Simple Power Supply for Audio Amplifiers. (Why? This is for audio)

[AP2]

Hi, all

I think that currently there is much confusion about generic and specific power supply for audio amplifiers.

(or some companies do not have the right knowledge to develop)
I saw in this forum, many declared power supply for audio use but none of them seem to fit the requirements. (I exclude use on commercial audio)

Minimum requirements for audio use.
Unregulated simple model:
Use of appropriate and good components.
development of the PCB with suitable characteristics to reduce emissions of interference and ensure.

proper electrical insulation for safety.
Output voltages clean (residual high frequency should not be present) is acceptable presence of a low ripple (100Hz).
(this is a problem) becouse on digital amplifier, PSRR (if good) is normally well below this frequency.
In short, even a simple unregulated psu, must solve these problems.
then I can say that this is for audio.

I simply measured spectum analyzer and oscilloscope, the output of an unregulated PSU, split for audio use by a famous company.
Ripple is enormous, high residual is present until the exit load on the amplifier

(class AB) ... imagine what is the exit of class d!
EMC measures on dipole (on air irradiation) ... if I put antenna on transformer near ,.... transmit up to Kenya!
if unregulated is simple, why? this is not well developed?.

I put a pic of PSU unregulated really developed for audio.
Simple and compact but...

Use fixed PWM with interventions on the waveform to drive the transformer as clean as possible. (This loses a small efficiency)
Realization of multilayer transformer (this reduces capacitance)
Special GAP (ceramic use) to find the knee of the curve, this increases the efficiency of inducer, (gain even, the small efficiency lost first)
Trasf and power circuits were included in a cover (with nickel to GND)
EMI filter adjusted for low conduction to AC-Line.
Power Vout use 4 pole filter for eliminate residual high frequency.
Aux Vout use 2 pole filter lc.
Active circuit reduces residual 100Hz up to 50% of power.
PCB is developed for EMC and electrical safety.
Components and materials ... is sufficient to look at the pic.
Thermal and fast protection con differenzial current sensing.

ok, this is the work that was done on a simple psu for audio.
..can add 2x6800uF and all measurements on your amp is good.

Best regards

[AP2]

Hi,
this is power curve of DPS-400.
I understand that this is a very simple PSU, not suitable to meet the needs of professional audience, but elegantly solves the generic use of AMP.
I put this, only to show "to some", that even a simple psu should have suited the requirements, not rudimentary circuit and bad features just to save money.
this is also low cost.

[okapi]

how about an output impedance and phase plot?

[AP2]

Hi,
"PowerCurve" is not from simulator, but from hw instrument.
it is clear that the output impedance is very low, if you see the voltage drop on max amperes (psu becouse not regulated), this reflected voltage drop on high voltage capacitor.
at 52V (8amp), transformer lost only 2.7 Vrms.
This contributes to very high efficiency.
tomorrow do other measures for your curiosity.

[AP2]

Hi,
These are 3 simple tests on "simple psu for audio."
no added output capacitors, the voltage drop can be greatly improved by adding 2x6800uF-63V.
but this is not important, even a good big psu regulated, has a voltage drop greater than 10V under burst signal. (try to believe)
very important is that PSU should not alter the sound, adding a lot of IMD and often distorts the signal source (CD player etc).
My opinion is, when you buy or choose to build a psu switch, check that the voltage outputs are clean and that iradiate (EMI) are low.
this ... is not easy to obtain.

[indianajo]

Interesting tests done on a DPS-400. Performance looks good. Where did you buy this? When? Who is the manufacturer? Retailer? Cost? I have internet searched 30 pages and got mostly a Pitney Bowles sorter, a Barfield electronics aircraft sensor, and a power supply for PC's with ATX form factor. There are some references to a repair part for a Sony amp, is that what this is? deltapowersupplies.com is a digitally controlled lab power supply manufacture in Germany, not at all suitable. A packaged switching power supply with +- 50 DC at 400W with 87 db down switching noise would be a useful component.

[theAnonymous1]

Originally Posted by indianajo

I have internet searched 30 pages......

http://www.audiopower.it/

It was on the second page of my search......

"DPS-400" power supply -sony -vaio - Google Search

[AP2]

Originally Posted by theAnonymous1

http://www.audiopower.it/

It was on the second page of my search......

"DPS-400" power supply -sony -vaio - Google Search

Hi,
thanks, this page is correct www.audiopower.it.
This company is a reseller on-line of some new products developed by "MDI R & D".

Regards

[AP2]

Originally Posted by indianajo

Interesting tests done on a DPS-400. Performance looks good. Where did you buy this? When? Who is the manufacturer? Retailer? Cost? I have internet searched 30 pages and got mostly a Pitney Bowles sorter, a Barfield electronics aircraft sensor, and a power supply for PC's with ATX form factor. There are some references to a repair part for a Sony amp, is that what this is? deltapowersupplies.com is a digitally controlled lab power supply manufacture in Germany, not at all suitable. A packaged switching power supply with +- 50 DC at 400W with 87 db down switching noise would be a useful component.

Hi,
DPS-400-1.3 is in production. (Much used by some companies for commercial audio from 2003)
This PSU is developed from research with professional components, specific for audio amplifiers.
despite the use of components "special" and quality (power-unit use), the cost to the public should be € 78 ... I think

NB. I am part of the team "MDI" but I have no connections with AudioPower (commercial)
(this company is expected to open on-line in a few days).

Regards

[AP2]

Hi,
because I have received many requests for info, this is the datasheet for the DPS-400-1.3.
This compact PSU is really good and very reliable, even for lm3866 amplifier
absolutely no noise or problems up to 10Amp out.

Regards