Vermes
Advanced Member level 4
It is a preamplifier with symmetrical output. System OPA 1632 (Burr Brown) was used as output buffer in a standard application with 1k resistors at the input and in coupling.
Everything was mounted on a universal board.
+-12V is provided by a power supply built on stabilizers LM 317/337. Flodded transformer from Indel with a capacitance 2x 0,25A was used.
Before the signal goes to the input of the OPA, it has to go through the source selector built on a military switch, then through the tone control. Then you have a resistor ladder on precise Dale resistors. Impedance of the ladder is 10k.
LINK
Pictures:
Housing was made of aliminum, with use of allen screws m3.
The preamplifier has also RCA sockets at the output. After soldering simple buffer on transistors 2sk170 on them, it can provide an asymmetrical signal.
And a picture of links:
Link to original thread (useful attachment) – przedwzmacniacz z regulacją barwy tonu, z wyjściem XLR