preamps are very nice, but unfortunetaly they do not have a RIAA
equalization for Phono and they are not too easy to handle (external
power supply needed).
So I decided to
build a stereo preamp on a 2154 base.
I achieved to
re-use all original cables to the front plate and changed one pot
for a pilot light and another one for the power switch (the two pots
on the right).
The I got from left to
- left volume - right volume - balance (works almost as switch) - input selector
(off-phono-line) - power light - on/off switch.
Of course the
lettering of front panel needed to be changed then. But flipping it
I found the back side looking good and so it is still the original
panel which is installed.
I used all parts from Siemens / Klangfilm (amps), except the output capacitors
which are paper in oil types from Rohde & Schwarz.
Tubes / circuit design (per channel):
- EF86 (connected as triode) RIAA amplifier
- ECC83 section#1: line preamp
- ECC83 section#2: catode follower output
- Catode follower output stage for very low
output impedance (uncritical to any
- double mono volume control
- Phono MM input possible (just bridge the
- famous Siemens / Haufe T41 input
- all original 2154 plates included (also the
very rare botton plate)
- gold plated RCA input and output jacks
- professionel symmetrical use with
balanced i/o possible (cut 3 jumpers)