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3e audio A7/A7 Mono Amplifier Review
- Thread starter amirm
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I got an email answer already from 3eaudio! That was quick! They answered in 4 minutes! The photos are from the pre-production unit, normal production unit has canceled that part. Thank you 3eaudio for the prompt response.
Roland68
Major Contributor
For both. These are specifications per channel, and the individual channels are the same for both devices.
So the only justification for extra cost of going 2x Mono is just the difference if any from shorter speaker wire runs?
Roland68
Major Contributor
The A7's amplifier is already a dual-mono design.
True mono amplifiers are originally intended to be placed near the speakers for slightly better channel separation.
Many people buy them because they think they look cool or that they're a good idea, or because of rumors or claims of improvements. The reasons don't matter; it's a personal decision.
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3eAudio user manual claims A7 vs A7 Mono, using balanced connections:
-20dB improvement in crosstalk (-110 vs -130)
+10Wpc @4ohms (250W vs 260W)
+10Wpc @8ohms (140W vs 150W)
which are indeed slight differences (improvements?) over the stereo version.
IMO, and as @Roland68 has mentioned above, they look cool.
They also have great specs across the board & I wanted the last ounce of power to drive vintage '87 Advent Maestros to nearly ear bleeding levels.
So far, so good.
I have yet to purchase the longer XLRs to place them near the speakers & shorten the speaker wire, so the jury is still out on that aspect.
PS: Love the website.
Keep on writing, y'all!
-20dB improvement in crosstalk (-110 vs -130)
+10Wpc @4ohms (250W vs 260W)
+10Wpc @8ohms (140W vs 150W)
which are indeed slight differences (improvements?) over the stereo version.
IMO, and as @Roland68 has mentioned above, they look cool.
They also have great specs across the board & I wanted the last ounce of power to drive vintage '87 Advent Maestros to nearly ear bleeding levels.
So far, so good.
I have yet to purchase the longer XLRs to place them near the speakers & shorten the speaker wire, so the jury is still out on that aspect.
PS: Love the website.
Keep on writing, y'all!
ziggurcat
Major Contributor
It's like that for mine as well -- purchased June 2025.
It looks like you got the answer to the mystery, though, with that component not being there because it was only on the pre-production model.
TurtlePaul
Major Contributor
I think that was where they had the daughterboard for a 12 volt trigger input. This didn’t make it to final production.
TheHighContemplator
Active Member
I got a pair of Monos simply because I've always wanted monoblock amplifiers - That's it. Get the stereo version for all other reasons.
Roland68
Major Contributor
The cooling system in the A7 is already perfectly adequate.
The problem with the TPA325x amplifiers is the maximum heat dissipation capacity of the small IC surface area. This is much lower than the cooling capacity of the A7. This is also the actual limiting factor for the maximum continuous power output of the TPA325x. Only a compressor or nitrogen cooling system would remedy this.
Therefore, there is no advantage to the A7 Mono in this regard. It might run slightly cooler at lower power levels, but that doesn't necessarily mean it's better.
Wouldn't a quiet fan mod do the job?
I suppose a minor factor in 2x Mono vs stereo, is that the included 5A PSUs should be enough even for those desiring every bit of possible SPL at 48V?
Paying over $80 usd for the 10A stings IMO, even more for GaN. I generally do not trust Ali generic for these.
Going to 52V seems to require an adjustable bench supply, even more costly, but nice flexibility only go high when needed.
I suppose a minor factor in 2x Mono vs stereo, is that the included 5A PSUs should be enough even for those desiring every bit of possible SPL at 48V?
Paying over $80 usd for the 10A stings IMO, even more for GaN. I generally do not trust Ali generic for these.
Going to 52V seems to require an adjustable bench supply, even more costly, but nice flexibility only go high when needed.
Roland68
Major Contributor
A fan is completely unnecessary and makes no difference.
Mean Well, and other manufacturers of industrial power supplies, offer plenty of proven 48-volt power supplies that can be fine-tuned to approximately 44-55 volts, at least to 52 volts. Examples include the HRP, HRPG, HRP N3, LRS, etc. These power supplies are affordable, meet worldwide safety standards, have passed all laboratory and long-term tests, and it would be difficult to find equivalent or better options. I've been using them for over 10 years.
Bleib
Major Contributor
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Yes, that's what I'm saying. But I dunno, maybe for some mods or something makes sense. I guess it depends where they place 'em and where they live.
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.
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.
TurtlePaul
Major Contributor
How does it drive one amp? Texas Instruments recommends that multiple TPA-based chip amps cannot be driven off a single power supply unless their clocks are synced.
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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.
Roland68
Major Contributor
It's a shame you had problems with your LRS power supply.
I had two LRS power supplies connected to TPA3255 amplifiers, and they were completely silent. We even briefly measured them to see if developing an additional filter would be worthwhile, but it wasn't necessary.
Did you ever try connecting just a single amplifier?
Of course, there can always be outliers or defective units, but that shouldn't happen with Mean Well.
However, you have to be careful when buying to avoid counterfeit products. The LRS series, in particular, has been affected by this for years, and they are often visually indistinguishable from the originals. Unfortunately, these counterfeit units keep popping up on well-known online marketplaces.
Personally, I only use HRP/G/N3 power supplies because their much higher current delivery capability makes them ideal for audio amplifiers.
TurtlePaul
Major Contributor
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