Understanding ideal Ring MOD gain structure..help?

[loss1234]

Hello. I am trying out a few different ring modulator designs (many from the experimentalists anonymous schematic folder) and one of the problems i am having with ALL of them is that the guitar signal (which is either going in with no amplification or through an opamp with a gain of around 11 (non-inverting), the guitar signal is always so much quieter than the LFO/OSC that i am using as a modulator.

So my question is, should i reduce the gain of the OSC with resistors, or should i boost the guitar BEFORE the ring mod, or should i boost it AFTER the ring mod?

in other words, do both signals need to be at equal volume? or can i boost post ring mod? The one that sounds the best to my ears is the AARON CRAM 13700 ringmod (out of the ones i built today..some using an ad633, others just using opamps (ian fritz's analog xor)

anyway....to make a long story short even with the offset trimmers, the problem i was having  was that the guitar was either TOO LOUD (you mainly heard cleanish guitar with mod way in the back) or the MOD was really loud but was bleeding the whole time when i stopped playing.

i guess ring mods are tricky things.

thanks for ANY help.

[frequencycentral]

Hi Loss

You should try a 1496 based ring mod, which I believe has over 60dB of carrier suppression.

Roland System 100M Ring Modulator Schematic

I have two, one Roland in my 100M, another I built from the above schematic. Just a case of trimming the pots - with only one input in use hardly ANYTHING comes out.

Paul Perry (Frostwave) is probably your man if you want more detailed info.

EDIT: And you should definately boost your guitar signal before the ring mod - maybe use a EH LPB-1 for 15db of boost.

[loss1234]

thanks

BUt let me re-state my problem. when i boost the guitar loud enough to hear it (with the OTA type of balanced mod) i hear TOO Much clean guitar. i am searching for the style of ring mod where you ONLY HEAR THE RINGING not any of the original clean sound.

does this make sense?

right now it sounds like a MIXTURE of ring mod and clean guitar. i got the bleed down to a small amount though if thats any consolation

[Paul Perry (Frostwave)]

BUt let me re-state my problem. when i boost the guitar loud enough to hear it (with the OTA type of balanced mod) i hear TOO Much clean guitar. i am searching for the style of ring mod where you ONLY HEAR THE RINGING not any of the original clean sound.

Note that the OTA type, when properly balanced to minimise bleed of signal and carrier, only remains balanced if the power rail is kept constant. Mind you, if you are fussy, you really need to stabilise the power rails no matter what ring mod design you have. I tried everything (except the transformer type) and, chose the AD633.

Still, you should be able to get nearly all the original signal out using the OTA type - note that you will probably have to do some serious tweaking to get it right. just be careful you never run more than 10mA through the control pin of the OTA, or it dies in a nanosecond.
The 'correct' level of guitar, is loud as you can without distorting.
And the correct level of the modulation signal is as loud as you can without hearing distorted bleedthrough.

That Aron Cran circuit - I think it assumes a + - supply, probably +15 and -15. If you are running it on 9V, I doubt you can balance it.

[snap]

Make that: 2mA absolute maximum rating into the control pin of an LM13600 or LM13700 !
http://cache.national.com/ds/LM/LM13700.pdf

[Paul Perry (Frostwave)]

Thanks Snap! I stand corrected. There's a LOT of LM13700s here that are 'mono' rather than 'dual'  (usually from multimeter probes slipping while I was 'testing' them..
And, on  a lighter from Grant Richter, "The EH Frequency Analyzer can be seen duck taped to the Devo guitar with one string that Boogie Boy plays some times."