[HeadphoneAddict]

Quote:

Originally Posted by tomb /img/forum/go_quote.gif Just an FYI from someone who also sells a PCM2702-based DAC (Bantam): there is no such thing as a "PURE" connection to the TI PCM2702*. It produces its analog output centered at 50% of Vcc. Vcc is the analog voltage supply. Typically, this is the +5V of the USB voltage, or some regulated portion thereof. It's quite simple to regulate the +5V down to +4.75V with significant benefit in noise and performance. This has been done for years on the AlienDAC and the Bantam, with oodles of test data that can easily be looked up. The main point, though, is that the voltage center of the analog output (the music signal) is positive voltage (typ, ~+2.5V). That means that any PCM2702 implementation must have output capacitors, or some other buffering device to remove the voltage offset. "PURE" from the DAC output connections is impossible. On the other hand, there is a Wolfson DAC chip, specifically the WM8524, that uses a charge pump to produce analog outputs centered at "0" volts. This means that in the case of the Wolfson 8524, it IS possible to make connections directly to the DAC's analog output, with no intervening circuit components whatsoever. The new grubDAC has been designed that way (full disclosure - I sell that one, too). I'm not certain how many other mfrs have started using this chip in this way, but it's entirely possible that if claims are made for a "PURE" output using this chip - it may, in fact, be true. *Also note that TI has declared the PCM2702 NRND for quite sometime - Not Recommended for New Designs. IOW, the chip will be phased out at some point in the future.

Is that the Wolfson in the Gamma 1 or Gamma 2 DAC? I'm mobile and can't look it up right now.

 

[BryanP]

The uDAC is definitely not a bad entry-level DAC to purchase for around 100 bucks if you're looking for an "engaging, upfront" sound as well as portability.

I've used mine for 3 months paired with a HifiMan EF2A (mainly running M8100s) and it was fun to listen to. The mids which are very forward on the uDAC gets tamed by the Mullard tubes real well.

I couldn't really listen to the uDAC through the headphone out unless I was just watching TV shows because it was just "too forward" for me. Vocals at times didn't seem to flow organically with the rest of the sound. It sounded like there was a "bold outline" set on the vocals where everything else just revolved around it. This got a little better or worse depending on the phones used with them (tested with Shure SRH440, HiFiMan RE0, AKG K701, Sennheiser HD600). This sound was tamed a bit using tubes, so my impression is contingent on the fact I'm using the uDAC's line out to an external tube amp, not the headphone out exclusively.... which means YMMV.

In the end the synergy wasn't bad at all... but not the "sound" I'm after in particular (note I'm not saying the sound is poor... just not to my taste).

I picked up a lightly used Marantz CD-63MKII (damn thing is new, reads burnt/scratched CD TOCs in less than 2 seconds... no tracking issues, sounds great) for 30 bucks and the DAC on that sounds much better than the uDAC IMO - considering the player is from the mid 90s. Very organic sounding when paired with the EF2A!

In conclusion, the uDAC can be a good portable DAC if you're looking for an upgrade to that laptop sound. It'll be a step up from most laptop soundcards, and for some, this may be enough. However, if you're looking for a flat sounding DAC, this isn't necessarily the solution. The sound can get somewhat better when paired with an appropriate amp.

Happy listening

 

[tomb]

Quote:

Originally Posted by userlander /img/forum/go_quote.gif None of it's specific to the uDAC, either, which has a Sabre dac, not pcm2702e. So personally I think it should be moved. Again, the dual mode didn't even have capacitors. So how you can say that something that isn't buffered really is buffered doesn't seem to make a lot of sense, regardless of whatever assumptions might exist about the amp the DAC will output to. What part of "has no capacitor" am I missing?

-sigh- "Buffer" is not "capacitor," they are two different things. A DAC can have an output buffer, output capacitors, or both. Capacitors are used to block DC, while allowing AC (the music signal) to flow through. Buffers are used to either provide greater output current or voltage, since there are very few DAC chips that provide that capability on their own.

Two completely different things we're talking about here. Capacitors will color the signal ... a lot, while buffers are derided - often because it's a cheap opamp, a poor discrete implementation, etc. This causes the sense that detail is lost. However, the very best high-end DACs will have very intricate discrete buffers.

Hope that helps ...

 

[HeadphoneAddict]

Quote:

Originally Posted by BryanP /img/forum/go_quote.gif The uDAC is definitely not a bad entry-level DAC to purchase for around 100 bucks if you're looking for an "engaging, upfront" sound as well as portability. I've used mine for 3 months paired with a HifiMan EF2A (mainly running M8100s) and it was fun to listen to. The mids which are very forward on the uDAC gets tamed by the Mullard tubes real well. I couldn't really listen to the uDAC through the headphone out unless I was just watching TV shows because it was just "too forward" for me. Vocals at times didn't seem to flow organically with the rest of the sound. It sounded like there was a "bold outline" set on the vocals where everything else just revolved around it. This got a little better or worse depending on the phones used with them (tested with Shure SRH440, HiFiMan RE0, AKG K701, Sennheiser HD600). This sound was tamed a bit using tubes, so my impression is contingent on the fact I'm using the uDAC's line out to an external tube amp, not the headphone out exclusively.... which means YMMV. In the end the synergy wasn't bad at all... but not the "sound" I'm after in particular (note I'm not saying the sound is poor... just not to my taste). I picked up a lightly used Marantz CD-63MKII (damn thing is new, reads burnt/scratched CD TOCs in less than 2 seconds... no tracking issues, sounds great) for 30 bucks and the DAC on that sounds much better than the uDAC IMO - considering the player is from the mid 90s. Very organic sounding when paired with the EF2A! In conclusion, the uDAC can be a good portable DAC if you're looking for an upgrade to that laptop sound. It'll be a step up from most laptop soundcards, and for some, this may be enough. However, if you're looking for a flat sounding DAC, this isn't necessarily the solution. The sound can get somewhat better when paired with an appropriate amp. Happy listening

Interesting. I think the DAC in my CD5001 might be better than uDAC as well, but I haven't done direct comparisons. When I first got the HR Micro DAC I wasn't sure it was much of an upgrade in musicality over my CD5001 either, except maybe slightly better micro-detail. As a matter of fact, my Apogee mini-DAC was my first clear upgrade over the CD5001 RCA output which was well burned-in at the time.

To me the uDAC is well suited to feeding amps driving Stax Lambdas, Jade or HE60, Denon LA7000, RS-1 with bowls, and even HD600 or HE-5. With HF-2 or RS-1 with flats the mids were a bit forward except when feeding uDAC into the WA6, and it was a bit dark sounding when feeding an amp driving my Stax O2 Mk1. I like how when using the uDAC while watching movies that the vocals don't blend into the rest of the soundtrack or background, yet for me I don't find it too forward with most headphones and music.

 

[BryanP]

Quote:

Originally Posted by HeadphoneAddict /img/forum/go_quote.gif ... I like how when using the uDAC while watching movies that the vocals don't blend into the rest of the soundtrack or background, yet for me I don't find it too forward with most headphones and music.

This is exactly what I experience as well. When I watch movies and TV shows, it really feels like you're right there with the people talking since the dialogs are up front.

To me carries on when I listen to music however, but this again could be due to the differences in peoples' hearing.

Either way, this has encouraged me to get some more used CDs... off to the record shop

 

[userlander]

Quote:

Originally Posted by tomb /img/forum/go_quote.gif -sigh- "Buffer" is not "capacitor," they are two different things. A DAC can have an output buffer, output capacitors, or both. Capacitors are used to block DC, while allowing AC (the music signal) to flow through. Buffers are used to either provide greater output current or voltage, since there are very few DAC chips that provide that capability on their own. Two completely different things we're talking about here. Capacitors will color the signal ... a lot, while buffers are derided - often because it's a cheap opamp, a poor discrete implementation, etc. This causes the sense that detail is lost. However, the very best high-end DACs will have very intricate discrete buffers. Hope that helps ...

And the dual mode DAC-Straight had NEITHER buffers NOR capacitors. A point you seem to keep ignoring.

 

[K_19]

Quote:

Originally Posted by Head Injury /img/forum/go_quote.gif Also, totally unrelated to you and your discussion but totally related to the product, is the uDAC going to sound exceptionally better connected to the Little Dot I+ through RCA interconnects rather than a mini-to-RCA adapter that came with the amp? Also, any suggestions for quality RCA interconnects I can use (I'm not a cable believer, and will be using cheapo $5 ones until I get a quality pair).

Most adaptors nowadays are quality enough so that they don't have (or have negligible) sound quality loss, but if you can go for a RCA interconnect it'd certainly look neater and not have to worry about whatever possibility there might be.

As for RCA interconnects, I'd look to something that's known to keep things transparent/bright as you have a warm DAC here with a tube amp to boot. You could try a cheap Silver-plated copper interconnect as they are on the bright side (and although they are known to suck the mids out a bit, since uDAC is already forward there it should even out). I'm using Kimber PBJ right now as my main interconnect, and I can vouch that this keeps things transparent, punchy and bright should you be willing to spend that much on it (under $100 if you buy it used). I've also used Vampire wire as well as Blue Jeans in the past and they stay relatively transparent as well, so they're good budget choices.

 

[grokit]

Quote:

Originally Posted by Head Injury /img/forum/go_quote.gif is the uDAC going to sound exceptionally better connected to the Little Dot I+ through RCA interconnects rather than a mini-to-RCA adapter that came with the amp?

If you are asking if the sound will be better through the RCA outs on the back or the mini-plug/headphone jack on the front, then the answer is yes, use the preamp (RCA) outs on the back to connect to your amp, the front mini-plug is made specifically for headphones.

Just wanted to add that, now that we're back on track (I hope).

Quote:

Originally Posted by HeadphoneAddict /img/forum/go_quote.gif The new saying now, "Welcome to head-Fi, and sorry about your nervous breakdown."

Hope he gets over it, I think he means well.

 

[Head Injury]

Quote:

Originally Posted by grokit /img/forum/go_quote.gif If you are asking if the sound will be better through the RCA outs on the back or the mini-plug/headphone jack on the front, then the answer is yes, use the preamp (RCA) outs on the back to connect to your amp, the front mini-plug is made specifically for headphones.

Yep, that's what I meant. What's the reasoning behind it? Bypassing the uDAC's amp and using the DAC directly? Is the headphone out perhaps the cause of the noise I heard when the uDAC was turned low and the LD high, or are my tubes possibly oxidized? Noise was gone when uDAC was high/maxed and LD low.

Not to turn this into a "Fix my Little Dot" thread or anything. I'm new to everything that's not just shoved into a 3.5mm jack.

Here's to hoping my dad has some RCAs lying around. He used to be into audio way back in the day, so it'll take some digging but I'm sure I'll find some. And maybe next week I'll order some Blue Jeans.

 

[K_19]

Oh, that is what you meant by that earlier comment.

Yeah, you wouldn't want to connect it through the front unless that was your only choice. That would be basically amplifying a signal that has already gone through an amplifying stage, and it is called "double amping" which is generally seen as a bad thing (do a search and you can find a lot of technical explanation on it) and is discouraged here.

The rear RCA outputs are the true line outs. Those are the ones you want to utilize.

 

[Head Injury]

Quote:

Originally Posted by K_19 /img/forum/go_quote.gif Oh, that is what you meant by that earlier comment. Yeah, you wouldn't want to connect it through the front unless that was your only choice. That would be basically amplifying a signal that has already gone through an amplifying stage, and it is called "double amping" which is generally seen as a bad thing (do a search and you can find a lot of technical explanation on it) and is discouraged here. The rear RCA outputs are the true line outs. Those are the ones you want to utilize.

Yeah, I know those are what I want to use. Just didn't have an RCA cable handy and was dying to use it.

If there isn't any RCA lying around then I'll take a quick trip to Radioshack or somewhere and pick up some cheap. Judging by the quick reading I did, this is probably the source of the static I heard, and I could damage my LD! Not putting up with that, no sir.

Does this mean I can expect better sound, too? Since I loved what I heard despite double amping.

 

[donunus]

waahahaha userlander da man. Seriously I would have thought the dt880s would be nice with the uDac unless a little extra bass hurts. Nevermind that now though because it seems to have turned to a hotaudio thread and has given the man a headache

 

[userlander]

Quote:

Originally Posted by donunus /img/forum/go_quote.gif waahahaha userlander da man. Seriously I would have thought the dt880s would be nice with the uDac unless a little extra bass hurts. Nevermind that now though because it seems to have turned to a hotaudio thread and has given the man a headache

I found it bloated and difficult to listen to once I had identified that problem (if I'm not mistaken, wasn't it you who said there were similar problems with the HD650?). It was better in that respect on the MS-1s, as I imagine it would be on heapdhones like K701/2, etc., but then you have the issue of the recessed vocal mids and the fizzy highs. So then I'm left wondering what exactly it's good for.

 

[donunus]

it wasnt me that talked about them and the hd650s. Also I really dont find them to have recessed mids and fizzy highs. They are actually more tubelike than my other past dacs. They are slightly soft sounding if anything. You really must have gotten a lemon.

 

[K_19]

I think the main difference between you two are how you guys perceive the upper mid/lower treble region. Based on past reviews and headphones you both like/dislike, it's clear that donunus is sensitive to any slight emphasis in this region (as with K701, SRH840, etc... this is bit like me as I am somewhat sensitive in this region as well) while userlander likes it out in full with his gear (with Grado/Alessandros, DT880, and accompanying gear). So it makes sense why the perception between you two are quite different.