[LajostheHun]

If you feel like exploring your Teac, maybe you have the problem this head-fier had (top of page 11 of this thread for graphics and more):
Just gonna drop this here in case anyone else has this happen in the future...

A couple of weeks ago I fired up the stereo to find I wasn't getting any audio out of the UD-301, neither the rear RCA jacks nor the headphone out. Computer could see it as a DAC and it would lock onto digital signals from either the USB or optical inputs with the LED showing the correct bitrate, but no sound from the outputs. Another giveaway was that I wasn't hearing the relay click.
I opened it up and probed around with my multimeter and found nothing obviously burned/charred, no voltage on the opamp supply pins. Fortunately the really obvious candidate turned out to be correct - the fuses for the analog section had blown. They are Littelfuse 372 series through-hole type, the little red parts by the two big 4700uF caps:

That might be it, I'll take a look, thanks.

 

[ScottFW]

The stock fuses were 200 mA and I replaced them with 250 mA. Using a higher current replacement is not something I would ever do on a mains voltage line, but to supply this analog section they're running at lower voltage and seeing a fraction of an amp so I reasoned it was probably safe enough to go 25% higher without starting a fire. I don't know if the stock fuses are being run at the ragged edge of their current rating (I really doubt it, though I might be pulling a few more mA than stock since I have socketed and swapped some opamps), or if heat cycling massively derates their lifespan, or if TEAC simply got a bad batch or what, but the replacements haven't blown.

If you have the ability and inclination, meter across your fuses and if they're confirmed blown I can send you some replacements (assuming you're in the USA). I have some extras on my workbench.
If you were going to put in an order to Mouser anyway, their part number is 576-37202500411 for the 250 mA ones. If you'd rather stick with the 200 mA stock rating that would be 576-37202000411.

 

[Allan Pedersen]

Just got this. No hiss in 35ohm ath-m40x and enough power to play 250ohm dt990 louder than I care for. Replaced a src2469 which had a buzzing transformer and would change sound/filter in the middle of playback. Also considered dacmagic plus and nad d 1050 which was priced similarly here. The teac, as my tascam interface, picks up noise if connected via usb, so toslink for me. When turning on, changing sample rate or regaining sync it fades in the sound, so no loud noises.

 

[147JK]

Just gonna drop this here in case anyone else has this happen in the future...

A couple of weeks ago I fired up the stereo to find I wasn't getting any audio out of the UD-301, neither the rear RCA jacks nor the headphone out. Computer could see it as a DAC and it would lock onto digital signals from either the USB or optical inputs with the LED showing the correct bitrate, but no sound from the outputs. Another giveaway was that I wasn't hearing the relay click.

I opened it up and probed around with my multimeter and found nothing obviously burned/charred, no voltage on the opamp supply pins. Fortunately the really obvious candidate turned out to be correct - the fuses for the analog section had blown. They are Littelfuse 372 series through-hole type, the little red parts by the two big 4700uF caps:


The third fuse over towards the left was still good, so I'm not sure what would have taken out the other two, but replacing them fixed the DAC and everything is good now.

I'll also mention that working on this thing is a pain in the butt. The factory must use newer soldering methods and/or a harder less- or no-Pb solder type because these joints take a LOT of heat to melt, and the stuff doesn't like to wick out of the joints without a little dab of flux on the braid. The extra heat is not a problem for removing already-blown fuses, but when installing the new ones you've got to be quick with the soldering iron or you'll blow them as you install them. Probably best to meter them to verify continuity after soldering and before you bother putting the board back in the chassis.

Thanks for posting this. My 301 is starting to act up, and it's also about a year old. In my case, it's the same problem - digital signal looks fine, but analog just stops. It will always start OK then drop out at some random time later. If I restart the digital feed, it starts right back up again, for some random amount of time.

I wonder if this is a common symptom of an about-to-fail fuse? Also, my 301 sits on top of my headphone amp, so I wonder if this is temperature-related. Is are there a higher temp rated fuse one could solder in so it doesn't happen again?

 

[ScottFW]

My 301 is starting to act up, and it's also about a year old. In my case, it's the same problem - digital signal looks fine, but analog just stops. It will always start OK then drop out at some random time later. If I restart the digital feed, it starts right back up again, for some random amount of time.
I wonder if this is a common symptom of an about-to-fail fuse?

Sounds like a different problem. These fuses are not the self-resetting type, and they don't work intermittently. They are either blown or they're fine.

 

[147JK]

Sounds like a different problem. These fuses are not the self-resetting type, and they don't work intermittently. They are either blown or they're fine.

Hmmmm yes that's what I am thinking. I wonder if the player (MusicBee) is getting wonky - sending syncing data but no content (wishful thinking on my part). Might have to pull the 301 out, malfunctioning after only 1 year(!) Super disappointing product.

 

[147JK]

Hmmmm yes that's what I am thinking. I wonder if the player (MusicBee) is getting wonky - sending syncing data but no content (wishful thinking on my part). Might have to pull the 301 out, malfunctioning after only 1 year(!) Super disappointing product.

Well after working with this for awhile, now I'm convinced it's not the DAC. It only happens occasionally when streaming music. When playing from a local source, it's always rock solid. Some bit of instability sourcing through the internet, I think. Will have to live with it..

 

[sff2008]

My UD-H01 died after years of great service. The UD-301 seems like the logical replacement, but I've not kept up on current DAC offerings. Are there better options in the same price range that also have XLR outs?

 

[buke9]

If you want the 301 to be a dac then it is not too bad the headphone amp is just way underpowered and on the warm side. I had one and it wasn’t that good for either to be honest. Just guessing but you are running a pair of monitor speakers ?

 

[sff2008]

If you want the 301 to be a dac then it is not too bad the headphone amp is just way underpowered and on the warm side. I had one and it wasn’t that good for either to be honest. Just guessing but you are running a pair of monitor speakers ?

I have a pair of LSR305's. I'd still like the option to use headphones, but my monitors are used most of the time.

 

[147JK]

My UD-H01 died after years of great service. The UD-301 seems like the logical replacement, but I've not kept up on current DAC offerings. Are there better options in the same price range that also have XLR outs?

FWIW, I replaced my UD-301 with a UD-501. I never thought I'd be able to hear a difference in DACs but it seems I can. The 501 is better built through-and-through and isn't trying to be eveything at once - just a really great DAC.

 

[buke9]

It looks like you can go xlr or 1/4” for balanced connection. It wouldn’t matter from a single ended amp. And a Schiit Modi Multibit would be a better Dac than the UD-301 as I had a 301.

 

[sff2008]

It looks like you can go xlr or 1/4” for balanced connection. It wouldn’t matter from a single ended amp. And a Schiit Modi Multibit would be a better Dac than the UD-301 as I had a 301.

Are you saying I should forego XLR, and switch to RCA with the Modi Multibit suggestion? Isn't that a bit of a downgrade? Admittedly I'm not well versed on the benefits of XLR beyond the ability of longer runs. I'm not against the idea as long as there's no audible performance degradation.

 

[DavidA]

Are you saying I should forego XLR, and switch to RCA with the Modi Multibit suggestion? Isn't that a bit of a downgrade? Admittedly I'm not well versed on the benefits of XLR beyond the ability of longer runs. I'm not against the idea as long as there's no audible performance degradation.

Which DAC you chose is a matter of preference IMO. I currently have the UD-301, Bimby, Bifrost Uber and Modi2uber and while there is a difference between the UD301 and Bimby its a matter of preference to me. I've used the XLR output of the UD301 when I had a friends Liquid Glass, Dark Star and Liquid Carbon but couldn't detect any difference between the SE or balanced connections, YMMV with this.

I have to disagree with @buke9 about the headphone amp of the UD301 since it seems to pair better with more of my headphones than some of my amps like Ember, Lyr2 and BH Crack and it has enough power to drive my HE560 to my listening level which is on the lower side (55-70dB) so if you listen at much higher levels the amp of the UD301 might/will be under able to properly drive some headphones.

The UD501 is better than the UD301 and they were on MassDrop at a really low price which I was considering but due to space limitations on my table I decided not to change. I also have a AH-01 which I really like for driving some small monitors and it does well with the headphones that I use on them (HD650, SR60-modded, Fidelio L1-modded and K553). Have you considered the AI-301DA?

 

[buke9]

You can disagree with me and that is fine and I still stand by my comments.