3e Audio A5 Stereo Amplifier Review

[wkamil]

I'm slightly following on from your answer here, and a couple of questioners about the V3 Monos...
A 'half A7' would have one op amp (for output) in each unit. Audiophonics have an image which bears this out - just checked and pasted below.

I have always wondered about the two op amps Fosi use in each of the V3 Monos ...

And my question also slightly relates here too : better? Why have an extra op amp? Fewer for me would = better!


Does anyone have any thoughts on this?

What kind of goo is this? There is nothing like that in my copy, it is a clean PCB.

 

[honn]

I can't imagine trying to drive my F208's w/ the PA5-or this amp if I had it. Never hooked it up to them, knowing it wouldn't be able to drive them to adequate loudness levels (that I listen to).

F208 is an 8 ohm speaker with 88.5 dB sensitivity. Given one's listening distance and the desired dB at listening position, we can calculate the wattage required for the F208s. Let's say 3 meters/9.8 ft listening distance with 80 dB loudness and some 10 dB headroom accounted, you will only need 13 watts. So say you have a 50 W amp, that should be sufficient, in fact that's the minimum wattage that Revel prescribes. If you listen at 5 meters, you''d need 69 W, 10 meters away or over 32 feet, you'd only need 141 W.

Do you know the level of loudness you listen at your listening distance? I have been asking myself why I need Buckeye Hypex or Purifi amps that delivers 500-750 watts if I don't have a mansion and not listening like 10 meters from my speakers (honestly I wouldn't even if I have the space!).

 

[howard416]

Power consumption? I'm talking about power production. I guess I will have to hook the little bugger up and see if it produces smoke to make u guys happy.

I guess there's just no way to figure out power production from power consumption, huh.

If you really thought it wasn't doable, then just make a couple of custom cables where your banana plugs turn into a power plug, put that into a watt meter, and then power plug back to bananas. Run a 60 Hz sine wave into your amp, at a volume that you think is more than loud enough, and see what happens.

(sarcasm above)

 

[SMen]

View attachment 420356What kind of goo is this? There is nothing like that in my copy, it is a clean PCB.

Interesting observation ... perhaps just put there for the audiophonics (or other public) photos. That would answer a lot of the comments here about the counter productiveness of / lack of benefit to adding such stuff to production units (they didn't).

 

[Rottmannash]

Why are you posting off topic to this thread at all? Just to show that you own a PA5 and a Purifi amp and just because of that you know how inappropriate the A5 is in your environment?

No need to make "us guys" happy. Just comment meaningful stuff or ... don't post.

Excuse me? meaningful? Someone asked if this amp would power F208's. The amp in question has almost identical power to the Topping amp and powered by the same chip. I was answering his question in a rather off-handed way. Perhaps you should avoid trying to be the post-police.

 

[Rottmannash]

I guess there's just no way to figure out power production from power consumption, huh.

If you really thought it wasn't doable, then just make a couple of custom cables where your banana plugs turn into a power plug, put that into a watt meter, and then power plug back to bananas. Run a 60 Hz sine wave into your amp, at a volume that you think is more than loud enough, and see what happens.

(sarcasm above)

I've induced clipping on the Purifi amps so pretty sure this amp wouldn't compete. Enough off-topic.

 

[Ropeburn]

View attachment 420356What kind of goo is this? There is nothing like that in my copy, it is a clean PCB.

Would you be so kind and post pictures?

 

[harkpabst]

What kind of goo is this? There is nothing like that in my copy, it is a clean PCB.

Others have complained about this goo in enervating detail right in this thread, all judging from pictures. It's also visible in at least one Youtube review. Could be it was present only.on the pre-production and review samples.

F208 is an 8 ohm speaker with 88.5 dB sensitivity.

It's "nominally" 8 ohm (which is simply a false claim by the manufacturer), but dips clearly below 4 ohm in reality in the bass and in the highs. I had posted a link.to the Stereophile measurements above. Consequently, the 1 W/1 m sensitivity is 3 dB lower than claimed by Revel. This doesn't invalidate your calculations in any way if the amplifier can double its output power into 4 ohm like the A5 can.

In the end it all depends on listening distance, room size, average listening levels and headroom required for the type of music just as much as it depends on efficiency and power. There's absolutely no reason to believe that a 120 W/channel amp (with perfect power delivery into reactive loads) was generally and fundamentally inappropriate to drive speakers with 85 dB efficiency (with good-natured phase angle).

Excuse me? meaningful? Someone asked if this amp would power F208's. The amp in question has almost identical power to the Topping amp and powered by the same chip. I was answering his question in a rather off-handed way. Perhaps you should avoid trying to be the post-police.

Excuse me, but you provided no reference to that question at all. If you had e.g. cited the original poster the intention would have been clear.

Anyway, stating that you didn't bother trying a different amp which you assume to be similar to the A5 really provides only limited insight for the OP. Mentioning the Purifi amp clipping comes closer to being meaningful. If you could add which amp you are talking about, what your listening distance and room size are and so on ...

 

[Ropeburn]

I find it very hard to believe a (as I assume) 2x400-500W amplifier can be driven into clipping without destroying half the neighbourhood, and probably these Revels too which are very average speakers in terms of load and sensitivity. Outdoor Techno parties perhaps...

 

[Rottmannash]

I find it very hard to believe a (as I assume) 2x400-500W amplifier can be driven into clipping without destroying half the neighbourhood, and probably these Revels too which are very average speakers in terms of load and sensitivity. Outdoor Techno parties perhaps...

They are roughly 170 wpc per @amirm measurements. This was playing multichannel music w/ the clipping indicators flickering. And btw I did reply to another's post who was also trying to answer the question about driving the F208's w/ the 3e audio amp.

 

[obsessive9119]

They are roughly 170 wpc per @amirm measurements. This was playing multichannel music w/ the clipping indicators flickering. And btw I did reply to another's post who was also trying to answer the question about driving the F208's w/ the 3e audio amp.
View attachment 420438

MIght want to re-do that screenshot so we can't see some of your tabs and bookmarks.....

 

[Ropeburn]

MIght want to re-do that screenshot so we can't see some of your tabs and bookmarks.....

Tee hee hee

 

[Rottmannash]

open book

 

[obsessive9119]

open book

Some books are better left closed

 

[MusicLover2112]

The Purifis drive them well. Should I hook the PA5 up and let it strain? Nah. No point.

I own a Benchmark AHB2, which I use in my home theater to power the Monoprice THX-460T front speakers in my theater. They are rated at 4ohms 89.0dB. Perhaps the 3e A7se could power those, and I move my AHB2 to power the Revel F208?

 

[amirm]

They are rated at 4ohms 89.0dB.

Unless you see a real measurements of such, these numbers tend to be fantasies. You specifically want to see the sensitivity, i.e. frequency response in bass where you want the most power.

 

[kyuu]

Monoprice doesn't detail how they generate their measurements, at least as far as I'm aware, so whether or not they are "real" I do not know. But they do post measurements for at least some of their speakers, including the THX-460T:

 

[wkamil]

Would you be so kind and post pictures?

 

[MusicLover2112]

Unless you see a real measurements of such, these numbers tend to be fantasies. You specifically want to see the sensitivity, i.e. frequency response in bass where you want the most power.

Thanks for the explanation, Amir. My assumption is that the A7se will perform at least as good (probably better) than the internal amplifier of my Denon AVR-X3600H receiver for driving the Monoprice Monolith THX-460T speakers. Then I can move my Benchmark AHB2 to the Revel F208 speakers.

 

[harkpabst]

Thanks for the explanation, Amir. My assumption is that the A7se will perform at least as good (probably better) than the internal amplifier of my Denon AVR-X3600H receiver for driving the Monoprice Monolith THX-460T speakers. Then I can move my Benchmark AHB2 to the Revel F208 speakers.

According to the measurements shown by @kyuu you should actually not go with the A7se but with the A7 (or A5) instead. The A7se may be be better than your AVR, but it's not ideal for a 3 ohm speaker!

The A5 and A7 are stable and capable of dumping a decent amount of current into even 2 ohm reactive loads.

The frequency response doesn't tell us anything about the sensitivity since it doesn't contain any info about the voltage used (and the mic distance if we want to be pedantic).