The image shows a 1981 Crimson 520 power amplifier that has been totally rebuilt. The original laminated tranformer has been replaced with a toroid for much lower noise. The new reservoir capacitors are 22,000uF. There was zero audible noise at the speaker. there was almost zero on and off transients despite no muting relay present.
The picture shows the PCBs with two 100W plastic power devices fitted to each and this produces 60W peak power and about 40W rms.
Key New Features of PWR20 PCB
- Superior high Hfe buffer transistor
- Higher power VAS device to reduce peak temp swings
- auto reset from overload shutdown approx after 1 min
- Better defined voltage level for the speaker protection latch
- Input terminated 75 Ohms at HF for better RF rejection
- spade terminal connection options
- triac protection fuse now inside feedback loop, THD much lower at LF
- thin film resisitors in signal path gives lower THD
- holes for front edge PCB support
- current source references improved
- Led driver modified to show clip in “or” mode for stereo operation when paralleled
- First production April 2026. PCB black finish.
- Crimson OEM build but can be supplied for Crimson kit upgrades. Please enquire.