TPA3251d2

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daniboun

daniboun

Banned
Joined 2019
bushellj said:
A pair of OPA1622 chips - Made in China ! - Soldering questionable !!

A pair of OPA1656 chips - Made in UK by me ! - Soldered using 5.5% Silver solder !! Op Amps sourced through Mouser - Shipped from Germany !

Ready to start doing some Op Amp Rolling with my Aiyima 07, TPA3255 Amplifier.

I only have some little KEF Uni-Q Q15 Speakers to play with at the moment. First tests with original NE5532 chips I thought the speakers were bad ! Took me ages to find some decent quality source music and actually they now sound pretty good but could also because the amp has now been burnt in for a week. This amplifier shows up a bad music source very dramatically - With a good source, it sings.
Click to expand...


I salute your work ... I am unable to solder a chip as well!
We are waiting for your test and feedback amigo :D
 
daniboun

daniboun

Banned
Joined 2019
Hi Daniboun.
Before you start this amp up again with any power I seem to remember that the problem with the Chip that burnt was probably not with the chip but most likely that the Inductor that is part of this Buck circuit is far too small.

From the photos, it does not appear that you have replaced the Inductor with one of a higher value so it is most likely just going to burn out again !!
Just a thought
James.
Click to expand...

Hi James, you did not see the picture correctly.... They changed the inductor of this new version ) It is a LM2676 and everything works absolutely fine now ! yeah !
Now let me test and show the final Amplifier asap ;)
 
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bushellj

Member
Joined 2013
daniboun said:
Hi James, you did not see the picture correctly.... They changed the inductor of this new version ) It is a LM2676 and everything works absolutely fine now ! yeah !
Now let me test and show the final Amplifier asap ;)
Click to expand...

Hi Daniboun.

Can you confirm or photograph what the full part number is on the chip. Standard part is only rated up to 40 Volts and I thought this board was good for up to 48 Volts. There is probably a high voltage version of this part.

Also can you photograph the Inductors on the board round this new regulator as I can't see them from the photos you posted.

James.
 
daniboun

daniboun

Banned
Joined 2019
I just finished my two DIY Amplifiers and they work great.
I will have something to compare now )

I did a two hour listening test, both are dead silent and sound really nice. I have
I continue my listening tomorrow to be able to compare with my Aiyima TPA3251.

So that you can know :

Amplifier 1 :
Zero Zone TPA3255 Amplifier + Linear Audiophile grade PSU + OPA1622

Amplifier 2 :
Double Mono Fully discret Amplifier based on IRS2092S + 800W SMPS PSU

TPAvs-MONO.jpg

TPAvs-MONO-bis.jpg
 
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daniboun

daniboun

Banned
Joined 2019
bushellj said:
Hi Daniboun.

Can you confirm or photograph what the full part number is on the chip. Standard part is only rated up to 40 Volts and I thought this board was good for up to 48 Volts. There is probably a high voltage version of this part.

Also can you photograph the Inductors on the board round this new regulator as I can't see them from the photos you posted.

James.
Click to expand...

Here some pictures so you can see better :

IMG-20200427-233401.jpg

IMG-20200427-233414.jpg

IMG-20200427-225715.jpg
 
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ClaudeG

Member
Joined 2015
Yep Daniboun, please let us know how your DIY beasts compare to the Aiyima :)

You wouldn't happen to have a reference (wellknown) Class A or A/B amp to compare them to, so as to know where they roughly "rank" and also your listening preferences / criteria when slecting amps (you know, taste & colours)?

Thanks in any case for all this feedback

Claude
 
daniboun

daniboun

Banned
Joined 2019
ClaudeG said:
Yep Daniboun, please let us know how your DIY beasts compare to the Aiyima :)

You wouldn't happen to have a reference (wellknown) Class A or A/B amp to compare them to, so as to know where they roughly "rank" and also your listening preferences / criteria when slecting amps (you know, taste & colours)?

Thanks in any case for all this feedback

Claude
Click to expand...

Sure, I will )
I have a MOS 120 A/B Amplifier, which is well known in Europe... and Still wonder why this wonderful Class A/B has not been really tested in the USA.
This one of the best AB Amplifier I heard and even despite its small power 2x68W, it's a monster of musicality )

Need now to spend some hours listening to my HD Playlist.
 
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ClaudeG

Member
Joined 2015
Sorry, had a quick look and never heard about that one... but thanks for sharing

I was more refering to well known manufacturers, say Marantz, Accuphase etc., or even non expensive Kenwoods & Co, units that are/ can be evaluated everywhere - but thanks anyway. Plus it will be interesting to read how you compare them to that MOS120 anyway.

Claude
 
rhing

rhing

Member
Joined 2007
ClaudeG,

Compared to my rebuilt McIntosh MC240 amp, the Aiyima does not have quite the same tonal richness, deep soundstage nor the presence, but it didn’t cost more than $3,000 either. What it does offer is a level of driver control and musicality that far belies its price. It reminds me of the sound of my Naim Nait 1 integrated amp, which was very musical and had quite some drive to power speakers like Quad ESL 57’s. I wouldn’t describe it as having the Naim signature “flat earth” sound, as it does have a deep soundstage with very good imaging.

Compared to my Pass DIY Sony VFET amp, it sounds almost as powerful, but it doesn’t have the holographic presence or inner detail like the Sony VFET amp. The Sony VFET and the McIntosh amp have more in common with each other than with the Aiyima as they are both very refined and offer a solidity that higher end amps offer. That all said, the Aiyima sounded better than my mom’s 90’s vintage Yamaha Natural Sound integrated amp, and this was with the stock NE5532 op amps. The OPA627AU op amps in the Aiyima are a significant improvement. I can’t wait until the OPA1656 op amps arrive. I have my BrownDog SOIC-to-DIP8 adapters now, and the OPA1656 op amps are due to arrive this Thursday from Mouser. I think this is a very impressive amp for its price, and I can equally enjoy listening to this amp driving my KEF LS50s in my living room system. Once I receive the OPA1656 op amps, I will try to draw more detailed comparisons between my amps. It will take some time to do this though.
 
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bushellj

Member
Joined 2013
daniboun said:
Here some pictures so you can see better


Hi Danny.

The picture with the new regulator :-

The new regulator has been replaced with the high voltage version which is good for 60 volts.

The three baby inductors that are next to this part seem to be the same as the original parts - ie. 10uH.

I don’t know the circuit diagram for this board but you may remember some comments when you first burnt the regulator that the inductor was of a too small value and this could of caused the part to overheat. The new regulator has a higher current rating of 3 amps but no heat sink so still need to be careful.

I still think that at least one of these inductors (the one closest to the regulator) should probably be a higher value. As I said previously the data sheet uses an example of 330uH inductor with this part. Maybe of course the designer knows better but the value of all the inductors does not appear to be marked on the board.

James.
Click to expand...
 
daniboun

daniboun

Banned
Joined 2019
bushellj said:
daniboun said:
Here some pictures so you can see better


Hi Danny.

The picture with the new regulator :-

The new regulator has been replaced with the high voltage version which is good for 60 volts.

The three baby inductors that are next to this part seem to be the same as the original parts - ie. 10uH.

I don’t know the circuit diagram for this board but you may remember some comments when you first burnt the regulator that the inductor was of a too small value and this could of caused the part to overheat. The new regulator has a higher current rating of 3 amps but no heat sink so still need to be careful.

I still think that at least one of these inductors (the one closest to the regulator) should probably be a higher value. As I said previously the data sheet uses an example of 330uH inductor with this part. Maybe of course the designer knows better but the value of all the inductors does not appear to be marked on the board.

James.
Click to expand...

I appreciate this feedback. I let the amplifier running 4 hours straight : nothing bad to report. I put my fingers on the heatsink and even into the inductors so I can check if there was overheating, seems to be OK )

The Linear PSU brings some deeper bass. Pretty happy for the moment.
Click to expand...
 
daniboun

daniboun

Banned
Joined 2019
ClaudeG said:
Thanks Rich for this additional details to your already very interesting posts... you were 'the other one' who triggered my interest in this unit!Claude
Click to expand...

Hi Claude, I forgot to share the little comparison of Chermann
His reference Board is an TPA3251EVM but gives you an idea anyway.

VS Hypex Double Mono UCD400

"Originally Posted by chermann View Post

Hi
I ordered mine immediatly after your hint. i let it run nearly a week in my lab on 4 R load (some hours every day brake included) and about 1-2W each channel. 378 euro over amazon- deliverd in 5 days.
My DAC Gustard A20H is connected with RCA (via blue NF6 Silver) and i compared it to my Class D - TPA3251EVM:
Class D Amp Photo Gallery
The STA 800D is very powerful amp for sure - i dont need that power at home - but the SQ is not as good as my amp. Speakers are Sonus Faber 1,5 venere or open baffle W5-2143 + 1x12" sub. the sound is fine no hard high but the room and holographic interpretation of the STA800D is much smaller. some instruments lack in natural sound- I mean that e.g. a piano is aslways a little smaller and a trumpet is not swinging out "correctly".
thanks for that hint
chris"
 
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bushellj

Member
Joined 2013
daniboun said:
bushellj said:
I appreciate this feedback. I let the amplifier running 4 hours straight : nothing bad to report. I put my fingers on the heatsink and even into the inductors so I can check if there was overheating, seems to be OK )

The Linear PSU brings some deeper bass. Pretty happy for the moment.
Click to expand...

Hi Danny,

Had another look at the TI Datasheets and suggested implementation guidelines.

Looking at the three small inductors surrounding the Regulator chip you replaced are most likely providing the following functions:-

Keeping in mind that the 12 volts generated by this regulator provide power to both the main TPA3255 chip and the power for the Pre-Amp part of the amplifier I think how this has been implemented.

The Regulator will have one Inductor dedicated to providing the main 12 volt supply. This Inductor should be 100uH or more - Some circuits are as high as 330uH.

I believe the 12volt supply is then split so there are separate supplies for the TPA3255 and the Op-Amps - Each supply has a small inductor of 10uH and a capacitor to reduce ripple/noise getting to the Op-Amps.

In more upmarket amplifiers there would be completely separate power supplies for the digital section and the analog sections of the amplifier to minimise any digital noise getting to the analog side of the amplifier.

If anything is likely to get hot with the current board I would monitor most closely the temperature of the Regulator Chip you replaced as it is still having to work a bit harder than normal with the reduced value of the inductor attached to this chip !

James.

PS. Just enjoying burning in the OPA1656's in my Aiyima TPA3255 amp. Seem to be warm and sweet with excellent soundstage. Certainly seems to work well with my KEF Q15 speakers. Certainly hear lots of detail and I can be become quite critical of how the tracks were mixed !!
Click to expand...
 
daniboun

daniboun

Banned
Joined 2019
bushellj said:
daniboun said:
Hi Danny,

Had another look at the TI Datasheets and suggested implementation guidelines.

Looking at the three small inductors surrounding the Regulator chip you replaced are most likely providing the following functions:-

Keeping in mind that the 12 volts generated by this regulator provide power to both the main TPA3255 chip and the power for the Pre-Amp part of the amplifier I think how this has been implemented.

The Regulator will have one Inductor dedicated to providing the main 12 volt supply. This Inductor should be 100uH or more - Some circuits are as high as 330uH.

I believe the 12volt supply is then split so there are separate supplies for the TPA3255 and the Op-Amps - Each supply has a small inductor of 10uH and a capacitor to reduce ripple/noise getting to the Op-Amps.

In more upmarket amplifiers there would be completely separate power supplies for the digital section and the analog sections of the amplifier to minimise any digital noise getting to the analog side of the amplifier.

If anything is likely to get hot with the current board I would monitor most closely the temperature of the Regulator Chip you replaced as it is still having to work a bit harder than normal with the reduced value of the inductor attached to this chip !

James.

PS. Just enjoying burning in the OPA1656's in my Aiyima TPA3255 amp. Seem to be warm and sweet with excellent soundstage. Certainly seems to work well with my KEF Q15 speakers. Certainly hear lots of detail and I can be become quite critical of how the tracks were mixed !!
Click to expand...

Many thanks for all these details.
I will monitor the Regulator chip, I am still testing the unit anyway.

Happy you enjoy your OPA1656. I answered to your PM. Let me know please. Take care
Click to expand...
 
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