"Bamboo V2" project. 3E Audio 260-2-29A Stéréo Rev. B (OPA1656) + PFC/LLC PSU. APx555 Measurements )

[Zek]

Здравствуйте! Сегодня я получил свой Yongzhuxing 600W PFC /LLC @48V, его индуктор и трансформатор издают звук! Были ли посторонние звуки в вашем? Могут ли эти звуки повлиять на качество звука усилителя?

Google translate:
Hello! Today I received my Yongzhuxing 600W PFC /LLC @48V, its inductor and transformer make noise! Was there any strange noise in yours? Can these noises affect the sound quality of the amplifier?

 

[hi30u]

Hi,
Get the Yongzhuxing 600W PFC /LLC @48V or the Mornsun, both are safe value.
The Yongzhuxing has the best performance / price value.

Does that mean that the love story and choice towards "unregulated" PSU is history?

And, trying to digest all Daniboun's projects threads at the same time ;-) did I miss an update about the need and will to test a Micro Audio Unregulated PSU V.S. another brand Regulated PSU with the same Amp Module?

 

[andrewg78]

@daniboun I bought LOF550-20B48 and there is an option to use the so called "Remote Sense" function. On the audiophonics website we can read "A 4-pin input for end-of-line voltage compensation (feedback compensation) and its offset are also present. This enables the power supply's output voltage to be self-regulated according to the needs of the powered module, should the voltage delivered suffer losses in the conductors due to the distance between the power supply module and the powered module."
Is the Remote sense function appropriate for this project?

 

[brunes]

Does that mean that the love story and choice towards "unregulated" PSU is history?

And, trying to digest all Daniboun's projects threads at the same time ;-) did I miss an update about the need and will to test a Micro Audio Unregulated PSU V.S. another brand Regulated PSU with the same Amp Module?

Also was looking out for that but never saw it.

 

[DaveFred]

I am also curious about regulated vs. unregulated power supplies for amplifiers in general as well as specifically for the 3e Audio boards.

 

[Audiomeisterei]

Google translate:
Hello! Today I received my Yongzhuxing 600W PFC /LLC @48V, its inductor and transformer make noise! Was there any strange noise in yours? Can these noises affect the sound quality of the amplifier?

@Samsonio I found a potential solution from the Yongzhuxing website: https://www.yongzhuxing.com/goods.php?id=296

"If some power amplifier boards have poor noise suppression, it is easy to cause static noise. The solution is actually very simple. Add a dummy load between the output +VCC and the ground, such as a high-power cement resistor. The specific amount of improvement is determined by the experiment, because different boards will be different. The maximum operating voltage of the matching power amplifier board must be lower than 90% of the maximum output voltage of the switching power supply. Then, when the switching power supply is at the highest voltage output, the waveform is the cleanest when it is static." (translated via Chrome from Chinese)
This raises two questions:

1. What would be a good starting value for the dummy resistor?
2. I'm considering buying one of these 600W PFC/LLC power supplies myself to use with my Aiyima A07 Pro (Class D amp, max 48V). However, I'm confused about the recommended output voltage of the power supply.

According to the hint, your amp's max voltage should stay below 90% of the PSU's maximum output voltage. But then I found a guide on the same site (https://www.yongzhuxing.com/article.php?id=155) that seems to suggest lower voltages for amplifiers. For example, they recommend 28-36V PSU for a TDA8954 amp (±42V), explaining that:

"It is recommended to choose 28-36V. In fact, it can be fine-tuned to about 40V. It is not recommended to choose 36-50V, because the switching power supply will be frequently shut down when lightly loaded, and a dummy load needs to be added!" (translated via Chrome from Chinese)

This seems to contradict the previous hint, even though the guide is linked in the hint. The explanation in the guide, however, makes more sense than the recommendation in the hint. So, I'm wondering if this could be a translation error.

Conclusion:
I'm leaning toward a 36V PSU for my Aiyima, even though it's rated for 48V. What do you think?

Lastly, I found two different versions of the 600W PFC/LLC single-voltage power supplies:

• https://www.aliexpress.com/item/1005005875722287.html -> https://www.yongzhuxing.com/goods.php?id=296
• https://www.aliexpress.com/item/1005005868431280.html -> https://www.yongzhuxing.com/goods.php?id=293

Does anyone know if there’s any difference between them aside from the dimensions?

 

[jlx]

@Samsonio I found a potential solution from the Yongzhuxing website: https://www.yongzhuxing.com/goods.php?id=296

"If some power amplifier boards have poor noise suppression, it is easy to cause static noise. The solution is actually very simple. Add a dummy load between the output +VCC and the ground, such as a high-power cement resistor. The specific amount of improvement is determined by the experiment, because different boards will be different. The maximum operating voltage of the matching power amplifier board must be lower than 90% of the maximum output voltage of the switching power supply. Then, when the switching power supply is at the highest voltage output, the waveform is the cleanest when it is static." (translated via Chrome from Chinese)
This raises two questions:

1. What would be a good starting value for the dummy resistor?
2. I'm considering buying one of these 600W PFC/LLC power supplies myself to use with my Aiyima A07 Pro (Class D amp, max 48V). However, I'm confused about the recommended output voltage of the power supply.

According to the hint, your amp's max voltage should stay below 90% of the PSU's maximum output voltage. But then I found a guide on the same site (https://www.yongzhuxing.com/article.php?id=155) that seems to suggest lower voltages for amplifiers. For example, they recommend 28-36V PSU for a TDA8954 amp (±42V), explaining that:

"It is recommended to choose 28-36V. In fact, it can be fine-tuned to about 40V. It is not recommended to choose 36-50V, because the switching power supply will be frequently shut down when lightly loaded, and a dummy load needs to be added!" (translated via Chrome from Chinese)

This seems to contradict the previous hint, even though the guide is linked in the hint. The explanation in the guide, however, makes more sense than the recommendation in the hint. So, I'm wondering if this could be a translation error.

Conclusion:
I'm leaning toward a 36V PSU for my Aiyima, even though it's rated for 48V. What do you think?

Lastly, I found two different versions of the 600W PFC/LLC single-voltage power supplies:

• https://www.aliexpress.com/item/1005005875722287.html -> https://www.yongzhuxing.com/goods.php?id=296
• https://www.aliexpress.com/item/1005005868431280.html -> https://www.yongzhuxing.com/goods.php?id=293

Does anyone know if there’s any difference between them aside from the dimensions?

Unless I misunderstand, his issue has no relation to the "poor noise suppression" solution the manufacturer references. They are referencing a ripple & noise level (probably excessively high) that is affecting an amp board with inherently poor PSSR.
Every once in a while you get a power supply that does not "play nice" with a particular amp module, it happens. I recently had a conversation with a manufacturer about a top of the line Meanwell supply that had a small issue with a superb high end amp module. Cheap/crappy power supplies on the other hand have a habit of doing strange things like this gentlemen is reporting.

edit:
looking into it further it seems this manufacturer is also warning you about a required MINIMUM load for the unit to operate correctly. Normally a supplies white paper will list a required minimum load expressed as a percentage of the rated maximum load. If you run it UNDER this amount bad things will happen..

a made up example:
a brand ABC supply 600W rated max power output, a 5% minimum load rating = 30W
using a single 3eAudio 2 ch module, idle power is about 6.1W (quiescent power)
you will have an issue! So they are advising adding a load resistor to reach the required min load (uuummmm no thank you, I will never add unwanted heat into a small amp case, just buy the right damn power supply please)
It may not turn on, it may falter in the output voltage regulation, it may do something else unpleasant.
I can not find any proper spec papers for these Youngzhuxing supplies and the warnings and suggestions they provide give me no confidence in the product design.

the 90% voltage suggestion from them is idiotic, if you can run at 48V, the amp module will probably spec out at around 50V max input to the board, so use a quality 48V REGULATED supply or you will lower the amps maximum power output substantially. I do not play around with cheap power supplies ever as I require quality and reliability/long life.
FYI a good regulated 48V supply will maintain +-1% of stated voltage to max power output so between 47.5V to 48.5V. Nice!
I have now used about 12 Mornsun supplies flawlessly with the 3e amps; lof350, lof450, lof550 and lof750. I think I used the 750W on 3 modules with no issues. I will be testing 3 Orchard Audio starkrimson modules this week (about $475 each) with the lof350 & lof550 supplies as well.

the 2 power supplies noted above from Aliexpress are 2 different form factors 184 x 88mm and 130 x 88mm, no other info is really given.
As always remember that these 600W supplies are likely 200-300W max continuous output, anything above that requires fan cooling
I can find no real documentation for these supplies

 

[Audiomeisterei]

Unless I misunderstand, his issue has no relation to the "poor noise suppression" solution the manufacturer references. They are referencing a ripple & noise level (probably excessively high) that is affecting an amp board with inherently poor PSSR.
Every once in a while you get a power supply that does not "play nice" with a particular amp module, it happens. I recently had a conversation with a manufacturer about a top of the line Meanwell supply that had a small issue with a superb high end amp module. Cheap/crappy power supplies on the other hand have a habit of doing strange things like this gentlemen is reporting.

edit:
looking into it further it seems this manufacturer is also warning you about a required MINIMUM load for the unit to operate correctly. Normally a supplies white paper will list a required minimum load expressed as a percentage of the rated maximum load. If you run it UNDER this amount bad things will happen..

a made up example:
a brand ABC supply 600W rated max power output, a 5% minimum load rating = 30W
using a single 3eAudio 2 ch module, idle power is about 6.1W (quiescent power)
you will have an issue! So they are advising adding a load resistor to reach the required min load (uuummmm no thank you, I will never add unwanted heat into a small amp case, just buy the right damn power supply please)
It may not turn on, it may falter in the output voltage regulation, it may do something else unpleasant.
I can not find any proper spec papers for these Youngzhuxing supplies and the warnings and suggestions they provide give me no confidence in the product design.

the 90% voltage suggestion from them is idiotic, if you can run at 48V, the amp module will probably spec out at around 50V max input to the board, so use a quality 48V REGULATED supply or you will lower the amps maximum power output substantially. I do not play around with cheap power supplies ever as I require quality and reliability/long life.
FYI a good regulated 48V supply will maintain +-1% of stated voltage to max power output so between 47.5V to 48.5V. Nice!
I have now used about 12 Mornsun supplies flawlessly with the 3e amps; lof350, lof450, lof550 and lof750. I think I used the 750W on 3 modules with no issues. I will be testing 3 Orchard Audio starkrimson modules this week (about $475 each) with the lof350 & lof550 supplies as well.

the 2 power supplies noted above from Aliexpress are 2 different form factors 184 x 88mm and 130 x 88mm, no other info is really given.
As always remember that these 600W supplies are likely 200-300W max continuous output, anything above that requires fan cooling
I can find no real documentation for these supplies

Thank you, @jlx, for your detailed analysis. This makes it even more interesting why @daniboun chose this PSU for his build. Based on his review, it seems to work quite well. Maybe he can help answer the following questions:

1. Is the dummy resistor really needed? If so, how do you calculate its value?
2. Which PSU voltage is recommended if my amp's max voltage is 48V (Aiyima A07 Pro)?
3. What is your overall opinion/experience with the PSU?

By the way, thanks for sharing, @daniboun !

 

[jlx]

my main issue with these less expensive power supply units is:
unknown output quality, no proper white papers
unknown build quality, will the components last for years? Will it die in 14 months? Good components and good engineering cost $$
Will it age poorly and cause issues even when it is still functional?
What about their quality control process before they let them out the door,
Do they have a good reputation in the industry?
After several negative experiences in the past I stopped buying these lesser units, not worth saving $40 on a supply that can easily run several channels

 

[JayR]

I made two attempts to purchase this supply from the above supplier first arrived in a crushed box, on opening you could see it had also impacted the board . I ordered another and filed a return . Second arrived with a box crushed in exactly the same way with even more signs of impact on the board . On examination I just didn't like it it felt flimsy and poorly made .

 

[HifiFan]

Delete if not appropriate - if anyone interested, I have extra unused 3e TPA3255 260-2-29A board for sale:

3e audio TPA3255 260-2-29A Stereo Amplifier board

This is the two channel (stereo) version 260-2-29A TPA3255. This is new, I just opened the box and never got a chance to build the project myself.The board was reviewed in ASR at highest rating

www.usaudiomart.com

 

[Azrael]

It is in fact in its official name Dr-Jordan-Design whose owner is Frank).

Well, that's where I bought my sound level calibrator years ago.

 

[ssashton]

I was wondering how you guys got on with these LLC-type PSUs for audio amps?

I’ve been considering this one for another amp I built (still TPA3255):
https://www.yongzhuxing.com/goods.php?id=292

My understanding is that LLC supplies are attractive because:

• They operate with a resonant tank that produces a near-sinusoidal drive waveform, unlike the hard-switched square pulses in more conventional SMPS designs.
• This typically results in lower high-frequency switching noise on the DC output and reduced EMI/RFI emissions.
• They are generally more efficient, which allows higher output power density or a smaller overall form factor.
  

However, LLC converters usually require a minimum load current for stable regulation, since the resonant tank does not behave well at very light load. This is not usually the case with other SMPS types (though those can be noisier at light load due to burst or skip modes).

I believe the Russian poster earlier was describing audible mechanical noise from transformer vibration. Has anyone here run into the same issues or any issue with the minimum-load requirement for these supplies when using them with audio amplifiers? Please let me know.

 

[LEOPOLNORD]

Hi everyone, I'm a niewbie in Hifi world and especially in diy. I'm reading asr threads for a while but this is my first post.
I'm French and live there (this could matter for choosing the good supplier for DIY) , I have currently a fosi V3 stereo, Acoustic Energy Evo3 speakers and I mainly listen CD and sometimes spotify (with SMSL SU-1) and less often LP's on a Thorens 160 mk2 with fosi X5 phono preamp.

I'm interested by making an amp following the micro bamboo project (and maybe use a Fosi ZH3 as preamp).
After reading all posts I have several questions but the first one will be for the power supply:

The quality of performances seems to be influenced by the power supply but after all the debates it's hard to choose one...
Could you help me ? I've listed
- The micro audio one - a bit expensive if you ad sending fee + other taxes, but if it really worth ok
- The MORNSUN LOF550-20B48 SMPS - Easy to get in France thanks to Audiophonics but seems to be
- The Yongzhuxing doesn't exist anymore but several power supplies look really similar on aliexpress like this one - are they reliable ?
- The MEAN WELL LOP-600-48 here - is 12.5 A too high ? easy to get in France.
Every other suggestion is welcome.

Thank you all.

 

[rsqt]

Hi everyone, I'm a niewbie in Hifi world and especially in diy. I'm reading asr threads for a while but this is my first post.

Hi,
in France you have Audiophonics, a very good supplier for DIY.
The 12.5A of a Meanwell is enough for 4Ohm speakers. But for 4Ohm a stereo board is only a little bit less powerfully. Mono has lots more power if using it for 2Ohms. I use monos and stereos of 3E and imo the stereo has little advantages in THD to higher frequencies.

 

[LEOPOLNORD]

Hi,
in France you have Audiophonics, a very good supplier for DIY.
The 12.5A of a Meanwell is enough for 4Ohm speakers. But for 4Ohm a stereo board is only a little bit less powerfully. Mono has lots more power if using it for 2Ohms. I use monos and stereos of 3E and imo the stereo has little advantages in THD to higher frequencies.

Hi, thanks for your reply.
So the meanwell can be a good choice ?
Which power supply did you choose for your projects ?
Thank you

 

[UA8890]

—

Hi everyone, I'm a niewbie in Hifi world and especially in diy. I'm reading asr threads for a while but this is my first post.
I'm French and live there (this could matter for choosing the good supplier for DIY) , I have currently a fosi V3 stereo, Acoustic Energy Evo3 speakers and I mainly listen CD and sometimes spotify (with SMSL SU-1) and less often LP's on a Thorens 160 mk2 with fosi X5 phono preamp.

I'm interested by making an amp following the micro bamboo project (and maybe use a Fosi ZH3 as preamp).
After reading all posts I have several questions but the first one will be for the power supply:

The quality of performances seems to be influenced by the power supply but after all the debates it's hard to choose one...
Could you help me ? I've listed
- The micro audio one - a bit expensive if you ad sending fee + other taxes, but if it really worth ok
- The MORNSUN LOF550-20B48 SMPS - Easy to get in France thanks to Audiophonics but seems to be
- The Yongzhuxing doesn't exist anymore but several power supplies look really similar on aliexpress like this one - are they reliable ?
- The MEAN WELL LOP-600-48 here - is 12.5 A too high ? easy to get in France.
Every other suggestion is welcome.

Thank you all.

I use a Mean Well LOP 500-48V power supply with a 3E stereo board. It works perfectly. It runs completely cool. Up to 320 watts requires no cooling. There is no noise at all. Neither mechanical nor in the speakers. No hissing. At its peak, it provides 150% of the rated power for 3-5 seconds. The operating temperature is up to 80 degrees. theoretically But mine runs cool. It has all the certifications. The ideal power supply for a Class D amplifier. The dimensions are minimal. You can get LOP 400-500-600. They will all work perfectly. Even LOP 300.The LOP series is a modern Meanwell development.There are already recommendations online for using the Mean Well LOP series for Class D amplifiers. The design and engineering are perfectly suited for completely trouble-free amplifier power supply.I'm writing through a translator. The meaning of the text may be distorted.

 

[UA8890]

Photo taken during assembly. The board is 3E and the Mean Well LOP is 500-48.

 

[UA8890]

This is at the installation stage. There's plenty of space left in the case. Both the board and the power supply don't require a fan at all. I removed it. It's not needed even at peak power. The temperature never rose above 30 degrees Celsius, even at high volume.

 

[LEOPOLNORD]

This is at the installation stage. There's plenty of space left in the case. Both the board and the power supply don't require a fan at all. I removed it. It's not needed even at peak power. The temperature never rose above 30 degrees Celsius, even at high volume.

Thank you for all your explanations and pictures. I might need some help for wiring latter.