Thanks, bro!Electric Warrior wrote:I forgot, I swapped them so often :D
will measure them tomorrow for you..
Tone Bender MKII Circuit Low Gain Trannys
Moderator: The Captain
- Stu
- Posts: 3153
- Joined: Wed Nov 19, 2008 9:35 pm
Re: Tone Bender MKII Circuit Low Gain Trannys
OC75 MkII (10K on Q1 base, 47K on Q2 collector)
Battery -9.01
Q1 c -8.50 b -0.038 e 0
Q2 c -0.13 b -0.076 e 0
Q3 c -8.29 b -0.13 e -0.08
OC81D MkII #1 (100K on Q1 base, 100K on Q2 collector)
Battery -9.55
Q1 c -8.51 b -0.06 e 0
Q2 c -0.13 b -0.068 e 0
Q3 c -8.72 b -0.13 e -0.07
OC81D MkII #2 (100K on Q1 base, 100K on Q2 collector)
Battery -9.50
Q1 c -8.76 b -0.062 e 0
Q2 c -0.22 b -0.075 e 0
Q3 c -8.13 b -0.22 e -0.14
Battery -9.01
Q1 c -8.50 b -0.038 e 0
Q2 c -0.13 b -0.076 e 0
Q3 c -8.29 b -0.13 e -0.08
OC81D MkII #1 (100K on Q1 base, 100K on Q2 collector)
Battery -9.55
Q1 c -8.51 b -0.06 e 0
Q2 c -0.13 b -0.068 e 0
Q3 c -8.72 b -0.13 e -0.07
OC81D MkII #2 (100K on Q1 base, 100K on Q2 collector)
Battery -9.50
Q1 c -8.76 b -0.062 e 0
Q2 c -0.22 b -0.075 e 0
Q3 c -8.13 b -0.22 e -0.14
- Electric Warrior
- Posts: 3620
- Joined: Sun Nov 09, 2008 2:19 am
- FUZZTX
- Posts: 170
- Joined: Thu Oct 29, 2009 10:39 pm
- Location: Funky Town FTW, Texas
Re: Tone Bender MKII Circuit Low Gain Trannys
Thanks, Stu! That is some great info!
- Electric Warrior
- Posts: 3620
- Joined: Sun Nov 09, 2008 2:19 am
Re:
gains were 96, 135, 68. plenty of leakage: 610µA, 525µA, 525µAFUZZTX wrote:What do your transistors measure gain & leakage wise, Electric Warrior? I'd really like to know what vintage units measured, too!
Regarding Q2 collector voltage, mine measures about the same as yours, but I noticed the voltages changes as I turn the "Attach" control up or down?
I'm experimenting with some other combinations right now, trying to match Stu's measurements.. some wild results so far
Everything is transitional.
- Taller76
- Posts: 104
- Joined: Wed Sep 23, 2009 11:34 pm
- Location: Tropicana Hotel Room 100 B
Re: Tone Bender MKII Circuit Low Gain Trannys
Cool numbers to have for reference, thanks for sharing!Stu wrote:OC75 MkII (10K on Q1 base, 47K on Q2 collector)
Battery -9.01
Q1 c -8.50 b -0.038 e 0
Q2 c -0.13 b -0.076 e 0
Q3 c -8.29 b -0.13 e -0.08
OC81D MkII #1 (100K on Q1 base, 100K on Q2 collector)
Battery -9.55
Q1 c -8.51 b -0.06 e 0
Q2 c -0.13 b -0.068 e 0
Q3 c -8.72 b -0.13 e -0.07
OC81D MkII #2 (100K on Q1 base, 100K on Q2 collector)
Battery -9.50
Q1 c -8.76 b -0.062 e 0
Q2 c -0.22 b -0.075 e 0
Q3 c -8.13 b -0.22 e -0.14
My most recent MKII build spec'd out like this:
10K on Q1 base, 100K trimmer (set just shy of half...probably around 47K) on Q2 collector
Volume and Attack set full
Battery -9.49
Q1 c -9.12 b -0.010 e 0 (Mullard "Red Head" OC84 2R5 107 hfe 0.04mA)
Q2 c -0.66 b -0.110 e 0 (Mullard "Red Head" OC84 2R5 88 hfe 0.04mA)
Q3 c -*6.81 b -0.40 e -0.29 (Mullard OC84 2T5 78 hfe 0.06mA)
*voltage depends on trimmer...seems to sound good anywhere from 4.80 to ~7v
Stu I am sure like anything sonically there were differences, but of the 3 was there one that clearly sounded better than the other ones?
Last edited by Taller76 on Sun Aug 01, 2010 9:18 pm, edited 1 time in total.
Thanks for the American dream,
To vulgarize and to falsify until the bare lies shine through.
To vulgarize and to falsify until the bare lies shine through.
- FUZZTX
- Posts: 170
- Joined: Thu Oct 29, 2009 10:39 pm
- Location: Funky Town FTW, Texas
Re: Re:
Thanks, man! I'd be interested to hear your results.Electric Warrior wrote:gains were 96, 135, 68. plenty of leakage: 610µA, 525µA, 525µAFUZZTX wrote:What do your transistors measure gain & leakage wise, Electric Warrior? I'd really like to know what vintage units measured, too!
Regarding Q2 collector voltage, mine measures about the same as yours, but I noticed the voltages changes as I turn the "Attach" control up or down?
I'm experimenting with some other combinations right now, trying to match Stu's measurements.. some wild results so far
Hey Taller76. That is great info to have. Much appreciated and thanks for sharing!
- Electric Warrior
- Posts: 3620
- Joined: Sun Nov 09, 2008 2:19 am
The transistor combination I had in there was pretty nice, albeit a bit dull sounding. Cleaned up ok. Noise was not an issue.
The one I'm putting together now has more midrange honk, clarity and sparkle. Doesn't clean up as well and it tends to be a bit noisier. I consider it much more useable. Has great character
Although the voltages are similar, I believe the transistor gains are not. I'll tweak and measure some more when the room temperature here is back to an average level..
The one I'm putting together now has more midrange honk, clarity and sparkle. Doesn't clean up as well and it tends to be a bit noisier. I consider it much more useable. Has great character
Although the voltages are similar, I believe the transistor gains are not. I'll tweak and measure some more when the room temperature here is back to an average level..
Everything is transitional.
- FUZZTX
- Posts: 170
- Joined: Thu Oct 29, 2009 10:39 pm
- Location: Funky Town FTW, Texas
- Electric Warrior
- Posts: 3620
- Joined: Sun Nov 09, 2008 2:19 am
yes, OC75s. I can get many different tones just by swapping transistors...
David published some hfe measurements: http://stompboxes.co.uk/forum/viewtopic.php?f=10&t=6569
David published some hfe measurements: http://stompboxes.co.uk/forum/viewtopic.php?f=10&t=6569
Everything is transitional.
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