Roger's Guitar Amplifier projects
Designed by Roger Knopp, M.Sc.E.E
phone/fax: +46 31 252345

The Universal Guitar Amplifier KEW/UA-92C seen in this page is my third attempt in building a cheap but good guitar amplifier for musicians or "poor" tube-loving enthusiasts. My chosen Williamson Power Amplifier KEW88-91DN is actually integrated into this Universal Guitar Amplifier. Output tube voltage clipping has been chosen as an optional dirstortion feature. The tone control rolls off at the standard RIAA frequency of 2.1kHz. The amplifier might even be used as a "travelling mate" to amplify for instance a CD-freestyle. Not to mention a guitar or RIAA correction for (MM) pick-ups. My next version will even include a DC/DC-converter for optional portable "beach" usage!

Main Data:
Power Consumption: 100W@230/115V 50-60Hz
Maximum Output Power: 40Wsqr@6R/1kHz
Mic/MM Sensitivity: 7mV/47k//150pF
Overall OL-gain: 84dB@Mic/1kHz
Miscellanous I/O:
1) Line-in: 150mV@100k (inverted)
2) Pre-in: 1.5V@1M
3) Rec/Pre-out: 230mV@400R
4) External Speaker: 4-8R (DF0=16dB@6R, BF=OL/17dB)

KEW/UA-92C, The Knoppson Universal Guitar-Amplifier Mk III.

More info:
Hints & Links
KEW/UA-92C, Cossor Rectified Knoppson Universal Guitar Amplifier circuit diagram
KEW/UA-92B, Solid State Rectified Knoppson Universal Guitar Amplifier circuit diagram
KEW/UA-92A, The original Knoppson Guitar Amplifier