Greetings,
Has anyone compared TDA7293 and LM3886 side-by-side with a pair of audiophile grade speakers? I am asking because LM3886 supposedly has lower levels of distortion. Is it really audible?
Design and implementation complexity of both is about the same and has been compared in earlier threads.
Thanks.
Has anyone compared TDA7293 and LM3886 side-by-side with a pair of audiophile grade speakers? I am asking because LM3886 supposedly has lower levels of distortion. Is it really audible?
Design and implementation complexity of both is about the same and has been compared in earlier threads.
Thanks.
There many onions regarding the subject. PLS consider that Operational Amplifier depends on a quality of passive components.
Also LM3886 uses quasi complementary BJTs for an output stage that is taking into account modern ICs optimization making LM a bit ahead of TDA.
imho LM3886 is more popular IC overall and therefore you can get better support that might be the most important concern for DIY project.
Also LM3886 uses quasi complementary BJTs for an output stage that is taking into account modern ICs optimization making LM a bit ahead of TDA.
imho LM3886 is more popular IC overall and therefore you can get better support that might be the most important concern for DIY project.
See this project:
Project 127
The absence of the Dreaded spike protection circuitry may give the TDA7293 the edge if there is any chance of getting close to the edge. Just a thought.
Project 127
The absence of the Dreaded spike protection circuitry may give the TDA7293 the edge if there is any chance of getting close to the edge. Just a thought.
Hi,
i have done some listening between LM1875 and TDA2050. LM1875 has a very transparent sound and clear sound, but i felt TDA2050 gave a much warmer and richer sound. Both i operated on 18V on medium listening level.
similarly i feel the best way to compare is to made both the amplifiers and do blind listening test. How you perceive sound is a very personal choice.
i have done some listening between LM1875 and TDA2050. LM1875 has a very transparent sound and clear sound, but i felt TDA2050 gave a much warmer and richer sound. Both i operated on 18V on medium listening level.
similarly i feel the best way to compare is to made both the amplifiers and do blind listening test. How you perceive sound is a very personal choice.
As far as the quality of ic I got here is concerned ,Lm1875 sounds like ****.I m back to TDA 2040 .It is just cool.After doing many tweaks in lm1875 ,the amp sounds like a class A amp.That thing is not negotiable 2 me.If my Lm ic is fake then Tda is also fake.Many people like Lm.I wud say a bias.May b our ears are dissimilar.Just a though no offence.
The best sounding TDA schematic according to Françis IBRE http://www.eyrolles.com/Accueil/Auteur/francis-ibre-61265
http://imageshack.us/f/256/ampli7293schma2.jpg/]Imageshack - ampli7293schma2.jpg
(inverting the minus BYW98)
http://imageshack.us/f/256/ampli7293schma2.jpg/]Imageshack - ampli7293schma2.jpg
(inverting the minus BYW98)
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AndrewT, I believe the first link was just to reference Mr Ibre as a recognized writer in France...
The second link has some wrong spaces so fail :
http://imageshack.us/photo/my-images/256/ampli7293schma2.jpg/
The idea is to separate pre-amp and amp DC supplies, Mr Ibre explained that the sound is really better this way and another guy realized the schematics :
Fangorn - comme un arbre dans la ville ...
http://fangorn.fr.free.fr/ampliTDA_sch.pdf
Important : seems that replacing the BYW98 by a resistor will destroy the chip, by delaying too much the power at pre-amp, at start-up...
This is a simplification of the "kit Hermes" tip (see description page 7 of 8) :
http://www.ermes.free.fr/kier313.pdf
Translated for you, thanks google :
"The drivers of entry to the CI are fed by pin 7 (+ Vs) and 8 (-Vs). The trick is to supply the drivers with a voltage higher than that of the power. A difference of 10V just about. Thus, we can remove the capacitor bootstrap (C8).
Specifically, just provide few volts further, and change a little the card. (We do can't provide a guarantee as a result of this optional intervention)
CHANGE OF THE CARD:
Cut two pieces of track with a cutter to locations detailed below. Move directly to the two square pads tensions + Vs and - Vs with isolated copper wires.
Beware short circuits, hazardous voltages you vehicle. There is no shame in using a microscope to check quality of your work!
EXTRA POWER
It should be double. We use a transformer with two separate secondary windings: these two additional voltages will be in series with the positive and negative power stage.
Do not exceed the + and - 30V for the transformer power section not to exceed the limits of constructor.
The second link has some wrong spaces so fail :
http://imageshack.us/photo/my-images/256/ampli7293schma2.jpg/
The idea is to separate pre-amp and amp DC supplies, Mr Ibre explained that the sound is really better this way and another guy realized the schematics :
Fangorn - comme un arbre dans la ville ...
http://fangorn.fr.free.fr/ampliTDA_sch.pdf
Important : seems that replacing the BYW98 by a resistor will destroy the chip, by delaying too much the power at pre-amp, at start-up...
This is a simplification of the "kit Hermes" tip (see description page 7 of 8) :
http://www.ermes.free.fr/kier313.pdf
Translated for you, thanks google :
"The drivers of entry to the CI are fed by pin 7 (+ Vs) and 8 (-Vs). The trick is to supply the drivers with a voltage higher than that of the power. A difference of 10V just about. Thus, we can remove the capacitor bootstrap (C8).
Specifically, just provide few volts further, and change a little the card. (We do can't provide a guarantee as a result of this optional intervention)
CHANGE OF THE CARD:
Cut two pieces of track with a cutter to locations detailed below. Move directly to the two square pads tensions + Vs and - Vs with isolated copper wires.
Beware short circuits, hazardous voltages you vehicle. There is no shame in using a microscope to check quality of your work!
EXTRA POWER
It should be double. We use a transformer with two separate secondary windings: these two additional voltages will be in series with the positive and negative power stage.
Do not exceed the + and - 30V for the transformer power section not to exceed the limits of constructor.
Last edited:
Mosfet versus bipolar at this level is very audible (not the distortion). Most people will prefer bipolar I believe. With big transformer and woofer, the TDA7293 will be a poor man's mini crescendo.
I said with big woofer and transformer, the TDA7293 will rival the mini-crescendo. Both amps have mosfet output stage.
Any amp will benefit from large transformer. It seems to me that mosfet requires more free current to charge the capacitance.
Mosfet amps have unique quality that is usually displayed when using big woofer.
Yes, I have. Currently I have a few 3886 amps, one 7293 amp, a few not so audiophile grade speakers such as Dynaudio, JMLabs, and some lower grade speaker designs (Vifa, SilverFlute, etc). Speakers with big diameter woofers were/are Peerless 3-way design and another 3-way design using local drivers.
Difference in THD is rarely audible. If you can hear a difference between 7293 and 3886, I would say it is the difference between mosfet and bipolar in common/most amp designs (they can be designed to sound more similar I believe), where mosfet amp tend to sound "muddy"?
--> Mosfet versus bipolar at this level is very audible (not the distortion).
If you want to know how 7293 will perform in comparison to 3886, you have to know how mosfet amps sound in general, then you could benchmark the 7293 with another mosfet amp (where they have similar characteristics in sound). I'll bet 80% at least will prefer 3886.
---> Most people will prefer bipolar I believe.
If "mosfet sound" is not a problem to you (or you are a mosfet fan), or you have heard mosfet amp before, or you have heard review about another mosfet amp, may be you should know how the 7293 would compete against the 50W mini-crescendo.
They have similar sound character. The mini-crescendo has more "full sound". The Hitachi K135/J50 has unique good character but the 7293 that I tried was at least as listenable as the mini-crescendo.
I had to do "everything" to beat the mini-crescendo with 7293, so I used big transformer, especially because the mini-crescendo had a "fuller sound" and used big trafo. Big transformer will for sure improve the characteristics of the amp in bass region and "power". I only asked one experienced man for his opinion about the two amps. He didn't explicitly say which one was better, only that the mini-crescendo had more body and fuller sound.
Speaker is more important than amp. The better the speaker, the less difference you can expect from amps. Sometimes, certain amp match better with certain speaker. In my case, I always found mosfet amps to sound great with big speakers.
So I think that with good implementation (I didn't even use the "best" schematic or matched preamp) such as using big transformer, high quality capacitors, and using suitably high end (big) speakers, the 7293 will be "comparable" to the mini-crescendo.
--> With big transformer and woofer, the TDA7293 will be a poor man's mini crescendo.
Of course, I have found many people prefer the 3886 than a better mosfet amp than mini-crescendo!!
You may be a lateral mosfet fan like me, or you might be surprised that many people had preferred a 3886 based amp compared to a sophisticated discrete lateral fet amp. That's why I have always emphasized this "taste/preference" issue.
Yes, bipolars have better transconductance. It is this parameter that I think is responsible for the better sonic in bipolar amps. And it is this sonic that will bring more objective enjoyment, not just subjective taste.
That's why I think that in designing a lateral fet amp, this weakness should be taken into account. I'm not an electronics educated person, but I always choose a design and build my amps in a way that I think will solve this issue. Assume for example that a lateral fet transistor is a load for the VAS, you sure want a low output impedance VAS stage. Designers should know how to do it and will do it if they have good ears.
Furthermore, I think that this issue with lateral fet amps is a bottleneck, so it should be solved with every available ways, even with increasing the supply rail and using big power transformer.
Can we express this in more scientific terms? Say damping factor and harmonic distortion.
Both bipolar and MOSFETs can be designed to keep harmonic distortion below audible levels.
Damping factor expresses the amount of control an amplifier has over a speaker - TDA7293's damping factor is 180 for an 8Ohm speaker. Does anyone know what the damping factor for LM3886 is?
Both bipolar and MOSFETs can be designed to keep harmonic distortion below audible levels.
Damping factor expresses the amount of control an amplifier has over a speaker - TDA7293's damping factor is 180 for an 8Ohm speaker. Does anyone know what the damping factor for LM3886 is?
I'm sure that most of us are familiar with the popular workarounds to dodge the harsh noise of the NatSemi spike system current limiter; however, there is little information on ST's limiter and their datasheets are seriously misleading.
For lack of anything else, try this post: http://www.diyaudio.com/forums/chip-amps/200195-tda7293-capacitors.html#post2826002
That also gives some tuning ideas to bring the TDA7293/4 up to approximately the same clarity and low bass performance as LM3886. Anyway, click the link and hear what you're missing.
I just think that we have to come a lot closer to individually optimized applications before it could be possible to compare audio quality of the chips.
For lack of anything else, try this post: http://www.diyaudio.com/forums/chip-amps/200195-tda7293-capacitors.html#post2826002
That also gives some tuning ideas to bring the TDA7293/4 up to approximately the same clarity and low bass performance as LM3886. Anyway, click the link and hear what you're missing.
I just think that we have to come a lot closer to individually optimized applications before it could be possible to compare audio quality of the chips.
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