[sdiy] MN3207 and MN3102 Reissues

[Gavin Muir]

Actually, this is why I was interested to see some discussion of the 
unit here. I never saw this so much as a "guitar" pedal, as it seems to 
be the ideal way to add depth to digital synths, and spaciousness to 
analogs.

Hey, if it can do THAT to the ol' DX tubular bells!! ;-)

I would LOVE to put together a couple of souped up "C" boards for my 
DIY synths (not to mention that I would love to introduce my Obie to it 
as well!!) ;-)

Gav

I
On 30-Oct-04, at 4:58 PM, Scott Stites wrote:

> I listened to the samples of this chorus device at Modzero.  Holy 
> moly, that
> *is* a great sounding chorus!  Checking out the switchboard on the
> schematic, I don't think I quite understand it yet.
>
> Cheers,
> Scott
>
>
> ----- Original Message -----
> From: <mirwin at qouest.net>
> To: "Gavin Muir" <gmuir at sympatico.ca>
> Cc: <synth-diy at dropmix.xs4all.nl>
> Sent: Saturday, October 30, 2004 8:56 AM
> Subject: Re: [sdiy] MN3207 and MN3102 Reissues
>
>
>> Gavin,
>> The guitar lists are really the most suitable place to discuss the
>> cloning of vintage guitar fx units - half the discussion revolves 
>> around
>>  cloning, subs, copyright issues etc.
>>
>> Regarding substitutions, most of the original Japanese parts are still
>> available, including the different transistors, the MN3207 (and the
>> companion MN3102 driver) are about as mainstream as it gets with 
>> BBD's,
>> relatively easy to find compared with ther BBDs, the NE570/571 
>> compander
>> is also a mainstream part. Parts warehouses that cater to the consumer
>> electronics repair industry usually have these (check Main Electronic
>> Supply in  Vancouver or www.bdent.com). The single supply op amp used 
>> in
>> the clock circuit (IIRC a BA718) may be hard to find, I tried several
>> single-supply op amps with better specs (including TLC272) but 
>> achieved
>> the best results with a lowly LM358.
>>
>> The neat thing about the Dimension choruses is that they try to 
>> achieve
>> a "vibrato-free" chorusing through "static" pitch detuning by means of
>> two parallel delay lines modulated by complementary LFO triangles.
>> Listened to individually, each delay line output has it's pitch 
>> shifted
>> alternately up and down (sounds like a VCO being slightly 
>> freq-modulated
>> by a slow square wave). When the two delay outputs are combined, the
>> result sounds like two static pitches, slightly detuned, with a slow
>> beating taking place. A wonderful effect. Roland patented this 
>> technique
>> in the early 80's. The "D" has a better clock circuit than the "C", as
>> well as more elaborate cross-mixing and filtering, plus the line 
>> drivers
>> and bar graph, etc.
>> Regards, Mike
>