[sdiy] cem3328 questions

[Bob Weigel]

remember...I've tried to include all special chips in pages on my 
website.  eg. http://cu.imt.net/~sounddoctorin/synthtec/ensoniq/mirage.htm

If anyone has anything important I've missed let me know.  Also I'm 
building a table that has the chip used for analog functions in all synths.
-Bob

NSSINC wrote:

>
> cem 3328, is that the filter used in the ensoniq mirage? Sounds 
> familiar... I'd look at mine, but I don't know where they are, I just 
> moved.
>
> I have a very dead mirage I thought about yarding the filters from and 
> building stand alone filters and run it off a paia midi>cv...
> but thinking about it has not made it happen, yet!
>
> I know they are not the prettiest filters, but I like them.
>
> -Al
>
>
>
>
> tony Rolando wrote:
>
>> Last night I tied the inverting input to ground and the circuit is 
>> actually improved in my opinion. I say this because with no audio 
>> inserted I am getting larger output swings when the filter is put 
>> into self oscillation.
>>
>> I reworked the then unused op-amp into an output buffer for the 
>> cem3328 following it with a 680 ohm resistor.
>>
>> The sound is nice. Let me know if anybody is interested in trading 
>> something for one of these 3328.
>>
>> TR
>>
>>
>>> From: "tony Rolando" <goldenechos at hotmail.com>
>>> To: cfmd at bredband.net, lanterma at ece.gatech.edu
>>> CC: synth-diy at dropmix.xs4all.nl
>>> Subject: [sdiy] cem3328 questions
>>> Date: Mon, 19 Feb 2007 07:34:01 -0500
>>>
>>> I just built myself a CEM3328 Low Pass filter using the application 
>>> notes from the data sheet and my limited design skills. The module 
>>> works well. I buffered all of the Audio and CV inputs, put some 
>>> bypass caps in there and added all of the ins and outs you could want.
>>>
>>> I would like to get some opinions on two things though...
>>>
>>> Should have buffered the output, because I feel like I should have 
>>> even though there is a buffer on the (expensive) chip? (I think I 
>>> already know the answer to this one).
>>>
>>> In my audio input buffering stage I have a non-inverting follower 
>>> directly followed by an inverting follower thus making use of the 
>>> 3328's differential inputs. Could I have just tied the inverting 
>>> input on the 3328 to ground and used a non-inverting buffer stage on 
>>> the audio input?
>>>
>>> Thanx for reading,
>>>
>>> TR
>>>
>>> _________________________________________________________________
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>>
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>>
>>
>
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