[sdiy] BA662 (Was Re: SPV-355 -15V rail issue)

René Schmitz synth at schmitzbits.de
Tue Jun 20 10:36:29 CEST 2023


Am 20.06.2023 um 07:00 schrieb Roman:
>
> Looks very much like LM13700 to me, so why bother?
>
It makes a difference in certain circuits.

Mainly because the Iabc sits only at 0.6V vs 1.2V above Vee for the 
LM13700. And the buffer is different.

Best,

  René

>
> Roman
>
>
>
> ---- Użytkownik Tom Wiltshire napisał ----
>
> Interestingly, thre are a few minor differences between the 
> reverse-engineered Open Music Labs schematic (which the Re-303 uses) 
> and the Alfa clone. Some of the differences are obvious stuff, like 
> diode-connected transistors being shown as diodes, for example, but 
> not everything.
>
> Here's the Open Music Labs version:
>
> http://wiki.openmusiclabs.com/wiki/x0xb0x
>
> And here's Alfa's:
>
> https://www.alfarzpp.lv/eng/sc/AS662D.pdf
>
>
>
>> On 19 Jun 2023, at 13:10, Todd Sines <sines_list at scale.la> wrote:
>>
>> Din Sync make them for their RE-X0X series
>> That link would be here
>> BA662 Clone – RE-303 Web Shop 
>> <https://shop.re-303.com/product/ba662-clone/>
>> shop.re-303.com <https://shop.re-303.com/product/ba662-clone/>
>> 	<favicon.ico> <https://shop.re-303.com/product/ba662-clone/>
>>
>> <https://shop.re-303.com/product/ba662-clone/>
>>
>>
>> Todd
>>
>>> On Jun 19, 2023, at 4:39 AM, Tom Wiltshire <tom at electricdruid.net> 
>>> wrote:
>>>
>>>  Yes, Alfa make a clone - or at least a chip with that number:
>>>
>>> https://www.alfarzpp.lv/eng/sc/AS662D.pdf
>>>
>>>
>>>
>>>> On 19 Jun 2023, at 04:41, Adam (synthDIY) <synthdiy at adambaby.com> 
>>>> wrote:
>>>>
>>>> Actually, yes you're right, the Roland BA662 OTA that they used a 
>>>> lot around this time, both for VCAs and VCFs. I've sent you the 
>>>> schematic.
>>>>
>>>> I think they've been cloned successfully in recent years
>
>
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