Breeze TPA3255 XLR Balanced Amplifier TearDown : DIP8 Op Amps.

[SMen]

My original BRZ came with JRC5532 which I understand to be bipolar, and JRC make the Muses, which makes your choice of bipolar Muses 8820 seem sensible.

 

[ICIETDIYEUR]

People hi

 

[ICIETDIYEUR]

Hello again

Regarding operational amplifiers, a little reminder:

- The bipolar OPAMPS are designed for resistances at their inputs less than or equal to 3KOhms maximum because after their 'voltage noise spectral density' rises steeply!

- THE FET OPAMPS are designed for resistances at their inputs greater than or equal to 3KOhms because their performance in terms of 'voltage noise spectral density' is no longer impacted afterwards.

I give you the comparative table of TEXAS INSTRUMENTS ->

 

[SMen]

Hello again

Regarding operational amplifiers, a little reminder:

- The bipolar OPAMPS are designed for resistances at their inputs less than or equal to 3KOhms maximum because after their 'voltage noise spectral density' rises steeply!

- THE FET OPAMPS are designed for resistances at their inputs greater than or equal to 3KOhms because their performance in terms of 'voltage noise spectral density' is no longer impacted afterwards.

I give you the comparative table of TEXAS INSTRUMENTS ->

View attachment 280808

I was wondering about this given the initial choice of bipolar by BRZ3255 with their JRC5532 (if I am correct this is bipolar)!

So presumably on BRZ TPA3255 they have resistances at their inputs greater than or equal to 3KOhms.
I am enjoying perhaps my BRZ enough with my OPA1656 without further tinkering!
Maybe just a low noise higher quality SMPS some day...

A useful reminder ICIETDIYEUR ... good to see you back!

 

[SIY]

Bad News: The sad sort of random flinging of parts without much target or understanding, much less any validation*, then lots of hand-waving fairy tales, which characterize far too much of DIY audio and have no business on a technical/scientific forum.

Good News: It kept people off the streets and out of trouble. And at least one person blew up his stuff, an object lesson for why this sort of random parts-flinging is a really bad idea for anything other than keeping people distracted.

*Well, one guy had some scope traces which may or may not have had much meaning.

 

[Schlippwhip68]

Hello @Schlippwhip68
Your experience is very similar to mine with the op amps, only in my case I had a pair of OPA1656 vs your Muses 8820. With regard to the decouplers, because I just put them in and left them there I really should take them out, and then put them back to really assess. Perhaps when yours come I will do this and compare. Your experience with the Muses 8820 makes me think that I should try the Muses 02 I have. I might do this over the weekend.

Overall this amp is a step up for me from the Aiyimas (07, 08) in clarity, muscularity and control, and running it with the volume contrul on maximum, but with a lossless volume control DAC upstream like v1adpetrov2 said: DAC SMSL D300, works very well. I use a Rod rain audio HIFI DA10 recommended by ICIETDIYEUR and I find it excellent. I also use passive balanced dual mono volume controls, and these are excellent also (a bit unconventional but I find it very useful). Also a balanced switch box here.

Yes, ICIETDIYEUR has done a thorough job there and I am also better for reading about his work. Funny you should mention Rod Rain as I have had a dac in the past from Rod Rain that was superb value for money but I sadly received a faulty unit and while it last only 10 minutes before the sound quality disappeared into an horrendous crunching sound it was actually very nice. I don't think it was a mark against Rod Rain as the seller was really surprised at the failure of the unit and they have sold over a 1000 units since with no issues. I will have a look at HIDI D10 later.
I have rigged a balanced connection this morning using newly acquired Belden 8402/Neutrik connects. The sound is definitely cleaner but I am also running a DBX 231s EQ directly into this amp amd the Topping E50 is feeding the DBX from the Mac. Interestingly the RCA connection using the same set up is on average 1/3 louder...?....but the XLR is better sound quality. I am going to take a deeper look into BRZHIFI as I am looking for a balanced preamp. Its also nice to see BRZHIFI have used Neutrik XLR on this 3255XLR amp, another point for good quality that they don't mention in the sales listing surprisingly enough. But anyway this is a good amp and I like it, I will be interested to hear back from you once you try the Muses02. I really like the 8820d. I also have the A07, good little amp. The footprint on BRZHIFI is a bit of sweet spot for me personally as it gives me the room to stack it easily unlike the A07. Incidentally Aiyima have just released an upgraded A04 with 3.5mm jack out.

 

[SMen]

Bad News: The sad sort of random flinging of parts without much target or understanding, much less any validation*, then lots of hand-waving fairy tales, which characterize far too much of DIY audio and have no business on a technical/scientific forum.

Good News: It kept people off the streets and out of trouble. And at least one person blew up his stuff, an object lesson for why this sort of random parts-flinging is a really bad idea for anything other than keeping people distracted.

*Well, one guy had some scope traces which may or may not have had much meaning.

There is scope on this forum for A/B listening, so long as it is controlled. An A/B comparison with the op amps qualifies.

"Random flinging of parts" is your subjective input - Don't be sad, be happy

 

[SMen]

Yes, ICIETDIYEUR has done a thorough job there and I am also better for reading about his work. Funny you should mention Rod Rain as I have had a dac in the past from Rod Rain that was superb value for money but I sadly received a faulty unit and while it last only 10 minutes before the sound quality disappeared into an horrendous crunching sound it was actually very nice. I don't think it was a mark against Rod Rain as the seller was really surprised at the failure of the unit and they have sold over a 1000 units since with no issues. I will have a look at HIDI D10 later.
I have rigged a balanced connection this morning using newly acquired Belden 8402/Neutrik connects. The sound is definitely cleaner but I am also running a DBX 231s EQ directly into this amp amd the Topping E50 is feeding the DBX from the Mac. Interestingly the RCA connection using the same set up is on average 1/3 louder...?....but the XLR is better sound quality. I am going to take a deeper look into BRZHIFI as I am looking for a balanced preamp. Its also nice to see BRZHIFI have used Neutrik XLR on this 3255XLR amp, another point for good quality that they don't mention in the sales listing surprisingly enough. But anyway this is a good amp and I like it, I will be interested to hear back from you once you try the Muses02. I really like the 8820d. I also have the A07, good little amp. The footprint on BRZHIFI is a bit of sweet spot for me personally as it gives me the room to stack it easily unlike the A07. Incidentally Aiyima have just released an upgraded A04 with 3.5mm jack out.

Yes, particularly his documents and input on the op amps in this BRZ configuration. It still does not explain the conundrum of the original design using bipolar, but with fets possibly being a better match - but it does introduce people like me to the scientific side!

 

[SIY]

Don't be sad, be happy

I am: it has made our streets marginally safer and less crowded.

 

[SMen]

I am: it has made our streets marginally safer and less crowded.

I note that you are currently off the streets

Look I get what you are saying, I am on ASR because of the silliness / snakeoil etc. elsewhere in HIFI, but I don't think things have gone the way you describe on this thread.

Getting back to a bit more about components, the other component I would like to try is the SMPS. I came across this ASR investigation with the Aiyima A07:

AIYIMA A07 TPA3255 amplifier with MW RS-100-24 SMPS power supply (measurements)

AIYIMA A07 TPA3255 Amplifier with MW RS-100-24 SMPS Power Supply I have just received the Mean Well RS-100-24 SMPS power supply, connected it to AIYIMA A07 and made a set of measurements and some listening. As the amplifier must be paired with a power supply and these 2 units make a complete...

www.audiosciencereview.com

It is interesting so I thought that I would share.

Changing the power supply he gets SINAD of 86.74db versus 82/83db in Amir's review here with the stock power supply:

AIYIMA A07 TPA3255 Review (Amplifier)

This is a review and detailed measurements of the AIYIMA A07 desktop amplifier based on TPA3255 class D amplifier chip. It was kindly purchased new by a member and drop shipped to me. The cost is US $72 on Amazon including prime shipping. And as of this shipping, it also included a 32 volt, 5...

www.audiosciencereview.com

I would love to know how far the SINAD on this amplifer could be elevated. Unfortunately I do not have the means or tools.

However, I find this interesting.

 

[SIY]

Look I get what you are saying, I am on ASR because of the silliness / snakeoil etc. elsewhere in HIFI, but I don't think things have gone the way you describe on this thread.

It is an absolute case study.

 

[SMen]

It is an absolute case study.

Answer my links and my question about power supplies please.

 

[SIY]

Answer my links and my question about power supplies please.

Pavel would be a better source. Unlike the folks on this thread, he states a specific problem to be fixed, documents it, fixes it, and documents the results of the fix.

 

[SMen]

Pavel would be a better source. Unlike the folks on this thread, he states a specific problem to be fixed, documents it, fixes it, and documents the results of the fix.

I'm not sure about Pavel ... but I agree about a change intended as an improvement being measured before and after. These amplifiers are so inexpensive, a comparator model should be possible to provide. I have been looking at doing exactly this.

What is interesting about this amplifier for me, is that it is balanced, and runs much cooler than the Aiyima A07 and especially the A08 amplifiers. The latter runs way too hot for me in summer ... so I was drawn to this model to run my balanced phono stage into.

On this thread there is a modification to the power supply which increases the voltage and power, and then there are modifations to accomodate this change. I am not sure that I need more power, but I am sure it is readily audible.

Then there is a suggested op amp replacement to FETs - because of the "unity gain buffer configuration". I think A/B testing is interesting and "allowed" on this. I certainly found this interesting to do a controlled swap ... does not take long and I did not blow myself up...

There could be really interesting debate on this last point, but, for me, I would be interested in seeking to achieve the kind of SINAD improvements (as per the threads I linked to) from an improved SMPS.

Furthermore, as you say, this change could be clearly measured. The links I made show exactly what could be measured (or what I would like to see).

And then I would like to be able to clearly hear an improvement. ... just need to find someone to do the SINAD etc. I am in France, and not really inclined to mailing a couple of these across the pond ...!

Then the ultimate point of this thread would be realized in my view.

 

[Schlippwhip68]

Bad News: The sad sort of random flinging of parts without much target or understanding, much less any validation*, then lots of hand-waving fairy tales, which characterize far too much of DIY audio and have no business on a technical/scientific forum.

Good News: It kept people off the streets and out of trouble. And at least one person blew up his stuff, an object lesson for why this sort of random parts-flinging is a really bad idea for anything other than keeping people distracted.

*Well, one guy had some scope traces which may or may not have had much meaning.

Yep, always better to choose the right shoes to go dancing in.

 

[Schlippwhip68]

I'm not sure about Pavel ... but I agree about a change intended as an improvement being measured before and after. These amplifiers are so inexpensive, a comparator model should be possible to provide. I have been looking at doing exactly this.

What is interesting about this amplifier for me, is that it is balanced, and runs much cooler than the Aiyima A07 and especially the A08 amplifiers. The latter runs way too hot for me in summer ... so I was drawn to this model to run my balanced phono stage into.

On this thread there is a modification to the power supply which increases the voltage and power, and then there are modifations to accomodate this change. I am not sure that I need more power, but I am sure it is readily audible.

Then there is a suggested op amp replacement to FETs - because of the "unity gain buffer configuration". I think A/B testing is interesting and "allowed" on this. I certainly found this interesting to do a controlled swap ... does not take long and I did not blow myself up...

There could be really interesting debate on this last point, but, for me, I would be interested in seeking to achieve the kind of SINAD improvements (as per the threads I linked to) from an improved SMPS.

Furthermore, as you say, this change could be clearly measured. The links I made show exactly what could be measured (or what I would like to see).

And then I would like to be able to clearly hear an improvement. ... just need to find someone to do the SINAD etc. I am in France, and not really inclined to mailing a couple of these across the pond ...!

Then the ultimate point of this thread would be realized in my view.

I am surprised as to how cool this amp actually runs. I have left the lid off until a few parts arrive and have been checking temps with balanced connection and volume around 11.00 o'clock, easily loud enough for a 5m x 5m room. After an hour or so the amp chips heatsink remained only slightly warm, much cooler than my A07 and A04 at the same levels. I certainly don't think there is any need to vent the box like i did with my A07. I then kept the lid on for a while and again very little heat.
The jury is still out on changing the power supply as we discussed earlier but if i was too then i don't have the need to increase voltage from 36v, I prefer to remain there but PFC is noted as an advantage here and it is that little extra quality that has my interest. I know this might sound like a rookie question but I have a better chance of learning here than anywhere else at present..especially a Bakery...so please correct me if I am wrong but staying with 36v and going with PFC will not require any further modification of other capacitors will it? It should be a clean swap...?

 

[SMen]

I am surprised as to how cool this amp actually runs. I have left the lid off until a few parts arrive and have been checking temps with balanced connection and volume around 11.00 o'clock, easily loud enough for a 5m x 5m room. After an hour or so the amp chips heatsink remained only slightly warm, much cooler than my A07 and A04 at the same levels. I certainly don't think there is any need to vent the box like i did with my A07. I then kept the lid on for a while and again very little heat.
The jury is still out on changing the power supply as we discussed earlier but if i was too then i don't have the need to increase voltage from 36v, I prefer to remain there but PFC is noted as an advantage here and it is extra that quality that has my interest. I know this might sound like a rookie question but I have a better chance of learning here than anywhere else at present..especially a Bakery...so please correct me if I am wrong but staying with 36v and going with PFC will not require any further modification of other capacitors will it? It should be a clean swap...?

Yes (clean swap), but look at the amp rating too - the original power supply was 36V / 9.5A @342W, it looked like the same SMPS actually as in the A08 ... but then BRZ had to change it as I presume parts supply became an issue. I think to another of the same rating.

Aiyma also discontinued the A08 at the same time and then released the A200 which looks very similar with a DC42V 7.5A smps ... this may mathmatically work out to be almost the same but someone else with the required knowledge can clarify ...

So if I try a different SMPS I'll be trying to get as close to the original rating as possible.

The Aiyima A07 could technically be used with 48V 10A and I am sure this would be the case with the BRZ ... but it it surely increases the heat.
Only v1adpetrov2 could say which modifications were solely due to his increasing the power rating of his power supply (apart from the holes obviously, for cooling), and any that were absolutely necessary because of the increase.

 

[SMen]

I am surprised as to how cool this amp actually runs. I have left the lid off until a few parts arrive and have been checking temps with balanced connection and volume around 11.00 o'clock, easily loud enough for a 5m x 5m room. After an hour or so the amp chips heatsink remained only slightly warm, much cooler than my A07 and A04 at the same levels. I certainly don't think there is any need to vent the box like i did with my A07. I then kept the lid on for a while and again very little heat.
The jury is still out on changing the power supply as we discussed earlier but if i was too then i don't have the need to increase voltage from 36v, I prefer to remain there but PFC is noted as an advantage here and it is that little extra quality that has my interest. I know this might sound like a rookie question but I have a better chance of learning here than anywhere else at present..especially a Bakery...so please correct me if I am wrong but staying with 36v and going with PFC will not require any further modification of other capacitors will it? It should be a clean swap...?

https://www.supercircuits.com/resources/tools/volts-watts-amps-converter I think !

So I am wondering about this one ... https://hifimediy.com/product/smps300r-38v-230v-power-supply/ it has much lower noise than that calculated originally by @v1adpetrov2 ... actually this one would not fit either (post edit)!!

Looking back I see that @v1adpetrov2 linked to this: https://www.aliexpress.com/item/1005001834039255.html - size?

yes ... page 5 ... , ICIETDIYEUR linked to this https://fr.aliexpress.com/item/1005....0.0.1d25378dOkgkWj&mp=1&gatewayAdapt=glo2fra

so it was looked at in theory, because of the noisy supply, but not tried as far as I know. The actual unit you can look up (at least on mine) is here: https://www.fs-czx.com/?kg/73.html

 

[Schlippwhip68]

https://www.supercircuits.com/resources/tools/volts-watts-amps-converter I think !

So I am wondering about this one ... https://hifimediy.com/product/smps300r-38v-230v-power-supply/ it has much lower noise than that calculated originally by @v1adpetrov2 ... actually this one would not fit either (post edit)!!

Looking back I see that @v1adpetrov2 linked to this: https://www.aliexpress.com/item/1005001834039255.html - size?

yes ... page 5 ... , ICIETDIYEUR linked to this https://fr.aliexpress.com/item/1005....0.0.1d25378dOkgkWj&mp=1&gatewayAdapt=glo2fra

so it was looked at in theory, because of the noisy supply, but not tried as far as I know. The actual unit you can look up (at least on mine) is here: https://www.fs-czx.com/?kg/73.html

Thanks, the only one i can find with correct fit (Ali Express) and PFC so far under £50 is 36v 11A. How much 1.5A difference will make in the system is a mystery to me. I am 50% it won't be a problem as the power supply will either only pull or push only what it requires and so thew extra 1.5A is just a little extra dormant headroom...

 

[v1adpetrov2]

For the power supply compatibility:

1. ORIGINAL power supply = CDXS438-36 -> W=81,5mm / D=127mm /H=38mm
max output ripple = 360mV - 4,2A
The actual unit you can look up (at least on mine) is here: https://www.fs-czx.com/?kg/73.html

So I am wondering about this one ... https://hifimediy.com/product/smps300r-38v-230v-power-supply/ it has much lower noise than that calculated originally by @v1adpetrov2 ... actually this one would not fit either (post edit)!!

2. HIFIMEDIY power supply = SMPS300RS -> W=100mm / D=100mm /H=40mm - OVERSIZE!
Although the noise characteristics of this power supply are very good: max output ripple = 26mV - 1A and 77mV - 7A

Looking back I see that @v1adpetrov2 linked to this: https://www.aliexpress.com/item/1005001834039255.html - size?

3. ADP power supply = A-D-P-40036-52 -> W=82mm / D=127mm /H=45mm - OVERSIZE!
max output ripple = 150mV - 11A

yes ... page 5 ... , ICIETDIYEUR linked to this https://fr.aliexpress.com/item/1005....0.0.1d25378dOkgkWj&mp=1&gatewayAdapt=glo2fra

4. MEANWELL power supply = EPP-400-36 -> W=76,2mm / D=127mm /H=35mm - size is OK!!!
max output ripple = 250mV - 7A