AW: AW: VCO-1C #2

[Fraser, Colin J]

> -----Original Message-----
> From: Sean Costello [mailto:costello at seanet.com]
> Sent: 07 January 1999 17:25
> To: Haible Juergen
> Cc: DIY; Tony Allgood
> Subject: Re: AW: AW: VCO-1C #2
> 
> I thought that the CEM VCO's for the JP-6 and MKS-80 were selected for
> how well they would behave using Roland's hard sync.  Chips that would
> not sync properly would still be perfectly suited for the SH-101 and
> MC-202, where no syncing ability was necessary.

One of the worst things about the 3340 is the implementation of osc sync -
to do it properly you have to use external circuitry (as Roland did).
I made some comparisons between the oscillators on my Pro-One and my
Prodigy. There isn't really any audible difference between the unfiltered
waves by themselves but the difference between the depth of swept synced
oscillator effects is incredible, the Prodigy blows the P1 away - pity the
Prodigy doesn't have the same modulation section (yet !).

According to Roland - "The factory has had to selectively use the ..
CEM3340. This is because of characteristic variations among later CEM3340s
supplied from the manufacturer. And this makes VCO adjustments difficult
especially in SH-101."

The selection criteria are - "Can generate at very low frequency with low
CV." and "Can linearly track to VCO adjustment."
They put selected chips into two groups, both groups may turn up in the JP6
and MKS80, only the best turn up in the SH101.

Colin f