[sdiy] High-power Moog ladder VCF

[Magnus Danielson]

On 12/09/2010 11:47 PM, lanterma at ece.gatech.edu wrote:
> I asked Kevin if I could repost this, and he gave me the thumb-up...

Feel the power of this VCF! The side-feature is that it is a 
power-supply modulated filter :)

Next thing I expect there to be followed by a tube equivalent...

Cheers,
Magnus

> - Aaron
>
> On Dec 9, 2010, at 3:05 PM, Kevin Lightner wrote:
>
>> Btw, I made a crazy thing the other day:
>>
>> A discrete Moog ladder filter made from Minimoog schematics using very large and mostly high-current components.
>> 2N3055 TO-3 transistors only, big orangedrop caps, big resistors, etc.
>> Just a crazy idea to see if I could make one that worked and for the hell of it, could run on higher voltages and current.
>> It worked the first time I powered it up. :)
>>
>> Technically I didn't make a VCF tho.
>> I left off a couple trannys normally used for converting voltage to current.
>> Instead I added a 2w pot and control the current directly.
>> I guess it's a CCF. ;-)
>>
>> This thing is about a foot long or more and maybe 6 inches wide.
>> Silliest thing you've ever seen, but amazed because it works and sounds great.
>> I can run it as low as 4 volts and as high as what my PSU puts out, 30 volts each rail.
>> Gain structure changes considerably of course, but that's kinda the fun of it all.
>>
>> So I guess I made the first Moog filter that can drive a speaker directly without an amp? ;-)
>>
>> Here's a pic.... http://www.synthfool.com/bigfilter.jpg
>>
>> Kevin
>
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