What's needed to build an amp around the 3e Audio TPA3255-2CH-260W EAUMT-0260-2-B?

[linuxfan]

Oops sorry, I was writing from my workplace, without access to my notes - those SMSL and Topping models do not have differential output.
The 2 balanced DAC's I meant to list are: Schiit Modius and Soncoz LA-QXD1.

I was looking at xlr out dacs with volume control, remote and, maybe, a rotary knob.

Yeah, the Modius has none of those features. The LA-QXD1 just has front panel up/down buttons for volume control.
So the SMSL M200 is your cheapest option, depending on the final pricing of the SMSL SU-9.

Since the op amps are socketed, can't we just short same pins on the socket to remove the op amps?

I prefer the term "jumper" but yes, that's what RogerMont and I were discussing in post#8 and #9. Rather than jumper the opamp sockets, I would run my differential input wires directly from the opamp socket to a female XLR panel jack. I posted the wiring information here -
TPA3251d2

 

[Vb15]

Thank you.

 

[Vb15]

I wonder if you could wire a cable to this brzhifi tpa3255

It would bypass the tone controls and it could be a very small size xlr amp with case and power supply.

 

[dekron]

Hi there,


I second the questions you got on this topic. Having 3 board to supply (3e tpa3255 from 2018) I get that a nice match would be a SMPS with a high switching frequency and inrush current limiter if possible.


However knowing my speaker I wonder what specific voltage output I require ?
The board tolerates 24V to 48V, but which document tell me the clues on the right one ? Definitely don't find it on the 3e website. What are the pro and cons btw 24, 36 and 48V supply ?


Regards

 

[autofocus111]

For the TPA3255 version you should go for 48V, and possibly the next model up the Connex single-output range, the SMPS600RS -
SMPS600RS | Connex Electronic

Hi all. I'm new to diyAudio. I stumbled into the 3eaudio tpa3255 module and this board and message thread while checking out potential class D amps to replace an old Lepai TDA7498E amp that died (the chip output pins are blown out... not sure what happened my nephew was using it at the time). I figured maybe I'll put together something better this time around.

The SMPS600RS spec sheet lists Ipeak for different output voltage options: 19A@38V and 15A@48V. At 38V a 4ohm load draws 9.5A and 8ohm 4.8A. At 48V a 4ohm load draws 12A and 8ohm 6A. Double these numbers for two channel operation.

For driving a pair of 8ohm speakers the 48V supply looks ideal, but given the power supply's current limitations, would the 38V unit be a better match for 4ohm speakers? Or do the amp module's supply input tank capacitors make this largely irrelevant except if running at high sustained power levels? I'd appreciate any insights or links to better understand the tradeoffs here thanks.

 

[jeff5may]

I'll answer the last two questions at once, as they're related to matching the power supply to the amp.

Autofocus is heading in the right direction. Sizing the power supply depends on a couple of factors: impedance being driven and safe operating area of the amp. Too little voltage or current from the power supply, and you run out of juice before the amp is at full blast. Too much voltage or current from the power supply, and things burn up at maximum volume.

With the particular setup autofocus is considering, I would probably go with the 38 volt supply option. With each channel maxing out at around 9 amps and the power supply rated for 19 amps, everything is operating within its ratings. Running 48 volts, one could get into trouble trying to drive a heavy load. If one wanted to push the amp board to its limit with 4 ohm speakers, the power supply could sag on demanding peaks, causing the amp board to cut off due to undervoltage. Then again, the power supply could let out the magic smoke trying to source 20 or more amps.

 

[DaveFred]

The biggest improvement to this amp was bypassing the SE-to-differential input stage - of course for this you need a playback device with differential outputs.
It used to be the case that such DAC's were uncommon, and expensive, but just recently there are 3 commercially available DAC's with differential output which are quite affordable -
SMSL Sanskrit 10th AK4493 edition, Topping E30, and Soncoz LA-QXD1. Any of these with your 3e-audio opamp-bypassed amp should be a killer combination.

I now have the 3eAudio TPA3255 2x260W 2Ch Class D Audio Amplifier and a Connexelectronic SMPS600RS 48V 110V Power supply.

To feed the amplifier I also picked up an SMSL SU-8 that has balanced outputs.

What specifically are you suggesting to do to the TPA3255 board to bypass the SE-to-differential input stage?

Or by simply selecting the right jumper for balanced input, and using balanced input, I am doing just that?

Thank you,

David.

 

[linuxfan]

What specifically are you suggesting to do to the TPA3255 board to bypass the SE-to-differential input stage?

Run the balanced input signals directly to the TPA3255 chip, by removing the opamps, and connecting the input wires to the relevant sockets where the opamps were removed. Refer here -
https://www.diyaudio.com/forums/class-d/276982-tpa3251d2-145.html#post6186207

by simply selecting the right jumper for balanced input, and using balanced input, I am doing just that?

No. You are still using the opamps as an input buffer, albeit in fully differential mode.