miniDSP users read this.

[charlielaub]

Re: miniDSP users read this.

This is an inexpensive regulated 12V supply that I use:

http://www.jameco.com/webapp/wcs/stores/servlet/Product_10001_10001_162996_-1

Likely better than USB power.

-Charlie

[cwad8505]

Re: miniDSP users read this.

Charlie..I was thinking miniDsp recommends 1.5A and the one you referenced is 500mA...
I could be wrong.
Chris

[charlielaub]

Re: miniDSP users read this.

Charlie..I was thinking miniDsp recommends 1.5A and the one you referenced is 500mA...
I could be wrong.
Chris

From the product datasheet:
Power supply: USB powered OR 5 ~24Vdc input via terminal block connector (Max 150mA @5V)

[cwad8505]

Re: miniDSP users read this.

I stand corrected.. what's new? lol I had that stuck in my brain from where I was reading about the 2x8 the other day. It says "miniDSP 2x8 requires a regulated power supply of at least 1.5A (18W)". Thanks!
Chris

[charlielaub]

Re: miniDSP users read this.

I stand corrected.. what's new? lol I had that stuck in my brain from where I was reading about the 2x8 the other day. It says "miniDSP 2x8 requires a regulated power supply of at least 1.5A (18W)". Thanks!
Chris

We're both right! I use the MiniDSP-in-a-box units (2x4), so I had those in mind...

-Charlie

[bwaslo]

Re: miniDSP users read this.

Is your laptop plugged in to the wall? If, so try it on batteries. Laptop supplies are very noisy and can inject a lot of noise through common powerline grounds.

I run my MiniDSP from a linear isolated cheapie 9vdc "wall-wart" supply, driving into power amps and then to high efficiency speakers. Noise isn't a problem at all.

[johnk...]

Re: miniDSP users read this.

I haven't noticed distortion with either the 2x4 or 2x8. Though I do notice a little noise when either unit is connected to my PC. But as soon as I pull the USB cable both are quiet.

I'll have to run some tests on my units.

The other things is that the 2x4 unbalanced has no analog gain stages, only the A/D on the input and the D/A on the output, if I recall correctly.

[Bob Brines]

Re: miniDSP users read this.

Something to think about:

Noise is noise, and as long as it is below the noise level of the listening room, who cares?

The problem I am addressing is THD, which is totally different from noise. Even it the computer power to the miniDSP is dirty, the result should be to push the THD curves up the scale. It is extremely rare to see the 3rd harmonic higher, even an order of magnitude higher than the 2dh.

Bob

[rone]

Re: miniDSP users read this.

I am using the miniDSP-in-a-box

How long does it take to get one after ordering?

[johnk...]

Re: Just ran a sweep....

Hi Bob,

I just ran a sweep of my 2x4 unbalanced, in a box. THD was better than -80dB 20Hz to 2k Hz. (I stoped the sweep at 2K.) And it was all 2nd order.

The miniDSP was powered thrpugh the USB port of the PC.

[jonasz]

Re: miniDSP users read this.

Using the 2x4 unbalanced with my Notes, can't hear anything wrong with it either. I think you must have a faulty unit.

[gregbegland]

Re: miniDSP users read this.

What is this, Fox news? Talk about a way to scare people away from a product....

Kinda misleading title and post. Seems obvious that a correctly working miniDSP would not do that.

Greg

[bwaslo]

Re: miniDSP users read this.

Try it on a real power supply. I've not measured any significant distortion either. Sure you aren't hearing heterodyning with switching (power supply) frequencies? Surely you have some sort of dc wallwart (2-prong, ungrounded) you can splice onto the input power terminals.

MiniDSP is just an implementation of the Analog Devices ADAU1401A, you can lookup its specs.

[Bob Brines]

Re: miniDSP users read this.

No, it is not the power supply!!!!! Both cases were powered by the same computer. The problem is not background noise, the problem is harmonic distortion. Johnk actually supplied a useful response. He swept his miniDSP and found no problem. Ergo, I have a defective unit. I will seek a replacement.

Bob

[Pallas]

Re: miniDSP users read this.

I stand corrected.. what's new? lol I had that stuck in my brain from where I was reading about the 2x8 the other day. It says "miniDSP 2x8 requires a regulated power supply of at least 1.5A (18W)". Thanks!
Chris

Speaking of which, I'm going to pick up an 8x8-in-a-box when they start shipping (few weeks, they've said). Any rec's for a good (not audiophool stupid expensive, just solid) 12V PS for an 8-channel miniDSP.

What is this, Fox news? Talk about a way to scare people away from a product....

Kinda misleading title and post. Seems obvious that a correctly working miniDSP would not do that.

I think it's a fair title and post. Bob measured an issue that hadn't previously come up. Worth every miniDSP owner reading, and figuring out how to measure their own.