot is the one working correctly.
But ill recheck those connections of the other pot.

[mac]

I bias Q1 adding a 1M - 1M2 resistor from collector to base, setting collector voltage at about 8v - 8.5v resp if hfe is near 70.  The resistor "acts like" the leakage bias in a Ge.

mac

[niggez]

thats what i did, added a 1M resistor across base/collector. And removed the base to ground 100k. Was it right to remove that one?

[mac]

Removing the 100k from B to Gnd set collector voltage at 5.5v or so, with 1M from C to B. You're changing the input impedance as well and so tonal characteristics, this could be good or bad to different ears.
To stay close to the original design I'd put the 100k B to Gnd back.

mac

[DougH]

According to your schematic, you are not biasing the base of Q1 properly. There is a missing resistor from base to -9v. Also, it appears that you have reversed the Q3 collector and emitter. Use the home-wrecker schematic that Frank linked for a comparison.

[Gus]

Not the same input circuit but something that has controlled gain about X10 look at the first transistor part of this circuit

http://www.aronnelson.com/gallery/v/DougH/hotsi/GS_Tonebender.gif.html

Yes looks like a LPB, that is a standard textbook circuit: however the input R collector R and gain were thought about.  Want more gain add a cap across the emitter resistor want an HF boost calculate the cap or control the gain/boost by adding a series RC across the emitter.

Now for the more advanced base to +9V OR base to collector resistor bias.   Same Ic and emitter and collector resistor values The C to B should have less distortion because of the feedback.  Also look at the gain and input resistance.

Doug voiced  a Si type circuit I drew my part was the input and distortion stage he added the follower and tone and eq voicing IIRC.  my drawing was a 3 transistor circuit with controlled gain at the input.  the collector R work with the following FF type part 47K feedback as does the cap size between.

Even could work with a Ge based circuit use the Si front to the Ge Ff type section you like

[niggez]

Hey thanks for all the help! Ive got it to my liking now. Sorry for the handdrawn schematic before, there were minor mistakes in there.

So now: I have the 1M biasing Q1 and put the 100k base to ground back in - And the tone is fixed! I will have to play around with the fuzz (attack) pot, right now its a 100k pot but maybe i can find a better value to give me more control.
Apart from that, nice sound!

[mac]

I will have to play around with the fuzz (attack) pot, right now its a 100k pot but maybe i can find a better value to give me more control.

... the fuzz pot should be 1K, not 100k...

mac