Fingolfen
Well-known member
- Build Rating
I'd gotten a request for a Peavey Decade Preamp - and since PedalPCB has the Decadence Preamp board - I got cracking!
The overall circuit is really pretty basic. It has a basic 3 band equalizer, but most of the actual work is done by the diodes which are set up in both soft and hard clipping configurations in different parts of the circuit. For this build I went with all new production components. The resistors are all 1% metal film. The pF range capacitors are all MLCC. The nF range capacitors are all film capacitors - mostly WIMA and KEMET. There are a few electrolytic capacitors which are all Nichicon. The diodes are all NOS 1N4148 from my local source. There is also a single IC which I socketed.
The PCB is fairly large and roomy, but is well laid out so final assembly looks very clean and neat. I decided to relocate the LED from the location on the main PCB to the daughter board (I used one of my "Steggo" daughter boards I had made up based on a layout originally done by Drunk Beaver Pedals) largely to accommodate the art I wanted to use on the pedal. The jacks are all connected using aviation grade wire from Tube Depot and insulated with heat shrink tubing. I used 2.54mm pitch ribbon cable to connect the main PCB to the daughter board.
For the dinosaur mascot this time around I went with Pachycephalosaurus - or in this case just "Pachy" - for obvious reasons. The pedal itself sounds pretty good overall and has quite a bit of range - especially if you're into especially early through late 80's hard rock. Getting the pedal to unity takes a little cranking, but the tone is good. If you flip the "Saturation" switch you go from a slightly dirty overdrive at higher volume levels into full distortion. The three band EQ allows you a lot of freedom in shaping your tone as well. The pedal will also run at 18V - so next I'm going to try to up the voltage and see what difference it makes. I'm guessing it is going to like 18V better.
Original blog entry (with more preamble and dino info): https://steggostudios.blogspot.com/2024/07/another-cool-custom-pre-amp.html
The overall circuit is really pretty basic. It has a basic 3 band equalizer, but most of the actual work is done by the diodes which are set up in both soft and hard clipping configurations in different parts of the circuit. For this build I went with all new production components. The resistors are all 1% metal film. The pF range capacitors are all MLCC. The nF range capacitors are all film capacitors - mostly WIMA and KEMET. There are a few electrolytic capacitors which are all Nichicon. The diodes are all NOS 1N4148 from my local source. There is also a single IC which I socketed.
The PCB is fairly large and roomy, but is well laid out so final assembly looks very clean and neat. I decided to relocate the LED from the location on the main PCB to the daughter board (I used one of my "Steggo" daughter boards I had made up based on a layout originally done by Drunk Beaver Pedals) largely to accommodate the art I wanted to use on the pedal. The jacks are all connected using aviation grade wire from Tube Depot and insulated with heat shrink tubing. I used 2.54mm pitch ribbon cable to connect the main PCB to the daughter board.
For the dinosaur mascot this time around I went with Pachycephalosaurus - or in this case just "Pachy" - for obvious reasons. The pedal itself sounds pretty good overall and has quite a bit of range - especially if you're into especially early through late 80's hard rock. Getting the pedal to unity takes a little cranking, but the tone is good. If you flip the "Saturation" switch you go from a slightly dirty overdrive at higher volume levels into full distortion. The three band EQ allows you a lot of freedom in shaping your tone as well. The pedal will also run at 18V - so next I'm going to try to up the voltage and see what difference it makes. I'm guessing it is going to like 18V better.
Original blog entry (with more preamble and dino info): https://steggostudios.blogspot.com/2024/07/another-cool-custom-pre-amp.html
