jaygunn
Active member
These are the parts I ordered over a decade ago for making compressors for my 'studio,' which never really got off the ground. The info for these projects came from online forums, especially groupDIY.com. Since Forssell Technologies is still functioning you may be able to get the schematic for their compressor boards, but online all I find is the optional sidechain schematic. I do have the schematic for the PICO compressor boards and the PICO LED metering boards.
Without figuring in the cost of the boards and other parts, I have about $125 in just the opto couplers and the THAT4301's alone. I'll take $93 plus $7 shipping for the entire lot within the 48 contiguous states. Paypal only.
Here are the parts:
(2) PICO compressor circuit boards, absolutely new condition, never seen a soldering iron. Also included are:
(2) THAT4301 chips, unopened, sourced from Wayne Kirkwood Electronics. Original price was $60.55
Documentation--the application notes from THAT showing the customary way to implement a full-featured compressor (soft knee/hard knee, attack, release, ratio). Also the original schematic that goes with the 2 boards.
(2) PICO meter boards for LED array display of gain reduction. Same new condition. Schematic included, and the component values are listed on the boards.
(4) Forssell Optical Compressor boards, absolutely new condition, never seen a soldering iron.
Also included are:
(4) VTL5C1 optocouplers, unopened, from Mouser/Digikey, in original box. Digikey has these now for $16.67 each.
(4) OPA604 op amps, unopened, sourced from Mouser/Digikey. When these parts ceased production (they have resumed) lots of fake OPA604 chips appeared on eBay and elsewhere. These are the real deal.
Documentation--only includes the Forssell sidechain schematic that is still available in the web site. The full schematic and BOM would need to be sourced from a helpful GroupDIY member.
Other interesting parts that are included:
(3) OPA2604 op amps, the dual version. Not needed for the compressor, but a fast and good product that is also sourced from Mouser/Digikey.
(2) OPA627 single channel op amps, awesome specs, like 55V/uS slew rate and 4.5nV per root Hz voltage noise. From Mouser/Digikey
Without figuring in the cost of the boards and other parts, I have about $125 in just the opto couplers and the THAT4301's alone. I'll take $93 plus $7 shipping for the entire lot within the 48 contiguous states. Paypal only.
Here are the parts:
(2) PICO compressor circuit boards, absolutely new condition, never seen a soldering iron. Also included are:
(2) THAT4301 chips, unopened, sourced from Wayne Kirkwood Electronics. Original price was $60.55
Documentation--the application notes from THAT showing the customary way to implement a full-featured compressor (soft knee/hard knee, attack, release, ratio). Also the original schematic that goes with the 2 boards.
(2) PICO meter boards for LED array display of gain reduction. Same new condition. Schematic included, and the component values are listed on the boards.
(4) Forssell Optical Compressor boards, absolutely new condition, never seen a soldering iron.
Also included are:
(4) VTL5C1 optocouplers, unopened, from Mouser/Digikey, in original box. Digikey has these now for $16.67 each.
(4) OPA604 op amps, unopened, sourced from Mouser/Digikey. When these parts ceased production (they have resumed) lots of fake OPA604 chips appeared on eBay and elsewhere. These are the real deal.
Documentation--only includes the Forssell sidechain schematic that is still available in the web site. The full schematic and BOM would need to be sourced from a helpful GroupDIY member.
Other interesting parts that are included:
(3) OPA2604 op amps, the dual version. Not needed for the compressor, but a fast and good product that is also sourced from Mouser/Digikey.
(2) OPA627 single channel op amps, awesome specs, like 55V/uS slew rate and 4.5nV per root Hz voltage noise. From Mouser/Digikey
