Ordered DIY 24/192 DAC

[Feanor]

I just ordered a new DAC in kit form from an eBay seller. My old Assemblage DAC 1.5 is decent but is strictly 16/44.1 and I wanted something to play hi-rez PCM up to 24 bit x 192 kbps.

What I order below is a complete kit except for the case: read about it HERE (http://cgi.ebay.ca/High-Grade-24bit-192khz-DAC-with-fully-assembled-kits_W0QQitemZ120433186464QQcmdZViewItemQQptZLH_De faultDomain_0?hash=item1c0a6096a0&_trksid=p4634.c0.m14.l1262&_trkparms=%7C301%3A0%7C293%3A1%7C294%3A30). By all rights it ought to sound like crap, but we shall see. I'm extremely impecunious at the mount so this is the most kind of money I was prepared to spend.

http://ca.geocities.com/w_d_bailey/Gigawork_24-96DAC.jpg

When I've got this installed in the case I'm making, and have determined that it works, I might spring a few more bucks to replace the common-place NE5532 op amp with this dual Burr Brown OPA627 unit (http://cgi.ebay.ca/2-X-Dual-to-Mono-Op-amp-AD827-LM358-NE5532-to-OPA627_W0QQitemZ120397511931QQcmdZViewItemQQptZLH_ DefaultDomain_0?hash=item1c08403cfb&_trksid=p4634.c0.m14.l1262&_trkparms=%7C301%3A1%7C293%3A2%7C294%3A30). I had the original op amps in my Assemblage replace with OPA627 for a worth-while improvement.

http://ca.geocities.com/w_d_bailey/Gigawork_DualOPS627.jpg

[basite]

Let us know how it sounds :)

I'm currently in the run for an external DAC too, I'm not looking at DIY kits, but I'm interested nevertheless :)

interesting project :)

Keep them spinning,
Bert.

[Feanor]

I just ordered a new DAC in kit form from an eBay seller. My old Assemblage DAC 1.5 is decent but is strictly 16/44.1 and I wanted something to play hi-rez PCM up to 24 bit x 192 kbps.
...
When I've got this installed in the case I'm making, and have determined that it works, I might spring a few more bucks to replace the common-place NE5532 op amp with this dual Burr Brown OPA627 unit (http://cgi.ebay.ca/2-X-Dual-to-Mono-Op-amp-AD827-LM358-NE5532-to-OPA627_W0QQitemZ120397511931QQcmdZViewItemQQptZLH_ DefaultDomain_0?hash=item1c08403cfb&_trksid=p4634.c0.m14.l1262&_trkparms=%7C301%3A1%7C293%3A2%7C294%3A30). I had the original op amps in my Assemblage replace with OPA627 for a worth-while improvement.



My <$100 24/192 DAC has arrived! I have hooked it up, sans a case for the moment, and it works!

The signal comes from Foobar2000 to my M-Audio Revolution 7.1 sound card via S/PDIF to this new DAC, and then of course, to my Sonic Frontiers preamp. To my partially deaf ears the sound far exceeds my expectations. Detail and air at least equal my old Assemblage DAC; the bass is as good; the upper midrange might be a tad more prominent but I wouldn't describe it as 'bright'. Of course the unit has only had a couple of hours of burn in.

To test higher than 16/44.1 input, I am using Foobar's Resampler to boost the frequency to 88,200 kHz and the bit depth to 24 bits: this sounds -- if anything -- a tad smoother and more resolved than the native resolution. At least that's my impression, (I don't limitless confidence in my own ears as some people do).

The decent sound for cheap might in part be the product of a relatively simple signal path (as I judge by the schematic; though you should understand that I'm not much of judge of such things). In the signal path, just before output and after the NE5532 op amp, is as CD4053 IC which is described as a "triple 2-channel analog multiplexer" -- can somebody tell me what such a component is supposed to do?

I didn't order the OPA627 op amps mentioned earlier, but instead one, much cheaper Burr Brown OPA2604 dual op amp which is recommended by Parts Connection as an upgrade to the likes of the NE5532. I'll wait 'till the unit has burned in for a while before swapping these components however.

[rob_a]

Is this for a headphone system or an office type small speaker system???

[Feanor]

Is this for a headphone system or an office type small speaker system???

No, for the time being it's going to be in my main system. Like I said, I want to be able to play 24/96 hi-rez files which I couldn't do with my old DAC.

[Feanor]

...
The signal comes from Foobar2000 to my M-Audio Revolution 7.1 sound card via S/PDIF to this new DAC, and then of course, to my Sonic Frontiers preamp. To my partially deaf ears the sound far exceeds my expectations. Detail and air at least equal my old Assemblage DAC; the bass is as good; the upper midrange might be a tad more prominent but I wouldn't describe it as 'bright'. Of course the unit has only had a couple of hours of burn in.
...

I didn't order the OPA627 op amps mentioned earlier, but instead one, much cheaper Burr Brown OPA2604 dual op amp which is recommended by Parts Connection as an upgrade to the likes of the NE5532. I'll wait 'till the unit has burned in for a while before swapping these components however.

After a few hours of burn-in I have concluded that the prominent upper mid is quite shrill unfortunately. Maybe a few more hours of burn-in would help, but there was no indication of a positive trend.

So I swapped waited no longer to swap out the NE5532 dual op amp for the OPA2604. The improvement was instantly evident. I've only been listening for an hour or so now but sound is no longer 'shrill' (if still not exactly 'sweet'). It's amazing how much improvement a relatively "expensive" component like the OPA2604 can make -- we're talking $4.00 here, folks, (vs. $2.00 for the NE5532).

One more observation: the output of this unit is very high -- have to use a much lower volume setting on my preamp. The output increased further still with the replacement omp amp.

[E-Stat]

So I swapped waited no longer to swap out the NE5532 dual op amp for the OPA2604. The improvement was instantly evident. I've only been listening for an hour or so now but sound is no longer 'shrill' (if still not exactly 'sweet').
Cool project. My GamuT CD-1 uses a similar TI/BB OPA2134 output.

rw

[Feanor]

After a few hours of burn-in I have concluded that the prominent upper mid is quite shrill unfortunately. Maybe a few more hours of burn-in would help, but there was no indication of a positive trend.

So I swapped waited no longer to swap out the NE5532 dual op amp for the OPA2604. The improvement was instantly evident. I've only been listening for an hour or so now but sound is no longer 'shrill' (if still not exactly 'sweet'). It's amazing how much improvement a relatively "expensive" component like the OPA2604 can make -- we're talking $4.00 here, folks, (vs. $2.00 for the NE5532).
...

I've been generally pleased with the results sinced swapping the omps for OPA2604's. Detail and air are a tad better than my old Assembage DAC, however this new one is a bit brighter sounding.

Since I'm on a roll for cheap equipment I decide to buy a tube buffer (http://cgi.ebay.ca/New-Tube-buffer-amplifier-PCB-w-parts-Musical-Fidelity_W0QQitemZ120434561341QQcmdZViewItemQQptZL H_DefaultDomain_0?hash=item1c0a75913d&_trksid=p4634.c0.m14&_trkparms=%7C301%3A1%7C293%3A2%7C294%3A30) from the same vendor. Perhaps the best know tube buffer was the Musical Fidelity X10-D (http://www.musicalfidelity.com/manuals/archive/x10d.pdf). The techical justification of such devices is that they show a very high input impedance to the upstream component, e.g. CD player or DAC, and low output impedance to the downstream preamp or amp; this makes for better matching and hence sound. But of course the tube buffer also gives the signal a chance to "smoothed" by a vacuum tube or tubes.

As for the unit I'll be getting, I intend to swap the provided tube for one of the several pairs of tubes I ealier bought for my Sonic Frontiers preamp. Some of these are likely better sounding. Also, the components in this case are all or mostly tradional through-the-board types, (not the tiny, surface mount variety as most are on the DAC I bought, above); so I might try swapping some of the capacitors for the audiophile brand types like Blackgate.
...

[Feanor]

I've been generally pleased with the results sinced swapping the omps for OPA2604's. Detail and air are a tad better than my old Assembage DAC, however this new one is a bit brighter sounding.

Since I'm on a roll for cheap equipment I decide to buy a tube buffer (http://cgi.ebay.ca/New-Tube-buffer-amplifier-PCB-w-parts-Musical-Fidelity_W0QQitemZ120434561341QQcmdZViewItemQQptZL H_DefaultDomain_0?hash=item1c0a75913d&_trksid=p4634.c0.m14&_trkparms=%7C301%3A1%7C293%3A2%7C294%3A30) from the same vendor. Perhaps the best know tube buffer was the Musical Fidelity X10-D (http://www.musicalfidelity.com/manuals/archive/x10d.pdf). The techical justification of such devices is that they show a very high input impedance to the upstream component, e.g. CD player or DAC, and low output impedance to the downstream preamp or amp; this makes for better matching and hence sound. But of course the tube buffer also gives the signal a chance to "smoothed" by a vacuum tube or tubes.

As for the unit I'll be getting, I intend to swap the provided tube for one of the several pairs of tubes I ealier bought for my Sonic Frontiers preamp. Some of these are likely better sounding. Also, the components in this case are all or mostly tradional through-the-board types, (not the tiny, surface mount variety as most are on the DAC I bought, above); so I might try swapping some of the capacitors for the audiophile brand types like Blackgate.
...

The tube buffer has finally arrived and is in operation for testing -- yet to be installed in a box. Gigaworks principle, Mr. Tai, sent me a revised model which he says is better, (of course): see picture below. He included a hand-written note explaining the upgrades presumed upgrades. I must say, I preferred the original screw-type risers to the pin connectors for input & output as on the new version.

Frankly I'm more impressed by what this unit doesn't do than what it does, at least in combination with the Gigawork DAC. I can hear essentially no "softening" or "blurring" that one might have feared with such a unit; in fact, to my ear there was not reduction in transparency or resolution.

As for improvements, these are subtle at best. With the supplier Russian 6DJ8 tubes, perhaps a very slightly improved sense of depth but no added warmth. I rolled these tubes for a pair of Amperex orange 'PQ' vintage 6922 I had earlier tried in my Sonic Frontiers preamp. With the Amperex my impression was more bass and slight increase in warmth due to a high-bass emphasis. I have other 6922 and E88CC tubes I can try and will likely do so.
...

[Feanor]

The tube buffer has finally arrived and is in operation for testing -- yet to be installed in a box.
...

Another pic of the board. I think I can give this a tentative recommendation for anyone who actually needs an impedence matching buffer; certainly a great values vs. the $400+ Musical Fidelitys, etc., that are out there.
...

[thekid]

Feanor

Thanks for the info on the DAC!
Sounds like a nice low cost upgrade when i get around to setting up my son's system.
A simple search on E-bay will bring up the vendor?

[Feanor]

Feanor

Thanks for the info on the DAC!
Sounds like a nice low cost upgrade when i get around to setting up my son's system.
A simple search on E-bay will bring up the vendor?

Hi, Kid,

Yep; reallly, this is a great cheap option if you willing to build yourself a simple case. Here's Gigawork's eBay store ...
http://stores.shop.ebay.com/gigawork-shop__W0QQ_armrsZ1

Actually, if you could spring just a few more bucks, I'd go for THIS (http://cgi.ebay.com/Gigawork-24-192-Up-sampling-DAC-DA-CONVERTER-w-USB-kit_W0QQitemZ120438083171QQcmdZViewItemQQptZLH_Def aultDomain_0?hash=item1c0aab4e63&_trksid=p4634.c0.m14.l1262&_trkparms=%7C293%3A1%7C294%3A30) model that feature optional upsampling, USB, and potentially better overall performance. There is a DIY Audio thread (http://www.diyaudio.com/forums/showthread.php?s=&threadid=137976) that deals very extensively with this model.

As for the cheaper DAC I bought, I do recommend the opamp upgrade I mentioned above. And, actually, I think I'm going to order the dual OPA627 opamp module (http://cgi.ebay.com/2-X-Dual-to-Mono-Op-amp-AD827-LM358-NE5532-to-OPA627_W0QQitemZ120400670691QQcmdZViewItemQQptZLH_ DefaultDomain_0?hash=item1c08706fe3&_trksid=p4634.c0.m14.l1262&_trkparms=%7C293%3A1%7C294%3A30)from Gigawork. The OPA627 is consider by many to be the crème de la crème of audio opamps.

[Feanor]

I have complete my DAC + tube buffer DIY project, (if anybody cares).

This is basically my first DIY project since assembling a Heathkit amp in the late '70s, so cut me some slack! :arf: It's also the first time that I have attempted to make any type of enclosure, and here again my efforts might seem paltry, but I wanted to keep cost and effort low given I had little confidence in the overall result.

First picture is the (back of) the completed enclosure (complete with signs of one or two evident mistakes). You can seen that it's made of 1/4 and 1/8" MDF -- no too elegant but it works. The holes on top are obviously to ventilate the valves. You can see too the completely separate DAC outputs and buffer inputs that allow me to use either compoment separately from the other.

http://ca.geocities.com/w_d_bailey/DAC-buffer-project03.jpg

Next pictures show the "guts". There's obviously lots of room to spare inside the box, but I want to build a standard 17" width component. The DAC has separate power supply and functional circuit boards; the tube buffer has the power supply and circuit combined. Each component has its own transformer. BTW, the RCA jacket are not part of the standard package; I bought these separately because of the partical impossibility of mounting the cheap ones that came with the kid in the MDF back panel.

http://ca.geocities.com/w_d_bailey/DAC-buffer-project02.jpg
http://ca.geocities.com/w_d_bailey/DAC-buffer-project01.jpg

Now for the not so good news. I still prefer the transparency and naturalness of my old Assemblage DAC 1.5 (as upgraded with OPA627 opamps). However I'm not terribly disappointed considering the low cost and that my main objective was to provide myself with 24/192 capability that the Assemblage lacked.

Overall I don't recommend the DAC since I'm pretty sure much better DIY ones are available for not much more money. The tube buffer, on the on the other hand, I suspect is a better deal offering a clean and transparent buffer for very cheap -- I recommend it for people who actually need to match the impedances of an upstream and downstream component.

[Rudy Gireyev]

Great Job Feanor, on the assembly and review. Did you ever get around to installing the 627?

I'm curious which DAC input would have the greatest bandwidth. Is it USB 2.0, Optical, SPDIF or something else?

I'm trying to decide if I should dream about getting the Benchmark or get a MSB Link III and see if I a software engineer can do what's necessary to upgrade it appropriately.

Much research to be done yet.
Rudy

[Feanor]

Great Job Feanor, on the assembly and review. Did you ever get around to installing the 627?

I'm curious which DAC input would have the greatest bandwidth. Is it USB 2.0, Optical, SPDIF or something else?

I'm trying to decide if I should dream about getting the Benchmark or get a MSB Link III and see if I a software engineer can do what's necessary to upgrade it appropriately.

Much research to be done yet.
Rudy

Hi, Rudy,

Thanks for your interest.

The DAC I bought from Gigawork doesn't have USB. I does have both coax and optical however. Gigawork has other DACs that have USB including one that has optional upsampling, a more sophisticated circuit, and a toroidal transformer. Frankly for the extra $50 I would suggest that model to any one interested in a little DIY project.

No, I haven't tried the OPS627, (I would need the pair mounted in the adaptor which Gigawork sells). I decided that this model of DAC doesn't sound as good as my old, Assemblage 1.5 DAC (which was upgraded to 627's). Of course, the Gigawork will do 24/192 which the Assemblage won't.

If I'm inspired, or if a get a few more 24/98 or 192 recordings, I might try the 627s and/or I might try to by-pass the cheap, audio mixer-based buffer in the Gigawork DAC and instead go directly to the Gigawork tube buffer I also bought from them, (see above).

[Luvin Da Blues]

Not sure how I missed this thread before. Looks like a very interesting DIY project especially considering the cost. Are you still considering the 627s for this? Have you done anything to "finish" the cabinet?

[Feanor]

Not sure how I missed this thread before. Looks like a very interesting DIY project especially considering the cost. Are you still considering the 627s for this? Have you done anything to "finish" the cabinet?

Ha! as for the cabinet, no, I've done nothing more to finish it. If I decide to use the DAC + buffer combo I might paint it. However I am considering using the tube buffer alone, in which case that cabinet is grossly oversized and I'd rather find or build a new one.

Like I said, if I acquire more hi-rez recordings I might get the dual 627 module from Gigawork. But I have no immediate plans.

[Rudy Gireyev]

Hi, Rudy,

Thanks for your interest.

The DAC I bought from Gigawork doesn't have USB. I does have both coax and optical however. Gigawork has other DACs that have USB including one that has optional upsampling, a more sophisticated circuit, and a toroidal transformer. Frankly for the extra $50 I would suggest that model to any one interested in a little DIY project.

No, I haven't tried the OPS627, (I would need the pair mounted in the adaptor which Gigawork sells). I decided that this model of DAC doesn't sound as good as my old, Assemblage 1.5 DAC (which was upgraded to 627's). Of course, the Gigawork will do 24/192 which the Assemblage won't.

If I'm inspired, or if a get a few more 24/98 or 192 recordings, I might try the 627s and/or I might try to by-pass the cheap, audio mixer-based buffer in the Gigawork DAC and instead go directly to the Gigawork tube buffer I also bought from them, (see above).
Have you ever considered using a balanced XLR output from your computer to the DAC? Would that not be the ultimate connection medium as far as bandwidth and sound quality?
Or would it be? On the down side this would require a sound card with balanced XLR output and I have no idea if such a beast exists. And if it does it probably will not be inexpensive. :sad:

I thought the whole point of upsampling is that you don't need the 24/192 source material. I understood that upsampling took 16/44.1 and upped it to 24/192 with magic algorithms and such. No? Just out of curiosity why would you go with Gigawork istead of getting a MSB Link III?

Rudy

[Feanor]

Have you ever considered using a balanced XLR output from your computer to the DAC? Would that not be the ultimate connection medium as far as bandwidth and sound quality?
Or would it be? On the down side this would require a sound card with balanced XLR output and I have no idea if such a beast exists. And if it does it probably will not be inexpensive. :sad:


In fact there is such a thing as a "balanced" digital connection that uses XLR connectors. That is defined by the AES/EBU standard which is the "professional" standard vs. the consumer standard, S/PDIF. No, in fact it is not the ultimate standard: I2S is considered superior because of its lower jitter characteristics.

However I think you're tending to confuse digital with analog signals. They are fundamentallly different. A balanced digital connection, i.e. AES3, pertains only to the electrical transmission and doesn't require a balanced sound card. Few consumer sounds cards output AES and fewer still output I2S. The majority of consumer DACs don't have AES connections (although some do).


...
I thought the whole point of upsampling is that you don't need the 24/192 source material. I understood that upsampling took 16/44.1 and upped it to 24/192 with magic algorithms and such. No? Just out of curiosity why would you go with Gigawork istead of getting a MSB Link III?

Rudy

Yes, it is possible to "oversample", e.g. go transform from 44.1 kHz to 88.2 kHz, or "upsample" e.g. 44.1 to 192. This has some esoteric advantages mostly pertaining to filtering the hypersonic frequencies and to some extent, reducing jitter in case of upsampling. However neither over- nor upsampling can improve the inherent resolution of the sound; to actually have higher resolution you have to start with a higher resolution signal.

[Rudy Gireyev]

However I think you're tending to confuse digital with analog signals.
Hmmmm.

Analog - RCA Connectors

Digital - SPDIF, Toslink, USB, XLR

No? Is that not correct?

Rudy

[Feanor]

Hmmmm.

Analog - RCA Connectors

Digital - SPDIF, Toslink, USB, XLR

No? Is that not correct?

Rudy

Well, not entirely. Let's understand that "connectors" are the physical things at the ends of the cable: they don't necessarily tell you much about the nature of the signal being sent/received.

Analog connectors can be RCA, XLR, or 1/4" Phone plug. XLR are generally used for balanced connections. (Do you understand 'balanced' vs. 'single-ended'?)

Digital S/PDIF can be sent by coaxial electrical cable ("coax") that usually has RCA or BNC (like TV cable) connections, nominally 75 ohms. S/PDIF can also be sent by Toslink, i.e. optical cables; there are standard and mini optical connectors.

Digital AES is usually uses XLR connections as we discussed above.

[thekid]

Feanor

Great thread and thank you for keeping us informed on your project as it progresses!!
I think it is something i will give a shot after I finish some of my other rehab projects.

[Rudy Gireyev]

Well, not entirely. Let's understand that "connectors" are the physical things at the ends of the cable: they don't necessarily tell you much about the nature of the signal being sent/received.

Analog connectors can be RCA, XLR, or 1/4" Phone plug. XLR are generally used for balanced connections. (Do you understand 'balanced' vs. 'single-ended'?)

Digital S/PDIF can be sent by coaxial electrical cable ("coax") that usually has RCA or BNC (like TV cable) connections, nominally 75 ohms. S/PDIF can also be sent by Toslink, i.e. optical cables; there are standard and mini optical connectors.

Digital AES is usually uses XLR connections as we discussed above.
Everything you've said here is in 100% accord with what was my understanding, save the wikipedea article claiming that XLR is a digital connection. :O
Having read the archives on these forums I think I finally get the difference between the balanced and unbalanced XLR connection.
I2S is completely new to me though, and you are the first person I've heard mention it.

I've been wondering about something since I've read this thread. Have you thought about adding a headphone amp capability to your DAC?

Rudy

[Feanor]

FINAL UPDATE; (last thread revival).

I wondered recently whether my Giga 24/192 DAC was the "best sound yet" that I've heard, when combined with with Foobar + SoX resampling to 176.4 kbps. Well it isn't.

Next episode in the saga: from the same eBay source as the Giga DAC I ordered a dual OPA627 opamp module to replace the 2604 I'd been using. Yes, opamps can make a small difference. In this case the slight "sharpness" of the DAC was mostly mitigated by the OPA627 -- a worthwhile upgrade, $40, bearing in mind that the DAC itself was only about $70 with shipping.

However here the tail must end. I extensively A/B'd with my old Assemblage DAC 1.5 and came away the conclusion that the latter the Assemblage is better after all. Basically no tonal difference but the Assemblage has a bit more "air" and thus better soundstage. Regard the Assemblage, note that that (1) it's strictly 16/44.1, so no hi-rez, and (2) that it too is equiped with OPA627 opamps, in this case four discrete components.

By the way, I have two, dual OPA627 opamp modules for sale if anyone is interested. (It think my supplier accidentally shipped me two modules instead of one: my gain.)

[poppachubby]

Ya Bill, could be a possibility with the TDA 1543. Don't know much about switching out OP amps. I think I'll definitely bring it by when I get it and you can school me during our shootout. That reminds me, I remember asking you but I forget your answer. You have the Technics TT hooked up but limited vinyl selection right?

[Feanor]

Ya Bill, could be a possibility with the TDA 1543. Don't know much about switching out OP amps. I think I'll definitely bring it by when I get it and you can school me during our shootout. That reminds me, I remember asking you but I forget your answer. You have the Technics TT hooked up but limited vinyl selection right?
Chubbs, I don't recall what DAC is used in the Assemblage, not sure that it's a TDA1543. I'll check as some point.

Yep, my anolog setup is operational, or at least was a few months ago when I last used it and I've changed nothing. My LP (and digital) collection is mostly classical so if you want something different, (and doubtless you will), you'll need to bring some stuff with you. Have you got your equipment yet? Email me (rather than PM) about date & time for the shoot out.