3e Audio A5 Stereo Amplifier Review

[anonyless]

A quick question for the owners - do you hear a quiet tick from speakers (not a pop at all) when the amplifier is manually turned on/off using the knob? I hear this tick a couple of moments after the relay engages/disengages only if I am in very close proximity to the tweeter. Did not even notice it for the first couple of days at all when the amp comes in/out the auto standby mode. I am using mine in RCA out, low gain, volume bypass engaged.

i hardly turn on/off the A5 manually using the knob, so i just tested this and couldn't hear a tick - only the a5's relay. but the speakers it's connected right now are not very sensitive

 

[ziggurcat]

A quick question for the owners - do you hear a quiet tick from speakers (not a pop at all) when the amplifier is manually turned on/off using the knob? I hear this tick a couple of moments after the relay engages/disengages only if I am in very close proximity to the tweeter. Did not even notice it for the first couple of days at all when the amp comes in/out the auto standby mode. I am using mine in RCA out, low gain, volume bypass engaged.

I have an A7, and there is a slight tick/pop from the speaker when the amp is turned off/put into standby mode. It's normal behaviour as far as I'm concerned (my PA5 II is the same, and it was a little louder in that regard vs. my A7, and I hear the same tick/pop when I shut down/power on my main HT), and also noted in the review:

I don't think it's anything to be concerned about, and it's certainly not going to do anything to damage your gear/speakers.

 

[bboris77]

i hardly turn on/off the A5 manually using the knob, so i just tested this and couldn't hear a tick - only the a5's relay. but the speakers it's connected right now are not very sensitive

Here are some more details. It is very faint and it occurs almost half a second after the second relay click on power up. On the power down it is instantaneous. The power up tick is quieter than power down, and it corresponds to @amirm measurements. The sound comes more from the woofer than the tweeter.

I am using the amp with Elac DBR62 which are 86dB. This is more for picky people like me to know what to expect and not worry unnecessarily

 

[Panelhead]

Bboris77,
Check dc voltage on outputs while powered up. The output relay may be a crowbar and short the speakers when opened.

 

[Panelhead]

Bboris77,
Check dc voltage on outputs while powered up. The output relay may be a crowbar and short the speakers when opened.

 

[bboris77]

Bboris77,
Check dc voltage on outputs while powered up. The output relay may be a crowbar and short the speakers when opened.

DC Voltage Offset on the speaker outputs is actually very good on both sides, around 10mV. In the meantime, I got a response from 3e Audio explaining that this subtle click audible through speakers is perfectly normal:

"Good day and thanks for reaching us, this is normal as there is a very small DC offset voltage on the chip itself(you can also refer to the datasheet in detail), so a smaller click noise during on and off is absolutely normal, nothing to worry about and hope you will enjoy our product."

They literally responded within an hour and immediately knew what I was talking about. Pretty impressive.

 

[bboris77]

Just to follow-up: I have decided to upgrade to the A7 after discovering that the TPA3251 chip in the A5 does not have DC Speaker Protection enabled when used in PBTL or SE mode. According to the datasheet for the TP3251, this chip only has DC Speaker Protection when used in BTL mode and is disabled in PTBL and SE modes. Both the A5 and the A7 use their respective TPA chips in PBTL mode.

On the other hand, the datasheet for the TPA3255, the chip used in the A7, says that DC Speaker Protection is only disabled in SE mode and works in PBTL or BTL modes. This is what made me bite the bullet and upgrade to the A7 as I have had some unpleasant experiences with PA5 II DC offset and prefer having an additional layer of protection.

This post is more for people who are debating between the two models and think (like I did) that the only difference is in their power output. It appears that the A7 offers some additional features like DC Speaker Protection. This is not meant in any way to criticize the A5 which is a fantastic sounding and well-made amplifier.

 

[harkpabst]

On the other hand, the datasheet for the TPA3255, the chip used in the A7, says that DC Speaker Protection is only disabled in SE mode and works in PBTL or BTL modes. This is what made me bite the bullet and upgrade to the A7 as I have had some unpleasant experiences with PA5 II DC offset and prefer having an additional layer of protection.

Good catch regarding the description given in the data sheets.

There are no technical details given, though. Did you notice that TI only mention this protection to be effective regarding an external error condition ("one terminal of the speaker is connected to the amplifier while the other is accidentally shorted to the chassis ground")? It doesn't mention any failure of the chip itself.

These data sheets have not been updated in roughly 8 years. I don't say it is, but this could also be a documentation error. I wonder if @3eaudio could shed some light on this documented difference.

 

[Punchy_Power_Cat]

This is what made me bite the bullet and upgrade to the A7 as I have had some unpleasant experiences with PA5 II DC offset

If this is true another reason to upgrade to a better quality power supply, isn't it?

 

[harkpabst]

If this is true another reason to upgrade to a better quality power supply, isn't it?

Is it? How can a DC power supply be responsible for higher (or lower) DC on the speaker output? Which parameters would make one PSU better than the other regarding DC offset?

 

[Punchy_Power_Cat]

It's getting interesting.

I have a small refrigerator standing in about 78inch/2m distance to the A5 amp and about 20inch/50cm distance to the left speaker. Whenever the compressor turns off I get a notable but not very loud "pop" in what I believe to be both speakers. This happend while the amp was on with both plugs (amp and fridge) plugged into the same outlet. It does not seem to happen when the A5 is in off/standby mode.

Why do I believe this to be an issue related to the A5? Because it didn't occur with the previous amp which was running off a Mean Well Medical PSU of the RPS-Series. The old amp was also cured from a very small shut-off-pop with this PSU. So this means the PSU is passing through voltage/current it shouldn't be passing through, even if it's small. Or am I reading it wrong?

 

[bboris77]

It's getting interesting.

I have a small refrigerator standing in about 78inch/2m distance to the A5 amp and about 20inch/50cm distance to the left speaker. Whenever the compressor turns off I get a notable but not very loud "pop" in what I believe to be both speakers. This happend while the amp was on with both plugs (amp and fridge) plugged into the same outlet. It does not seem to happen when the A5 is in off/standby mode.

Why do I believe this to be an issue related to the A5? Because it didn't occur with the previous amp which was running off a Mean Well Medical PSU of the RPS-Series. The old amp was also cured from a very small shut-off-pop with this PSU.

Yea, this is not great. I somehow have a feeling that these Class D amps are for us enthusiasts only to help the companies work out all the kinks. My Yamaha Class A/B receivers and amplifiers have been pretty much 100% free of all of these kinds bizarre events.

 

[Punchy_Power_Cat]

Yea, this is not great.

I don't think this is the amps fault, rather the PSUs passing through leakage- or outrush currents from the mains induced by the compressor turning off (it's a small 100W compressor after all, imagine I'd put a big one into the same outlet). With a better/medical PSU I suppose it can be fixed. Since I wanted to install a 36V Mean Well PSU anyways, I will report on it in a few weeks. Currently looking into a LOP-200-36 for excellent rising times and medical certification.

 

[Raiju]

I got the A5 today and I feel like I am hallucinating, it sounds so different from the Fosi Za3. How is that possible?

 

[somebodyelse]

I got the A5 today and I feel like I am hallucinating, it sounds so different from the Fosi Za3. How is that possible?

The ZA3 has load dependent frequency response, so if you've got a speaker with large impedance swings it could be that you're hearing. Or it could be the usual problem with sighted comparison and lack of volume matching.

 

[Raiju]

The ZA3 has load dependent frequency response, so if you've got a speaker with large impedance swings it could be that you're hearing. Or it could be the usual problem with sighted comparison and lack of volume matching.

I do not think it is load dependent frequency response, I compared both the curve of the Za3 and speaker, and maybe there is tenths of dB rise in the upper range. That is not what I am hearing, the Za3 sounds harsher, the A5 is tight, more detailed, harmonic and very easy on the ears. I was thinking the following, yes I had to crank the preamp up to match same volume level, that could have something to do with it since digital volume control alters sound quality? Or maybe it is the bypass the A5 has, but I doubt that could make that much of a difference. Really I am puzzled and even thought of different op-amps used in the amps but that should not be possible either. First I hear such a noticeable difference between amps.

 

[harkpabst]

I do not think it is load dependent frequency response, I compared both the curve of the Za3 and speaker, and maybe there is tenths of dB rise in the upper range. That is not what I am hearing, the Za3 sounds harsher, the A5 is tight, more detailed, harmonic and very easy on the ears. I was thinking the following, yes I had to crank the preamp up to match same volume level, that could have something to do with it since digital volume control alters sound quality? Or maybe it is the bypass the A5 has, but I doubt that could make that much of a difference. Really I am puzzled and even thought of different op-amps used in the amps but that should not be possible either. First I hear such a noticeable difference between amps.

Or it could be the usual problem with sighted comparison and lack of volume matching, to quote a wise man.

Having said that, the 3E AUDIO A5 is technically the better product, no doubt, so there's no reason to be over critical with your perception. Whatever it is you prefer, you're certainly not wrong.

 

[Birdy]

I got the A5 today and I feel like I am hallucinating, it sounds so different from the Fosi Za3. How is that possible?

I had the same when i went from my Aiyima A07 to the Douk A5. The 07 is load dependent but my planar tweeter is a flat 8 ohm load, so that can not explain all of it. In general the sound sounds more clean, open and even at higher volume it sounds great, an indication of less distortion. It was more of an "upgrade" then expected. A good surprise! After a few months i have the impression i could not go better then this, the HP filter is a game changer to reduce distortion.

 

[Jimster480]

I do not think it is load dependent frequency response, I compared both the curve of the Za3 and speaker, and maybe there is tenths of dB rise in the upper range. That is not what I am hearing, the Za3 sounds harsher, the A5 is tight, more detailed, harmonic and very easy on the ears. I was thinking the following, yes I had to crank the preamp up to match same volume level, that could have something to do with it since digital volume control alters sound quality? Or maybe it is the bypass the A5 has, but I doubt that could make that much of a difference. Really I am puzzled and even thought of different op-amps used in the amps but that should not be possible either. First I hear such a noticeable difference between amps.

Well the ZA3 is worse all around, so between the lower IMD scores to the higher frequency dependence to the volume control dependence... ZA3 has much worse scores. If you can test both side by side; try to play some tracks you are very familiar with and switch back and forth and try to hear where there is a difference if you want to better understand (and try to confirm) what you are hearing. If you have just only plugged in the new amp without really testing the old one side by side; then the differences are likely more sighted bias then anything else. You can "think" you are hearing things you aren't really hearing, which is why side by side comparisons are important.

 

[somebodyelse]

Not just side by side, but with controls like level matching etc. otherwise it could still be your brain playing tricks on you - which just means you're human.