Sunn Model T

[K Pedals]

Sunn Model T (1st Gen) Preamp

Collection of vero (stripboard) & tagboard layouts for 100s of popular guitar effects, with over 1000 verified designs. DIY your own boutique effects!

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[Nostradoomus]

I built the offering from guitar PCB, sounds pretty damn good.

 

[Robert]

I have something else you might like...... It just needs to be verified.

 

[K Pedals]

I have something else you might like...... It just needs to be verified.

???

 

[Devoureddeth]

You know what I have been playing around with on the breadboard is the IVP Poweramp simulation I believe that is what is used in the Model Fet. This schematic is similar to what is done in the IVP preamp.

 

[Robert]

Yep, the phase inverter section does look similar to what is done in the Model FET....

 

[Devoureddeth]

Yep, the phase inverter section does look similar to what is done in the Model FET....

Yeah this is what I figured when I looked at the PCB. It also sounds like it is more then just a Model T preamp. An IVP-like preamp would be pretty cool as well especially with that power amp module.

 

[temol]

You know what I have been playing around with on the breadboard

How did you like it? Any samples, simulations, comments?
T.

 

[Devoureddeth]

How did you like it? Any samples, simulations, comments?
T.

I found, similar to EAE, that the phase inverter simulation and transformer is the way to go. I tried playing with the LM386 just never worked out and were too noisy. Maybe in the future I will revisit it, it is a cute idea. For a transformer I used a 10k/10k xicon I had laying around this is similar to what was used in the IVP preamps. Someone else was playing with this recently and drew a schematic for a module or pedal. I haven't tried it yet but I saved it for when I had time. GK bass solid state amps use a similar circuit for their tube/power emulation.

 

[Devoureddeth]

It could be cool to have this as a stand alone utility board to pair with all the preamp that are starting to accumulate here. That tiny bit of transformer distortion adds that bit of something that I find many preamps lack.

 

[chongmagic]

I built the offering from guitar PCB, sounds pretty damn good.

View attachment 2570

I have one of those with the JFETs included I need to build.

 

[temol]

Interesting idea. My goal is to find something that does not require transformers. Or at least uses easily available, cheap transformers. I'm still jumping from circuit to circuit, trying different possibilities. But it's getting more and more complex, beyond my limited knowledge...

T.

 

[Robert]

I have one on the way. It uses the phase inverter circuit above, but no transformer.

 

[bifurcation]

I picked up this from coda-effects, which has similar claims (I haven't built it yet.)

Here's the PCB for reference:


And here's his build docs: https://drive.google.com/file/d/1v6ewctuVTcQh_FMEzD_LcnKRfY3F2P4k/view

 

[benny_profane]

The coda project is pretty cool. I recommend it. The whole concept here is a little funny, though, because the sunn amps are renowned for their ability to get loud without breaking up.

 

[Devoureddeth]

I have one on the way. It uses the phase inverter circuit above, but no transformer.

I was going to say the Model Fet PCB doesn't have a transformer. I have mainly been playing with the IVP preamp design but you probably don't need a transformer.

 

[Chuck D. Bones]

I picked up this from coda-effects, which has similar claims (I haven't built it yet.)
And here's his build docs: https://drive.google.com/file/d/1v6ewctuVTcQh_FMEzD_LcnKRfY3F2P4k/view

I went to Benoit's site and looked up the schematic. Very similar to the FET-based tube preamp emulators on this site: Covert, Tweed Man, Bohemia, Sabbra Cadabra, M800, Marble, Deofol, Pineapple, Corduroy, Boogie Monster, Sorcerer, Tantric, SOB, Distortr... (did I miss any?)

Not too surprising since they're all based on Fender, Marshall, or Sunn amps which trace their origins back to Fullerton.

 

[Chuck D. Bones]

On the topic of transformers, one of the things I did in a previous life was design inductors and transformers. Talk about voodoo. There are so many degrees of freedom and trade-offs in transformer design, it boggles the mind. Wire size, number of turns, winding geometry, core material, core geometry all play into the performance of an output transformer and it's not at all intuitive.

I don't think Leo Fender and his engineers set out to design their output transformers for a specific sound, any more than they did with the power supply, phase inverter, etc. But when they found something that sounded good, they new it and did their best to mass produce it.

All this is to say that simply putting a transformer into a pedal does not a good sound make.

 

[benny_profane]

I have something else you might like...... It just needs to be verified.

Is this still in the pipeline? Curious to see a circuit with the phase inverter / power amp section.

 

[Robert]

Is this still in the pipeline? Curious to see a circuit with the phase inverter / power amp section.

I have some prototype boards, I just need to order parts to build one.