3E Audio 260-2-29A : TPA3255 / HA3588 CoilCraft / PFFB Fully differential.

[daniboun]

À 36 volts, une alimentation nominale de 6 ampères est plus que suffisante pour amener un canal BTL TPA3255 à des niveaux de puissance où le THD+N dépasse 1 %. Tout dépassement de 6 ampères ne fera que l'amener dans un territoire de puissance beaucoup plus déformé. Si une personne a besoin d'autant de puissance et n'hésite pas à payer le prix en THD+N accru, alors : a) chez ASR, elle est probablement au mauvais endroit ; b) ils pourraient envisager à la place le Behringer iNuke nu6000 2 x 3 100 Watts @ 4 Ohms ; THD+N : 12,13 livres (Oui, je sais que c'est son poids mais c'est la seule autre spécification disponible sur la fiche technique détaillée de Behringer !

This is probably the reason why Topping provides a 38V/4A PSU with their PA5/ RA3 amps. This allows a good THD+N figure
In any case the measurements of the PA5 in this direction do not lie

 

[antcollinet]

Ohm's Law doesn't work like that:

Don't forget that other flavour of ohms law - P = I^2*R

In fact that 6A power supply can only get to the rated 108W if nearly all the current goes to one speaker. 36*4. Perhaps we can give some benefit of the doubt that the PSU can probably do a slightly higher short term current.

If both channels are driven then there is only 3A per speaker = 9x4 = 36W into each channel.

In many amplifier designs it is 8ohm loads that tend to be voltage limited for power. 4ohm loads are often limited by current.

 

[daniboun]

Just to pick up on the subject. Let's assume that the manufacturer's specifications are correct )
In theory, with the PSU suggested by 3E Audio: (LOF550-20B48(48V / 11,4A@ 550W) we have :

in practice depending on others TPA3255

PSU 32V / 5A
AIYIMA A07 : 77W / 4R & 55W / 8R

PSU 32V / 5A
Fosi V3 : 63W / 4R

PSU 48V / 5A :
Fosi V3 : 141W / 4R

PSU : 38V / 4A :
PA5 : 83W / 4R & 48W / 8R

 

[3eaudio]

Just to pick up on the subject. Let's assume that the manufacturer's specifications are correct )
In theory, with the PSU suggested by 3E Audio: LOF350-20B48 (48V / 7.3Ac@ 350W) we have :


View attachment 310210

in practice depending on others TPA3255

PSU 32V / 5A
AIYIMA A07 : 77W / 4R & 55W / 8R

PSU 32V / 5A
Fosi V3 : 63W / 4R

PSU 48V / 5A :
Fosi V3 : 141W / 4R

PSU : 38V / 4A :
PA5 : 83W / 4R & 48W / 8R

Hi @daniboun
we test with LOF550-20B48 which is more powerful but similar to LOF350-20B48 as they are same series, the SMPS output capability is quite important to maintain 1% before its voltage rail drop(good load regulation).

 

[antcollinet]

Hi @daniboun
we test with LOF550-20B48 which is more powerful but similar to LOF350-20B48 as they are same series, the SMPS output capability is quite important to maintain 1% before its voltage rail drop(good load regulation).

Out of interest - how do you square your measurement, with TI's chart from the data-sheet (posted above) which suggests only 230W is available from a 48V PSU?

Is it simply a case of the actual devices being slightly better than the data sheet (EG not needing as much voltage headroom as specified)

 

[antcollinet]

Hi @daniboun
we test with LOF550-20B48 which is more powerful but similar to LOF350-20B48 as they are same series, the SMPS output capability is quite important to maintain 1% before its voltage rail drop(good load regulation).

Another question - are you going to send one of your devices, in your test configuration to Amir for testing?

 

[daniboun]

Another question - are you going to send one of your devices, in your test configuration to Amir for testing?

I already spoke with Jason (3E Audio):

"Hi Danny
Thanks for let us know people are interesting in our product,will try to share our thought as more as we can in ASR.
regarding the test,we did sent sample(AMP+SMPS) to Amir before,but unfortunately,when he got it and start test,some problem happen to SMPS can not work properly,result in Amir can't test anymore,this may cause by shipping during it translate from China to US. which is quite sad for us.
and also.after.that,Amir indicate us that further test should be with a box with good assembly to ensure the AMP and SMPS keep very well.
we are planning to make one sample for ASR in coming months,but still working on that hopeful it will make everything happen."

Since Amir already has the module, I will ask him to test it with a 36V PSU, he normally has one. (from the FOSI or AIYIMA amps).
Let's wait for the answer )

 

[daniboun]

Hi @daniboun
we test with LOF550-20B48 which is more powerful but similar to LOF350-20B48 as they are same series, the SMPS output capability is quite important to maintain 1% before its voltage rail drop(good load regulation).

Thanks for the info. well noted ) just corrected

 

[S=klogW]

Don't forget that other flavour of ohms law - P = I^2*R

In fact that 6A power supply can only get to the rated 108W if nearly all the current goes to one speaker. 36*4. Perhaps we can give some benefit of the doubt that the PSU can probably do a slightly higher short term current.

If both channels are driven then there is only 3A per speaker = 9x4 = 36W into each channel.

In many amplifier designs it is 8ohm loads that tend to be voltage limited for power. 4ohm loads are often limited by current.

You absolutely right. My tired old brain had forgotten we were dealing with both channels driven and that I should have multiplied my suggested ampage for the psu by two, so 12amps not 6amps in the BTL configuration.

 

[daniboun]

Hi @daniboun
we test with LOF550-20B48 which is more powerful but similar to LOF350-20B48 as they are same series, the SMPS output capability is quite important to maintain 1% before its voltage rail drop(good load regulation).

Question for you too :

In your spec, you say : "* 7G23B and APG2923 are China customized version also performance is the best."

As far as I know Sagami 7G23B is an entry-level inductor.... AGP2923 Series from Coilcraft are high quality High Current Power Inductors that's OK... )
So , with what configuration did you complete this test ? Which inductors and which PSU? 4R or 8R load ?

 

[3eaudio]

Question for you too :

In your spec, you say : "* 7G23B and APG2923 are China customized version also performance is the best."

As far as I know Sagami 7G23B is an entry-level inductor.... AGP2923 Series from Coilcraft are high quality High Current Power Inductors that's OK... )
So , with what configuration did you complete this test ? Which inductors and which PSU? 4R or 8R load ?

Question for you too :

In your spec, you say : "* 7G23B and APG2923 are China customized version also performance is the best."

As far as I know Sagami 7G23B is an entry-level inductor.... AGP2923 Series from Coilcraft are high quality High Current Power Inductors that's OK... )
So , with what configuration did you complete this test ? Which inductors and which PSU? 4R or 8R load ?

this is another version(not diy) and i think you see that in diyauido?
it test in this config:
1. LOF550-20B48 adjust to 51V
2. 7G23B inductor
3. 4R with both channel drive

 

[S=klogW]

And may I add to daniboun's questions:

a) What is the overall gain value that this amplifier has been set to for this test?

b) You have used a AES17 measurement filter on the output of your amplifier to make these measurements; most of us here on ASR cannot afford/don't want to pay for an AES17 measurement filter. Can you tell us what the above graph measures like when a simple RC low-pass filter is used on the output, R=100ohms, C=56nF, or alternatively R=100ohms, C=47nF? Or put another way what is the measured thd+n at 5watts into 4 ohms when the simple RC filter is used in place of the AES17 filter?

Thank you.

 

[daniboun]

this is another version(not diy) and i think you see that in diyauido?
it test in this config:
1. LOF550-20B48 adjust to 51V
2. 7G23B inductor
3. 4R with both channel drive

Yep )
So I'm quite surprised.... According to the measurements, the version with Sagami 7G23B inductors measures better than the version with the Coilcraft HA3588 one ?
Any other mods in the "Special version" that could explain the results maybe ?

Thanks )

 

[daniboun]

a) What is the overall gain value that this amplifier has been set to for this test?

I guess the one is spec ?

 

[S=klogW]

I guess the one is spec ?

View attachment 310256

Was this spec attached to the custom design graph (the 'Special' unit which gives 108dB thd+n, 5W, 4ohms ) and so definitively states that the custom design runs 20.5dB gain? I haven't seen the DIYaudio post and wanted to establish if the custom design , which we are now told runs at 51volts and has the inferior inductors, is running a lower gain to get such good numbers. Other than gain reduction, it can only be golden sample TPA3255s or a new 'secret sauce' PFFB network design.

 

[daniboun]

Was this spec attached to the custom design graph (the 'Special' unit which gives 108dB thd+n, 5W, 4ohms ) and so definitively states that the custom design runs 20.5dB gain? I haven't seen the DIYaudio post and wanted to establish if the custom design , which we are now told runs at 51volts and has the inferior inductors, is running a lower gain to get such good numbers. Other than gain reduction, it can only be golden sample TPA3255s or a new 'secret sauce' PFFB network design.

These specs are those shared on page 1) therefore relating to the module presented in this thread.
Concerning the inductors on the "custom version" I might be wrong in saying that the Sagami 7G23B are less good than the Coilcraft AGP2923 / HA3588...what makes me think this is that we find those Sagami on most inexpensive TPA325Xs....

108dB sinad @5W (Custom version) vs 103.2dB sinad @5W (standard version) I don't think this is really audible to ordinary mortals )

Anyway, I would like to have Jason Wong's interpretation (3E Audio) wait and see....




7G23B vs AGP2923 (Sagami left / Coilcraft right)

 

[antcollinet]

I spoke with Jason (3E Audio):

"Hi Danny
Thanks for let us know people are interesting in our product,will try to share our thought as more as we can in ASR.
regarding the test,we did sent sample(AMP+SMPS) to Amir before,but unfortunately,when he got it and start test,some problem happen to SMPS can not work properly,result in Amir can't test anymore,this may cause by shipping during it translate from China to US. which is quite sad for us.
and also.after.that,Amir indicate us that further test should be with a box with good assembly to ensure the AMP and SMPS keep very well.
we are planning to make one sample for ASR in coming months,but still working on that hopeful it will make everything happen."

Since Amir already has the module, I will ask him to test it with a 36V PSU, he normally has one. (from the FOSI or AIYIMA amps).
Let's wait for the answer )

I'd rather see it tested with @3eaudio 's configuration - otherwise we only get another data point, rather than full validation of 3eaudio's test results.

 

[daniboun]

I'd rather see it tested with @3eaudio 's configuration - otherwise we only get another data point, rather than full validation of 3eaudio's test results.

It's not wrong... in a sense, if Amir could test it with a 36/5A power supply it would still give a very nice idea...
But we keep in mind what has been tested by 3E Audio, namely with a 48V / 11.5A Morsun PSU )

No need such a huge PSU to get ASR measurements @THD+N in 4Ω / F = 1kHz, Po =5W or 10W

 

[3eaudio]

@S=klogW i don't have experience on the RC filter as i used to test with AES filter,someone diy maybe did this just google it should be help.

@daniboun the special verison is 12dB Gain,ther is nothing to discuss here so i suggest to maintain our topic on current version: 260-2-29A。
regarding inductor we probebly can't only refer to DC current chart as there mine not-linear chart in high frequency switching condiction.in our test result it did show HA3588 THDN earlier rise higher than 7G23B when output >100W/4R
but all in all,how is the different between 105dB and 108dB impact on sound quanlity,IMO it is really make not sense for most of people.

 

[daniboun]

@daniboun the special verison is 12dB Gain,ther is nothing to discuss here so i suggest to maintain our topic on current version: 260-2-29A。
regarding inductor we probebly can't only refer to DC current chart as there mine not-linear chart in high frequency switching condiction.in our test result it did show HA3588 THDN earlier rise higher than 7G23B when output >100W/4R
but all in all,how is the different between 105dB and 108dB impact on sound quanlity,IMO it is really make not sense for most of people.

Ok sounds good for me.
We expect to get a real ASR review asap for the 260-2-29A -) I sent an email to Amir....I wish he could answer now