[sdiy] BBDs

[anthony]

> Is it really true you can run the MN3207 or MN3007 up to 1.5Mhz?  The 
> datasheets rate them only up to 200 or 100 KHz.
> Do you think this would this overheat the chips, or degrade the sound 
> quality?

Yeah it's easy and it works. I've done it without a buffer with a MN3207. 
Something happens as it gets out of its range. I think the datasheet 
mentions that the clock biasing becomes nonlinear after 200kHz or something 
like that. There's also ever the hint of the effect 'fading' as the 
frequency gets past the rated range. The Reticon ones seem to fall flat 
right above their rated range. You can feel it 'drop out' or something. I 
was using a crummy clock though. The datasheet refers to this as 
'dispersion' I think. No big deal with those though since their range is 
about 1.5 MHz anyway.

> I guess the driver chip (e.g. MN3102) would cope fine as long as it was 
> buffered as you describe.

I wouldn't even bother with the MN3102. 4046's and 4047's are a lot cheaper. 
(Their numbers are close but they're different...) The MN3102 makes the Vgg 
supply a tiny bit easier but that's about it.


>> A lot of the earlier flangers and choruses used SAD1024's and SAD512's 
>> and R5106's which have a higher rated max clock speed. These seem to be 
>> the more prized of the vintage flangers.
>>
>
> Or perhaps an MN3009 or MN3209 would be good? (still only rated up to 
> 100KHz, but only 256-satge)

The less stages the easier it is to overclock it. Less capacitaive 
reactance.

> Seb