[sdiy] Moog ladder theory questions

[cheater cheater]

Ah sure, but the document I'm reading assumes beta is +infinity, so
I'm wondering what it is in reality.
What transistors do you guys use for moog filters normally?

What transistors were used in the originals?

Cheers
Damian

On Wed, Jan 14, 2009 at 4:37 PM, Tim Ressel <madhun2001 at yahoo.com> wrote:
> Dear cheater^2,
>
> If you are talking about the transistors in the ladder itself, I don't think the beta is critical. The transistors are being used not for their amplification quality but for their ability to change AC impedance in relation to their collector current. I believe other transistor qualities, like noise, are much more important. I'm toying with the idea of making an ARP ladder phasor which uses 28 transistors in a ladder configuration similar to the Moog ladder filter. The MAT04 transistor quad is looking attractive for its low noise. With 28 transistors, noise is a real issue.
>
> Of course, the sonic quality of the filter is affected bt transistor choice as well. But you cannot determine that from a data sheet. BTW the choice of capacitor type will affect sound quality as much as transistor choice.
>
> --Tim (had $0.02 to spare) Ressel
>
> --- On Wed, 1/14/09, cheater cheater <cheater00 at gmail.com> wrote:
>
>> From: cheater cheater <cheater00 at gmail.com>
>> Subject: [sdiy] Moog ladder theory questions
>> To: synth-diy at dropmix.xs4all.nl
>> Date: Wednesday, January 14, 2009, 3:29 AM
>> Hi guys,
>> I'm reading up on the moog ladder.
>> What beta do the transistors used in the moog vcf normally
>> have?
>> I bet there's a difference between the case of
>> 'original instruments
>> of lore' and 'nowadays', so let's consider
>> both options.
>>
>> Cheers
>> Damian
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