3e audio A7/A7 Mono Amplifier Review

[Luvchampagne]

You’ll have to explain that to me because I don’t understand why TI would caution about that. Might TI be referring to the use of multiple 3255s on a single circuit board? (Although I had the TI 3255 datasheet, I mustn’t have read it carefully enough because I didn’t note that caution.)

To my mind, as long as the DC voltage is clean and the PS can provide sufficient current it shouldn’t matter. What would clocking have to do with anything when dealing with the output from a PS?

I experimented with consolidating to a single power supply after reading that others had been successful. I wanted to replace the three 32V/5A power supplies that came with the amps with a single 36V/16.6A power supply. I chose the Meanwell LRS-600-36 because it met my requirements (at least on paper) and because Meanwell has an excellent reputation. It worked, but the PS output was too noisy for use in an audio application.

Perhaps the PS might be OK if used with less efficient speakers where small amounts of noise wouldn’t be as audible. I used it to drive Klipsch La Scalas which are >100 dB @1W @1m efficient.

Klipsch La Scalas and using 1 Meanwell power supply to replace 3 power supplies sounds like a science experiment to test an edge case. You're using budget amps on super highly efficient speakers and trying to replace $50 power supplies? smh

 

[Roland68]

You’ll have to explain that to me because I don’t understand why TI would caution about that. Might TI be referring to the use of multiple 3255s on a single circuit board? (Although I had the TI 3255 datasheet, I mustn’t have read it carefully enough because I didn’t note that caution.)

To my mind, as long as the DC voltage is clean and the PS can provide sufficient current it shouldn’t matter. What would clocking have to do with anything when dealing with the output from a PS?

I experimented with consolidating to a single power supply after reading that others had been successful. I wanted to replace the three 32V/5A power supplies that came with the amps with a single 36V/16.6A power supply. I chose the Meanwell LRS-600-36 because it met my requirements (at least on paper) and because Meanwell has an excellent reputation. It worked, but the PS output was too noisy for use in an audio application.

Perhaps the PS might be OK if used with less efficient speakers where small amounts of noise wouldn’t be as audible. I used it to drive Klipsch La Scalas which are >100 dB @1W @1m efficient.

You can find the application note here:
SLAA787 Multi-Device Configuration for TPA32xx Amplifiers

This can have an effect, especially if you connect multiple amplifiers with very short cables.

 

[Dave TR3A]

Klipsch La Scalas and using 1 Meanwell power supply to replace 3 power supplies sounds like a science experiment to test an edge case. You're using budget amps on super highly efficient speakers and trying to replace $50 power supplies? smh

I was displeased with the performance of the La Scalas with any of the passive crossovers that I tried (and I tried 5 different ones) so that I wanted to see if using an active crossover (DSP) and tri-amping would be more satisfactory. Since I wasn’t sure that it would pan out, I wanted to keep the initial costs down.

I documented my efforts in this thread. There are subsequent threads on Audiokarma dealing with refinements that I have made.

I have been extremely happy with my foray into tri-amping/DSP. Some of that may be due to Beranek’s Law, but my REW measurements show that my system performs very well.

The three Aiyima A07 amps perform extremely well. They are certainly the equal of the much more expensive Yamaha amp that I was using with the passive crossovers. In the past couple of years, new class D amps have come on the market from several manufacturers (e.g., 3e Audio, Topping, Fosi, Aiyima, etc.) that are superior to the A07.

Having three amps necessitated having 3 power bricks. Moving to a single (more capable) power supply might slightly improve the power of the amps (due to higher voltage) while eliminating the clutter associated with three separate power bricks. Getting rid of the clutter was my primary objective. My idea wasn’t novel; several people have reported doing a similar consolidation. Indeed, FOSI sells a PS that was designed to be shared between two of their amps.

Why would you shake your head about that?

 

[Roland68]

I was displeased with the performance of the La Scalas with any of the passive crossovers that I tried (and I tried 5 different ones) so that I wanted to see if using an active crossover (DSP) and tri-amping would be more satisfactory. Since I wasn’t sure that it would pan out, I wanted to keep the initial costs down.

I documented my efforts in this thread. There are subsequent threads on Audiokarma dealing with refinements that I have made.

I have been extremely happy with my foray into tri-amping/DSP. Some of that may be due to Beranek’s Law, but my REW measurements show that my system performs very well.

The three Aiyima A07 amps perform extremely well. They are certainly the equal of the much more expensive Yamaha amp that I was using with the passive crossovers. In the past couple of years, new class D amps have come on the market from several manufacturers (e.g., 3e Audio, Topping, Fosi, Aiyima, etc.) that are superior to the A07.

Having three amps necessitated having 3 power bricks. Moving to a single (more capable) power supply might slightly improve the power of the amps (due to higher voltage) while eliminating the clutter associated with three separate power bricks. Getting rid of the clutter was my primary objective. My idea wasn’t novel; several people have reported doing a similar consolidation. Indeed, FOSI sells a PS that was designed to be shared between two of their amps.

Why would you shake your head about that?

Just a quick note: you don't have a tri-amping system, but an active 3-way system. That's a huge difference and they're completely unrelated.

There's nothing to laugh about here. One can only admire anyone who completely rebuilds their speakers into an active system themselves.

 

[Dave TR3A]

Just a quick note: you don't have a tri-amping system, but an active 3-way system. That's a huge difference and they're completely unrelated.

You’re mistaken.

I’m running an active, tri-amped, 3-way system with two powered subwoofers. The active crossover is a MiniDSP Flex Eight DL. It serves as both crossover and DSP for all 6 drivers (woofers, midranges, and tweeters) and the two subwoofers. The three 2-channel amps are directly connected to the drivers: one for the L&R woofers, another for the L&R midranges, and the third for the L&R tweeters.

 

[Roland68]

You’re mistaken.

I’m running an active, tri-amped, 3-way system with two powered subwoofers. The active crossover is a MiniDSP Flex Eight DL. It serves as both crossover and DSP for all 6 drivers (woofers, midranges, and tweeters) and the two subwoofers. The three 2-channel amps are directly connected to the drivers: one for the L&R woofers, another for the L&R midranges, and the third for the L&R tweeters.

You just described exactly what I wrote.
This is the perfect example of an active 3-way system (plus subwoofer).

With bi- or tri-amping, the entire frequency range is delivered from the amplifiers to the individual passive crossover branches.
In an active system, the active crossover is located before the amplifiers.

 

[Dave TR3A]

You just described exactly what I wrote.
This is the perfect example of an active 3-way system (plus subwoofer).

With bi- or tri-amping, the entire frequency range is delivered from the amplifiers to the individual passive crossover branches.
In an active system, the active crossover is located before the amplifiers.

Here’s how Wikipedia describes tri-amping: “Tri-amping is the practice of connecting three channels of amplification to a loudspeaker unit: one to power the bass driver (woofer), one to power the mid-range and the third to power the treble driver (tweeter).”

We’ll have to agree to disagree.

 

[harkpabst]

With bi- or tri-amping, the entire frequency range is delivered from the amplifiers to the individual passive crossover branches.
In an active system, the active crossover is located before the amplifiers.

That's just the "Hi-Fi" definition of bi-amping (or tri-amping). In pro audio bi-amping (or tri-amping) always implies active crossovers.

Maybe it's even just a German thing ...

 

[somebodyelse]

Here’s how Wikipedia describes tri-amping: “Tri-amping is the practice of connecting three channels of amplification to a loudspeaker unit: one to power the bass driver (woofer), one to power the mid-range and the third to power the treble driver (tweeter).”

We’ll have to agree to disagree.

Thanks for pointing out the wikipedia definition. I'll have to add a dead-tree citation to the talk page section about alternate definitions as when I first heard about it (before WWW existed) it meant amps driven full range feeding split passive crossovers.

 

[astamixa]

I would not recommend the Meanwell LRS series power supplies for this application.

I tried using a Meanwell LRS-600-36 power supply to consolidate the 3 separate 32V 5A power supplies that came with the Aiyima A07 amps I’m using to drive my tri-amped system. Unfortunately the Meanwell power supply was much noisier than the power supplies that came with the amps so that the speakers produced a soft — but certainly noticeable — buzzing sound. I ended up reverting to the separate Aiyima power supplies and putting the Meanwell LRS-600-36 on a shelf.

I had thought that whatever noise I’d be seeing would be close to the frequency of the power supply oscillator (i.e., 50 kHz – 130 kHz, well outside the audio range). Instead, the frequency of the noise was around 600 Hz on average (range is 19 Hz to 10 kHz) --- right in the audio band.

View attachment 514518

The peak-to-peak voltage of the noise was 568 mV, which is almost 60% higher than the 360 mV (peak-to-peak, measured at 20 MHz) cited in the LRS-600-36 specs for ripple and noise.

The remedies that Meanwell suggested when I contacted their support group (ferrite choke, parallel 0.1 uF and 47 uF capacitors) actually made the noise worse. Ultimately, Meanwell suggested that I try their RSP or HEP series power supplies instead. I didn’t.

Hi Dave! Was the built-in fan on the power supply spinning during the measurements when you got the 568mV noise reading? And was the power supply loaded in any way?

 

[Dave TR3A]

Hi Dave! Was the built-in fan on the power supply spinning during the measurements when you got the 568mV noise reading? And was the power supply loaded in any way?

If I recall correctly (it’s been a while), the fan was not running.

I don’t recall if the measurements (and screenshots from the scope) were taken unloaded or if they were connected to an 8 ohm dummy load. My hunch is that they were likely taken unloaded.

When I used the LRS-600-36 to power my three amps, I could hear a quiet but noticeable buzzing sound from my speakers when nothing was playing. The buzzing was most noticeable from my midrange driver (a 16 ohm Klipsch K-55 compression driver with K400 horn).

The buzzing disappeared when I replaced the Meanwell with the three original power bricks.

 

[john61ct]

I'm guessing the mistake was trying to run three amps off one PSU, rather than choosing the wrong Mean Well series

 

[Dave TR3A]

I'm guessing the mistake was trying to run three amps off one PSU, rather than choosing the wrong Mean Well series

No. The buzzing was present even when running just one of the amps.

 

[john61ct]

No. The buzzing was present even when running just one of the amps.

Do you mean only one of the amps was - directly - connected to the PSU?

 

[Masavanas]

Hi everyone, I'm new to the forum. I'm building a pair of 2-way OB speakers with 1 SB Nero-12MWN400D as the Mid-woofer (85-800Hz) and 1 ESS-AMT tweeter controlled by DSP + a sub with 2x15" already amplified by a Behringer. I listen to all kinds of music in a 30m2 asymmetrical room at medium volume 80-85 but I also don't mind going up. I'm undecided whether to use two A5 or two A7 ..or 1+1. Thanks in advance for any suggestions.

 

[RandomEar]

Hi everyone, I'm new to the forum. I'm building a pair of 2-way OB speakers with 1 SB Nero-12MWN400D as the Mid-woofer (85-800Hz) and 1 ESS-AMT tweeter controlled by DSP + a sub with 2x15" already amplified by a Behringer. I listen to all kinds of music in a 30m2 asymmetrical room at medium volume 80-85 but I also don't mind going up. I'm undecided whether to use two A5 or two A7 ..or 1+1. Thanks in advance for any suggestions.

I would get one A5 + one A7. Arguments:

• The tweeter doesn't require that much power, so one A5 for the tweeters will not result in any power limitation
• You save some money
• The noise floor of the A5 is even lower than that of the A7 (which is already very good), so with very sensitive tweeters in a nearfeld setup, it might make the difference between a tiny amount of tweeter hiss and no audible tweeter hiss at all

I would not get 2x A5 because the additional power of the A7 doesn't cost that much more and I would sleep better knowing that the woofer amp clips 3 dB higher (which, to be fair, isn't a lot)

 

[Roland68]

Hi everyone, I'm new to the forum. I'm building a pair of 2-way OB speakers with 1 SB Nero-12MWN400D as the Mid-woofer (85-800Hz) and 1 ESS-AMT tweeter controlled by DSP + a sub with 2x15" already amplified by a Behringer. I listen to all kinds of music in a 30m2 asymmetrical room at medium volume 80-85 but I also don't mind going up. I'm undecided whether to use two A5 or two A7 ..or 1+1. Thanks in advance for any suggestions.

I would get one A5 + one A7. Arguments:

• The tweeter doesn't require that much power, so one A5 for the tweeters will not result in any power limitation
• You save some money
• The noise floor of the A5 is even lower than that of the A7 (which is already very good), so with very sensitive tweeters in a nearfeld setup, it might make the difference between a tiny amount of tweeter hiss and no audible tweeter hiss at all

I would not get 2x A5 because the additional power of the A7 doesn't cost that much more and I would sleep better knowing that the woofer amp clips 3 dB higher (which, to be fair, isn't a lot)

With that sound pressure level and impedance, even the A5se or Topping Mini 300 would be more than sufficient and perhaps even the better choice.

The A7 is certainly a good choice for the midrange driver.

 

[Masavanas]

With that sound pressure level and impedance, even the A5se or Topping Mini 300 would be more than sufficient and perhaps even the better choice.

The A7 is certainly a good choice for the midrange driver.

I hadn't considered the Topping Mini300
I asked for information to clear up my doubts and instead the doubts increase... ..
Do you think that for ESSs, Mini300 is really more suitable?

 

[somebodyelse]

With that sound pressure level and impedance, even the A5se or Topping Mini 300 would be more than sufficient and perhaps even the better choice.

The A7 is certainly a good choice for the midrange driver.

Given the SB Nero-12MWN400D is nominally 8R with a minimum of 5.3R there's no reason not to go for the A7se instead of the A7.

 

[harkpabst]

Do you think that for ESSs, Mini300 is really more suitable?

No, it's not more suitable, but quite a bit cheaper. Performance will make no difference in this use case.