Bricks List: 36V & 48V Power Supplies (for Fosi, Aiyima etc.)

[Zuiko]

FYI was looking at the source for the 'FJ' logo:
Manufacturing Plant: Huizhou Fujia Appliance Tech
Brand: Shenzhen Fujia Appliance Tech
https://en.sz-fujia.com/
List of products:
https://device.report/huizhou-fujia-appliance-tech

 

[Charger]

What PSU upgrade would you guys recommend for a Douk Audio H7 amplifier?

 

[Ronnie1963]

I just ordered the pre-order PSU FJ-GN224048005000 from the Aiyima shop at Ali for my Fosi v3. There is a sales coming up making this currently an even better deal for nearly 30 Euro sent to NL. I asked seller to confirm they will be sending the model number as pictured. Will report back what they reply. The v3 is currently powerd by the FJ-SW21283606000D which I received despite MXD 3606000 being shown at the time. This was bought from a different seller though, Yimaglobal, and they have since updated the picture to reflect the new 36v version.

 

[Ronnie1963]

I cancelled the pre-order as I received answer it's not the one they are advertising with they will be sending. @Idrago , your doubts were right.

Edit: pictures are changed now to different PSU.

 

[Guddu]

What PSU upgrade would you guys recommend for a Douk Audio H7 amplifier?

I am not 100% sure but seems like H7 uses 50v caps, so you can use 36v psu safely.

 

[Idrago]

I cancelled the pre-order as I received answer it's not the one they are advertising with they will be sending. @Idrago , your doubts were right.

Edit: pictures are changed now to different PSU.

No comments, it is obviously a practice, they have already changed the offer, there is another image, a model that does not match, model FJ-SW21283606000D with 48V 5A, their paper supports whatever they want to write!
https://www.aliexpress.com/item/1005006060750495.html;

 

[Forte]

Amateur looking for advice on power upgrade for Fosi BT30D Pro:

Great website, thanks for having me. I bought the BT30D Pro to power a pair of JBL Studio 30 "bookshelf" speakers. I'm disappointed with the volume output. I have to turn the volume knob up to 9 to reach a modest "party" volume level.

The JBL Studio 30's are 6-Ohm and suggested power is 125W.
I'm running about 60' of 14 gauge cable to the speakers in a 14'x20' room.

I have read this thread twice and still not sure which direction to go or what to buy to get more power.
Fosi 48v 5a price is $60 on Amazon, plus shipping.
Are there any good options?
Do I/Should I spend $60+ on a $99 amplifier?
Should I sell the BT30D Pro and spend $160 on a more powerful amp?
Will the 48v Power Supply really boost the power output of the BT30D Pro?

Any advice is deeply appreciated - Thank you.

 

[NTK]

Amateur looking for advice on power upgrade for Fosi BT30D Pro:

Great website, thanks for having me. I bought the BT30D Pro to power a pair of JBL Studio 30 "bookshelf" speakers. I'm disappointed with the volume output. I have to turn the volume knob up to 9 to reach a modest "party" volume level.

The JBL Studio 30's are 6-Ohm and suggested power is 125W.
I'm running about 60' of 14 gauge cable to the speakers in a 14'x20' room.

I have read this thread twice and still not sure which direction to go or what to buy to get more power.
Fosi 48v 5a price is $60 on Amazon, plus shipping.
Are there any good options?
Do I/Should I spend $60+ on a $99 amplifier?
Should I sell the BT30D Pro and spend $160 on a more powerful amp?
Will the 48v Power Supply really boost the power output of the BT30D Pro?

Any advice is deeply appreciated - Thank you.

Welcome to ASR!

I wouldn't use a 48 V power supply on the Fosi BT30 Pro. From its published spec, the PS input range is 12-36 VDC. The components Fosi have chosen for the BT30 Pro (e.g. the power supply bypass capacitors) may not be rated for 48 V power input.

 

[Forte]

Welcome to ASR!

I wouldn't use a 48 V power supply on the Fosi BT30 Pro. From its published spec, the PS input range is 12-36 VDC. The components Fosi have chosen for the BT30 Pro (e.g. the power supply bypass capacitors) may not be rated for 48 V power input.

Thank you! That eliminates one option for me. I'm reading that long thread on the Fosi Audio V3. That looks like it has more power, but I'm not sure (yet). I like the BT30D Pro because it has Treble and Bass knobs. I only listen to Spotify and YouTube audios with no DAC or other equipment. If I buy the V3, I'd need some kind of unit to control the Bass and Treble? Anyway, thank you for your time.

 

[Joe Smith]

I just received an evaluation unit of the A07 MAX from Aiyima and the power adapter shipped with it is Model Number FS-SW21283606000D, listed as 36v/6a/216 watts. It has the CE mark but not UL. So far, performs well, seems to give both the Aiyima and the Fosi V3 a bit more power than the 32v Fosi brick. I don't have the means to test output of the power supply, but I haven't experienced any problems with it.

 

[NoMoFoNo]

Thank you! That eliminates one option for me. I'm reading that long thread on the Fosi Audio V3. That looks like it has more power, but I'm not sure (yet). I like the BT30D Pro because it has Treble and Bass knobs. I only listen to Spotify and YouTube audios with no DAC or other equipment. If I buy the V3, I'd need some kind of unit to control the Bass and Treble? Anyway, thank you for your time.

I'm using the V3 with an inexpensive Fosi P1 preamp that includes extra gain in the circuit and offers bass/treble controls. The P1 has performed remarkably well for me. It replaced an AR LS-1, which would cost ~$600-800 used, and other than the lack of multiple inputs, I'm just as happy with the sound from the P1/V3 combo as I had been with the LS-1 feeding much more substantial and more expensive amps.

 

[WhyLee]

What is the point of the GAN power brick offered by Fosi? I don't get it.

GaN switches are faster than 'normal' mosfet switches. that has two advantages:
1: faster switching means less time spent between 0 and 1 where power is converted into heat
2: higher switching frequencies can be used, that means the filter frequencies can be higher, that means the filter parts can be smaller ==> cost savings.
depending what you want to achieve, you can go the route with the same switching frequency and reduce power loss and reduce cooling costs,
or you can go the route to increase switching frequency and have the same power loss. or somewhere in between.
the GaN switches are of course a bit more expensive compared to traditional switches, but you can save money on other parts in the circuit.

 

[WhyLee]

My experience with the Fosi Audio BT30D that i got last week:
* 36V 5A power supply
* compared to a Rotel Pre + Rotel Class AB Amp from the 90's with pimped power supply (bigger, better caps).
* output comes from a very good pimped Rotel DAC
my listening experience:
* the biggest difference was the noise in higher frequencies (like the hihat on a drum set or "S"-vocals in voices)
for the normal listener that does not make a huge difference, but for an experienced hifi/high-end listener this difference is the first thing that you can notice
it is not nice.
* the rest of the listenening experience is good / very good.
* the channel separation is not perfect but good.
* the bass punch is not perfect but good
* no other imperfections where noticable

my interpretation what's going on:
i think that the noise of the switching power supply is going through the class-d amp. the result is a kind of amplitude modulation of the power supply noise with the class-d switching. if you are familiar with amplitude modulation you will understand that there are two side bands. below and over the main AM frequency. that means the noise from the power supply can get mirrored below the switching frequency of the class-d amp. and because you don't have a single switching frequency in the class-d amp but more adaptive to the signal (if my understanding is right), then the modulation of the power supply noise and the switching of the class-d amp result in a crazy modulation mess that is audible in the high frequency range of the audio ouput signal.

this is my interpretation. i did not do any measurements. with a high-res measurement of a digi-scope on the output of the power supply while playing music or a 1khz sine wave test signal, it would be easy to measure.

if i am right - which i don't know - what could be the solution?
==> A signle or double L-C lowpass between the power supply and the amp.
A capacitor alone would not do it, because usually switching power supplies do not like high capacity loads.
That means an L-C lowpass filter that can handle currents for at least 5 amps.
maybe two stages in series, first with a corner frequency of 1kHz, second with a corner frequency of 100Hz (is this too much regarding part size and price???)

another benefit with such an L-C lowpass filter (with a low-ESR cap at the end) could be a better channel separation.

 

[asimze]

I also have a doubt whether to get a GAN PS or a standard 48V?
If you look at Mean well SPS, you will see that there is a whole series of technical data about the product. In this case, no one on the forum talks about the technical data that can be measured. And all the time there is talk about various technical data in case they don't mean anything at all, the human ear cannot register it. So we are left to guess!!!
This is very strange to me!!!

 

[TurtlePaul]

I also have a doubt whether to get a GAN PS or a standard 48V?
If you look at Mean well SPS, you will see that there is a whole series of technical data about the product. In this case, no one on the forum talks about the technical data that can be measured. And all the time there is talk about various technical data in case they don't mean anything at all, the human ear cannot register it. So we are left to guess!!!
This is very strange to me!!!

The chips in the amp (the opamps and the TPA3255) have power supply filtering and the board has additional filter capacitors so sonically it doesn’t matter. If you were directly powering a discrete circuit with no additional power filtering the ripple figures Mean Well reports would be more important.

The most important numbers for a power supply are the rail voltage (which is important for high impedance speakers) and the total power output (a function of voltage and max current).

GaN or standard doesn’t really matter for audio performance. I have the 48V 5A brick which was tested. I am sure a GaN version could be smaller, but the brick lives under my desk so I don’t care (I might care for a laptop charger). I am sure a GaN brick could be a couple percent more efficient but also who cares, audio amps are idle most of the time and idle draw for the V3 is reasonable.

 

[asimze]

The chips in the amp (the opamps and the TPA3255) have power supply filtering and the board has additional filter capacitors so sonically it doesn’t matter. If you were directly powering a discrete circuit with no additional power filtering the ripple figures Mean Well reports would be more important.

The most important numbers for a power supply are the rail voltage (which is important for high impedance speakers) and the total power output (a function of voltage and max current).

One question more?! If I run my V3 max 20% power what is diff 32 or 48 V? Better sound???

 

[TurtlePaul]

if i am right - which i don't know - what could be the solution?

No, your theory is incorrect. The problems with highs in these amps is attributable to the load dependency of the output filter.

Rather than a flat frequency response regardless of speakers used, these amps have droop or boost at the highest frequencies depending if the load is less than or greater than ~6 ohms in this band.

The solution is to implement post-filter feedback, which allows the amp to see the droop or boost and correct for it while also reducing any distortion from the output inductor. Texas Instruments (who makes the chips in this amp) has a white paper on how to do this, but Fosi hasn’t successfully implemented it in a shipping product yet.

 

[TurtlePaul]

One question more?! If I run my V3 max 20% power what is diff 32 or 48 V? Better sound???

It should sound the same but the 32V may save you a slight bit of electricity.

 

[asimze]

Is there anyone on this forum who can practically measure the quality of these power supplies. And that is much easier than measuring various parameters about the amplifier that many people don't even understand and we really don't get much use out of that information.
A friend of mine who has many years of practice with high-quality hi-fi equipment said it nicely: "Power supply plays". I agree with him. That is why it would be in the common interest to start an action for "Someone" to measure the quality of these power supplies.

 

[Teddy KGB]

Tiptoeing in as a long time reader/first time poster to ask: (if this is not the optimal spot for this question, feel free to redirect me. Google led me to this thread

I can't help but think that the power supply is an obvious avenue for upgrade for these evolving tpa3255 amps. Has anyone looked into a dedicated switching ps like this one? Tia