$100-200 linear power supply


Trying to remove the digital glare from my Fosi Audio TDA7498E amp. Would changing to a linear power supply do the trick? Speakers are similar to Devore O/baby and Micr/O and listen at 70-80dB max.

Open to any suggestions. Would any of these be suitable?

 

25W 12V Regulated Linear Power Supply

I like this because it uses FRED’s but only 2 amps at 12VDC.

 

5A Output Regulated Voltage Linear Power Supply 50VA Transformer

 

Finished 50W Ultra-low Noise Linear Power Supply

cdc

I purchased it simply based on recommendations of long time member here. Was not aware of the v3 or za3 at the time. But am interested now

I'm using same amp to drive Avalon Ascendant, with WiiM Pro Plus...no "digital glare" here ...and it's down to $59.95 including shipping...

@ericgale 

I am of the school of thought that one would be better off buying a better amplifier than sticking 2 or 3 times the cost in a power supply.

Sure, what amp would that be? It would help if you have heard this amp so you can know what type of sound I am talking about.

From the same review:

 

What is less good are the spikes overlaying the waveform at the signal’s zero-crossing points, which imply inadequate standing bias current in the Gaincard’s output stage. When RD writes about "a hardness or glare in the upper midrange and treble," I do wonder if that correlates with the presence of the high-order harmonics that will result from this behavior. Of course, RD also found that this character dissipated after a very long break-in period.

 

Lab 4706 Gaincard, 1kHz waveform at 22W into 4 ohms (top), distortion and noise waveform with fundamental notched out

Lab 4706 Gaincard, 1kHz waveform at 22W into 4 ohms (top), distortion and noise waveform with fundamental notched out

I am of the school of thought that one would be better off buying a better amplifier than sticking 2 or 3 times the cost in a power supply. It’s an $80.00 amp.

I think I am one of the few people not impressed with iFi power supplies.

I have had better luck at a fraction of the cost using medical grade power supplies from Mouser (don't buy this type of thing on Amazon).

 

If a battery did not fix your issue, then the issue is the amp itself. Battery power, while "pure," usually leads to loss in dynamics since they have a very limited discharge rate. Any 'haze' or color in the upper ranges should be from the amp.

 

At the end of the day, what you listen to is the power supply colored by the transistors. If you give it "perfect" power and do not get "perfect" sound, then the issue is the circuitry. You can attempt to mitigate this by using different filters in the DAC to roll off the upper frequencies or even use parametric equalization.

 

I think in you case, the best thing is to accept the limits of what you have, spend the least to get rid of the worst issues, and enjoy the music.

@akg_ca

I don’t see the merit in an approach of a new LPS at equal to or double the MSRP price of the amp unit itself. I’d put the $200 toward the cost of a better amp first.

Because from my admittedly one-sided and purely subjective listening, I like the basic sound character of this amp. It gets the first 80% right but lacks the last 20%’s refinement. It has a lively, fun sound that just bounces along to the music. The Fosi Audio V3 300W TPA3255 has the more refined "audiophile" quality sound that most people prefer. For example compare Naim to Arcam.

IME it is easier to tame an amp than put life into a dead one (ie switching to the larger 48vdc vs 24vdc P-S.)

I did try running it in for over 100 hours but sound did not change. So I first tried Talentcell 24vdc / 5 amp output. I was expecting the sonic equivalent of an electric car’s instant full torque power as compared to fuel powered engine. What I got was less dynamics and a more flat sound. The sonic character became more like the Fosi Audio V1.0 - TPA3116 50W x 2.

I also tried the $300 IFI power elite. Dynamics were the same as the stock PS but "glare" was reduced by a haze over the music.

That annoying digital “glare”, or digital “edge”, or “brittleness” is a direct function of the minimalist build quality of the amp’s components themselves, that isn’t going to be magically eliminated.

You may very well be right. I am trying to find out if cleaner input power eliminates the need for better internal amp filtering. The Pro-Ject power box I used with their transport (now departed so can not try it out) reduced just the noise to allow hearing deeper into the music. That is what I am trying to duplicate. Battery and IFI switching PS did not do that.

I can smooth out the sound by using my NOS DAC. But don’t like to fix one error with another one.

@carlsbad2

Digital glare does not exist.

Can you elaborate? To give a corollary, it sounds more like a delta-sigma DAC than NOS.

 

My favorite trick for treble glare - 4 6mm girasol opal beads tied together with flexible beading cord and slipped over the speaker cables about 3-4 inches from the speaker terminals - adjustment to taste. This in essence is a cable "choke" but much more refined than the ferrite versions. The result is a sound very much like that of tubes. Four beads fit over my 16 gauge "western electric" cloth cables. Larger diameter cables require more beads for making the "ring."

This is not technically "opal" but is called that because of the way it handles light. The beads below are 8mm diameter, and it is sometimes hard to find them in the smaller sizes. 8mm diameters will work for larger diameter cable or even the thinner gauges - it is just more difficult to make the "ring" of beads to encircle the cable with some spatial uniformity.

Girasol Opal Beads

.7mm Elastic Beading Cord

 

Hmmm …. Spending $100 to $200 extra on an external linear power supply for a cheap $80 MSRP FOSI mini integrated amp, (per the FOSI website page) ?

Everything in this crazy hobby is built to its price-point…., full stop.

That annoying digital “glare”, or digital “edge”, or “brittleness” is a direct function of the minimalist build quality of the amp’s components themselves, that isn’t going to be magically eliminated. 

.I don’t see the merit in an approach of a new LPS at equal to or double the MSRP price of the amp unit itself. I’d put the $200 toward the cost of a better amp first.

carry on and choose wisely, sir.

Put a thin  plate of shungite with a copper tape  on the Fosi
 
There are five types of shungite rocks, categorized by their carbon content:
  • Shungite-1 (noble elite shungite): 90%-98% carbon; this has the metallic sheen.
  • Shungite-2 (raw shungite): 35%-80% carbon.
  • Shungite-3: 20%-35% carbon.
  • Shungite-4: 10%-20% carbon.
  • Shungite-5: Less than 10% carbon.

If you don't buy the size LPS that is specified by the amp maker you are wasting money.  In your case that's 24 volts and 4.5 amps.  Only one of the three you linked met that standard. 

I will also use a linear power supply ...

but i will ad this :

Put a thin  plate of shungite with a copper tape  on the Fosi and/or  on the linear supply ... Add a piece of quartz if it compress the sound a bit too much...

it is my homemade creation...

I dont buy tweaks but make my own ... 😊

 

Pick up an Astron RS12A 12V  power supply off E-Bay for well under $100 including shipping. Over 10 amps of current, American made, built to last for many decades. They sound fantastic, and better than many "audiophile grade" power supplies I have tried priced in the $400-$800 range. You won't regret it. 

I’ve successfully used Acopian power supplies. It’s powering my FireTV cube, it has enough reserves I could power another device. They are designed primarily for scientific devices. Very quiet, clean. Far better than wall worts.