Imitating TX series feedback loops

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joey
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Imitating TX series feedback loops

Post by joey » Sat Aug 01, 2020 4:13 am

hey guys

TX1/2/3 + tm7 are very interesting circuits with feedback loops, but obviously very hard to find these days

im curious how one would go about patching similar things with the euro modules

obviously with a few RK2s or R57s you could probably get in similar territory, but what exactly is the internal feedback routing of the various TXs? they use multiple tubes - are the tubes in series, parallel, etc, what tubes feedback the other?

i get some cool oscillation when i patch my r56 in a feedback loop

perhaps we can all share some experiments

cheers :)

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darmklacht@gmail.com
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Re: Imitating TX series feedback loops

Post by darmklacht@gmail.com » Sun Aug 02, 2020 8:44 am

I don´t know if this helps but:

with the TM-7 the feedback (Teabagmode) sounds diffrent than putting the entire pedal in a feedback loop.
so the only thing I can tell you is in the TM-7 its not the input thats connected to the output. Which is great because putting it in a feedback loop will add just another kind of feedback noise.

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joey
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Re: Imitating TX series feedback loops

Post by joey » Sun Aug 02, 2020 10:29 am

yeah thats what I was kind of getting at, i'm assuming the feedback loops lie between the different tubes

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darmklacht@gmail.com
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Re: Imitating TX series feedback loops

Post by darmklacht@gmail.com » Sun Aug 02, 2020 11:12 am

Yeah I just tried to confirm your thinking.
If I´m right the TM-7 has thee tubes one for the input level and two others for subsequential gain and distortion.
My guess would be the feedback loop is at the second tube. the lower the first gain knob is set the less the passing sound interferes with the feedback noise. the most interesting tweaking is done with that knob in my opinion.
I cant try right now but perhaps a r51 or r57 going into the RK2 would work similar. You have the feedback control built into the rk2 or perhaps you can try using the second output as feedback for diffrent sounds.

The f-1 also has a feedback loop around whatever the first knob does, I dont think the volume knob interferes with the feedback. The Feedback loop is straight at the beginning of the circuit as the impedance of the outputand the amplitude of the incoming signal play a great role in how it sounds.

All of this are just straight guesses. Mabey Eric will come and tell me I´m wrong

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metasonix
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Re: Imitating TX series feedback loops

Post by metasonix » Mon Aug 03, 2020 2:45 am

darmklacht@gmail.com wrote:
Sun Aug 02, 2020 11:12 am
If I´m right the TM-7 has thee tubes one for the input level and two others for subsequential gain and distortion.
My guess would be the feedback loop is at the second tube. the lower the first gain knob is set the less the passing sound interferes with the feedback noise. the most interesting tweaking is done with that knob in my opinion.
I cant try right now but perhaps a r51 or r57 going into the RK2 would work similar. You have the feedback control built into the rk2 or perhaps you can try using the second output as feedback for diffrent sounds.
Wrong
The f-1 also has a feedback loop around whatever the first knob does, I dont think the volume knob interferes with the feedback. The Feedback loop is straight at the beginning of the circuit as the impedance of the outputand the amplitude of the incoming signal play a great role in how it sounds.
Right
All of this are just straight guesses. Mabey Eric will come and tell me I´m wrong
lol

I have the schematic of the TX2 and 3 handy. Do you want to see them and build your own, or is all this just "academic"?

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joey
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Re: Imitating TX series feedback loops

Post by joey » Mon Aug 03, 2020 3:31 am

i'm more interested in the actual feedback loops themselves than replicating the designs

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joey
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Re: Imitating TX series feedback loops

Post by joey » Tue Aug 04, 2020 4:04 am

adding to this, here is RK3 + RK4 in a couple feedback loops with a two oscs and an R56 on the end


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