The Elektor PreAmp 2012, April 2012
As of now, there are two articles published about this project. The first module is now ready to be set up. The partlist (BOM, bill of materials) for module 2 can be downloaded here, including Farnell numbers. This is the assembly of module #1. Update May, 19th: The PCBs for module #2 just arrived and I started to put the parts to it. The PBCs for part 3 are now ordered. The partlist (BOM) for the LLLL (#110650-6) is here (Farnell numbers).
This is the set-up of the first module:
Resistors and Polystyrene Capacitors
Except the potentiometers all resistors are in. The polystyrene capacitors are the silver ones.
Bipolar Capacitors
C3, C4, C28 and C29, 47µF/35V bipolar
Polypropylene Capacitors
C32 and C7, responsible for the basses.
Sound Adjustment
C32 and C7, with R 15/14 and Poti 2 for the bass, high is controlled by C9, Poti 3 and IC2.
Power
C52 and 53 for smoothing the power supplied.
Output Stage
Bipolar capacitors C15/16 and 40/41.
June 20th 2012. I have started to work on the case of the preamplifier. Well, I was somewhat lazy with posting, and there is also a thread in diyAUDIO which is a really fascinating portal.
Again I use the casing from Fischer Elektronik in Lüdenscheid (G111), the same model as used for the power amplifier. BTW, this power amplifier I have presumably a second time since a friend of mine likes it very much because of its crisp and clear sound. This amp might outcrisp a Linn amp which is said to be close to sterile. But you know, me, a tube fan…
Also I decided to have the cinch and xlr sockets on the same side as with the power amp, so this matches. When now running both, the tube with the Clearaudio Basic phono preamp and the PreAmp 2012, I wonder if it might make sense to have a by-pass inside that allows to get the phono signal to either one for easy changing the source to both amps. Might be a bad idea. Don't know.
So, on the lower right side is the switch, ground and fuse, and the transformer is on the back, here upper right side as you see.
Again I use the casing from Fischer Elektronik in Lüdenscheid (G111), the same model as used for the power amplifier. BTW, this power amplifier I have presumably a second time since a friend of mine likes it very much because of its crisp and clear sound. This amp might outcrisp a Linn amp which is said to be close to sterile. But you know, me, a tube fan…
Also I decided to have the cinch and xlr sockets on the same side as with the power amp, so this matches. When now running both, the tube with the Clearaudio Basic phono preamp and the PreAmp 2012, I wonder if it might make sense to have a by-pass inside that allows to get the phono signal to either one for easy changing the source to both amps. Might be a bad idea. Don't know.
So, on the lower right side is the switch, ground and fuse, and the transformer is on the back, here upper right side as you see.
Setting up the power supply.
Some details.
The power supply is set up pretty straight forward.
With the power input from the transformer it immediately delivered +/- 18 Volts.
With the power input from the transformer it immediately delivered +/- 18 Volts.
By the time this image was taken I was of the opinion to use the right board also for the sockets. Since I did not get the right ones and from my work I know that XLR like to be mounted firmly into the housing, I decided to have besides the front panel also the side panel done by Schaeffer and the sockets to be mounted in the aluminum directly. Short wires connect then to the boards that are behind.
The power is next to the transformer. Clearly, I am not building this preamp for saving space… A luxury. I am not industry.
The power is next to the transformer. Clearly, I am not building this preamp for saving space… A luxury. I am not industry.
Couple of images...
The front panel, as the side panel, will come from Schaeffer, Berlin. Currently its in production. Well, that will be the next chapter then… But I can see it might look really good. I couldn't resist - the front for the power amp, even if no control is placed there, will also have one with some writing. I'll post this later.
