3e audio A7/A7 Mono Amplifier Review

[ziggurcat]

Welp, the A7 was ordered yesterday, and it has already shipped. Should arrive in a few weeks!

EDIT: One question I have is does this amp have a 12v trigger input? It's shown to have one in the introduction images, but the AliExpress stock images don't show it, and the maybe one photo of the back of the unit from a buyer doesn't indicate there is one. Also, I'm going through another A7 thread here, and I'm in the middle of some discussion about the auto on/off feature, and asking to have a 12v trigger put back in for the next production models. I also read somewhere else that there's a way to disable the auto on/off functionality?

The naming came up before in another thread ....

Thanks for that info. Not having seen that response from them, it was honestly the main reason why I was suspicious about the AliExpress page.

 

[Good Vibes]

Glad to see this reviews well, as I bought one off the back of the A5 review. There are some differences in releases I think. Mine came with 48v 5a GAN supply, it doesn't have the trigger and the auto on/off can be switched off, so not sure if this is the latest version, or mine is a later iteration. 3e look to still be developing this one on the fly. For UK buyers, I didn't like the Audiophonic's price @ £400 inc. VAT. FYI direct from 3e Audio store on Ali, it was £221 delivered and Royal Mail didn't ask me to pay any VAT. I think it's a good deal at that price, but obviously more hassle if you ever need to return it etc. Mine also runs pretty warm after a few hours.

I have been seriously considering buying either the A5 or A7 because of the great measured performance but also because of the trigger. Can anyone tell me if 3e has stopped production with the trigger input or is this something that must be requested?

Thank you.

 

[Crook]

My understanding is that there is no trigger, it is auto sense on/off, but from version 2 the sensitivity is reduced to prevent unwanted turn off issues. Auto function can also be turned of via front buttons (which I what I have done). I turn my equipment fully off when not in use and the A7 turns on when plug socket is activated. Their website is back up and running, I would contact them directly to clarify.

 

[Good Vibes]

My understanding is that there is no trigger, it is auto sense on/off, but from version 2 the sensitivity is reduced to prevent unwanted turn off issues. Auto function can also be turned of via front buttons (which I what I have done). I turn my equipment fully off when not in use and the A7 turns on when plug socket is activated. Their website is back up and running, I would contact them directly to clarify.

Ahh, ok so the trigger input is unnecessary then. I would be pairing with a WiiM Ultra so it would auto sense if it is activated then?

 

[Crook]

Ahh, ok so the trigger input is unnecessary then. I would be pairing with a WiiM Ultra so it would auto sense if it is activated then?

As I noted I have auto sense off, so I cannot comment on functionality, but this is from the manual:
Audio sensing threshold = RCA: 2mVrms; XLR/TRS: 4mVrms (1KHz, both channel drive)

 

[Good Vibes]

Thanks Crook, very helpful.

 

[anonyless]

As I noted I have auto sense off, so I cannot comment on functionality, but this is from the manual:
Audio sensing threshold = RCA: 2mVrms; XLR/TRS: 4mVrms (1KHz, both channel drive)

i'm pretty sure those numbers from the manual were not updated for the "newer" versions of the A5/7 - from the A5 review thread:


3eaudio said:
we had made some change base on user feedback and suggestion from ASR member, thanks again for all of your advice and help us keep improve.

• Auto power off time set to 20 mins
• Increase audio detection sensitivity RCA: 200uVrms; XLR: 400uVrms,this significantly meet some user listening in very very low volume.
• Auto audio sensing power on/off can be disable/enable by user.

 

[Crook]

i'm pretty sure those numbers from the manual were not updated for the "newer" versions of the A5/7 - from the A5 review thread:


3eaudio said:
we had made some change base on user feedback and suggestion from ASR member, thanks again for all of your advice and help us keep improve.

• Auto power off time set to 20 mins
• Increase audio detection sensitivity RCA: 200uVrms; XLR: 400uVrms,this significantly meet some user listening in very very low volume.
• Auto audio sensing power on/off can be disable/enable by user.

Thank you. I must have been sent a V1 manual with a V2 unit. That's not very good!

 

[anonyless]

Thank you. I must have been sent a V1 manual with a V2 unit. That's not very good!

how did you know to turn the "auto sense" off? (the default is on)
it's a newer feature that 3e added "on the fly", and doesn't appear in the manual I received or the PDF i downloaded from the website

point being, there is no "V2 manual"

 

[ziggurcat]

The only thing that's missing from this review is the graph showing the power on/off sequence like this:

How quiet is this amp when you power it on/off? It's not a deal breaker if there's some kind of audible pop/tick, I just want to know what to expect so there are no surprises.

 

[harkpabst]

Can anyone tell me if 3e has stopped production with the trigger input or is this something that must be requested?

3e Audio never produced any consumer units with 12 V trigger input. The review samples were pre-production models, which still had a trigger input, as it was originally considered. None of the amps shipped to customers ever had this and you cannot request it on order.

I would be pairing with a WiiM Ultra so it would auto sense if it is activated then?

This combination works fine with the first batch already unless you sit very close to your speakers or they are extremely sensitive or you want to listen at extremely low volumes. Not using the volume bypass switch and turning down the volume a little is the easy solution in these cases.

The amps produced since the second batch should allow even lower volume listening out of the box and with volume bypass enabled. Plus you can completely disable the auto standby.

 

[Good Vibes]

3e Audio never produced any consumer units with 12 V trigger input. The review samples were pre-production models, which still had a trigger input, as it was originally considered. None of the amps shipped to customers ever had this and you cannot request it on order.


This combination works fine with the first batch already unless you sit very close to your or they are extremely sensitive or you want to listen at extremely low voltages. Not using the volum bypass switch and turning down the volume knob a little is the easy solution in these cases.

The amps produced since the second batch should allow even lower volume listening out of the box and with volume bypass enabled.

Hi thanks for the reply, can I clarify what you mean when you say “unless you sit very close to your or they are extremely sensitive or you want to listen at extremely low voltages“

Seems like important information but unsure of what you mean. Is there an issue with volume and sensitive speakers?

 

[harkpabst]

Hi thanks for the reply, can I clarify what you mean when you say “unless you sit very close to your or they are extremely sensitive or you want to listen at extremely low voltages“

Seems like important information but unsure of what you mean. Is there an issue with volume and sensitive speakers?

Sorry, I corrected this mess of typos above. It was late and I was in a hurry to reply.

Some buyers of the first batch of the A5/A7 series amplifiers were not fully satisfied (with volume bypass enabled), because the auto standby would kick in after 5 minutes of listening at very low levels. If the Amps did not detect a signal above a certain threshold they would enter standby.

When used for a desktop system, you need very little power from the amp, so potentially the signal from your pre-amp/DAC/computer would be so low that auto standby judged it as "no signal".

Similar situation with extremely efficient speakers, or when just using the amps for the tweeter section in an active setup. Low input voltage, because low output power is required => amp might go into standby mode.

Personally, I have no problems with a first batch A5, listening at a distance of ~2.7 m with small 3" full range speakers and a sub with high pass and low pass filters set to 110 Hz. The high pass filtering of the main speakers also leads to a lower input voltage to the amp, as all the deep bass is handled by the subwoofer, but still no problem.

One workaround with the first batch was to not set the toggle switch on the back in the bypass position and to use the volume knob to reduce output. This way a higher input signal is required for the same output signal, so the amp is less prone to entering standby. Technically, it is not ideal to attenuate the input signal, just to amplify it again. You do lose some SNR.

So, from the second batch on, 3e Audio changed the sensitivity of auto-on/auto-standby, so the amps will only go into standby after 5 minutes of half the input voltage as before. This should eliminate the issue for most all use cases. For those cases where the amp might still go into standby because of a too weak signal (e.g. used for feeding the tweeters only behind an active crossover) they also introduced the possibility to turn of auto-on/auto-standby completely.

Hope it was more clear this time. Bottom line: There is no issue at all with the current production run (but there is still no trigger input).

 

[Good Vibes]

Ok I am with you now. Thanks for the info.

 

[Crook]

how did you know to turn the "auto sense" off? (the default is on)
it's a newer feature that 3e added "on the fly", and doesn't appear in the manual I received or the PDF i downloaded from the website

point being, there is no "V2 manual"

I asked them by email on AliX, as I made sure from them, that I had 2nd issue unit (with auto sense defeat) before I bought it.

 

[somebodyelse]

One workaround with the first batch was to not set the toggle switch on the back in the bypass position and to use the volume knob to reduce output. This way a higher input signal is required for the same output signal, so the amp is less prone to entering standby. Technically, it is not ideal to attenuate the input signal, just to amplify it again. You do lose some SNR.

In this situation the gain of the power stage is fixed, so it's just a choice of where to do the attenuation as it has to happen somewhere - in a pot at the amp, in the source (DAC, preamp, streamer or whatever), or a combination of both. The pot will attenuate noise from the source as well as signal, which might be an advantage if your source is a bit noisy. On the other hand pots may have a left/right mismatch, particularly with high attenuation. I'd go for a bit of both - set the pot so that with the source at maximum the volume is the loudest you want, then use the source's volume control to dial it back for everyday listening. If the source ever gets accidentally set to maximum it's still at a volume you would listen to rather than deafening (a common worry people have with using a DAC for volume control - not sure how often it happens in reality, but if it does you're covered.)

 

[Alannn]

...with small 3" full range speakers...

wtf?

 

[harkpabst]

wtf?

If you mind to elaborate some more I might be able to give you the required what the fuck lesson.

What's so unusual about 3" full range drivers in a TQWT enclosure?

 

[Alannn]

If you mind to elaborate some more I might be able to give you the required what the fuck lesson.

What's so unusual about 3" full range drivers in a TQWT enclosure?

My post was a somewhat vague question.
So more specifically, I wonder about the response in the 14,000 to 20,000 hz range with no tweeter.

 

[harkpabst]

My post was a somewhat vague question.
So more specifically, I wonder about the response in the 14,000 to 20,000 hz range with no tweeter.

Too vague for me to recognise the intent.
Dayton Audio RS100-4. They go easily up to 20k. Not as smooth as a dome tweeter. Higher directivity, too. But they measure and sound quite excellent (if they don't have to perform bass duties).

A WiiM Ultra plus 3e Audio A5 (the A5 se would also do) plus basically any subwoofer and these full range speakers make a highly enjoyable, low cost system.