I finally finished Project 97 Hi-Fi Tone-Control Preamplifier. I ordered the board and it arrived within a couple weeks.
I wanted to incorporate a USB/SDcard music player and a SPDIF OR TOSLINK input with a couple Aux inputs.
The PreAmp needs +/-15 vdc, the Music player needs 12 vdc and the SPDIF converter and input selector needs 5 vdc.
The USB Music player was a bit much for a LM7812, even with a heat-sink so I Built a regulator using a TIP3055, TIP31C and a 13v Zener diode.
For the SPDIF I used a LM7805 and powered it from the 12v regulator.
Nothing gets hot and the ripple voltage is about 1mv from the toroid power supply.
I'm using LM337 and LM317 for the +/-15v for the pre-amp.
It sounds very good, Quite (No Hum or hiss).
I did try the pre-amp kits from ebay and they did not sound as good.
I wanted to incorporate a USB/SDcard music player and a SPDIF OR TOSLINK input with a couple Aux inputs.
The PreAmp needs +/-15 vdc, the Music player needs 12 vdc and the SPDIF converter and input selector needs 5 vdc.
The USB Music player was a bit much for a LM7812, even with a heat-sink so I Built a regulator using a TIP3055, TIP31C and a 13v Zener diode.
For the SPDIF I used a LM7805 and powered it from the 12v regulator.
Nothing gets hot and the ripple voltage is about 1mv from the toroid power supply.
I'm using LM337 and LM317 for the +/-15v for the pre-amp.
It sounds very good, Quite (No Hum or hiss).
I did try the pre-amp kits from ebay and they did not sound as good.
Attachments
12vdc regulator that I used...Works perfect!😀 and the powersupply I used from Elliott Sound
Attachments
Last edited:
I'm curious about your USB Music player. What kind of external logic support does it need? Do you have a link to datasheet? Thanks.
This is what I found from Mouser https://www.mouser.com/ProductDetai...uUO1xpEvx5w5raGxQe2OzcymsgGkIeh/zt%2BV2iMig== Nice but not what I'm looking for.
This is what I found from Mouser https://www.mouser.com/ProductDetai...uUO1xpEvx5w5raGxQe2OzcymsgGkIeh/zt%2BV2iMig== Nice but not what I'm looking for.
Some people say it's noisy... I had to have very little ripple voltage on the power-supply to get it as quiet as I can. When playing through the USB, and I pause the music and turn the volume up, there is some noise but not too bad. During music play, it sounds fine. I have not tried Blue Tooth on it.
https://www.amazon.com/gp/product/B07GF31T2Y/ref=ppx_yo_dt_b_asin_title_o05_s02?ie=UTF8&psc=1
https://www.amazon.com/gp/product/B07GF31T2Y/ref=ppx_yo_dt_b_asin_title_o05_s02?ie=UTF8&psc=1
Look at Elvee's Denoiser thread---it is a very simple mod to LM317/337 regulators that improves their performance significantly.
I have LOTS of Rod Elliott's circuits--they perform wonderfully. He is a true treasure to our community!
I have LOTS of Rod Elliott's circuits--they perform wonderfully. He is a true treasure to our community!