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Monday, August 14, 2017

Tortenmann TA-100

Came across the schematic for this and thought it would be a good addition. It's a unique germanium overdrive using PNP AC128s, though the effect is a negative ground effect (so it can be daisy chained with other pedals). The TA-100 has been used by Ryan Adams and sounds great through a Princeton Reverb. Schematic here on FSB.


12 comments:

  1. Layout is good y'all.... The only thing is the gain pot goes from just breaking up to all out crazyness in the last 5%. The gain switch kicks things up a notch for sure. Turn your guitars volume pot down and you can get some great tones out of this. You should build this. I built mine with NOS 2n408s and bat41's cause I ran out of 1n34s. Have some on order so will report back once I receive them. Another great layout brotha!!!

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    Replies
    1. Cool. Thanks for verifying! You might want to try a C50k (rev log) pot for the gain to even out the sweep.

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    2. Works great, thanks a lot !
      Same remark for gain pot.

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  2. Does this require AC128's of a certain gain/hfe? Thanks for the layout!

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    Replies
    1. Nothing was posted about the transistors being a certain hfe. You'll probably have to experiment with that. But it should work with other PNP germanium transistors as well.

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  3. HI
    Ive built this and I am getting no affected sound. Using GT 313B trannies. Only part sub was 220nf cap.
    Voltages at trannies are:E-B-C
    Q1 9.1 8.3 0.0
    Q2 6.8 6.6 6.8
    Q3 9.2 8.6 0.0
    Also, FWIW, I am getting continuity between the input and ground. That does not seem right?
    Thanks!

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  4. P.S. Using 9volt battery reading 9.5V to power

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  5. I have a short question: Would it be possible to use a SPDT Switch for this layout and then just change Pin 1 to 3?

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    Replies
    1. A SPDT is fine. You don't need to change the pins tho. Just use pins 1-2, and ignore pin 3.

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  6. i think there is mistake with Q1. It has to be npn, just look on resistors on collector& emiter! I used Q1 npn mp38a, tried bias, working great from slight over to fuzz teritory. Second thing - gain pot should be 2or 5 kom max!! Just do it, people! look at my changed scheme here: https://imgur.com/TU07btD

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  7. Made a couple of these with Texas Instrument R591 transistors and a C50K gain pot. Excellent stuff - raw and lots of fun.

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