reasonable low cost DAC

[rowuk]

My oldest son uses the computer as his sole audio source. We have trouble with hum when it is connected to the hi Fi. I took the easy way out and slapped an isolation transformer in between, but the audio quality leaves something to be desired.
I think I want to take the toslink out from his soundcard and run it to an external DAC. No copper between them, no ground loop is my thinking.
He is not posessed by things audio, has a decent amp/preamp (Carver) and very fine speakers (built by me). I have tried various sound cards hoping that I would get a hum-free match - no luck yet. EUR 200 is the limit.
Any ideas?

[dc]

some low cost options to research:
Zhaolu, DAC-AH, Beresford TC-7510

[Deleted]

Robin
How far apart are they when working together?
I had a minor hum problem with my home brew mains operated headphone amplifier.
Completely cured with an earth jumper using banana plugs and sockets , between the case of the PC and case of headphone amplifier.
Alex

[sometrolls2]

Moodlab has 2 low costs DACs with identical inside bits, the more expensive one( Dice) has a USB connection, the cheaper one ( Concept) doesn't. Reviews suggest that they are more than a match for most of their competitors.
www.tnt-audio.com/sorgenti/moodlab_dice_e.html
www.avreview.co.uk/news/article.asp?SP=&v=1&UAN=953
The Beresford design has been improved again so they will do a £20 mod on new DACs before sending them out, and I think they do a returns/audition deal.

Moodlab and Beresford sell via their respective own web sites and Ebay.

[fanboi]

Unclear on whether the SQ was lacking pre or only post insertion of the iso trans.
ie was SQ acceptable except for the hum - reason for asking being that my recent testing of a couple of soundcards gave me the impression that the analogue out of the Terratec DMX 6 fire was of better SQ than a Monica2 USB DAC. Comparison was brief as I was trying quite a few combinations but all with PC based sound files.
The Monica2, in all fairness, has only had around 150 hrs yet and has had no tweaking done and is said to respond to higher voltage than the 12v I was running it at, it did however show the difference between a cheapie 2 RCA -> mini TRS and a better quality pair of ICs into an RCA/mini TRS adapter.
Testing was done using the same headphones, and Foobar 2000 running ASIO drivers.
That Terratec card uses the Envy24 chip and was a semi-pro card, discontinued but can probably be found at a very reasonable price on ebay. Came in two versions, both the same PCI card but one had a front panel connector box with mic in, headphone socket, phono input, etc.
The point being, I guess, that I am not sure a cheapie DAC will give better SQ than a good soundcard. I liked sandyks idea of trying an earth lead ala turntables.

[minivan]

buy my zhaolu d3? i am still trying to get rid of it so i can upgrade my dac.
still under warranty from coemaudio.com.au

[Deleted]

minivan
I saw it on StereoNET !
I agree with Tony, that a good soundcard gives better results than a typical USB DAC.
In fact, a good soundcard into Voyager (or Green Solo ?) can sound extremely good.
Alex

[minivan]

alex : what is your username in stereonet?

[Deleted]

"Google" ;D

[rowuk]

Hi all,
I was in the hospital for a couple of days for a stem cell donation to help somebody with leukemia. Otherwise I would have responded earlier.

The sound was not good after the insertion of the isolation trafo (no slam in the bass and a veiled top end).

I tried various grounding schemes - the only one that worked was to disconnect the earth on the computer PS (not safe and not a real solution)
Of course a hum free USB solution would also be of interest. I am going to try an M-Audio Fast Track-Pro first (have it laying around)
There are extensive mods for the TC7510 (and its little brother the TC7500). This looks similar to the BT928 mods documented at RockGrotto. I am not sure that this is the best way to go!

[Deleted]

Robin
I hope the donation works. Unfortunately it appears that stem cell donation is not the answer to every type of Leukaemia. A friend of mine, and fellow audio fanatic's twin brother,has recently been diagnosed with this bastard of a disease, and prior to radiation is being treated with a "green tea " therapy.
To me ,it is a bastard of a disease, as it left me without a father just before my 5th birthday.
SandyK

[rowuk]

SandyK,
sorry to hear that. I left the doctors the choice between bone marrow or stem cell (or both). THEY picked stem cell. I hope that is significant. I lost my mother to another form of cancer, albeit a couple of years later.

[slwiser]

I think the Beresford TC-7510 Mk6/3 is a very good deal. I only got mine last Thursday and then it was in need of having some time on it. Today it sounds much better and very surprising. It is moving up on my Lavry DA10 but not catching it as yet. I really don't see it ever catching the Lavry but one never knows. With my hearing it could get so close as to be a mute point but not yet.

Edit: I have had my Beresford running all weekend and have at least 125 hours on it. It does sound very surprising to me, very good into my micro-ZOTL, feed from the optical out of my SB. But still not the same as the Yamamoto and Lavry with the UE9s.

[noddyisking]

I have been researching the options available for low cost DAC's through review and forums. In the end I went over budget and bought a Paradisea+ from MHdt laboratories in Taiwan for $600 through ebay. This company have a number of different DAC's. Google them and read the various reviews and threads on their products. From what I have read USB, properly executed, is the cleanest way of taking sound files from a computer to an external DAC. The Paradisea+ has USB, toslink and co-ax inputs. I intend to use the co-ax for my CD transport and try both the USB and toslink for my iMac input. It is a NOS DAC. I am continuing to look into over and up-sampling but as I prefer good vinyl to CD, I am not sure if I want to go this route.

[raytira]

Nov 6, 2007 10:00:55 GMT minivan said:

alex : what is your username in stereonet?

Hi,
Is it still for sale???
How nuch do you want for it??

[derekrumble]

Not sure what quality level is the least you'll settle for but technically you can achieve your objective with a simple, low cost, external (USB) soundcard from, say, Creative.

I used to use one (an SB 0270) for some years when I had a laptop which didn't have good on-board soundcard. Did a lot of work through this little beauty. The headphone output was poor, but the phono line-outs are fine. It even had toslinks in and out. Cost at the time was around 50 Euros.

Regards,

Derek

[rickcr42]

My oldest son uses the computer as his sole audio source. We have trouble with hum when it is connected to the hi Fi. I took the easy way out and slapped an isolation transformer in between, but the audio quality leaves something to be desired.
I think I want to take the toslink out from his soundcard and run it to an external DAC. No copper between them, no ground loop is my thinking.
He is not posessed by things audio, has a decent amp/preamp (Carver) and very fine speakers (built by me). I have tried various sound cards hoping that I would get a hum-free match - no luck yet. EUR 200 is the limit.
Any ideas?

For "computer as audio source" this is hard to beat (I have and use a "cloned" version with some minor changes on the analog output and power supply section ),especially now ith the exchange rate (euro vs dollars).Just use the Headphone Output as a Line Output (or even better see if you can get Jim Hagerman to do one with a capacitor value better suited for line driving duties )

www.hagtech.com/hagusb.html


Ompaper and according to who you talk to not the ultimate but the damn thing plays MUSIC and that is all that matters

Robin
How far apart are they when working together?
I had a minor hum problem with my home brew mains operated headphone amplifier.
Completely cured with an earth jumper using banana plugs and sockets , between the case of the PC and case of headphone amplifier.
Alex

Not entirely sure if i am following what you are saying Alex.I would think you are CREATING a ground loop by attaching an extra ground connection between the two chassis which would be an another ground connection in addition to the one made by the RCA interconnect and USUALLY because it would allow a separate path for the ground but at a different impedance would in fact CAUSE a ground loop thus "hum"

A "simpler' fix may turn out to be just plug the computer into ONE AC outlet and the Amp ANOTHER which can in some cases eliminate the contamination the switcher/shitty grounds of the computer can INJECT into the mains....unless again i am not understanding your "fix'

SandyK,
sorry to hear that. I left the doctors the choice between bone marrow or stem cell (or both). THEY picked stem cell. I hope that is significant. I lost my mother to another form of cancer, albeit a couple of years later.

Mother,father,grandparents on both sides,possibly further back in my family tree but not diagnosed for what it was....all lost to The Big "C" in one form or another making me ground zero at some point which is fine by me if it "skips" a generation and that generation my sons.At 52 I have seen several lifetimes so having lived a very full life so better me than those close to me is how i feel

rickeraptor out

[rickcr42]

BTW-there are some "known' issues with computer audio systems so i thought maybe some background would be in order in this very thread

Ground Loops :

www.ptsdcs.com/whitepapers/7.pdf


Digital Ground noise : (will get back to this later-very important topic and needs to be done right...)

www.rane.com/pdf/compgrou.pdf



Fire wire & USB Sound Card Guides :

www.silentway.com/tips/equip/io.php

home.earthlink.net/~rongonz/home_rec/soundcard.html


General Computer Audio ;

www.positive-feedback.com/Issue22/nugent.htm




The Recording side-Getting Sounds IN :

www.tweakheadz.com/setting_up_your_audio_card.htm

will add more content here when i get a chance

[rickcr42]

Seems I am not allowed to edit my own post (sabotage is what or as bugs would say "Sabotagee Doc" ) so rather than have a single easily accessable "dumpster" for the links i would have or will add it will now go to organized chaos (i know,don't say it )

ecmweb.com/mag/electric_bringing_grounding_down/

blueguitar.org/new/articles/other/ground_loop.pdf


getting bored with this so will just say i use transformer isolated "mains" filters on all low level digital gear that uses a main powered supply to keep crap OUT plus at some point an audio line 'bridging" transformer to keep the crap generated by the lowlevel digital device from being transmitted downstream to the next device.That in combination with SPDIF transformer isolated handles digital sends and retreceives PLUS using USB has kept a damn lot of nasties out of my PC Audio signal path so where there once was way too much "hum and buzz" there is now didital black...or as close to it as i am capable of acheiving

Rickmongo out

[Deleted]

Rick
Even though my PC and HA for the P.C. are plugged into the same powerboard , I had an annoying low level hum. My HA sits on top of the PC, so an easy fix in my case , was to fit a banana socket to the HA case, for case earthing, and a short lead with a banana plug on the other end back to the metalwork of the PC near it's switchmode PSU. The result was a dead quiet HA. Obviously, this won't work in every situation, BUT it has also helped to do the same with my preamplifier and amplifier, due to having about 6 different inputs, half of which have SMPS in them, and the resulting 80-100VAC (low current!) between the earth side of their output RCAs and mains earth. BTW, I only have one double socket mains outlet available in the part of my bedroom where the PC is located. This also rules out the use of the PC directly into the main HI-FI system. In any case, I wouldn't want anything but a fanless PC in the main listening area, as the low level noise does help obscure very low level ambience. Even the fridge running in the kitchen, or air conditioning also affects low level ambience. I am not disagreeing with your methods, just suggesting there is more than one way to "skin a cat" (assuming you still have any of those destructive little blighters left ?)
Alex

[rickcr42]

If even after your fix you still have noise issues then you still have a ways to go before you have it whipped.

For one you need to isolate the sound card or DAC all by itself from the mains because digital circuits are sympathetic to RFI (your low level noise).I use a AC line transformer isolated mains feed to clean up the input side.Once you have "dirty" power you have problems inside the DAC/Soundcard that can be very hard to eradicate if at all (obviously the best solution is a "home run' mains feed dedicated to digital audio but too extreme for most )


If the "low level noise" is instead digital ground noise then you are pretty much stuck with it since no way will you ever try galvanic isolation of the digital grounds which is the ONLY method that can totally isolate the feed and why many ultra-high-end audio companies are either incorporating such devices or selling aftermarked "add-ons" to address the issue

You need to understand it is not just the "hots' that can have contamination but the grounds as well and because of have to be dealt with either at the design/layout stage or later with the working device in system.this is not theory or conjecture but documented facts and why if you pay more up front for a very good digital device you have to spend less or nothing later to "fix" problems inherent in the design.cheap usually means corners cut somewhere and those corners usually at the design/layout stage rather than the implementation of