Cgs synth

> Hi, I've just come across this group, and have some questions about
> Ken's passive ring modulator boards (I like ring mods, so I'm

> to try one). Does a passive ring mod drop the signal level enough

> need some sort of gain stage after it (and if so, does it need
> anything special, or would a basic op-amp stage do the job?)Also,

> does the sound differ from a standard balanced modulator? My
> intended use is to modulate the output of two VCOs with each other,
> or one VCO against a preamped signal from another instrument.

>
> Message: 1
> Date: Tue, 27 Jul 2004 13:36:28 -0000
> From: "charlesosthelder" <osthelder@...>
> Subject: Re: Ring modulator questions......
>
> The passive ring modulator sounds different because of the losses
> inherent in the transformers and to a lesser extent, the diodes.
> However, these losses are frequency specific, making the circuit
> very "organic" sounding when compared to an active balanced
> modulator. I liked the sound so much I made a dual RM module.
>
> The signal loss is enough for most to add a make up amp. I went with
> a non-inverting op-amp with a gain of about 3, followed by a buffer.
> This arrangement uses a single TL072.
>
> A "ring" modulator is a nickname for a diode-based balanced
> modulator. Ken's article on his website clearly points out why.
> This is a very old radio circuit (from the 30's) designed to improve
> radiotelephony by using the sidebands of modulated speech. Sideband
> information is of higher frequency, and therefore covers a much more
> narrow band of radio frequencies. An AM signal is over 6KHz wide,
> while a single sideband signal is about 1.5KHz wide. It is also much
> easier to filter the sideband signal.
>
> Any information you'll need is available in the message archives of
> this list. Also, I still have a small cache of germanium diodes and
> I'd be happy to send you a matched quartet.
>
> Chub

--- In cgs_synth@yahoogroups.com, "R. Drake" <rdrake@d...> wrote:
> Chub,
>
> I'd like to take you up on the offer of a set of diodes, but at
the very
> least let me reimburse you for shipping... if your offer stands,
send to
>
> Bob Drake
> PO Box 585
> Cleveland OH 44107
>
> and I'll shoot you back whatever the postage is, plus a little
something
> from the parts bin...
>
> best
> luigi-bob drake
>
>
> on 7/28/04 5:40 AM, cgs_synth@yahoogroups.com at
cgs_synth@yahoogroups.com
> wrote:
>
> >
> > Message: 1
> > Date: Tue, 27 Jul 2004 13:36:28 -0000
> > From: "charlesosthelder" <osthelder@n...>
> > Subject: Re: Ring modulator questions......
> >
> > The passive ring modulator sounds different because of the losses
> > inherent in the transformers and to a lesser extent, the diodes.
> > However, these losses are frequency specific, making the circuit
> > very "organic" sounding when compared to an active balanced
> > modulator. I liked the sound so much I made a dual RM module.
> >
> > The signal loss is enough for most to add a make up amp. I went
with
> > a non-inverting op-amp with a gain of about 3, followed by a
buffer.
> > This arrangement uses a single TL072.
> >
> > A "ring" modulator is a nickname for a diode-based balanced
> > modulator. Ken's article on his website clearly points out why.
> > This is a very old radio circuit (from the 30's) designed to
improve
> > radiotelephony by using the sidebands of modulated speech.
Sideband
> > information is of higher frequency, and therefore covers a much
more
> > narrow band of radio frequencies. An AM signal is over 6KHz
wide,
> > while a single sideband signal is about 1.5KHz wide. It is also
much
> > easier to filter the sideband signal.
> >
> > Any information you'll need is available in the message archives
of
> > this list. Also, I still have a small cache of germanium diodes
and
> > I'd be happy to send you a matched quartet.
> >
> > Chub