[sdiy] Moog 904A VCF best type of ladder capacitors.. orange drops or any good film caps.. ??

Jean-Pierre Desrochers jpdesroc at oricom.ca
Sat Oct 27 00:30:58 CEST 2018


 

I think the following question has been answered somewhere

In this forum but anyway..

 

In 2014 I built some Moog 904A clones for my modular

and so far have been happy with them.

I copied the exact Moog 904A schematic and reverse engineered

the pcb layout to fit my front panel needs.

 

http://www.arcenson.com/projects/Modular/M104A_Lowpass_Filter_Moog_904A_clon
e/Module_pictures/M104A_VCLPF_front.JPG

http://www.arcenson.com/projects/Modular/M104A_Lowpass_Filter_Moog_904A_clon
e/Specifications/M104A_VCLPF_schematic.pdf

http://www.arcenson.com/projects/Modular/M104A_Lowpass_Filter_Moog_904A_clon
e/Module_pictures/M104A_VCLPF_assembled_back.JPG

 

For the low pass ladder caps I used Vishay film capacitors.

0.075uf, 0.33uf and 1.2uf @ 10%.

Differently from Moog's choice these Vishay caps have the exact uf values.

Looking at some vintage Moog 904A VCF I found that over time

the factory did not always put the same type of caps

in their VCF.. Mostly orange drops but not always. 

And because orange drop caps didn't have and still don't have 0.075 and
1.2uf values

Moog used parallel caps to get these values.

Enough talk about Moog's preferences.

 

My question is:

Would it make any differences in my 904A vcf sounding

if I'd replace all the Vishay film with orange drop caps ??

I found that for instance many fine guitar amps

decided to use orange drop caps over any other types..

Doing so I will have to do what Moog did and parallel

caps to get 0.075 and 1.2uf values.

That will give a 'funky' looking to my pcb tough.

Vishay's caps fitted right on my pcb, but orange drop caps could be

a nice 'sounding' replacement.. or it does not worth it.. ??

 

What do you think ?

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