[sdiy] ALFA clone chips?

[cheater cheater]

What's a TZ 3340?

On Sun, Mar 28, 2021 at 12:36 AM ColinMuirDorward
<colindorward at gmail.com> wrote:
>
> >>Is that just the AS3340 or the CEM3340 as well?
>
> My understanding is that some but not all cem3340 suffered from the same problem (some early versions?) Even for the as3340, I wondered if there are varying degrees of the problem.
>
> I chatted with a rep at Alfa Rpar a couple years ago and tried to convince him to do a TZ 3340 version. He said something like "oh that looks easy enough", but of course they did the 3396 and whatnot, instead. It would be amazing if they solved the PWM/pitch issue and added linear TZ in one fell swoop. Then we might have drop-in TZ upgrades to existing gear that uses the linear FM input.
>
> On Sat, Mar 27, 2021 at 7:34 PM cheater cheater <cheater00social at gmail.com> wrote:
>>
>> >> On 27 Mar 2021, at 18:19, cheater cheater <cheater00social at gmail.com> wrote:
>> >>
>> >> Thanks. was the original CEM3320 equally easy to damage? Did the other
>> >> chips have similar problems in their original versions?
>> >>
>>
>>
>> On Sat, Mar 27, 2021 at 7:48 PM Tom Wiltshire <tom at electricdruid.net> wrote:
>> >
>> > Yes, the early CEMs were just the same, and the early SSMs were worse, since Dave Smith had to move the Prophet 5 from one chipset to the other to get it to stay in tune.
>> >
>> > The current CEM3340 is Rev.G. My understanding is that Rev.G was only a datasheet change and an acknowledgement that some of the claimed figures for Rev.F weren’t likely in practice, but that still means there were five versions fixing earlier problems. I think that’s worth bearing in mind when we compare chips from Coolaudio and Alfa with the originals. We’re comparing later versions with early versions in most cases. CEM took a decade to get the chips to the final state that we’re judging against.
>>
>> I thought what these companies did (CoolAudio aka Uli Behringer, ALFA,
>> SSI) was take photos of the old chips and re-issue them based off
>> that?
>>
>> > BTW, there’s a good application note now for the PWM problem:
>> >
>> > https://www.alfarzpp.lv/eng/sc/AS3340%20tip%20VCO%20_%20PWM%20.pdf
>> >
>> > I’m sure it’s not the only solution. I’d like to see something like this integrated onto the silicon and an AS3340 Rev.B get released. Fixing things is not a failure, but a success. No-one expects everything to be perfect first time. It’s what you do next that counts.
>>
>> (...which may or may not mean reissues are impossible)
>>
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