Hifi Preamps for your Record Player

By: skrodahl | March 15, 2017

The instructions give you three alternatives for powering the Muffsy Phono Kits. Here's another one:

Step-down power converter - Dual power supply
Step-down converter - Size comparison

This step-down power module is available on Tindie, and can provide up to two amperes of power. Use two of them and connect a 15V DC power supply at VIN/GND as shown in the picture above, and you will get a +/-12V output. This will provide sufficient headroom for the Muffsy Phono Kits.

The ripple is some 18-20 mV. This is waaaay higher than the Muffsy Power Supply, but should work reasonably well. Especially if you're strapped for space.

A small word of caution: The output voltage is set using very small surface mount resistors (included). You will have to do SMD soldering. It keeps the common ground though, so it should be able to work alongside other power supplies with all grounds connected.

No complaints on the price either, I paid $20 for five of these modules and international shipping is $3.

By: skrodahl | March 11, 2016

Hot on the heals of the official Muffsy PCB, here comes another option.

Over at theslowdiyer's blog, you can now find the project files for the Muffsy Clone.

The Muffsy Clone PCB

Everything you need to build your own Muffsy Clone is available at his site. There's an impressive lot of information about his design goals and on how you should go about building the project.

Go here to see all of it, and build your own Muffsy Clone: 

Theslowdiyer - Muffsy Clone Project Files

If you are looking for a suitable power supply, theslowdiyer's got you covered as well with his GP-PSU v2.

theslowdiyer's GP-PSU v2 - Silkscreen

By: skrodahl | November 19, 2015

After receiving quite a few requests, it's now time for an upgrade of both the Muffsy Phono Preamp and the Power Supply. Both products are available on Tindie, right now!

You can finally build the complete Muffsy Phono Preamp, using the Muffsy Phono Preamp, the Hifi Power Supply and the Back Panel. Just add an enclosure and a wall adapter.

The most visual change is that the boards are black, with gold plated solder pads. This also means that the boards are now completely lead free.

Muffsy Phono Preamp PP-3 Rev A

As the name suggests, this is only a revision of the board.

Muffsy Phono Preamp PP-3 Revision A

Apart from the change of color, it now has more space for audiophile resistors in the signal path and in the RIIA equalization filter.

There is one small functional change, the phono stage now has a 110k ohm output resistor. It's a pull-down resistor to make sure the circuit behaves correctly when the output's not connected to anything.

Muffsy Hifi Power Supply v3 - Now as a Kit!

The only change is in the AUX power circuit, which is now regulated as well. This provides the convenience of deciding the AUX power's output voltage.

Best of all, the power supply is now available as a kit! No more hunting around for those components. As capacitors are important in power supplies,  Nichicon HE-series electrolytic capacitors are used for smoothing.

Muffsy Hifi Power Supply v3

The PSU matches the phono stage, with the same beautiful black and gold board.

The regulation of the AUX power is of course not as good as the main power. Its use is primarily to power components that don't need super-clean power, such as LEDs and relays. 

The AUX power circuit uses the LM7815 voltage regulator, and has been tested for small loads down to 5 volts (LM7805). 

Documentation Updated

All the documentation is now updated as well. I have received a lot of feedback from all of you, and the build instructions are now much clearer and easier to follow.

Category: News 

Tags: muffsy, phonostage, vinyl, psu 

By: skrodahl | August 28, 2015

Both the Muffsy Phono Preamp and the Muffsy Hifi Dual Power Supply were both quarterfinalists in the Hackaday Prize 2015 contest.

Hackaday Prize 2015
Hackaday Prize 2015

In addition to that, the Muffsy Phono Preamp won one of the weekly prizes for using Texas Instruments parts, and was awarded TV-B-Gone kit.

The Muffsy Hifi Dual Power Supply was awarded a Stickvise for solving a community problem. The problem solved was of course that you don't need to work with mains power when using the Muffsy Hifi PSU.