[sdiy] ALFA clone chips?

Benjamin Tremblay btremblay at me.com
Mon Mar 29 15:23:09 CEST 2021


Ooh yes I toasted a 303 back in the early 90s. I thought: this instrument is worthless, maybe I can just use the filter. I forgot how the traces just melted away when I tried to desolder. And forgot that when I recently tried to desolder the lcd socket on a DR-202.

Benjamin Tremblay

> On Mar 29, 2021, at 7:36 AM, Richie Burnett <rburnett at richieburnett.co.uk> wrote:
> 
> 
>> 
>> They were built out of floor-sweepings grade parts.  They were shit.
>> 
>> And no two sounded even vaguely the same.
> 
> Well, I think they all sounds great! :-))
> 
> There's also an electrolytic capacitor that's fitted backwards in the TB-303 too!  I've not heard it discussed much, and can't even remember which one it is now, but I discovered it when analysing the circuit and checking it against the actual populated PCB.  It has got significant DC bias across it, and it's a polarised capacitor but fitted the wrong way round.  I didn't get round to de-soldering it and comparing its C and ESR with the others that were fitted with the correct polarity but I'd imagine that has got to have an effect over the years.  To be honest the crappy phenolic PCB in there is so old that I'd get worried de-soldering anything from it now!
> 
> -Richie,
> 
> 
> 
> 
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