Yamaha CS80

From: "JH." <jhaible@...>
Subject: Re: [yamahacs80] heatpipe?
Date: Thu, 8 Nov 2007 00:07:11 +0100
Message-ID: <117901c82192$ef856de0$0400a8c0@jhsilent>

Dear J\ufffdrgen,

> Nice to hear from you Magnus. It's been a while ...

Um Yes, I realize that. Been busy. Moving my studio to a separate shop among
other things.

Also doing unspeakable things like almost fooling people that I am the boss.
Not to worry, not at work!

> >> I once heard about someone who put a heatpipe into his CS-80.
> >> I can imagine that will be quite an undertaking, mechanically.
> >> But then you could force all the oscillators to be on a more or less
> >> fixed
> >> temperature, couldn't you?
> >
> >No, more or less the same temperature, not a fixed temperature.
> 
> The idea is a heatpipe with 17 contact points:
> 16 for the VCOs, and 1 with a *regulated* temperature (a heater or a peltier
> cooler with thermostat).

That was certainly not clear from what I had to go on (see text above).

Question is weither you need to go that drastic. Normal polyphonics certainly
don't need that. It is a bit of a heavy project.

You could do it much leaner and meaner if you attempt to approach it similar to
what we have seen in OB-8, Xpander or for that matter other modern analog
poly-designs.

That would mean a combination of temperature compensation and auto-tune.
Neither would require the rocket science and level of intrusion that the heat
pipe exercise would require.

In the old days you had a wooping Z80 and a 8253 doing the magic. These days
you have the necessary stuff sitting in a cheap of the shelf ARM. I doubt that
a very large range of tuning values actually is needed, but if so a better DAC
with associated S/H can be arranged for.

As with the OB-8 you can ignore hitting the autotune button. Sometimes you
would even like to have a detune mode where the autotune was canceled.

Or am I being too much of an advanced Synth-DIY man now?

Cheers,
Magnus