Modified Passive Ring Mod build question

[dr.benway]

I've built a passive Ring modulator and want to have the option of switching between an external and an internal carrier wave . Is it enough to place an spst switch between the carrier input and the onboard wave generator circuit ?

[Mick Bailey]

Ideally you need a SPDT switch - the centre terminal connects to your ring mod carrier input. One outside terminal then connects to the onboard wave generator, the other connects to your external carrier. Ground connections must all be tied together.

However, you can use a SPST switch as you suggest, so long as the external input is unplugged when the internal wave generator is selected. Otherwise the internal signal will be connected to both the ring mod carrier input and the external circuit simultaneously and you may get unexpected or peculiar interactions. 

[dr.benway]

Thanks for the tip . Next on my list is your ugly face lfo which sounds great.


I actually used a toggle dpdt to switch between wave generator and external carrier input- I guess it wasn't necessary.
I have three circuits connected : escobedo utility boost to input, the passive ring mod, and the wave generator.
initially i connected them with patch cables and the result was good. Now I grouped everything using a dpdt to bypass the ensemble, but I'm having ground hiss yet all the grounds are connected.

My wave generator uses a 9v bipolar battery supply, the boost a 9v dc jack for power....could the problem be coming from this situation ?

Hope you or someone else can provide some insight. I'll try to sketch something up if you wish.

Thanks

[dr.benway]

well i looked at the effect again...the dpdt is there for a reason in fact (i think): when the switch cuts the input it powers on the tone generator.