[cheesegrados]

I just received my Teac UD-501. I been listening for 52 minutes and All I can say is "WOW" music sound like High definition now! It can power my Audeze LCD-2 just right. This is so cool. 

 

[37mil]

  I just received my Teac UD-501. I been listening for 52 minutes and All I can say is "WOW" music sound like High definition now! It can power my Audeze LCD-2 just right. This is so cool. 

enjoy!

 

[37mil]

  I decided to improve sound quality of my 501. First of all, I want to upgrade transport quality, but no sure: usb or spdif. My music collection is redbook and vinyl rips. No DSD. So, what will be the best: upgrade usb transport (with Uptone USB Regen or Wyrd or iFi USB Power) or upgrade coaxial transport (with Gustard U12 or MX-8)? Any suggestions?


 

Not sure about the uptone, word or iFi as I don't use any of those. Instead I modded the 501 with better output caps, bypassed with film caps. Very effective.
 
I also changed regulators which allowed me to use small film caps on its output which had a profound effect - that cap position really coloured the sound when using Silmic and other electrolytics. 

 

[DObleX]

  Not sure about the uptone, word or iFi as I don't use any of those. Instead I modded the 501 with better output caps, bypassed with film caps. Very effective.



 
I also changed regulators which allowed me to use small film caps on its output which had a profound effect - that cap position really coloured the sound when using Silmic and other electrolytics.

There are too many caps in the 501. Here is the photo of all of cap's groups, that I found and mark:

 


Could you specify the parameters of the capacitors (manufacturers, models), which you replaced the original capacitors in each of the groups?

 

[37mil]

There are too many caps in the 501. Here is the photo of all of cap's groups, that I found and mark:


 




Could you specify the parameters of the capacitors (manufacturers, models), which you replaced the original capacitors in each of the groups?

First of all, group 1 is not a group at all. You've grouped the audio output and regulator output caps together.

The two green caps near the op amp ics at the top of the pic near the xlr in group 1 are the audio output caps. These are 100u/25V. You can replace these with Elna Silmics or whatever you like as your preference but be careful as the space is very limited in there. There are 4 of these, 2 for each channel (not in your picture).

The two green caps below the op amps in the middle of group 1 are voltage regulator output caps, and there's 2 more not in your pic (this is a dual mono design remember). These are 100u/25V. These are very sensitive to cap quality. I replaced with Elna Silmics but the sound was so dull and congested I replaced again with a tiny film cap. You can use a film cap if you replace the regulator with a Dexa voltage regulator as the designer said it is stable even with no output cap as it is so fast. Be warned the Dexa are not cheap and you'll need 4 of them. The voltage regulators are +12V and -12V, two of each. Another good regulator replacement is Sparkos.

The last bottom two in your group 1 is a regulator output cap and an headphone output cap. The brown one is the headphone out, 220u/25V. Replace with your preference.
The other one is a regulator cap but not in the signal path - it's for a relay - so you don't have to replace if you don't want to.

Group 2 is the main power supply cap. There's 4 of these, 4700u/35V. It's not easy to replace these because the diameter is so small (18mm). You can, however, squash in Nichicon KW up to 6800u/35V.

Group 3 are power supply caps for another rail, 1800u/16V. Again replace with Nichicon or other low ESR cap. A lot more space available here.

Group 4 cap is not in signal path, no replacement needed.

I also bypass these caps with a film cap. The best performance to price film cap I've found is the JB capacitor JSX series. If you solder caps to the underside PCB you can fit a 10mm diameter cap in. Just be careful of chassis screws. On the audio output caps I'm bypassing with 1u JSX's soldered beneath. They take a long time to burn in (hundreds of hours) but gives a massive soundstage, deep bass and good treble extension - makes it easy to hear differences in upsampling to 384kHz in JRiver.

I use the 501 slow filter setting which is the best, I feel. It even seems to make a difference when listening to 384k even though the filter should be off by then.

If you're good at modding, remove the cheap op amps and replace with a DIP socket so that you can roll op amps. There's 4 to do (2 for headamp and 2 for RCA/xlr). For some reason the through holes are wider than standard DIP so use an extra socket with slightly bent out pins to insert. If you're not good at desoldering, pay someone to do it.

Finally, please do modifications at your own risk. I'm not advocating any of it.

 

[DObleX]

37mil, thanks for very helpful and detailed description! But it's difficult for me to do all these updates at ones. It will be better to move step by step, from simple to complex.
So, the first step will be to change audio output and headphone apm caps:


I'm not sure about my preferences, because I have no any experience with replacing caps. I just want to improve sound quality. You told about JB JSX caps. Could you specify more detail the parameters of these caps (link will be great!)? I can't find JB JSX with 100uB 25V parameters.
And I could to replace 5532A with something better. For example, dual to mono op amp module AD797BR, or something of discrete op amps.

 

[37mil]

JB Caps are film type which means that they are really big in physical size. You won't find a 100u cap to fit in that space. This means you'll have to use something else, like the Elna Silmic I mentioned before which are very common. I didn't like them anywhere in the 501 to be honest although they are used throughout the whole signal path in my amps. You've got to remember the fewer caps the better. Another popular choice is the Nichicon Muse.

The JB film caps are soldered across these output caps known as bypassing (some people swear by this). Small value caps are used, like the one I mentioned previously. I actually used Mundorf bipolar caps on the audio outputs (Raw type) - they just about fit. For regulator outputs maybe you could try some panasonics which I think are less coloured than Silmics.

Replacing op amps? Yes, I've done it. I've changed them all. I would recommend keeping the Muses because they're already quite good. Replace the 5532s. I used discrete ones from Sparkos and Dexa. Neither are cheap but sound very transparent. I prefer the Sparkos for being smaller and running cooler.

It's very difficult for a novice to desolder the 5532s. I would get a TV repair guy to get the components off who would charge around $60. So you may as well replace all the caps in one go. I'm pretty good with an iron (did electronics work for years) but even I got stuck on the 5532s without the right desoldering equipment. I looked up an electronics repair guy near by in the Yellow Pages and dropped off the pcb for him to desolder everything, then picked it up the next day. Money well worth spent.

 

[DObleX]

Thanks! I will try to do that.
 
Anyway, what to upgrade - USB or coaxial?

 

[37mil]

It depends on what you use most, USB or co-ax? I use USB only but I have noticed that some interference (EMI or other electrical) is conducted through my cheap USB cable causing the DAC to momentarily stop playing for a split second. For example, if I plug an ethernet cable into the laptop connected to the DAC by USB, it would cause this. Other times it might be switching on of lights, combi heater, heaters, etc.  Quite annoying. So, I might contemplate something like the Uptone Regen. I'm not sure about how well the ground isolation is on the regen - it would need to be good to mitigate this problem.
 
As for co-ax, I have a CD transport (high end Marantz SACD with pure silver digital cable and 75 ohm WBT connectors) but it doesn't seem to be as good as listening through USB on the laptop. It's also a lot more convenient to use the laptop to access the music library and not need to change disc.
 
So, my vote would be to improve USB via cable upgrade and/or regen. I will possibly do both.

 

[DObleX]

Here is a question in 501's inputs quality and in quality of feeding source. USB input, in comparison with coax input, has two advantages: DSD and possibility to use Teac HR Audio Player. But, if DSD and player are not important, I believe, that coax input with quality feeding source, ceteris paribus, will be better. Especially with Melodious MX-U8. USB input quality is limited of USB-plate. Anyway, direct listening is the best decision.

 

[37mil]

The Melodius is probably the better USB implementation with its 3 TCXOs. However, a problem with adding this is the cost and the need for having a USB and coax cable, both of which should be good quality if you believe in that.

 

[kookoo]

hey guys, any body would be able to tell me if the TEAC can output both line outs at the same time or better yet if it is user switchable? I am planning to run my headphone amp (RCA) and monitors (XLR) through them.

 

[37mil]

  hey guys, any body would be able to tell me if the TEAC can output both line outs at the same time or better yet if it is user switchable? I am planning to run my headphone amp (RCA) and monitors (XLR) through them.

It's selectable with selectable hot pin out.

 

[kookoo]

 
It's selectable with selectable hot pin out.

Awesome, now all i gotta do is find the 230V version of this thing

 

[Adriel]

First of all, group 1 is not a group at all. You've grouped the audio output and regulator output caps together.

The two green caps near the op amp ics at the top of the pic near the xlr in group 1 are the audio output caps. These are 100u/25V. You can replace these with Elna Silmics or whatever you like as your preference but be careful as the space is very limited in there. There are 4 of these, 2 for each channel (not in your picture).

The two green caps below the op amps in the middle of group 1 are voltage regulator output caps, and there's 2 more not in your pic (this is a dual mono design remember). These are 100u/25V. These are very sensitive to cap quality. I replaced with Elna Silmics but the sound was so dull and congested I replaced again with a tiny film cap. You can use a film cap if you replace the regulator with a Dexa voltage regulator as the designer said it is stable even with no output cap as it is so fast. Be warned the Dexa are not cheap and you'll need 4 of them. The voltage regulators are +12V and -12V, two of each. Another good regulator replacement is Sparkos.

The last bottom two in your group 1 is a regulator output cap and an headphone output cap. The brown one is the headphone out, 220u/25V. Replace with your preference.
The other one is a regulator cap but not in the signal path - it's for a relay - so you don't have to replace if you don't want to.

Group 2 is the main power supply cap. There's 4 of these, 4700u/35V. It's not easy to replace these because the diameter is so small (18mm). You can, however, squash in Nichicon KW up to 6800u/35V.

Group 3 are power supply caps for another rail, 1800u/16V. Again replace with Nichicon or other low ESR cap. A lot more space available here.

Group 4 cap is not in signal path, no replacement needed.

I also bypass these caps with a film cap. The best performance to price film cap I've found is the JB capacitor JSX series. If you solder caps to the underside PCB you can fit a 10mm diameter cap in. Just be careful of chassis screws. On the audio output caps I'm bypassing with 1u JSX's soldered beneath. They take a long time to burn in (hundreds of hours) but gives a massive soundstage, deep bass and good treble extension - makes it easy to hear differences in upsampling to 384kHz in JRiver.

I use the 501 slow filter setting which is the best, I feel. It even seems to make a difference when listening to 384k even though the filter should be off by then.

If you're good at modding, remove the cheap op amps and replace with a DIP socket so that you can roll op amps. There's 4 to do (2 for headamp and 2 for RCA/xlr). For some reason the through holes are wider than standard DIP so use an extra socket with slightly bent out pins to insert. If you're not good at desoldering, pay someone to do it.

Finally, please do modifications at your own risk. I'm not advocating any of it.

 
No wonder I had such problems inserting DIP sockets. The pins on the sockets were getting splayed out to the point of getting loose and popping out; I had to re-insert a few of them. All op-amps rolled have gotten stretched out as well.
 
The two NE5532 were replaced with the Sparkos equivalent. I tried DEXA but it was not a good match sonically, so the DEXA went back into another DAC. The Sparkos was much more in keeping with the 501's original sound characteristics, maintaining its smoothness and character.
 
I had no idea what one could swap for the JRC Muses, so I left those.