Electronics: NE5534 / OPA134 (+ others) based preamp projectThis is a preamp I recently designed.
This project is based on single opamps, and will accommodate several different single opamps.
The following can be used without modification.
+ many others.
The topology used is: input buffer -> vol control -> gain stage -> output buffer
I used OPA134 for the buffers, as the NE5534 requires external compensation for gains less than 3.
Positions for compensation caps have been provided for all 6 opamps, these are C15,16,18,19,33,36
Compensation caps are not required if using OPA134 (or other internally compensated opamp) for the buffers.
If the gain of the gain stage is reduced to less than 3 and a 5534 is used, then a compensation cap will be required.
The gain is quite low, as it was designed to be used with digital sources, but the gain can be usefully increased if required.
Below is a 3d model of the board - I ordered my boards from JLPCB and have build a couple of them and they work well.
This version is AC coupled, but the coupling capacitors can be omitted if desired.
See this link for the alternative dual opamp based version.
All project files can be downloaded here - these were generated using DipTrace