[sdiy] RE: Arp filters. LM3900 VCF

[Rob]

Hi,
I have built a number of ARP 4075 filters based on original schematics. The
design is available as a blank PCB or a populated PCB. The filter sounds
excellent, and modern transistors are close enough to not require matching.
I have made some capacitor and op amp upgrades which have really helped the
sound. It has a new Tempco resistor too. Have a look here:

http://www.emulatorarchive.com/AM/AM4000/AM4075/am4075.html

I have a populated and tested 4075 PCB for sale right now. It uses pot
brackets and can be easily mounted to a panel with 40mm pot centres. That is
very close to MOTM spacing, and it has a MOTM style power connector. Contact
me off list if you are interested in this or blank PCB's.

I also have many other designs from the past, including ARP 4023. Recent
clients have bought an ARP4075 for a Roland 100M and SSM2030 VCO's for a
Serge system. I custom build high quality synth modules for clients.

Regards
Rob
www.emulatorarchive.com

In the meantime I have been looking at the Arp filter schematics. I have 
several pdf's and even a patent. I really like the design, but it looks like

a lot of transistor matching would be involved. I guess you'd really only 
need matched pairs?