[aimlink]

Since reading these discussions on whether or not headphone cables really make a difference; I started doing some looking up and came across this nicely written article Cables, Interconnects & Other Stuff - The Truth.

I found the section on Power Supplies to be rather intriguing since I suspect I may have been in denial when I switched from using the Astrodyne PSU that came with my Ultra Desktop Amp, to the DPS sold by HeadRoom. I can't say that I'm hearing any appreciable difference since playing with them recently.

What's the take here? I'm suspecting that again, the point of diminishing returns may not be as bad as with cables, but it seems to kick in a LOT sooner than some are willing to admit.

I'm beginning to have faith only in my cans and even then, I'm beginning to be less and less thrilled as the differences between them grow smaller and smaller.

 

[9pintube]

Out board power supplies make a huge difference, The Tube ones are the best IMO! My tube Lamda power supplies are also regulated ......I've noticed that a turntable "out board power/generator/ speed controller" is a must......Remember these are just my opinions!

 

[nealric]

If we are talking about for amplifiers: I think as long as you are not getting electrical noise above the audible threshold and the component is getting the power it needs, power supplies don't really do much.

 

[aimlink]

Yes. I'm referring to headphone amps, DAC's or DAC/Amp combinations.

 

[DanielCox]

I agree with nealric.

 

[Leny]

Power supplies do everything. Turn them off and see what happens!!!

It actually comes down to suitability for purpose. The supply must be matched to the circuit. Some circuits have the ability to highly reject supply fluctuation, and this is known as their Power Supply Rejection Ratio / PSRR. Other circuits are very sensitive to supply fluctuation.

Likewise some circuits are not bothered by high-ish supply impedance whereas others require constant low impedance with respect to frequency.

It's actually a complex subject and the answer is "it depends" !

Remember that commercial power supply vendors are out to make a profit, so the less reasonable companies might make claims that are rather exagerated.

So you need 'the right power supply' and not necessarily the most expensive power supply.

 

[dexter3d]

My table is currently stuffed with 4 different PSU's for HTPC (CMP optimized custom 0db low power system with RME s/c, using analog out). PSU's: 1) partly linear PSU: picoPSU + linear lab psu (picoPSU passes 12v untouched) 2) old cheap ~200w PC smps 3) Antec EarthWatts EA380 (those have perhaps the lowest ripple among PC smps) 4) Corsair HX450. I am going to devote some time for doing blind tests with those (htpc->shanling PH100 -> k701). Can post my findings, if anyone interested

 

[mmerrill99]

The most direct proof/realisation that power supplies intimately influence what we hear is in my modded HiFace - the stock unit uses the USB 5V to supply an internal regulator which feeds 3.3V to the internal clocks, Cypress USB chip & Xilinx CPLD. I changed the power to the clocks to a direct feed from a 3.3V battery & noticed a huge jump in sound quality. I then disabled the 3.3V regulator & fed 3.3V from another battery - so now cleaner PS to the USB & FPGA chips - again an improvement in sound though not as dramatic as the clock.

Somebody once said in relation to power/pre amplifiers - it is the power supply that we are listening to!

 

[aimlink]

Quote:

Originally Posted by jkeny /img/forum/go_quote.gif The most direct proof/realisation that power supplies intimately influence what we hear is in my modded HiFace - the stock unit uses the USB 5V to supply an internal regulator which feeds 3.3V to the internal clocks, Cypress USB chip & Xilinx CPLD. I changed the power to the clocks to a direct feed from a 3.3V battery & noticed a huge jump in sound quality. I then disabled the 3.3V regulator & fed 3.3V from another battery - so now cleaner PS to the USB & FPGA chips - again an improvement in sound though not as dramatic as the clock. Somebody once said in relation to power/pre amplifiers - it is the power supply that we are listening to!

Nice stuff there Jkeny. One day I do wonder if one day, I'd have tinkered and read enough to be able to do what you're doing there.

Be that as it may, it would seem that there are some who feel that a power supply would have to be really, really poor by current modern standards to impact on sound significantly. Demonstrating a measurable difference would not be enough.

Take my experience for example. I got my HeadRoom Ultra Desktop Amp with an Astrodyne Unit. HeadRoom sells a dedicated PSU for their desktop units. This PSU uses the same enclosure as their desktop amps and dac. It's recommended that you upgrade to this DPS if you want to maximise on your sound. Initially, I did so with my Ultra Micro Stack. Can't say I heard any difference between the DPS and the Astrodynes I was using.

In fact, I can't say that I heard much, if any difference between the Astrodynes and the stock Walwarts!!

I eventually got the Ultra Desktop Amp which I now use at home and moved the Ultra Micro Stack to my office at work. The Ultra Desktop Amp ended up having a DAC issue and during trouble-shooting, I checked the DPS by switching to the Astrodyne PSU that comes stock with the Ultra Desktop. Again, I observed, and with some unease, that I wasn't hearing a difference.

Anyway, I passed it off as the DPS giving really quality power when you really need it, which isn't all the time, so it could be possible that I'd hear a difference in some situations, ie., with some dynamic tunes and with particular headphones, while not so with others. I'm beginning to think now that I may have just been consoling myself considering the US$500 expense for the DPS.

I'd put big money on a bet that no well conducted DBX blinded test would demonstrate an audible difference between the Astrodyne and DPS when either are used with the Ultra Desktop Amp.

 

[nikongod]

A very large part of what you are hearing is a result of the power supply rejection ratio (PSRR) of the audio circuits.

With high enough PSRR, the power supply dosnt matter much. With low PSRR it is critical.

 

[Shark_Jump]

Quote:

Originally Posted by nikongod /img/forum/go_quote.gif A very large part of what you are hearing is a result of the power supply rejection ratio (PSRR) of the audio circuits. With high enough PSRR, the power supply dosnt matter much. With low PSRR it is critical.

Interested. How is PSRR defined. Can I work out what it is for my amp?

 

[aimlink]

Quote:

Originally Posted by nikongod /img/forum/go_quote.gif A very large part of what you are hearing is a result of the power supply rejection ratio (PSRR) of the audio circuits. With high enough PSRR, the power supply dosnt matter much. With low PSRR it is critical.

Does this PSRR vary greatly between amp and dac audio circuits today? How about tube vs SS amps? Is there a way of knowing or predicting what this ratio would be like for a given component? If not, then one would have to assume the worse and ensure that a good power supply is being used.

Never knew of this PSRR until you mentioned it here....

 

[mmerrill99]

Quote:

Originally Posted by Shark_Jump /img/forum/go_quote.gif Interested. How is PSRR defined. Can I work out what it is for my amp?

Here's a very good but technical thread about poer supplies in amplifiers on Greg Ball's SKA amplifier which was designed with high PSRR in the right places to minimise the influence of the power supply on the sound SKA sponsored Audio Forum - Solid State Audio

 

[t/sound]

Quote:

Originally Posted by jkeny /img/forum/go_quote.gif The most direct proof/realisation that power supplies intimately influence what we hear is in my modded HiFace - the stock unit uses the USB 5V to supply an internal regulator which feeds 3.3V to the internal clocks, Cypress USB chip & Xilinx CPLD. I changed the power to the clocks to a direct feed from a 3.3V battery & noticed a huge jump in sound quality. I then disabled the 3.3V regulator & fed 3.3V from another battery - so now cleaner PS to the USB & FPGA chips - again an improvement in sound though not as dramatic as the clock. Somebody once said in relation to power/pre amplifiers - it is the power supply that we are listening to!

I have read your post's and what you have done makes sense but I simply cant trust you.

I think I have to send you some money, you buy a new bnc HiFace do your mod and send it over . I would love to expose you for the genius you are.

All jokes aside, this is a relevant thread and as we all would like to squeeze out as much SQ from our components as we can, a little heads up in the right direction always helps.

Bound to come up sooner or later as with the Hiface powermod is the whole question about battery ps and" off the grid " power. Is this a panacea towards better SQ ?

I notice more and more aftermarket PS activity, so seems a huge interist in this, even Wadia touts their new i171 as the major upgrade of ps and holds out its hands for more money, they would have us believe ps is very important.

Thanks for the comments and sharing of knowledge.

Powershade.

 

[mmerrill99]

Quote:

Originally Posted by t/sound /img/forum/go_quote.gif I have read your post's and what you have done makes sense but I simply cant trust you. I think I have to send you some money, you buy a new bnc HiFace do your mod and send it over . I would love to expose you for the genius you are. All jokes aside, this is a relevant thread and as we all would like to squeeze out as much SQ from our components as we can, a little heads up in the right direction always helps. Bound to come up sooner or later as with the Hiface powermod is the whole question about battery ps and" off the grid " power. Is this a panacea towards better SQ ?

One of the overlooked issues with power from the grid is the rectification to DC. The sudden charging of the PS caps on each AC cycle often causes lots of ringing in the transformer & a spray of HF into the PS. So DC isn't just DC from a rectifier - it has lots of HF riding on top. There are lots of other issues such as noise, ability to deliver current when demanded (low impedance), etc.

The reason I chose Lithium NanoPhoshate batteries is because of their ability to deliver current (70Amps continuous, 120Amp in 7 second bursts) due their low internal impedance (<8moHm) & their continuous delivery of about 3.3V output until exhaustion. I don't have a figure for noise but I have seen test results for Lithium-Ion batteries showing something like -200dB broadband noise under load>

Most regulators would be hard pressed to match these figures.

In theory they could be used for powering amplifiers, turntables, etc & audio consulting does exactly this 6moons.com - industry features: A Visit To Audio Consulting

I notice more and more aftermarket PS activity, so seems a huge interist in this, even Wadia touts their new i171 as the major upgrade of ps and holds out its hands for more money, they would have us believe ps is very important.

Thanks for the comments and sharing of knowledge.

Powershade.[/QUOTE]