Xiang Sheng DC-01a

[Andrew Heck]

Howdy. I'm a circuit novice trying to dig into this piece of equipment and get the most out of it. There are no schematics available, so I've been relying on bits and pieces of advice floating around the internet. The three things that I've found to be important are tube rolling, upgrading the opamps, and better output capacitors. I need your help with the output caps. This is what I got off of one site:

"So being a typical bottlehead, I figured it was time to mess with some caps. I have been unable to dig up a schematic for this device anywhere on the net. If anyone knows where to get one, I would be grateful. So I spent a while following traces on the circuit board, and digging around in the extra cap pile. I ended up replacing the output caps, which were 3 uf boxy things, WIMA I think, with some Solen 3.9s, and bypassing those with some Auricap 0.22s. Also, I replaced some 10 uf electrolytics that I think are cathode resistor bypass caps with 10 uf Solens. Fitting all of this in there was tricky, but doable. Being totally non-scientific, I did all of this at once, so I can't tell you which change did what."

There will be picture on down the thread.

I suppose he's referring to c36-39.

Is changing the values or the quality of the capacitors driving the sonic improvement?

Would it be advisable to keep the values and just improve the type of component? I read that foil capacitors are better than film. Is that close to right?

Knowing next to nothing about this circuit, what would you do?

Thanks for any help you can give.

 

[Andrew Heck]

 

[StimpyWan]

You should check out this Maverick thread in the DAC forum. Lot's of good info there. It should help with your Xiang Sheng questions, as both of these DAC's are variations of the same design.

Also, for what it's worth, I have a DAC-01A too. I've upgraded the tube to a JAN GE5670W. I added op-amp sockets and upgraded to better Linear Technology op-amps, that were recommended on one of the headphone forums. Next, I'd like to try some of the discreet op-amp designs. Not sure which yet? If I change any capacitors, I'd like to try Mundorf, as I'm a fan of how they sound.

 

[Hibou49]

Hi. I'm bumping up this tread to ask a question that may sound stupid. How do you remove the tube from this thing? I feel very frustrated at the moment. Do I have to unscrew something? Should I use lubricant? Please, someone help me!

 

[eickmewg]

There may be a wire tube retainer. Simply remove that from the top of the tube and then pull the tube out of its socket. It should come out rather easily. Don't use the retainer on the replacement tube.

 

[Hibou49]

Thanks for the reply. I did remove the wire retainer. Could the tube be soldered in? That will be a mess to desolder. I'm not good with the soldering station. I barely passed the speaker-wire-end-tinning stage. I'll get pictures another day, I closed back the unit for now.

 

[Hibou49]

I finally got it! A little cleaner-lubricant took care of it. Now, I'm considering upgrading the opamp 2604. What do you think of Burson's Supreme Sound discrete opamps? They look nice.