this amp is not pretty, BUT it is one of my absolutely favourite units. It is
found in the Concerto 2500 tube receiver and comes along with 2 of the
coolest audio tubes I know: the Telefunken ECC83 and the Telefunken round
The circuit is very
simple and the unit sounds very nice in original condition.
output transformer is designed for 4 Ohms use only, so that the amp works
best (better bass and output power) with 4 Ohms speakers.
should do for HiFi use:
1. Remove the equalization
PCB. Instead of it you should solder 10kOhms resistors in the
signal path (connector 1-2 and 5-6).
2. Install an
input jack. The easiest way is to use a DIN jack as there is a hole provided
above the speaker connectors to install it.
3. Remove the
power connector for the radio/preamp section to avoid electrical shock.
If you want more:
Disassamble the amp and
rebuilt it (using the same PCB and OPTs) on a bigger chassis with a bigger
power transformer. Use better filter caps and a choke in the power supply.
With a B+ of 320V you will get 5 watts of great sounding ouput power!
a modified unit here !!!