TOPIC:

Hi Folks;
The miniDSP has been in my system for more than 3 years and I would never be without a DSP again!....However, the miniDSP requires unplugging and re-plugging almost every second day, to get the laptop to link with it. This has been an issue from day 1, although the audio performance has been perfect.
The switching power supply provided with the miniDSP does isolate the DSP from Earth ground (or hydro neutral). I don't have hum issues but could the reference to ground via the power supply (the 12 VDC output connector measures 55 VAC above earth with no load connected) be causing issues? The laptop, which also has a switching supply, is always connected to the DSP as it is used to adjust EQ while listening.

Could a conventional power supply, with simply bridge and massive filter cap be used? Is there any further regulation or filtering of the 12 V power before it is used in the analogue output section?
Thanks for any advice, Peter in Canada

Hi Peter....

I just came across your post and had to respond ... The minidsp forum / community has to be the worst I have ever seen ... Never any decent responses... I've been told to go away and buy something else if I have any issues... WTF?
Any how I've wondered about the switching ps for a while.... No answers here !

Awful......

Hi Mattoe; (and all)
I have connected the minidsp to a switched outlet with the thoughts that the unit will 'wake up' each day with a fresh start. Unplugging the unit was my solution when the laptop did not recognize the unit, or the volume would not respond to the remote.
I would love to discuss other solutions. I'm at hennioriginals at gmail dot com (no spaces).

I have a mini DSP upgraded to DDDC24. I made my first real improvement buying a Wireworld entry level USB cable designed for audio cost about 40.00. The difference was immediately evident. I have a pro audio background in which we modified analog recording consoles for better performance. The first thing we did was replace the digital switching power supplies with linear analog ones. I found out about a reasonable linear supply for the Mini DSP from Jameco.com It is the Reliapro part no 170245. I plugged it in today and it is absolutely crystal clear. Jameco is located in South San Francisco, and this item sells for about 25.00 plus freight. These are truly worthy upgrades which bring the immediacy of the music into much better focus. HIGHLY RECOMMENDED.

I have my computer and all audio power supplies fed from Furman equipment. a PL8 Series two which has excellent filtering of the AC lines and is a surge protector. The power supplies are plugged into a special strip that has widely spaced plugs and screw down holders to secure the "wall warts" When I go away for the evening or longer I shut down the computer and then hit the master switch on the Furman PL8. In the morning I hit the master switch, then Push the boot button on the computer. It works every day this way. I am a dealer for Furman and Panamax. I am willing to make killer deals on this stuff for Mini DSP owners.....

Actually the price for this power supply before shipping is $14.95!!!!!! A GENUINE NO BRAINER!

I think for 14.95 this is no linear power supply, but a switching power supply. Switching power supplies are a nogo IMHO in hifi installations.
I bought a 12V LPS on Alibaba for round about 50$ and use it now with my DDRC-24. Satisfied.

Think again, higginsd this is the real deal a 1 amp 12 v linear power supply. It weighs about ten times more than the stock one. Go to Jameco.com and check it out! I was please to find it, I am not easily fooled with this stuff!

You have a link to this? They seem to have millions of power supplies, but mostly unregulated.

I think it is a mistake to automatically assume any linear power supply will be better than any switch-mode power supply. There are good and bad performing versions of both.

To assume a switching PS is a good alternative for HiFi parts is surely a mistake... And yes, I know the iFi SPS, which are not bad, but in the price region of a LPS.

Yes, there are bad LPS on the market, but I know where to buy and don't have any problems.

Anyway, it's up to you what you use, if it makes sense for you and sounds good - fine!

I meant no more than I said. There are good and bad versions of both types.

This may be of interest to some though:

benchmarkmedia.com/blogs/application_not...r-supplies-are-noisy

Thanks Folks;
Interesting link regarding the power amp with a switching power supply. It was a general consensus that switching power supplies don't belong in a high fidelity system, in many expert circles. In my application, the switching supply included with the miniDSP 4x10HD is dead quiet. My concern was the isolation from the AC line and possible ground loop issues.
I have been assured from an unbiased source that a switching power supply must still provide isolation from the line (as any conventional power supply) but there may be caps installed for noise suppression. I am told;

"The output is isolated from the line, for sure. That is a mandatory safety requirement. So it is 3 prong and you are connecting all three.
Switching PSUs nearly always have Y caps from AC line to safety ground for filtering purposes in order to pass the conducted EMI portion of the FCC regulations. This creates purposeful leakage current in the safety ground lead. It has to be kept below a certain level, also by regulation."

So I found 53 VAC measured with a dvm from the negative or positive side of the DC output, to the wall outlet ground. This reduced somewhat by using a line cord with ground pin removed. A little soon to conclude, this may have reduced the "locking up" issue with the miniDSP.

Here's another concern with the miniDSP; when unplugging the DC power plug from the DSP or just wiggling this plug, 'scratching' can be heard from the speakers. I realize that the power amps should be powered down before unplugging the DSP, but I'm impatient.
POINT: Should there be some more internal power supply filtering in the miniDSP?
Thanks, Peter in Canada

Peter wrote:

Interesting link regarding the power amp with a switching power supply.

Note that the article also covered Benchmark consciously choosing to change from linear to switching power supplies in their very high quality DACs.

I am sure Benchmark Media is not using off the shelf power supplies. I am sure that intense research has taken place to make this possible. This does not change the thinking that off the shelf generic switching power supplies are not ideal for audio circuits. In my own experience my own system has never sounded better, with a regulated linear power supply and a high quality usb cable. I hope that everybody who loves good sound will check this stuff out!