Just ordered the 3e 3255 2x 260w board from ebay.
Read the below build article recently- it uses a less powerful ti chip board - guessing the supply is good enough for 3e 3255 3e board but will need bigger toroid. Can I get away with a lower voltage (than 48v)?
Build Your Own Professional-Grade Audio Amp on the Sort of Cheap - IEEE Spectrum
Read the below build article recently- it uses a less powerful ti chip board - guessing the supply is good enough for 3e 3255 3e board but will need bigger toroid. Can I get away with a lower voltage (than 48v)?
Build Your Own Professional-Grade Audio Amp on the Sort of Cheap - IEEE Spectrum
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I use a linear psu with my 3e 3255. 35v 525va toroid gives me about bang on 50vdc.
I use one of these boards
HiFi Single Power Supply Rectifier Filter Board Kit For 1969 Amplifier PSU | eBay
I leave it powered on 24/7 and is working great
I use one of these boards
HiFi Single Power Supply Rectifier Filter Board Kit For 1969 Amplifier PSU | eBay
I leave it powered on 24/7 and is working great
Thanks, great info! Not sure about my soldering skills so will go for ready built.
If possible, I'd like to add a simple tube buffer... guessing I wd need a separate supply. Asking an electrician friend to help with this.
If possible, I'd like to add a simple tube buffer... guessing I wd need a separate supply. Asking an electrician friend to help with this.
Hi
for more power use the original heatsink from the TI EVM boards
ATS-TI1OP-519-C1-R3 Advanced Thermal Solutions Inc. | Lufter, Warmemanagement | DigiKey
but at the chinese boards its maybe not enough space to mount it....
chris
Did you use the 50V rated caps included with the kit? Are you only using one secondary off the torroid?
Thanks Chermann,
Your link provides a good starting point for me. I will have a design similar to the EVM boards.
There are SMD caps around the TAS3251 chit. I don't know if a flat bottopm heatsink can make the job, and not touch the surrounding components when pressed on the amplifier chip.
The TI heatsink seems to have some "central pad" to rest on the chip and have additional margins to avoid the SMD components around...
JMF
A lot of learning and trial and errors. And for sure I would need some advices of more experienced people:
- are there some ground loops ?
- GND copper plane on the top and bottom, or only on the bottom (currenltly there is one on both sides) ?
- other design flaws or checks to perform...
JMF
- are there some ground loops ?
- GND copper plane on the top and bottom, or only on the bottom (currenltly there is one on both sides) ?
- other design flaws or checks to perform...
JMF
And Chermann, last to say: having a dedicated design compared to the TI EVM board is to implement all the community feedback. So if you have advices on improvements, thanks to share 🙂
The TA3251 is badically a DSP+TPA3251, so all your improvements should make sense.
JMF
The TA3251 is badically a DSP+TPA3251, so all your improvements should make sense.
JMF
Hi
Sorry...but i gave you the wrong signal.... actually i am not able to design any of a pcb... i am really not the right person...
chris
Sorry...but i gave you the wrong signal.... actually i am not able to design any of a pcb... i am really not the right person...
chris
No, I understand. It was more about which caps you used. Which changes provided benefits in your experiments, and which ones had no effect 🙂
JMF
JMF
Ahhhh. ok....now i feel better 😉
at the TPA3255 chinese YJ board i was most happy with the 2x green UHE 10µF muse caps directly at the input (before the opamp) + the 4 x ukz 10µ (unluckly i just had the 50V version) at the TPAchip inputs.
as i wrote..there was a discussion at The TI EVM board about using electrolytic cpas instead of SMD...because the sound of the ceramic/tantal are not nice...
output filter i am happy with the 8R configuration= 10µH Würth 74439370100, TDK Epcos caps B32652A3684J or 0,47µF...
opamp 1602
Rail caps = by Doctor = Chemicon EGPD630ELL242MM40H
or similar (high ripple at 100khz low ESR/ESL)
Important is to seperate the voltage regulation (low noise) for the TPA chip and the opamps . Faux French did a +/- double voltage for the opamps to provide a better THD....at the TI EVM its not realiszed like this. i personally havn´t tried this.
As i do not have THD measrument equipment i can just say that my result was listening test.
chris
Did anybody try to bypass that opamp and feed signal directly to TPA3255 input pins via 10µF caps?
Whats the purpose of that opamp? buffer?
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Thanks for sharing Chris. I have to have look at my circuit to se how it could be applied
hi zek
if i remember right. if you use a single ended signal -rca connector --> the opamps are therefore to "build" a inverted signal for the TPAchips input Input A....input D.
for differential input you can go directly to the tpachip over the 10µF.
there are some ideas to use bipolar caps here instead of the polarized eleytrolytics...but now idea what happend if the TPAchip get some DC voltage there....
chris
design:
look at TI ´s new incarnation of the TPA chip- TPA3220 board.....they use dual coils and 1000µF würth low esr caps. maybe you can find something for your design😉
tpa3220: diy, evm-micro, UA801x-AL inductors, etc
chris