repair of regulated power supply?

drphoto · « **on:** 1 Sep 2009, 08:23 pm »

Hi all. My digital front end is an Awia XC-35/MSB Link DAC that was heavily modded by Stan Warren. Some of you might remember this being considered a 'giant killer' setup from about 7 or 8 years ago. Anyway last night I damaged the custom outboard regulated PS for the DAC. The setup came w/ two umbilicals, and I decided to try the one I'd never used. Must have been a short in it, as immediately there was a puff of smoke and the telltale smell of fried electonics. I pulled off the cover and a transformer (not the main input one, but a smaller one) was rocket hot.

Does anyone know who could fix this? I suppose I could just put in a new tranny, but there's probably more damage than that alone. Unfortunately there's no schematic, and I think Stan's off the radar these days.

I need to save this, as it sounds incredibly good for the money, I don't think I could afford anything close. (however any suggestions are welcome....maybe the NOS DACS would be the equal....I've never heard one)

Thanks for any help.

BTW: I have the stock PS from MSB, so the DAC is still functional, but of course, it doesn't sound as smooth or as large as w/ the custom unit.

markC · « **Reply #1 on:** 2 Sep 2009, 01:15 am »

Sounds nasty. I assume this has discrete components rather than surface mount? \First thing to do is test the tranny and the accompanying diodes/ bridge rectifiers. Then on to the caps. There could also be resistors and fets in there. With any luck you only took out the tranny, but honestly, I doubt it.

drphoto · « **Reply #2 on:** 2 Sep 2009, 02:39 am »

Yes it's all discrete components w/ PtoP wiring. I'd like advice on who to send it to. I can solder and I know the difference between a diode and a resistor, but that's about the extent of my electronic knowlege.

This really pisses me off, as I had bunch of other stuff to upgrade.....room treatments for one, rather than new DAC PS's. Oh well.....'it happens'.

Actually, as the stock PS has had time to burn in and reform the caps, it doesn't sound that bad. At least it's also a linear supply rather than a switcher.

Any suggestions on decent, affordable (loaded question I know) DAC that take optical input? I thought about the Nixon NOS units, but they're s/pdif or usb and my Aiwa is Stan's take on optical output only. Supposedly his special optical cable was part of the magic of this particular setup.

poseidonsvoice · « **Reply #3 on:** 2 Sep 2009, 05:22 am »

Time to whip out that camera and start taking pics, perhaps its something we can fix through the forum. If not, I'm wonder if Wayne at Bolder could give it a try. Another place to try is Reference Audio Mods.

Best,
Anand.

BPT · « **Reply #4 on:** 2 Sep 2009, 11:33 am »

Though Stan is retired, I believe he is still doing his audio thing (at a reduced pace and enjoying his family much more). I have a customer that just received a new piece of gear from him. Give him a try.
Chris H.

drphoto · « **Reply #5 on:** 2 Sep 2009, 10:35 pm »

Pics I can do. I thought about emailing Wayne. Dunno if he's interested in repair work. Anyone know how to get in touch w/ Stan? He might do this, as this unit was originally built for a personal friend of his out in Oregon. It was suposedly the uber version of this mod.

poseidonsvoice · « **Reply #6 on:** 2 Sep 2009, 10:41 pm »

Only way to get in touch with Stan that I know of is by phone or a letter.

I got this from Lynn Olson's website:

Stan Warren
Supermods
2375 W. 21ST Ave.
Eugene, OR 97405
(541) 344-3696

mgalusha · « **Reply #7 on:** 2 Sep 2009, 11:08 pm »

Almost certainly Wayne @ BOLDER could fix it for you, if he has time.

Quote from: drphoto on 2 Sep 2009, 10:35 pm

Pics I can do. I thought about emailing Wayne. Dunno if he's interested in repair work. Anyone know how to get in touch w/ Stan? He might do this, as this unit was originally built for a personal friend of his out in Oregon. It was suposedly the uber version of this mod.

*Scotty* · « **Reply #8 on:** 2 Sep 2009, 11:57 pm »

I used to have one of these setups and I was warned that the umbilicals,which were made from T1, were very susceptible to shorting out internally. The insulation on the conductors is teflon foam and and was prone to being pinched when the cable was bent and the conductors would short against the foil shield. You should check for this condition in the umbilical with an ohm meter. If an internal short exists in the umbilical then the power supply will just short out again when when the umbilical is reconnected to the repaired power supply.
Scotty

drphoto · « **Reply #9 on:** 3 Sep 2009, 12:33 am »

Hey Scotty, the one that got me was one w/ four separate cables, which I'd never used. The one that had worked for years had a single cable. You'd better bet, if I get it fixed I won't use that four cable version. Maybe if Wayne can fix this for a reasonable price, I can get him to make up an umbilical too.

Since I suppose I can derail my own thread, I've been pondering a whole new setup. I've been thinking about the NOS Dacs like the Nixon or Ack. But, as they don't have optical in, that means a new transport. What's the best option? A Bolder digital mod. SB3? (I have a stock unit) Are the decent, affordable DVD players that make good transports?

I can't spend a ton of money, because I've got that pharmacy school tuition coming up next year.

While the Stan Warren unit is very smooth and listenable, it's not the last word in tranparancy. I know that while it was considered a killer in it's day, when decent digital playback cost a fortune, things have improved greatly over the past few years. Scotty, would you care to comment on what you thought of the Stan Warren Aiwa/MSB setup?

*Scotty* · « **Reply #10 on:** 3 Sep 2009, 01:14 am »

I liked it while I had it. One of its strengths was the fact that DAC was a voltage out piece and a simple discrete zero gain MosFet buffer with a Bessel filter could be used to get the music out the door. This buffer had very low distortion and was free of negative feedback. The unit had a very big three dimensional soundstage,your entire room would disappear with certain recordings. It was replaced with a Philipps SACD1000 which sounded markedly better in every way but especially in the areas of pace and rhythm. Of course it turned out that the SACD 1000 was critically flawed and all of them failed in the field and were not repairable. The AIWA was not a clocked transport at that time and the BB 1716 DAC used in the MSB did not have very good jitter rejection. One of the best improvements that could be done to the setup was to connect a Monarchy DIP 24/96 to the link DAC via it's coaxial SPDIF input with a male to male RCA connector. This solves a lot of transparency issues as well as PRAT problems. Your best bang for the buck might be a Cambridge DAC Magic playing back WAV or AIFF files from your harddrive on your computer.
Scotty

drphoto · « **Reply #11 on:** 3 Sep 2009, 01:27 am »

Scotty, are talking about some sort of optical to RCA adaptor to use the Monarchy DIP? As you know the Aiwa/MSB rig is Stan's take on an optical only output from the Aiwa.

I would think Monarchy units could be found pretty cheap.

I took a quick look at the Cambridge and it has optical in, until I could get a modded SB3.

Thanks for your input.

joe

*Scotty* · « **Reply #12 on:** 3 Sep 2009, 01:33 am »

The DIP has an optical input. Wild West Electronics has the Dac Magic in stock. http://www.wildwestelectronics.net/cambridge-audio-dac-magic-upsampling-audio-converter.html
Scotty

drphoto · « **Reply #13 on:** 3 Sep 2009, 01:37 am »

Ok, so you think the Cambridge would sound better than the MSB? For $430 it would probably be cheaper than trying to repair the MSB PS. Is this a better solution than a NOS Dac.

Again, thanks for your help.

j

*Scotty* · « **Reply #14 on:** 3 Sep 2009, 02:08 am »

Very few options that are inexpensive will beat your Awia MSB combo and that includes the DAC Magic in stock form. I would recommend getting the power supply repaired as your first option. The diode bridge failed in the supply and even if the transformer went they came from Radio Shack and Parts Express, both transformers together don't cost $50.
Scotty

drphoto · « **Reply #15 on:** 3 Sep 2009, 02:37 am »

Hey Scotty, I really do appreciate your help as you are familiar with my setup. So even though you mentioned the Cambridge, you don't recommend replacing the MSB unit with it, despite the jitter problems? So, should I get the PS repaired and add a Monarcy DIP?

What's you take on the Ack and other NOS DAC's, which from my limited understanding of these things is the opposite approach of the Cambridge.

The stock MSB PS, while not awful, if definitely harsher sounding in the midrange area. I'm beginning to believe in the importance of good power supplies. As you said, Stan's unit doesn't have any really fancy stuff in there outside a couple of Blackgate caps. The trannys look like fairly cheap units.

When you mention the Cambridge in stock form....I take it there are mods for it as well.

BTW: I hooked up a stock SB3 w/ both the coax input (using a std. IC, not a 75 ohm digital cable, which I don't own) and optical, and it pretty much sucked compared to the Awia. So it would be nice to save this setup.

*Scotty* · « **Reply #16 on:** 3 Sep 2009, 03:59 am »

I don't care for the NOS approach. Many of these DACs are based on DACs that have even poorer jitter rejection than the BB1716. In addition,they frequently have no filter at all. The presence of a large amount of noise at 44.1kHz causes downward intermodulation distortion that reaches clear into the midrange. The attraction that these DACs have is related to the very simple output stage they have. There are less components between you and the music. If you have the Uber supply for the Link Dac it has a 3 amp transformer for the digital supply and a 5 amp transformer for the analogue supply, in both cases the dynamic impedance of the power supply is serveral times lower than the stock supply,expensive transformers are not needed. The diode bridges have 16amp schottky diodes and if you have blown them they should be replaced with the same size diodes even if you can't get schottkys. Like anything else the Cambridge DAC Magic can be moddified and the Wolfson DACs it uses are known to sound good. The weak point is the analogue output stage and the power supply. The opamps in the DAC Magic can be replaced and the internal power supply storage caps can be upgraded. The outboard supply is a simple AC wallwort. This could be upgraded to a custom supply via a 5 to 8amp transformer plunked in a small enclosure with an IEC on one end and a 2 wire umbilical on the other end.
Here is a link to the Stereophile review of the Dac Magic. The measurements of this thing are near state of the art,all the more remarkable when you consider what it can purchased for.
http://stereophile.com/digitalprocessors/cambridge_audio_azur_dacmagic_da_converter/index2.html
http://stereophile.com/digitalprocessors/cambridge_audio_azur_dacmagic_da_converter/index3.html
The preferred lowest jitter input is the toslink connection.
Scotty

drphoto · « **Reply #17 on:** 3 Sep 2009, 04:21 am »

Yup, that's what I have in the 'uber' PS.

Ok, one more question....if I can get Wayne at Bolder to save this for me at a reasonable cost, should I add the Monarchy DIP? Will that help w/ the PRAT and transprancy issue?

*Scotty* · « **Reply #18 on:** 3 Sep 2009, 06:20 am »

The DIP will improve all aspects of the presentation,however I would not expect the Link Dac to outperform some of the newer more expensive offerings in the market today. The AIWA really should have a clock installed it, I wouldn't go overboard, a $2 VCXO clock with a Panasonic FM series local decoupling cap would be a good improvement. Here is a link to a DIP,you may also find a better price on the used market. My bad here is the one you want, look for the DIP Classic on the left side Microwise link http://www.monarchyaudio.com/microwise/index.html
Scotty

clearsound · « **Reply #19 on:** 28 Sep 2009, 06:56 pm »

Hi, hope you are well.. I work with Cambridge and the dacmagic in addition to Wild West..

-Neil