Apollon 1ET6525SA ST Amplifier Review

[pma]

Very nice results.

 

[Roland68]

((edit after @JSmith 's insides)) I would prefer the speaker wires to be soldered at binding posts.)

I would always prefer crimped cables with ferrules and screw terminals/binding posts, as this results in a significantly cleaner, better, more consistent, and lower-resistance connection than soldering. The same applies, of course, to speaker cables.

 

[daniboun]

@Apollon Audio congrats for the superb measurements. What is the opamp option installed on the DUT?

Default Op amps = 1656
Options :
+ $ 200 = Sonic imagery 994
+ $ 400 = Sparkos labs SS2590 pro

 

[daniboun]

Thanks for the testing and to the member for sending it to you, impressive results.

Pics;

View attachment 503325

View attachment 503326


JSmith

These are not the pictures of Apollon 1ET6525SA but Ncx500.... The Purifi 1ET6525SA have a red PCB )

 

[Jukka]

And doesn't change much in bass either:

Wait, what's this?! I've been eyeing for a quiet woofer/subwoofer amp, but this hints that many amps suck at low frequencies. Does your old reviews have this information in other charts?

 

[daniboun]

It was kindly loaned to me by a member and costs 1,190.00€ (USD $1,348).

Keep in my guys total price = 1497€ including Vat + shipment (see attached file) for Europe only and $ 2500 for USA !!!

US alternative = VTV @ $ 1150

VTV AMPLIFIER Stereo Purifi Audio 1ET-6525SA Amplifier | VTV Amplifier

 

[FraPia-62]

Thank you Amir for the review! I hope that pro audio companies are reading and taking note.

 

[boXem]

Default Op amps = 1656
Options :
+ $ 200 = Sonic imagery 994
+ $ 400 = Sparkos lavs SS2590 pro

These opamps have very different input noise levels, thus impact in a non neglectible manner (several dB) the measurements. Since they also impact the price from several dB, the info could be useful for the reader.
In addition that's an interesting benchmark for us.

 

[daniboun]

These opamps have very different input noise levels, thus impact in a non neglectible manner (several dB) the measurements. Since they also impact the price from several dB, the info could be useful for the reader.
In addition that's an interesting benchmark for us.

Right I agree. BTW I read an interview of Bruno Putzeys who recommended the 1612 and 1656 op-amps for the Purifi.

 

[JSmith]

These are not the pictures of Apollon 1ET6525SA

They are shown as older green PCB on the Apollon site;

Purifi Eigentakt 1ET6525SA ST Stereo Amplifier

The Apollon Audio Purifi 1ET6525SA Stereo Amplifier is built around the amazing Purifi 1ET6525SA amplifier module in a very compact and light weight design with amazing clarity and brutally linear sound.

apollonaudio.com

... but must be older pics taken with 2022 eval boards sent out before the red production models modules @Apollon Audio? Also seen here in older @Buckeye Amps thread;

Buckeye Amps: Purifi 1ET6525SA (the successor to the 1ET400A)

Option 2 for me. It is nice to be able to put monoblocks side-by-side on a shelf, and 11" is not too deep for most consoles or racks. How much space between amps would be needed if they are side-by-side? Hopefully still fit a 17" rack space.... There are no side vents so could put them right...

www.audiosciencereview.com

Buckeye Amps: Purifi 1ET6525SA (the successor to the 1ET400A)

I have been reading various places about buffers for the 1ET400A. One thing I came across is that the stock Hypex buffer that some builders use, does not have filtering to prevent noise from being picked up from other devices. I know that you are not using that buffer, though it just got me...

www.audiosciencereview.com

JSmith

 

[JensA]

Thanks @amirm for the review and @Apollon Audio for another great Purifi ET amp.

 

[huw]

@JSmith The pictures on the Buckeye Amps thread you posted are of Purifi 1ET400A modules (you can read this on the sticker). I think the thread title was changed later. The Apollon pictures are of NCx500 modules - the Hypex logo is visible on the PCBs.

 

[daniboun]

They are shown as older green PCB on the Apollon site;

Purifi Eigentakt 1ET6525SA ST Stereo Amplifier

The Apollon Audio Purifi 1ET6525SA Stereo Amplifier is built around the amazing Purifi 1ET6525SA amplifier module in a very compact and light weight design with amazing clarity and brutally linear sound.

apollonaudio.com

Zoom in amigo ))
See attached file

 

[delta76]

Default Op amps = 1656
Options :
+ $ 200 = Sonic imagery 994
+ $ 400 = Sparkos labs SS2590 pro

Should have named it Sonic imaginary. Will be ironic

 

[daniboun]

Should have named it Sonic imaginary. Will be ironic

Eternal debate debunked by Amir....

 

[JSmith]

@JSmith The pictures on the Buckeye Amps thread you posted are of Purifi 1ET400A modules (you can read this on the sticker). The I think the thread title was changed later.

Thanks, yeah I see that now after zooming in on a PC monitor.

The Apollon pictures are of NCx500 modules

Yes, I assumed must have been an eval board and posted from a mobile, unsure why @Apollon Audio is showing these on their site for the 1et6525sa-st model?

I gather the layout is the same, using;

JSmith

 

[Ropeburn]

Slow down, eh.

Amir, probably:

 

[daniboun]

why @Apollon Audio is showing these on their site for the 1et6525sa-st model?

Because they are lazy ) one picture for a few amps

 

[nothingman]

Am I missing something? This is supposed to be the successor to the 1ET400A but it’s down on power on that older model and on the newer 1ET6525SA spec?

E.g. NAD 298 1ET400A design: 187w into 8ohm, 345w into 4ohm

This unit: 158w 8ohm, 276w 4ohm, 367w 2ohm

1ET6525SA spec is 230/450/510w, respectively. Why is the Apollon so far off?

 

[phoenixdogfan]

Going on five years with my DIY Purifi. All it does is sit there, cool as a cucumber, and do its job. Flawlessly. I'm sure this one will do the same with a few added features like the gain variability and the 12v triggers. Very nice.

Btw, op amp rolling, especially op amp rolling with things like the Sparkos, actually tend to degrade measured performance. We've seen where Amir reviewed the original Eigentact with the stock Eval 1 buffer then reviewed the same 1ET400A based amp only with a premium buffer using the Sparkos as in a Nord amp, for example, only to see SINAD drop by 4-5 db. It's a tweak highly recommended by the like of Positive Feedback writers to impart a sense of "tubelike smoothness" to the overall sound. Nuff ced.

Thank you, Amir. You've really been prolific this week.