Transistor preamps and ring modulator

[Omnirath]

Hello guys,
First I want to thank you all for the forum which, even as an observer was extremely helpful in lots of my builds !

I'm tackling again the age old transformer ring modulator but now I choosen to omit using a sine wave generator and ics as buffer... Not because they aren't good but because it's not the sound I'm seeking with it right know,

So I'm asking if you guys have any ideas for fet or transistor based buffers able to drive transformers. I'm planning on using 2 slightly tweaked octavia's circuits with lower gain for the inputs and the carrier and a fet buffer at the end but any help or advise would be appreciated !


Omni

[antonis]

Hi & Welcome..

Although I don't think you need a buffer for transformer driver (at least for Octavia alike transformer), a BJT based buffer of about 5mA or so working current should be prefered contrary to JFET one due to higher transconductance..
(hence lower output impedance..)

[Omnirath]

Thanks for the advice on fets, I think I'll go with a circuit based on the axis with germanium pnp cause I wanna dial a bit of fuzz into this (it supposed to blend the guitar and an homemade electric zither for noise purposes even if it is sometimes used as a sitar, close to the amp to resonate)

Anyhow my transformers are 1:1 10k but I think this configuration should work thanks !

[antonis]

A draft schematic of what you set out to build should be helpful..

[Omnirath]

Yeah you're right! Really its just one basic mayer axis fuzz plugged into the input transformer of the ring mod, one other axis into the carrier and one other at the output of the second transformer

Well I'll build it to see how it sounds, trace the schematic for it and report back thanks !

[Omnirath]

Hello guys,
So I said I'd report back but I had a lot of things to take care of in the meantime but anyhow I ended up making the ring modulator using this configuration : a octavia driver and a small recovery stage running on 18v. It's very simple and far easier to make than most circuits I've seen.

For now I use a xr2206 based function generator which works well even if I choose to not incorporate it in the pedal itself.



And for the transformers I used 10k:10k ones, to my surprise it worked quite well but I would suggest trying some closer to the 42tm022 it might be louder but even without that it already have enough volume.







I'm very pleased with the result the ring mod sound fantastic and the extra dirt of the Octavia gives interesting sounds too

[sinthmart]

Просто по теме кольцевых модуляторов: