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M-DAC + Swagman Labs PSU

ArthurG

Member
Whilst waiting for the FDAC I decided to treat myself to a new PSU for the M-DAC.

The PSU does improve on the already very good M-DAC, however the remote not longer works.

On powering the M-DAC with the standard PSU the remote works.

I checked the voltage using the M-DAC display and with:
  • Standard PSU 17.2V
  • Swagman PSU 15.2V
however I doubt that would prevent the remote from working.

Any ideas as to what the issue is JohnW?

Before anyone asks I did contact Swagman Labs who have not had this problem reported before.
 
What Voltage is specified for the DAC? What about the current draw required?

Did you mention your readings to Swagman?
 
Whilst waiting for the FDAC I decided to treat myself to a new PSU for the M-DAC.

The PSU does improve on the already very good M-DAC, however the remote not longer works.

On powering the M-DAC with the standard PSU the remote works.

I checked the voltage using the M-DAC display and with:
  • Standard PSU 17.2V
  • Swagman PSU 15.2V
however I doubt that would prevent the remote from working.

Any ideas as to what the issue is JohnW?

Before anyone asks I did contact Swagman Labs who have not had this problem reported before.

They appear to have sorted out the Remote control Bus signal on the PSU connector which is also sent to the PSU reserved for "future" products.
 
They appear to have sorted out the Remote control Bus signal on the PSU connector which is also sent to the PSU reserved for "future" products.

Hi John, I am not sure that I follow you. Do you mean that they have shorted out the Remote control Bus signal on the connector?

I have found the connector details http://www.pinkfishmedia.net/forum/showpost.php?p=1704807&postcount=22
are you referring to Pin 1 - (Comms bus - do not connect)?

Also John would there be any advantage to getting the input to the MDAC any closer to 16V?
 
Hi John, I am not sure that I follow you. Do you mean that they have shorted out the Remote control Bus signal on the connector?

I have found the connector details http://www.pinkfishmedia.net/forum/showpost.php?p=1704807&postcount=22
are you referring to Pin 1 - (Comms bus - do not connect)?

Also John would there be any advantage to getting the input to the MDAC any closer to 16V?

Yes - the "Comms Bus" should be left open - DO NOT CONNECT :) looks like the PSU is either shorting this connection to Ground or worst to a power rail.

15.2V is OK....
 
Yes - the "Comms Bus" should be left open - DO NOT CONNECT :) looks like the PSU is either shorting this connection to Ground or worst to a power rail.

15.2V is OK....

Thanks for that John, I've checked through the cable with a multimeter and Comms Bus is connected to Ground, all other connections are correct.
 
Thanks for that John, I've checked through the cable with a multimeter and Comms Bus is connected to Ground, all other connections are correct.

So you can either break the pin off the MiniDin connector or modify the lead. Being shorted to Ground will not damage the MDAC - only stop the RC working.
 
I bet they make all sorts of claims about sonic improvements for the PSU they didn't test.... Very minor improvements in my experience and barely worth the few quid it cost me in using bits rom the spares box
 
I have a Swagman PSU on my MDAC, and the remote works fine, so I suspect the fault is with the termination of the cable at the PSU end, and I think it would be easy to do a DIY fix. I feel mine made a small but worthwhile improvement, but, like the OP I really bought it to have something to play with whilst I was waiting...
 
Calex 52000 Series Embedded Linear Power Supply:10-15V dc output - NEW- 5424401. This PSU is currently on ebay, I bought one about 2 weeks ago for £20 inc post. The improvements over the standard are slight but are audible on my system (MDAC/Creek EVO50/Cambridge CXC/B&W 686 S2). Bass has improved somewhat and just a general all round very slight improvement to midrange and top end. I have found that I have to increase the volume to achieve the same level when I used the standard PSU. I use the MDAC as a pre amp and 30db was normal listening now it is 27db for the same volume. I have cut and used the original lead, input is mains and the output is -15-0-+15. set at maximum the output is 15.3v on my unit. These units retail at around £75 + VAT at RS so at £20 I thought they must be worth a try and the improvements are definitaly worth the money.
 
Hi Dave, welcome aboard.

Thanks for sharing this information, I should like to try this with my Mdac. do you have the details of how you wired this up ?
 
Hi Dave, welcome aboard.

Thanks for sharing this information, I should like to try this with my Mdac. do you have the details of how you wired this up ?
Hi, I used the wiring diagram on PFM to wire the plug it was straightforward enough as there are only 6 connections to make to the PSU - L,N, E for the mains. For the +15v I soldered the RED/ORANGE/GREEN/BLUE/WHITE wires together, for the ground solder the BROWN/YELLOW/BLACK(the black that is soldered to the shield not to the No1 pin) and then the PURPLE is connected to the -15v. The plug wiring is on PFM somewhere but I can't find the link sorry. Good luck hope it works as well for you.
 
Cheers for that guys, I have one on order.

I took the liberty of copying the info. onto the Mdac thread,
 


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