Behold the new Muffsy Phono Preamp!
It'll be available on Tindie, very soon. Actually, it is available: https://www.tindie.com/products/skrodahl/muffsy-phono-preamp-kit/
What's New?
These are basically the same circuits as before. The focus has been on making the build experience even easier than before, and improve noise prevention.
- The op amps are OPA2134 and LM4562
- SNR improved by 2.9 dB, from 79.4 dB to 82.3 dB
- No screw terminals facing the side walls of the enclosure
- The AC power cables do not cross the input
- The DC power cables do not cross the output
- The AC and DC power connectors line up on the PP-4 and PSU boards
- The signal inputs and outputs line up with the RCA connectors on the back panel
- The grounding scheme is redesigned to avoid ground loops
- The input impedance switches are grouped together
- The gain switches are grouped together
- The back panel has a ground pad in one of the corners, to ground the cabinet
- The back panel now has gold pads and the golden "M" logo
- The power supply now has the golden "M" logo
- There's room for heat sinks on the power supply voltage regulators (if needed)
- The solder pads for the screw terminals are beefier
- The mounting holes have been increased from 2.8 to 3.0 mm
- The board width is approx 0.5 mm narrower for a better fit in the B0905 cabinet
- The board's corners are even more rounded to make it easier to insert into the B0905 cabinet
Built-in Grounding of the Enclosure
One prime example of the thought that's gone into this new version is the fact that the back panel connects to the enclosure for improved grounding and shielding from noise:
Crisp, Clear Pictures
I've put my new lightbox to good use, and produced some really nice pictures for the instructions.
Here's one of the new photos compared to the corresponding old phono. Judge for yourself:
Thanks
This new version of the Muffsy Phono Preamp couldn't have been created without the (without exceptions) enjoyably long and fruitful email conversations with so many people. Keep using the contact form.
A special thank you goes to the loyal customers who helped me test the prototypes and provided valuable feedback, you know who you are. ;)