Roger's Williamson Amplifier Mk IV Options
Designed by Roger Knopp, M.Sc.EE
knopp.electronics@iname.com
phone/fax: +46 31 252345

The "Magic Eye"-version, KEW88-91DM, seen below uses a pair of PM84 Tuning Indicators for push-pull plate imbalance indication. This is normally, i.e while using my special cored KE57613-C+ OPT, not that critical but zero imbalance still improves both LF output power and distorsion. In time the tubes may actually age differently, which makes this option more than just nice to look at! And for an extra $100, it's yours!! (obsolete tube limited option)

Main Data:
Power Consumption: 150W@230/115V 50-60Hz
Supply Voltage: 2X440Vdc@150mA
Heater Voltage: 2X6.2V@4.2A (1.5A@6550)
Closed Loop Gain: 20dB
Std Feedback (BF+1): 15dB
BW(+/-3dB): 7Hz-280kHz@67mW
Output Power (4-8R): 2X20W/6Ohm/1kHz/10%THD









KEW88-91DM, The Billington KT66 armed "Magic Eye"-version using a pair of PM84 Tuning Indicators for push-pull plate imbalance indication.

More info:
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KEW88-91DUL, Ultra Linear Version
KEW88-91DT, Directly Heated Triode Version
KEW88-91DN, Nostalgic Mono Version
KEW88-91DM, Magic Eye Version (Sovtek KT66 armed)