Tone Bender Mk.II - Help Needed
- Electric Warrior
- Diode Debunker
And where would you get a matched transistor set by someone who knows what he's doing?
People come here all the time with sets selected for gains that are way off and then rebiased to voltages that are off even more.
You're pretty close to the right ballpark already and you're taking the right steps to fix the gating.
Q1c and Q2c are a little low, Q3c is alright, but could be a little higher. Less leakage for Q1 and Q2 and more leakage for Q3 should fix that.
Using smaller values for Q1's base and Q2's collector resistance (like you already tried) will make up for too much leakage at Q1 and Q2, but that will bring Q3C further down, so might want to use a leakier transistor there (of which you seem to have plenty).
I try to get Q1C somewhere between 8.5 and 9V, Q2C between 0.13 and 0.20V and Q3C between 8 and 9V with a battery measuing around 9.5V.
People come here all the time with sets selected for gains that are way off and then rebiased to voltages that are off even more.
You're pretty close to the right ballpark already and you're taking the right steps to fix the gating.
Q1c and Q2c are a little low, Q3c is alright, but could be a little higher. Less leakage for Q1 and Q2 and more leakage for Q3 should fix that.
Using smaller values for Q1's base and Q2's collector resistance (like you already tried) will make up for too much leakage at Q1 and Q2, but that will bring Q3C further down, so might want to use a leakier transistor there (of which you seem to have plenty).
I try to get Q1C somewhere between 8.5 and 9V, Q2C between 0.13 and 0.20V and Q3C between 8 and 9V with a battery measuing around 9.5V.
- ljn
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Thank you. Finally a clear, straightforward answer. So, the two low hfe- low leakage transistors I have would be good for Q1 and Q2? Will I have to change anything else? I only ask that because I'm low on parts at the moment and I think I used the last 100k resistor I had in this circuit. Thanks.
- Electric Warrior
- Diode Debunker
Give them a try, but they may not be gainy enough.
- ljn
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That's what I'm afraid of. I'd hate to put them in and lose that fuzziness it's getting. I guess I won't be able to do much for either of my Tone Benders until I can get more transistors. I'm wanting to order a bag of AC125 from eBay. It's a sealed bag and they're untested , but it's so expensive. It'll be a long time before I can afford such a thing.
- ljn
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Okay, so I haven't changed anything in this one yet. I did some experiments with it the other day using different attack settings along with different volume settings on my guitar. I used Led Zeppelin I as a comparison along with a couple of songs by Cream from the "Disareli Gears" album (for which I read Mr. Clapton used a Mk. II ). It seems I can get closest to those sounds with the attack set at about noon and my guitar volume on 8. It's not identical, but really close. Of course, I'm using different equipment. My amp is a solid state Kasino from the early 1970s and my Epiphone Les Paul has those cheap "classic" humbuckers. So, I guess it would sound even closer to the real thing with a tube amp? If I had one, I'd definitely try it. Thanks.
- Electric Warrior
- Diode Debunker
I believe Disraeli Gears was just a cranked Marshall JTM45/100 like this:
- ljn
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You may be right. I did read somewhere that he used a Mk.II, but that could've been someone who was just trying to boost the pedal's reputation. Can't remember where I read it, though.
- Electric Warrior
- Diode Debunker
Clapton often played with the amp cranked and the tone control on his guitar down, which can sound rather similar to some fuzz pedals.
- ljn
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- Completed builds: Fuzzrite (Si and Ge versions) , univibe, companion fuzz, fuzz face(si version), FY-6 super fuzz, FZ-1S, Scrambler, Tone Bender MkI (nearly complete). I have modded my vox v847,Seymour Duncan tweak fuzz, my bass and my guitar ( slightly).
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Yeah. I actually used to think that Tony Iommy was using some sort of Tone Bender until I looked into it. It amazing what a studio can do, isn't it? Somehow I keep forgetting about those things.
- Electric Warrior
- Diode Debunker
Electric Warrior wrote:And where would you get a matched transistor set by someone who knows what he's doing?
People come here all the time with sets selected for gains that are way off and then rebiased to voltages that are off even more.
You're pretty close to the right ballpark already and you're taking the right steps to fix the gating.
Q1c and Q2c are a little low, Q3c is alright, but could be a little higher. Less leakage for Q1 and Q2 and more leakage for Q3 should fix that.
Using smaller values for Q1's base and Q2's collector resistance (like you already tried) will make up for too much leakage at Q1 and Q2, but that will bring Q3C further down, so might want to use a leakier transistor there (of which you seem to have plenty).
I try to get Q1C somewhere between 8.5 and 9V, Q2C between 0.13 and 0.20V and Q3C between 8 and 9V with a battery measuing around 9.5V.
Whoops, I made a mistake there. All three collector voltages decrease with increased leakage of their transistor - BUT Q3C depends a lot on Q2's leakage (and collector resistor). The higher Q2C, the lower Q3C.
- ljn
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- my favorite amplifier: Sears 125 xl, Kasino U100-P
- Completed builds: Fuzzrite (Si and Ge versions) , univibe, companion fuzz, fuzz face(si version), FY-6 super fuzz, FZ-1S, Scrambler, Tone Bender MkI (nearly complete). I have modded my vox v847,Seymour Duncan tweak fuzz, my bass and my guitar ( slightly).
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It's cool, man.
- Electric Warrior
- Diode Debunker
I figured someone might use this thread for reference in the future, so it's better to clear up where I was wrong.
- ljn
- Solder Soldier
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- Posts: 222
- Joined: 29 Nov 2014, 00:48
- my favorite amplifier: Sears 125 xl, Kasino U100-P
- Completed builds: Fuzzrite (Si and Ge versions) , univibe, companion fuzz, fuzz face(si version), FY-6 super fuzz, FZ-1S, Scrambler, Tone Bender MkI (nearly complete). I have modded my vox v847,Seymour Duncan tweak fuzz, my bass and my guitar ( slightly).
- Location: United States
- Has thanked: 7 times
- Been thanked: 7 times
I can definitely understand that.