Author Topic: DIY Peterson preamp (tremolo) pedal  (Read 146 times)

Offline JanneI

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DIY Peterson preamp (tremolo) pedal
« on: September 11, 2019, 01:06:57 AM »
Hi,

I made a DIY peterson preamp pedal. It uses vactrols (like VV preamp), otherwise it's identical with original Peterson. Here's a quick demo which compares it to VV model:

https://youtu.be/d2y6bqWHQtU

Best,
Janne

Offline sean

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Re: DIY Peterson preamp (tremolo) pedal
« Reply #1 on: September 12, 2019, 05:31:26 PM »


Janne,

18 seconds?  Really?  18 SECONDS!??  That's all you are giving us?

This looks wonderful!  Awesome job.  Did you make only one? 

Can you share the Gerber files for the PCB?

Can you tell us what model Vactrol you used, and where you bought it?

This is really awesome, so we want to hear a whole lot more about the whole project.

Sean

Offline JanneI

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Re: DIY Peterson preamp (tremolo) pedal
« Reply #2 on: September 13, 2019, 12:55:23 AM »
 ;D

The whole project started with taking a closer look at Vintage Vibes stereo vibe preamp, which I had purchased long time ago. I got interested in how it differs from the original Peterson schematic and by back-engineering I found out that the only difference was in the tremolo section (bulbs -> VTL5C1's). This simply been just some resistor value changes and a slew generator to simulate bulb behavior.

I opened up their power supply (that red one) and noticed that there's only that mean well supply and some jacks. Preamp current draw is only <30mA with the vactrols. For my pedal I used DC-DC converter (9-36v -> 24v) and now it powers even 9v battery, wall wart being a better option of course.

I designed a pcb and used parts that fit Hammond 1590B enclosure, so no wiring needed. Only expensive parts on the VV preamp (besides vactrols) are the pots, so for this pedal I used single pots instead of dual concentric ones. It needs C50k for depth control (can be modded with b100k&100k res) but for speed control I left out the 82k res for the "slow speed switch" and used b100k instead. So, this pedal has larger scale, which I liked more.

That's basically it. I'll not be sharing gerbers but I can sell pcb for personal use. This as a courtesy towards VV, they do excellent work and I don't want to harm their business. PM if interested.

Cheers,
Janne