Breeze TPA3255 XLR Balanced Amplifier TearDown : DIP8 Op Amps.

[Kevinfc]

Long live hot air soldering!

I need to set myself up with one of those too

 

[daniboun]

I need to set myself up with one of those too

Get this one, crazy ratio performance / price

Station de fer à souder ESD 2 en 1 et station de révision à air chaud, température réglable, station de soudage pour BGA SMD PCB IC 750 W : Amazon.fr: Bricolage

Station de fer à souder ESD 2 en 1 et station de révision à air chaud, température réglable, station de soudage pour BGA SMD PCB IC 750 W : Amazon.fr: Bricolage

www.amazon.fr

 

[decomo]

I sold my 3E and Shui yuan amps...
But if you re looking for a full balanced xlr tpa3255 amp and if you have skills to mod : this is a very good amp to go with )

Just found your thread and thank you for sharing the mod. If I get this amp in the near future, will definitely try replacing the opamps to the one that you recommended.

 

[daniboun]

You re welcome, my next amp is on the way ) Will share a new discovery soon

 

[andrewjohn007]

You re welcome, my next amp is on the way ) Will share a new discovery soon

Any insight or updates in regards to Allo's 3255's amp?

 

[daniboun]

For unknown reason Allo is not responding anymore....was supposed to get a sample what a pity ((

 

[andrewjohn007]

Weird? I would imagine that the scarcity of RPIs and the outrageous prices being asked for those on the market can't be beneficial for Allo. I purchased a Bossmini earlier today for a 3B+ that I have lying around.

Thanks for the quick reply Daniboun.

 

[daniboun]

To be honest... as per last answer, I ve been told that they were facing an issue with their new ultra low noise PSU.
Allo's founder also reported me that the prototype is now in Toulouse in the R&D department.... But the project is 8 months late ....

 

[Lambda]

- Insulated the Power cables from PSU to Module

Insulated against what?

- Add ferrites on Speakers cables

This is not how they shuld be used!
Both cables shuld go trough the same clamp. This type of high Perm material Saturates fast and is intended for common mode filtering (current compensated)
Like this they work as an inductor in series with your speakers.
This alone is normally unwanted but they are also highly non linear. with frequency but and with current.
I would assume they have about 1-4µH at low signal levels and 1/100 of this at An Amp of Speaker current.

2 of them might only give you max. ~8µH and you wont hear a difference at all.
But if the 8µH get modulated (with Bass) how much is this shifting Phase? Is this Phase shift in the order of >3µs?
if so it might affect sound stage.

Cookie Absent

- Added a copper film around the PSU transformer

also not

Flux band [Encyclopedia Magnetica]

e-magnetica.pl

Four cheap ferrites? -> They works > 1 MHz

Würth 150 kHz ferrites are better idea.

Ferrite beads/cores have no lower Frequency limit.
They have added Loss and imaginary impedance lose to there maximum frequency but they work like a normal inductor down to DC.

 

[daniboun]

This is not how they shuld be used!
Both cables shuld go trough the same clamp. This type of high Perm material Saturates fast and is intended for common mode filtering (current compensated)
Like this they work as an inductor in series with your speakers.
This alone is normally unwanted but they are also highly non linear. with frequency but and with current.
I would assume they have about 1-4µH at low signal levels and 1/100 of this at An Amp of Speaker current.

You re right. My bad, just corrected it

 

[Toku]

I don't think the XLR input on this amp is a balanced connection.
I'm using an XLR connector, but I think it's the same unbalanced input as the RCA input.
Two OP amplifiers are placed on each of the left and right channels, but it is difficult to configure a balanced connection in this input circuit with a volume pot.

 

[daniboun]

I don't think the XLR input on this amp is a balanced connection.
I'm using an XLR connector, but I think it's the same unbalanced input as the RCA input.
Two OP amplifiers are placed on each of the left and right channels, but it is difficult to configure a balanced connection in this input circuit with a volume pot.

I think you're wrong ) Have you tried it at least? Because there is a level difference between the two inputs.
There are a lot of balanced amps that use an op amp for each channel and volume pot...

 

[Toku]

I think you're wrong ) Have you tried it at least? Because there is a level difference between the two inputs.
There are a lot of balanced amps that use an op amp for each channel and volume pot...

If a DAC with both unbalanced output and balanced output is connected to this amplifier and the input is switched, there should be almost no difference in volume between the unbalanced input and the balanced input if the circuit is correct.

 

[daniboun]

With the XLR the signal is better and cleaner than the rca. At least with my Gustard AK4499 dac )

 

[Xulonn]

I find it amazing how modifying an amplifier can also rewire one's brain, leading to profound changes in the "perception" of sound! /s

The stock amp is really good but these little mods improve the sound undoubtedly but I think the main update lies in the change of OP amps.
Less harshness in the treble, better definition of the bass, an excellent soundstage, mediums are also a bit more natural.

 

[B&WTube]

If a DAC with both unbalanced output and balanced output is connected to this amplifier and the input is switched, there should be almost no difference in volume between the unbalanced input and the balanced input if the circuit is correct.

My understanding is that most DAC and Pre-Amp manufacturers ground the RCA’s, which results in half the voltage/gain being output on RCA’s. If you pull the specs on most DAC’s you will see double gain on the XLR’s.

 

[B&WTube]

I find it amazing how modifying an amplifier can also rewire one's brain, leading to profound changes in the "perception" of sound! /s

I find it amazing that someone would think different circuitry of opamps means they all sound the same, that shielding doesn’t reduce interference/crosstalk, and that all caps are created equal despite having different tolerances and different discharge rates.

 

[ModDIY]

I find it amazing that someone would think different circuitry of opamps means they all sound the same, that shielding doesn’t reduce interference/crosstalk, and that all caps are created equal despite having different tolerances and different discharge rates.

I completely agree. But many people don't have enough ears to hear the differences. I have a collection of OP's of varying quality, and often people's appreciation of DAc's for example, is the result of the conversion stages and the buffering of the analog stages.

 

[Xulonn]

I find it amazing that someone would think different circuitry of opamps would all sound the same, that shielding doesn’t matter, and that all caps are created equal.

Indeed - I agree, but that certainly doesn't apply to me - and I do not know any intelligent, educated and rational audio enthusiasts who believe that. Such a statement is a very obvious defensive non-sequitur with respect to my clearly noted snark, although my snark was based on many confirmed studies from the hard-science field of psychoacoustics.

ASR is a science-based forum. Scientific measurements of frequency response, distortion and noise in audio electronics are not the end-all and be-all in audio, but modern instruments can be far more sensitive than even the best human ears. Most sonic differences that can only be "detected" when the listener knows in advance what they are listening to have been found to be inaudible in proper and robust science-based blind listening.

Science is based on confirming findings by independent verification of postulates and hypotheses, and not by "proving" things. The concept of proofs is found in the domains of mathematics and philosophy. (I initially misspelled "proofs" as "poofs" which is funny, because "poof" is what happens to most audiophile claims of audible differences in properly designed and engineered "high fidelity" audio electronics.)

Psycho acoustics is a legitimate branch of science, and some audio websites adhere to the lessons that science teaches us. Decades of working directly with scientists has enabled me to quite accurately recognize science-based conclusions - like this one from NwAvGuy:

OP AMP ROLLING: Swapping op amps out, often using a socket so they’re easy to switch, is known as “op amp rolling”. Countless words have been written describing one op amp as having more “depth”, another as having a “blacker background”, etc. The Tangent headphone amp site has a typical list of subjective comments. As explained above, sometimes the differences might be real because some of the op amps are seriously unhappy in that particular configuration. But, more often, it’s just the usual sighted listening bias described above. If the swaps are done blind, and they’re using suitable op amps operated correctly, the alleged differences seem to always disappear.

DISCRETE OP AMPS: There’s another tiny grain of truth here. There are some very expensive discrete op amps that were designed specifically to outperform IC op amps in very specific ways. Their highly specialized benefits, to my knowledge, don’t offer any real world advantages in typical audio use. And audiophiles seem to favor much less rigorously designed discrete replacements for IC op amps. These discrete substitutes typically lack any sort of valid test data to demonstrate their real performance. So how does anyone know they outperform ICs? They mostly use Sighted Listening which is completely invalid (see above). Audio-GD discrete op amps were tested by Samuel Groner using an Audio Precision analyzer and the results were horrible. See The Discrete Is Better Myth.

 

[B&WTube]

Indeed - I agree, but that certainly doesn't apply to me - and I do not know any intelligent, educated and rational audio enthusiasts who believe that. Such a statement is a very obvious defensive non-sequitur with respect to my clearly noted snark, although my snark was based on many confirmed studies from the hard-science field of psychoacoustics.

ASR is a science-based forum. Scientific measurements of frequency response, distortion and noise in audio electronics are not the end-all and be-all in audio, but modern instruments can be far more sensitive than even the best human ears. Most sonic differences that can only be "detected" when the listener knows in advance what they are listening to have been found to be inaudible in proper and robust science-based blind listening.

Science is based on confirming findings by independent verification of postulates and hypotheses, and not by "proving" things. The concept of proofs is found in the domains of mathematics and philosophy. (I initially misspelled "proofs" as "poofs" which is funny, because "poof" is what happens to most audiophile claims of audible differences in properly designed and engineered "high fidelity" audio electronics.)

Psycho acoustics is a legitimate branch of science, and some audio websites adhere to the lessons that science teaches us. Decades of working directly with scientists has enabled me to quite accurately recognize science-based conclusions - like this one from NwAvGuy:

Everyone who has been on ASR for 30 seconds knows about psychoacoustics. But the classic ASR of argument of ‘psychoacoustics’ on any subjective feedback bothers me, IF it is deployed when there is some scientific merit to what one is doing. I wish everyone had thousands of dollars of measuring equipment, but I am not willing to write something off to psychoacoustics IF that person has A) vast experience and/or B) a pragmatic and logical approach. I don’t know anyone who has owned more Class D stuff than Dani, and I see the logic in what he did.
As you are clearly aware (which I greatly appreciate)- the measurements are not perfect (although they are easily the best baseline from multiple standpoints). As I have learned more about filtering methods for audio devices- the SINAD measurements on the forum are concerning. Speaking with two DAC engineers (and looking at as technical of data I can handle), it seems you can run endless feedback loops and filters to make them perfect, from a SINAD perspective. However, you are actually losing source data/micro details in the process. I am told you also alter timbre.
For me I take value from the SINAD, engineering principles, and certain subjective observations, for my audio journey. I do thank you for a polite response.