Muffsy Phono Preamp

[Crazyblocks]

Me and my dad (a fellow Audiokarma user) put together the Muffsy phono preamp last weekend.
It was fun to put together
No Affiliation
Front while on

On top of Oinker

LED we put in


LED mounted with hot glue


I/O from back

Back Panel

Front


Internals


Internals from different angle

 

[dirtman]

This was a super fun and relatively easy project to build. I read some reviews about it and, for the price, it seemed like a pretty good deal. I have nothing but good things to say about the sound. Way!! better than the stock phono section of the Oinker! (and most of the other receivers I've had in this system for that matter) Profound improvement. Better sound stage, separation between instruments, clarity, etc. The Onkyo preamp has a "CD direct" mode that it's inputting to. Very little coloration of the signal from what I can tell. What a simple and cost effective way to improve a system. Like Craztblocks (my son) said... we have no affiliation with this product. Just thought some would find it interesting.

 

[Tedrick]

Nice, clean build. Looks great, too. Well done!!

 

[jgscisum]

Built one and totally pleased with the quality and sound. EXCELLENT!

 

[AlphaEcho35]

Its a great little DIY project that results in a very nice phono preamp. I took mine a step further and integrated the transformer.

 

[Crazyblocks]

Its a great little DIY project that results in a very nice phono preamp. I took mine a step further and integrated the transformer.

View attachment 1216863

looks nice, good idea putting the transformer inside

 

[dirtman]

gguillot - Thats a nice build. Like crazy blocks said, I like that you used an internal transformer. Do you have the burr-brown or Texas Instruments opamps? We used the stock TI opamps and are very pleased with the results but have nothing to compare to. I’ve read some prefer the B-B. I don’t think I’m going to go too far down that “rabbit hole” but I am curious if you’ve experimented with different opamps and if you have a preference.

 

[mkane]

The difference as negligible IMO.

 

[dirtman]

That’s what I figured. I’m just going to enjoy it as is. Next up will be a nice dyi headphone amp kit for us to build. The onkyo/hafler combo doesn’t have a headphone jack.

 

[mkane]

You can roll inexpensive OPA in the Muffsy. I don't know what comes with the stock unit. 49720's are close to the now dis-continued 49990

 

[dirtman]

This is the set that came with it. My son is a big fan of TI so we will stick with them. In fact, we'll be in Dallas next week and he wants to go to the factory. He'd rather do that then Six Flags. No arguments here...

 

[Pioneered]

Looks great young man, glad to see a father and son enjoying and doing things together.

 

[sregor]

FWIW Burr-Brown is owned by Texas Instruments (acquired in 2000)

 

[EngineerNate]

I have the NE5532 that came with mine, OPA2132, and the LE49720s. I'd be happy to do some high-rez recordings of each and post up to see if you hear any differences. Once I finish the muffsy build that is.

 

[dirtman]

Sregor -

EngineerNate - thx. I’m thinking we will order a variety of OAs when we place the next mouser order. They’re are not that expensive. It could be fun just as an experiment if nothing else. Recommendations are welcome.

 

[mr.jones]

Nice work!

 

[EngineerNate]

Sregor -

EngineerNate - thx. I’m thinking we will order a variety of OAs when we place the next mouser order. They’re are not that expensive. It could be fun just as an experiment if nothing else. Recommendations are welcome.

The 2132 is simply a higher binned version of the 2134. For the $1 per difference in price when I purchased directly from TI it seemed worth it.

I also want to try the OPA627 on a 2-up riser board. That will depend on budget though.

Since all of the opamps I've got are from TI, I was also going to find an AD or Linear opamp to throw into my next mouser/Digikey order to try. I don't know what one yet.

 

[absolon]

I liked the AD827 better than the LME 49720 and thought both the AD825 and the AD823 were notably better FET opamps than the OPA 2134. There is an ebay seller, audjade_chn, no affiliation, who sells OPA627 on the 2-up board based on salvaged chips. I've purchased quite a few and in all cases, the chips passed both the resistance test (48 to 56 kohms both ways across pins 1 and 5) and the quiescent current test (7 to 7.5 mA on both legs) indicating that they are genuine. The price asked means that it's a very small risk.

 

[AlphaEcho35]

gguillot - Thats a nice build. Like crazy blocks said, I like that you used an internal transformer. Do you have the burr-brown or Texas Instruments opamps? We used the stock TI opamps and are very pleased with the results but have nothing to compare to. I’ve read some prefer the B-B. I don’t think I’m going to go too far down that “rabbit hole” but I am curious if you’ve experimented with different opamps and if you have a preference.

Honestly, I don't recall what opamps Havard included with the kit when I built it. I've done the "opamp rolling" thing on a little headphone amp I had a few years ago and didn't hear any significant difference, so I don't bother with it.

 

[EngineerNate]

The stock opamps are the NE5532 and his upgrades are the 2134s. From reading some listening impressions here, it seems like a combo of the 2134 and the 49720 is a good bet if you don't want to roll, I can't remember off the top of my head which position each was supposed to be in for the best sound according to the guy I was talking to. The idea was that by using one of each you avoid overly coloring the sound with the character of either opamp.