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

[Tazio]

Ehm ...the file ...

 

[3eaudio]

@Tazio your connection looks right, is the amplifier output volume keep low(or lower then another cheaper pot) even pot at Max position?

 

[Tazio]

The volume stays low for 22 steps. With the last two it reaches max, or at least a clipping level for the speaker I'm using for the test.
I tried a cheap100k linear pot and got a decently gradual increase to max.
Measuring the resistance between the wiper and ground ("IN" and "GND") pins of the EIZZ the result is a neat logarithmic curve.
I'm really confused!

 

[Tazio]

The volume stays low for 22 steps. With the last two it reaches max, or at least a clipping level for the speaker I'm using for the test.
I tried a cheap100k linear pot and got a decently gradual increase to max.
Measuring the resistance between the wiper and ground ("IN" and "GND") pins of the EIZZ the result is a neat logarithmic curve.
I'm really confused!

Of course the pins measured are OUT and GND. Sorry.

 

[3eaudio]

Of course the pins measured are OUT and GND. Sorry.

can you compare to the cheaper curve?
the last 2 step change from 50K to 100K which is huge.

 

[Tazio]

See below. The dark line is the linear pot.
I tried connecting the terminals as in the attached sketch obtaining a quite good result but the volume would increase rotating the wiper CCW, and swapping GND and IN nothing changed! That's weird ... makes me think of a connection error ...may you confirm that the input pins are physically matching the marking on the board?

 

[3eaudio]

it is correct.
IN+ and GND is input of the amp, swap.between them surely no any change only phase opposite.

 

[Hall of Canons]

I'd be leaning towards 36V if you can get about 10A peak. Would squeeze a little more peak power than 48V 7.2A peak. Plus keeping the amp at the safer end of voltage range.

I like the look of the Connex. Looks a little more expensive though not so much as the meanwell

Does the lower voltage affect the output power, or would it be just as loud? From what I understand, the pulse width widens with higher output which I think means more current but not more voltage, so as long as it has enough overall power it should be fine (like you mentioned, 10A or higher at 36v), right?

And if I have an 8ohm load instead of a 4ohm load, should that affect the decision on which voltage to choose?
I saw one PSU that allowed to set a custom voltage and thought maybe something like 42 could be a good compromise if there’s any effect on the audio quality, but just trying to understand the main concern around choosing an output voltage for the PSU.

 

[antcollinet]

Does the lower voltage affect the output power, or would it be just as loud? From what I understand, the pulse width widens with higher output which I think means more current but not more voltage, so as long as it has enough overall power it should be fine (like you mentioned, 10A or higher at 36v), right?

And if I have an 8ohm load instead of a 4ohm load, should that affect the decision on which voltage to choose?
I saw one PSU that allowed to set a custom voltage and thought maybe something like 42 could be a good compromise if there’s any effect on the audio quality, but just trying to understand the main concern around choosing an output voltage for the PSU.

Lower supply voltage will provide lower output power - depending on your speaker impedance.

Higher impedance speakers typically require more voltage and less current for the same power as lower impedance speakers. With 8 ohm speakers you are likely to hit the voltage limit before you hit the current limit. So yes, in this case a lower power supply will limit your power output.

 

[Hall of Canons]

Lower supply voltage will provide lower output power - depending on your speaker impedance.

Higher impedance speakers typically require more voltage and less current for the same power as lower impedance speakers. With 8 ohm speakers you are likely to hit the voltage limit before you hit the current limit. So yes, in this case a lower power supply will limit your power output.

Thank you, I appreciate that. Class D stuff is somewhat confusing for me...
So maybe I'm missing something obvious, but why not use something like this and save some money?

https://www.meanwellusa.com/upload/pdf/ERPF-400/ERPF-400-spec.pdf

It has more than enough power, protection features, and PFC and it's about half the price as many of the other PSUs I've seen mentioned here so far. I assume there's a spec I'm not taking into account though, so I'd be curious to know what it would be, since I don't think I've seen one like this mentioned yet.
(ripple and switching frequency seem within normal ranges as well I think, from my limited knowledge of PSUs for comparison)

 

[Hall of Canons]

Thank you, I appreciate that. Class D stuff is somewhat confusing for me...
So maybe I'm missing something obvious, but why not use something like this and save some money?

https://www.meanwellusa.com/upload/pdf/ERPF-400/ERPF-400-spec.pdf

It has more than enough power, protection features, and PFC and it's about half the price as many of the other PSUs I've seen mentioned here so far. I assume there's a spec I'm not taking into account though, so I'd be curious to know what it would be, since I don't think I've seen one like this mentioned yet.
(ripple and switching frequency seem within normal ranges as well I think, from my limited knowledge of PSUs for comparison)

After scrolling down I noticed the mounting method... :/
Also, from some others I was looking at, I assume a fan isn't very desirable, and I didn't realize that variations in the model can mean that there's lower output power due to derating curve.
Still though, all other things considered, I'd be curious to know what specs are a dealbreaker when looking at less expensive PSUs.

I did a whole lot of digging and comparing and just went with the Meanwell RPS-400-48 to be on the safe side (saw it mentioned here somewhere), and because I could get it from Mouser with relatively fast delivery instead of having to wait.

By the way, thank you everyone for putting up with me trying to figure out a hobby I shouldn't reasonably have enough time for. lol

 

[DimitrisK]

I plan an integrated amp with the following:
3E 3255
Smps 48V 15A from audiophonics
PGA2311 wondom digital pot
Aikido ACF2 tube buffer 6sn7
Balanced unbalanced input selector

 

[audiotechno]

Hi Daniboon and others,
Is it necessary to use a DC protection with this amplifier ans if yes which one can I use ?
Greetings fron France
Alain

 

[Hall of Canons]

I plan an integrated amp with the following:
3E 3255
Smps 48V 15A from audiophonics
PGA2311 wondom digital pot
Aikido ACF2 tube buffer 6sn7
Balanced unbalanced input selector

I was looking at the data sheet for that digital pot (one like it, at least), and was wondering how you make sure it doesn’t have issues regarding output/input impedance?

 

[Hall of Canons]

Has anyone made a dual-mono setup with this board yet? I don't recall seeing one, but would love to see a build.