DAC64 & Torodial power supply

I've just had an amusing secondhand purchase experience which I thought I'd share with you guys (seeing as I saw some interest in this topic on a previous thread).. I bought a DAC64 (mk I) secondhand & was very happy with the sound improvement it gave me over my old Audio Alchemy DDE3 & DTI 1.0 (although it didn't blow it away - which I was slightly surprised at considering the AA DAC is getting a bit old). However, after an hour it would lose its lock on the signal & refuse to regain it until I'd let it cool down & messed around switching everything on & off. The DAC was also running incredibly hot - so much so the first time it cut out I went to bed wondering if I'd melted something ! I ended up sending it back to Chord to be checked over. It turns out that one of the previous owners had substituted the power supply for a torodial version ! To cut a long story short Chord blamed the problem on the power supply & replaced it with a conventional one & also repaired a problem with the digital circuitry that they reckoned was caused by the switch. But heres the funny bit:

I got it back, switched it on & my initial impressions were not as good. Its still an improvement but it sounds a little more harsh than before & just not quite as clear. I haven't got the best ear so I can only put it down to one of the following

a) immediate post purchase ecstasy (not the drug ) leading to wishful thinking
b) The power supply did make a difference with the DAC
c) The firmware update they also did for me actually detracted from the sound !

Don't get me wrong - its still a fantastic DAC - just not quite as good as I remembered it (although I only got a couple of hours listening in before it went back). Maybe the secret is to replace the power supply - but only listen to it for half an hour at a time !

On a related subject - what do you guys think of the Trichord Digital output Board in relation to the DAC64. My transport is a Sony 400 CD megachanger (stop giggling at the back) & I'm planning to either get it reclocked or put the DOB in. I know the preferred connection is optical for the DAC64 so I'm wondering if its worth going the whole hog or just reclocking it ?

 

Interesting post Steve. Wadia-miester who will no doubt be along shortly doesn't have kind things to say about switched mode power supplies (SMPS) as used by Chord and reckons an external conventional supply with toroidal xformer is a big improvement. I remain to be convinced though.

It's amazing that you had a DAC64 with a built in linear (toroidal) PSU. Some of the prototype DAC64s used a linear supply but apparently all production models have the SMPS. It's possible that Chord were telling you porkies and you somehow came into possesion of a prototype model or very early non SMPS one.

The locking thing was also an issue in early models of the DAC64. The jitter window they allowed for was quite small and more than a few transports had issues with it. Chord later widened the allowable jitter window (they more than doubled it) to get around the problem without (apparently) any degradation in sound quality. This is probably the fix that Chord did with yours.

FWIW I don't think the PSU would have caused the problems you mentioned. My (MkII) DAC64 gets very hot aswell and I the locking issue is a well known thing with the earlier models.

The Trichord digital output boad is very good - I have one in my ancient Marantz CD50SE which I used to use a transport (and now use again as a CDP in my office system). However, the clock on it is not the latest Clock4 spec and it needs a dual rail power supply to power it. For those reasons I had my current transport (Teac VRDS T-1) fitted with a Trichord Clock4 and their new NeverConnected PSU (to power the clock). I use the optical connection between the Teac and DAC and it works extremely well. If I were you I'd go for the Clock4 mod rather than the digital output board.

Michael.

 

Welcome Steve .

A good and interesting first post as well !

What digital connection/cable are you using from the Chord ?

I'd give the new power supply a while to run in. I'm not sure whether SMPS are susceptable to the voodoo () known as break-in but it's wortha go.

Out of interest, did Chord charge you for the changes they made ?
If not, Michael may be right and you may have had your hands on a [very] early model that wasn't meant to reach the public domain .

Transport wise, I hate to say it but I'd ditch the Sony Multi-Changer and spend some cash (not much, mind you ) on a s/h TAG or Teac transport (there's loads of threads relating to this on the forum).

But, if your happy - just buy some more music :music:.

Cheers,

Steve

 

All I'm going to say on the matter, is implementation of said power supply & spoon bending, a must have pre-Requisite, I find quite useful Paul, espeicaly went reterminating Cat 5

 

Tony - you forgot to include the decryption key in your post

Michael.

 

Replies......

Michael,

According to Chord the serial number indicates it came out of their production line about 22 months ago & went straight to the dealer. As the DAC64 has been around a fair while longer than that I don't think I can have a prototype version. Re the firmware update thats why I sent it back to them in the first place, when I talked to their production guy on the phone he suggested it was that issue. Only then did the power supply business emerge. I'm also a little dubious that the power supply was the problem. Some Sony players are apparently notorious for not complying with redbook standards. But the heat level on the DAC was pretty incredible. When I touched the screws on the back of the power supply socket accidentally I thought I'd shocked myself they were so hot ! I could have fried an egg on it ..... (might have spoilt the look a bit tho).

I was leaning towards the clock4 mod so your opinion on that is pretty reassuring.

I can post up a piccie of the torodial power supply that Chord sent me if anyone's interested (I think the jpg is too big at the mo tho).

Steve,

I'm using an optical connection as thats the only connection the Sony has. The reason I've been chasing a DAC64 is its relative transport independence cos I know the Sony is a pretty cruddy player. The thing is that I'm running a DIY multiroom setup & the changer, DAC & amps are actually in a different room to my main speakers. Therefore getting up & down flights of stairs every time I want to listen to a CD is not desirable (especially as I live in a townhouse with far too many stairs). I'll probably go the hard drive route in the long term but I'm waiting for the tech to improve & the costs to come down.

Chord charged £110 for the power supply plus shipping as the DIY mod voided their warranty. I chased up the guy who I bought it off & he coughed up for it after I got pretty shirty (pretty decent guy - could have been a nightmare). Chord have now reinstated the warranty so I'm pretty happy with the situation.

Tony,

wibble ....?????

 

Steve, mail me the pic (michael AT luacheia DOT com) and I'll host it on my server and include it the thread. I'm interested to see what it looked like as there's not a lot of room in there for a linear PSU...

Michael.

 

BTW Steve, in case you haven't already read it, you might find this thread interesting:

https://www.audio-forums.com/as-rediect/showthread.php?threadid=1202

Michael.

 

Right, The PSU's are external not enough room (realistcaly) to but them in side that £80 cam case.
there are 2 in exsistance, and along with some output stage mods, and slight rejigging of the supply to fifo and *other* bits, it makes the dac 64 quite a bit better in all areas It's not an early torriodal factory fit job. Wm

 

Tony - looks like there is enough room in the case :



...here's the Chord SMPS one (slightly out of focus):



Thanks to Steve for the pics (btw, I've slightly improved them with PhotoShop since I posted them - might require a browser refresh).

Michael.

 

i would have thought the lack of room, cooling vents or anything of that sort would have meant a very small linear psu working way harder than it was ever designed to in a small thick metal box. was the guy you bought it off just out of the booby hatch?
cheers


julian

 

As I said Mike, not enough room to a proper psu, remember it's not just a torriodal I use some rather unquie cucritry, that just won't fit my good man, hense the use of another box

 

I don't understand the photos, they're not of the same excavation in the box, are they?

I'm rather partial to an SMPS, the Linn 'Brilliant' implementation is packaged in a case a similar size to a toroidal and fits in its place. Plug compatibile as it were... (although you have to remove the rectifier)

Paul

 

No, I noticed that too. The orientation is different aswell.

The top photo (with the linear PSU) is the "right" way up and the bottom one of the SMPS is upside down (ie the power cord enters at the bottom of the photo instead of the top).

There have been several versions of the DAC64 all with subtle differences to the design of the case and one difference must have been the size of the cavity for the PSU because the one with the linear PSU in it is much bigger.

Also, you'll notice that in the top (older) photo the Chord logo "plaque" is visible and attached to the main chassis. The "lid" for this version has a deep bevelled edge hole that let you see the (recessed) logo as in this pic:



..and this pic:



On the newer models the Chord logo is attached to the lid and (as the SMPS photo shows) not the main chassis as in this pic (which is my DAC64 since I couldn't find another pic):



Also, newer models had holes drilled into the PSU side of the case on the top - presumably for cooling. There are some of the older model (recessed logo) which also have the drilled holes which means there are at least 3 different case variants, not to mention the differences between MkI and MkII which were primarily the addition of a power switch at the back and dual BNC inputs for 192kHz operation.

Michael.

 

That makes sense of it, thanks.

Paul

 

"and Michaelab, your chosen subject on Mastermind tonight is : "The History and Circuitry of the Chord DAC64."

 

LOL I forgot to mention another difference that's clear from the photos: the older versions used only 4 screws on each side to attach the lid, the newer ones like mine have 5 screws on each side :bookworm:

Michael.

 

Mate, I think you have a screw loose .

 

To add to the confusion,

I understand that early versions of the DAC64 used a linear power supply, not a SMPS.

 

This is turning out to be an educational thread !

I would love to know which previous owner did the mod as I'd like to find out if he sold the DAC on cos of the problems I experienced. The guy I bought it off pleaded ignorance but did cough up the money surprisingly easily to cover the repair - a guilty conscience perhaps ?

Re the Sony transport I'm using I'm still not sure whether to bother getting it mod'd at all. The other DAC64 threads imply that through a toslink connection the DAC64 is completely immune to jitter. That means that reclocking the player is probably a pointless exercise. However, I've also read other threads that swear that the transport does make a difference to the DAC64. Is there anything I should be considering doing to the player to improve it as a transport ? (apart from replacing the mechanics or throwing it away as I'm sure some people will recommend ). Maybe its not worth doing anything to the transport & applying my upgradeitus to other areas......