3e Audio A7 [TPA3255 PFFB Stereo] Finished Amplifier - User Impressions | Owner's Thread

[r-36m2]

You can either measure the actual impedance with REW and a sound card, or simulate it with Visaton Boxsim (a free program you can download).
Without this data, it's just hot air.
Without this data, buy A5 , you will be certain that it will be able to drive any load, within its power envelope. if you want more power , buy A7

I couldn't find a Boxsim for Mac. I'll try to measure it somehow. It's inconvenient because the computer with the sound card and these speakers are in different rooms.
I don't need extra power. I currently have a 50-watt amplifier and it's more than enough.

 

[melomane13]

i can simulate your speaker if you give me exact speaker and crossover
also, what is the problem with actual amplifier ?

 

[Alannn]

"I replaced the standard NE5532 op amps in their previous amplifier with the same old and cheap MC33272, and the sound improved."

Sure than "Sure thing" is refers to the part in bold of your syllogism. It could be either a confirmation of what you're saying or irony. I don't know.

Sarcasm.

 

[r-36m2]

i can simulate your speaker if you give me exact speaker and crossover
also, what is the problem with actual amplifier ?

Height 83.5 cm, width 40 cm, depth 31.5 cm.
Wall thickness 32 mm. Internal volume 65 liters.

There are no problems with the amplifier. It's a TPA3250 with ADAU and no PFFB. It's just time to upgrade the quality.

 

[melomane13]

yous speaker have high impedence, A5 is not usefull. Given the high impedance at high frequencies (10 ohms), the A80 aiyima will boost even more, so I advise against it. Consider the A70 aiyima instead; it's cheaper than the A5SE, more powerful, and well-implemented PFFB. That's what I personally chose, but you can't go wrong with the A5SE or A7SE, they are very good. it all depends on the power you need.

 

[harkpabst]

Assuming that BG8 should read BG 20, this is a BoxSim impedance simulation of the full loudspeaker, including the SC 10 N tweeter, the BG 20 woofer, the crossover and the cabinet (no electrical phase, amount only) :

This is not a hard to drive speaker, but not too well suited for high output impedance amplifiers either. I have also attached the numerical values traced from this graph using VituixCAD's SPL Trace function. This does included (derived) phase values, which I would not put much trust in.
(The above sentence has been edited, because the all-important "not "had been missing.)

Next up is a simulation of the electrical transfer functions of the crossover (effective voltage as could be measured right at the terminals of the actual drivers):

Electrically, the crossover point is a bit above 3 kHz, but that doesn't take into account the frequency response of the individual drivers, of course.


Here is the acoustical transfer function simulation of the tweeter and the woofer and their combined response:

The individual curves do not exactly follow any classical filter type, but the summed response is reasonably flat for this kind of speaker. The acoustical crossover point is somewhere around 4.3 kHz.


Finally, here's a simulation of the directivity index:

As should be expected with an 8" woofer and such a high crossover frequency, the DI is rough and peaky. The actual performance will be room dependant.

Personally, when it comes to TPA325x based amplifiers I would only care about a good PFFB implementation, not about op-amps.

 

[r-36m2]

As should be expected with an 8" woofer and such a high crossover frequency, the DI is rough and peaky. The actual performance will be room dependant.

Thank you for your work! This information is very valuable to me!
Of course, it's Visaton BG20/8. Sorry, I forgot the name.
Do you think changing the filters and moving the crossover point down a bit will improve the overall response?

 

[r-36m2]

yous speaker have high impedence, A5 is not usefull. Given the high impedance at high frequencies (10 ohms), the A80 aiyima will boost even more, so I advise against it. Consider the A70 aiyima instead; it's cheaper than the A5SE, more powerful, and well-implemented PFFB. That's what I personally chose, but you can't go wrong with the A5SE or A7SE, they are very good. it all depends on the power you need.

Thank you!
I looked at the A80 schematic and didn't like the astronomical number of op amps. I also read Amir's reviews of the A70, A80, and other amplifiers. I'll follow your advice and ditch the A80. I agree with you that the A70 should sound very good. However, Amir's 3D audio rating is significantly higher. Perhaps the nuances between positions 95 and 105 are inaudible, but I'll probably stick with the A5se.
I don't need increased power because I listen to 90% of my music at 3-5 watts, and 30-40 watts is more than enough for movies.

I also like the Douk Ampapa D1 amplifier. It looks good and has Bluetooth, which is important because I watch a projector that transmits audio to the amplifier via Bluetooth, eliminating the need to run wires across the room. But I doubt its internals are as well organized as the A70 or A5se, or that its sound quality is comparable.
If the Ampapa's sound quality is worse, I'd rather get the A5se, but then I'll have to buy a separate DAC with Bluetooth.
If you're familiar with this amplifier, I'd appreciate your opinion!

 

[harkpabst]

Thank you for your work! This information is very valuable to me!
Of course, it's Visaton BG20/8. Sorry, I forgot the name.
Do you think changing the filters and moving the crossover point down a bit will improve the overall response?

That's probably not going to be easy. The SC 10 N has a pretty high resonant frequency (1.5 kHz, even thought it is highly damped). I would not use this tweeter below 3 kHz (and that's exactly what the datasheet recommends), certainly not with a simple 2nd order high pass.

For a favorable spinorama rating you would have to use a tweeter that can deal with a crossover frequency below 2 kHz. Since you put some effort into the cabinets it would be virtually impossible to find a tweeter that exactly fits the dimensions of the SC 10 N. This kind of speaker (full range woofer with light weight paper cone and a simplistic network is not exactly what ASR folks typically love. Personally I find the results pretty decent. If the speaker works OK in your room, why modify it?

Another (counter-intuitive) approach would be to let the BG 20 run even higher and push the crossover frequency into a region where phantom image stability in stereo degrades, anyway. This is more along the lines of Zu Audio and similar offerings. You would accept the the further narrowing of the directivity, up to a frequency range where localization mostly collapses into just “brightness” and “airiness”. Apart from the fact that this is less accepted technology around here, ideally the full range speaker would have to cover a range up to ~10 kHz, which the BG 20 is not exactly ideal for. In any case you would have to perform acoustical measurements to see if this could lead to any improvement ... or just not.

 

[r-36m2]

Personally I find the results pretty decent. If the speaker works OK in your room, why modify it?

Thank you!

I built these speakers a long time ago on a tight budget. I consulted about the enclosure and filter on audio forums and in person with a specialist who makes speakers in his workshop. He talked me out of using phase inverters. And indeed, the bass turned out quite good, and there's a subwoofer for movies.

To hear the difference in sound with and without a crossover, I installed 4-pin switches that turn on the BG20 without a filter and the SC10 with a 1.3 µF filter. Some people claimed the BG20 doesn't need filters. Of course, without a filter, it sounds like a squawking jay.

I've read mixed opinions about the crossover, including that the cutoff could be a bit lower. But I hear you regarding the SC10.

The thing is, I don't have several similar speaker systems to compare the sound to a standard and say, "Yes, I do hear excessive brightness around 4-5 kHz or a dip at 7-8 kHz."
The sound seems fine, but without comparison, it's impossible to discern the nuances.
Therefore, I'm unlikely to change the tweeter anytime soon. Firstly, I'm not sure if it's necessary; secondly, with the borders now closed, many trusted Western brands have disappeared from sale; thirdly, everything else has quadrupled in price. The only products left are Chinese, but no one's familiar with them, so it's a pig in a poke. And frankly, I'm too lazy to redesign the enclosure to accommodate a different speaker.

We've strayed from the topic of amplifiers, and I apologize. Thank you for the pleasant conversation!

 

[r-36m2]

Another (counter-intuitive) approach would be to let the BG 20 run even higher and push the crossover frequency into a region where phantom image stability in stereo degrades, anyway. This is more along the lines of Zu Audio and similar offerings. You would accept the the further narrowing of the directivity, up to a frequency range where localization mostly collapses into just “brightness” and “airiness”. Apart from the fact that this is less accepted technology around here, ideally the full range speaker would have to cover a range up to ~10 kHz, which the BG 20 is not exactly ideal for. In any case you would have to perform acoustical measurements to see if this could lead to any improvement ... or just not.

I didn't quite understand what you meant, sorry. It's difficult to translate.
It's clear that measurements need to be taken in any case. I agree. But I'm not ready to dive into this process head-on yet.

 

[andrewwnbanks]

For exactly the same reason that there are a million audiophile cables available. Snake oil sales for the scientifically ignorant obsessive audiophile.

If people think it sounds better, and they can afford it, what is wrong with that? I happen to think speaker cables and interconnects are important. I get that spending £3500 on balanced interconnects and similar on speaker cable isnt for everyone, and that almost certainly you don’t get £3500 worth of improvement, but it’s my money and if it gives me pleasure and satisfaction, then so what?

You can diss it all you like but I am very satisfied with the equipment and alleged snake oil products I have in my system and I would buy them all over again if I had to do it again. I think paying £ 1 million for a Banksy scribble is worthless, but if it means something to the buyer then good luck to him/her

 

[Dave TR3A]

If people think it sounds better, and they can afford it, what is wrong with that? I happen to think speaker cables and interconnects are important. I get that spending £3500 on balanced interconnects and similar on speaker cable isnt for everyone, and that almost certainly you don’t get £3500 worth of improvement, but it’s my money and if it gives me pleasure and satisfaction, then so what?

You can diss it all you like but I am very satisfied with the equipment and alleged snake oil products I have in my system and I would buy them all over again if I had to do it again. I think paying £ 1 million for a Banksy scribble is worthless, but if it means something to the buyer then good luck to him/her

You’re on the wrong site then. This is Audio Science Review.

 

[TurtlePaul]

If people think it sounds better, and they can afford it, what is wrong with that?

You can diss it all you like but I am very satisfied

The post you were replying to wasn’t a diss.

You like to buy expensive cables? Good for you, have fun.

You think cables and opamps make an audible difference? They don’t.

There are several categories or audio tweaks where hundreds or thousands can be spent but we can test them and cheap options are provably audibly perfect. This includes opamps, interconnect cables, DACs, capacitors and resistors, headphone amps and digital transports (e.g. CD/DVD/Bluray players). (Please note this is different than saying they all sound the same, as there can be flawed devices in any of these categories)

 

[oleg87]

If people think it sounds better, and they can afford it, what is wrong with that? I happen to think speaker cables and interconnects are important. I get that spending £3500 on balanced interconnects and similar on speaker cable isnt for everyone, and that almost certainly you don’t get £3500 worth of improvement, but it’s my money and if it gives me pleasure and satisfaction, then so what?

You can diss it all you like but I am very satisfied with the equipment and alleged snake oil products I have in my system and I would buy them all over again if I had to do it again. I think paying £ 1 million for a Banksy scribble is worthless, but if it means something to the buyer then good luck to him/her

You're entirely free to make your own decisions.

For anyone for whom £3500 is not pocket change, it is an extremely foolish decision.

 

[Mort]

If people think it sounds better, and they can afford it, what is wrong with that?

Absolutely nothing. They have the whole rest of the Internet to enjoy their cables.

The problem we encounter on this site every day of the year are people that come here specifically to win an audio argument about which they are uninformed and wrong. At best it's disingenuous, at worst it's ignorant.
So yeah we are jaded. But that doesn't mean we want to deprive anyone of their cables.

I like nice cables but I stop at $75 a pair.

 

[Alannn]

If people think it sounds better, and they can afford it, what is wrong with that? I happen to think speaker cables and interconnects are important. I get that spending £3500 on balanced interconnects and similar on speaker cable isnt for everyone, and that almost certainly you don’t get £3500 worth of improvement, but it’s my money and if it gives me pleasure and satisfaction, then so what?

Getting pleasure and satisfaction from the purchase is fine.
The part that's wrong are the bogus pseudo-scientific marketing claims. Just because you are a happy customer, doesn't mean they weren't sold fraudulently.

 

[Mort]

doesn't mean they weren't sold fraudulently

I know what you mean but if that's fraud, almost every item we buy would be sold 'fraudulently'. It's just consumer marketing right?

 

[Alannn]

I know what you mean but if that's fraud, almost every item we buy would be sold 'fraudulently'. It's just consumer marketing right?

The example sited is spending £3500 on balanced interconnects and similar on speaker cable.
You do know that 3,500 Pound sterling equals 4,702.84 United States Dollars?
Can you agree: Every item we buy is being sold (much) less fraudulently.
Personally, I don't recall ever buying anything that utilized pseudo-science marketing.

 

[Matt_Holland]

If people think it sounds better, and they can afford it, what is wrong with that? I happen to think speaker cables and interconnects are important. I get that spending £3500 on balanced interconnects and similar on speaker cable isnt for everyone, and that almost certainly you don’t get £3500 worth of improvement, but it’s my money and if it gives me pleasure and satisfaction, then so what?

You can diss it all you like but I am very satisfied with the equipment and alleged snake oil products I have in my system and I would buy them all over again if I had to do it again. I think paying £ 1 million for a Banksy scribble is worthless, but if it means something to the buyer then good luck to him/her

People are free to think what they like. Nothing wrong with that. People claiming things to be fact that are provably false is another thing.

You're not on the wrong forum, BTW. All are welcome. But certain view points will be challenged. There is a huge amount to learn and enjoy here, so worth sticking around.