Apollon 1ET6525SA ST Amplifier Review

[Fletcher Munson]

Edit to the last message

This thing is great, dead silent on the highest gain settings and takes control of my huge B&W Matrix 800 with frightening ease. Its the best i've ever heard these speakers. Its going to be a long time before anything beats this class of amplifiers IMO

 

[David_M]

Edit to the last message

This thing is great, dead silent on the highest gain settings and takes control of my huge B&W Matrix 800 with frightening ease. Its the best i've ever heard these speakers. Its going to be a long time before anything beats this class of amplifiers IMO

Dead silent, when ears are pegged to the tweeters or from your listening position?

 

[Fletcher Munson]

Dead silent, when ears are pegged to the tweeters or from your listening position?

Dead silent, ear on tweeter

 

[ChrisJJ]

Hi
New in this forum.
Could I expect the same-ish performance from a pair af Apollon Audio Purifi Eigentakt 1ET6525SA M amp?
Thanks.

 

[David_M]

Hi
New in this forum.
Could I expect the same-ish performance from a pair af Apollon Audio Purifi Eigentakt 1ET6525SA M amp?
Thanks.

If the monoblock uses the same stereo buffer (I doubt it), then yes. If they use an optimized mono buffer, then it's possible it could perform better (maybe ).

 

[Oniiz86]

Dead silent, ear on tweeter

@Fletcher Munson That's an impressive feat on the highest gain setting, seeing how the B&W Matrix 800s are fairly sensitive at 93dB. I have March Audio's P482 1ET6525SA based amp & on the highest Gain setting of 27dB, I have moderate hiss coming from my Klipsch RF-7 IIIs when I put my ear to the Horn Compression Drivers, I guess it may be the source of the upstream component, my Denon X8500H AVR, although there was never any hiss at all when the AVR's internal amps were connected to my RF-7 IIIs.

 

[Fletcher Munson]

@Fletcher Munson That's an impressive feat on the highest gain setting, seeing how the B&W Matrix 800s are fairly sensitive at 93dB. I have March Audio's P482 1ET6525SA based amp & on the highest Gain setting of 27dB & I have moderate hiss coming from my Klipsch RF-7 IIIs when I put my ear to the Horn Compression Drivers, I guess it may be the source of the upstream component, my Denon X8500H AVR, although there was never any hiss at all when the AVR's internal amps were connected to my RF-7 IIIs.

upstream i have a Fosi ZH3 as a pre amp and a wiim pro plus feeding optical to that. all very quiet

 

[Oniiz86]

upstream i have a Fosi ZH3 as a pre amp and a wiim pro plus feeding optical to that. all very quiet

So you are using the Gain setting at 29dB, that seems awfully high for these Purifi amps although your typical D+M AVR is around 29dB?

 

[Fletcher Munson]

So you are using the Gain setting at 29dB, that seems awfully high for these Purifi amps although your typical D+M AVR is around 29dB?

Yes because I'm only running unbalanced until i get some more neutrik xlrs delivered then it will be balanced and thus a higher voltage. i can get it up to 70% or a bit more on the pre-amp at the moment. 50% for normal. i like to have a bit of headroom ))

Oh and remember my tweeters are over 30 years old and the Matrix 800 are 4ohm nominal and B&W claim they drop to 3 Ohms

 

[harkpabst]

So you are using the Gain setting at 29dB, that seems awfully high for these Purifi amps although your typical D+M AVR is around 29dB?

The Purifi 1ET6525SA modules themselves have fixed gain of 12.3 dB. Doesn't that mean that any additional (and switchable) gain is provided by the input buffer board. As long as the input buffer is of sufficiently high quality the 1ET6525SA are perfect for high gain settings as they add almost no noise

i can get it up to 70% or a bit more on the pre-amp at the moment. 50% for normal. i like to have a bit of headroom ))

Technically, t's not really amplifier headroom you get from that setup, but flexibility with low level sources (like with old digital resources). I guess that's what you ment.

 

[Oniiz86]

The Purifi 1ET6525SA modules themselves have fixed gain of 12.3 dB. Doesn't that mean that any additional (and switchable) gain is provided by the input buffer board. As long as the input buffer is of sufficiently high quality the 1ET6525SA are perfect for high gain settings as they add almost no noise

Yes I know, I meant the Apollon amp as a whole, its input buffer provides a fair bit of flexibility with its Gain settings & yes you're correct the high Gain settings will be fine not impacting anything negatively, well nothing audible.

 

[Fletcher Munson]

The Purifi 1ET6525SA modules themselves have fixed gain of 12.3 dB. Doesn't that mean that any additional (and switchable) gain is provided by the input buffer board. As long as the input buffer is of sufficiently high quality the 1ET6525SA are perfect for high gain settings as they add almost no noise


Technically, t's not really amplifier headroom you get from that setup, but flexibility with low level sources (like with old digital resources). I guess that's what you ment.

I knew as i was typing it someone would question the use of the word lol. In this case I meant headroom that enables me to play stupid high levels without getting out of my seat, turning the amp off turning it round and fiddling with two tiny switches. Pendant.

 

[Fletcher Munson]

The Purifi 1ET6525SA modules themselves have fixed gain of 12.3 dB. Doesn't that mean that any additional (and switchable) gain is provided by the input buffer board. As long as the input buffer is of sufficiently high quality the 1ET6525SA are perfect for high gain settings as they add almost no noise


Technically, t's not really amplifier headroom you get from that setup, but flexibility with low level sources (like with old digital resources). I guess that's what you ment.

That would be meant Technically

 

[harkpabst]

Pendant.

I take that as a compliment.

 

[MicroAudio]

Micro Audio power supplies, like most SMPS solutions used in high-power audio amplifiers, do not employ tightly regulated high-voltage rails for the output stage. Instead, they provide an unregulated (or loosely regulated) high-voltage DC bus whose voltage varies with mains input voltage and load conditions.

@Apollon Audio

What is your evidence that the Micro Audio SMPS output voltage varies with mains input voltage?

The SMPS1K-PFCR2 for example gives you fixed output voltage at any AC input voltage, from 85VAC ~ 265VAC.

Another example. SMPS1K-PFCR2 output voltage +-65VDC and it will remain +-65VDC at any AC input voltage. NO LOAD.
With 7.5V drop at 1200W. 3.75V drop per rail and that gives you +-61.25V.

The SMPS1K-SN drops 6V at 1800W.

The HYPEX SMPS1200 output voltage will vary based on the AC input voltage. and the output voltage is NOT regulated at all.
Its all shown in the HYPEX SMPS1200 datasheet.

Its disappointing to see big OEM like you publishing unsupported claims about my products.

Really disappointing.

Thanks

 

[Apollon Audio]

@Apollon Audio

What is your evidence that the Micro Audio SMPS output voltage varies with mains input voltage?

The SMPS1K-PFCR2 for example gives you fixed output voltage at any AC input voltage, from 85VAC ~ 265VAC.

Another example. SMPS1K-PFCR2 output voltage +-65VDC and it will remain +-65VDC at any AC input voltage. NO LOAD.
With 7.5V drop at 1200W. 3.75V drop per rail and that gives you +-61.25V.

The SMPS1K-SN drops 6V at 1800W.

The HYPEX SMPS1200 output voltage will vary based on the AC input voltage. and the output voltage is NOT regulated at all.
Its all shown in the HYPEX SMPS1200 datasheet.

Its disappointing to see big OEM like you publishing unsupported claims about my products.

Really disappointing.

Thanks

Thank you for the clarification and for detailing the behavior of your SMPS units. I want to clarify both my assumption and my wording.

At the time of writing, I was under the impression that your supplies did not employ mains-regulated high-voltage rails, and that the output voltage would vary with AC input voltage. Based on the information you’ve provided, that assumption was incorrect for your designs, and I’m sorry for that incorrect assumption.

My broader comment that all SMPS exhibit some output variation was meant in the general engineering sense, namely that no high-power SMPS behaves as an ideal, load-invariant voltage source under all operating conditions. Even when regulated against mains variation, practical designs allow predictable voltage droop under high load, as reflected in the figures you quoted.

I should not have attributed mains-dependent voltage variation to your products specifically, and I appreciate you taking the time to clarify this with concrete data.

My reference to the Hypex SMPS1200 was intended only to contrast a different, documented regulation strategy, not as criticism of your engineering choices.

I respect the engineering behind your designs and have no intention of publishing misleading or unsupported claims.

 

[Fletcher Munson]

Well xlrs turned up, made some cables, turned the gain down to the lowest setting and placebo be damed it sounds better haha. Yeah I know. The magic of knowing the gain structure is correct

 

[mrehorst]

Question for anyone who knows: do they put some special input circuit on the switch mode power supply in these amps to minimize the inrush current?

I have a device that uses a LRS-350-24 MeanWell switcher (350W) for power and the spec on that supply is for 60A inrush. I used a 6A rated switch for it and about the 5th time I switched it on the contacts welded together in the 'on' position. I have since added a NTC thermistor and timed relay that shorts it out after 3 seconds to limit the inrush current seen by the power switch. My thermal camera reports that the thermistor gets up to about 10C over ambient in the 3 seconds that it's in the circuit.

 

[NTK]

Question for anyone who knows: do they put some special input circuit on the switch mode power supply in these amps to minimize the inrush current?

I have a device that uses a LRS-350-24 MeanWell switcher (350W) for power and the spec on that supply is for 60A inrush. I used a 6A rated switch for it and about the 5th time I switched it on the contacts welded together in the 'on' position. I have since added a NTC thermistor and timed relay that shorts it out after 3 seconds to limit the inrush current seen by the power switch. My thermal camera reports that the thermistor gets up to about 10C over ambient in the 3 seconds that it's in the circuit.

This amplifier uses Hypex SMPS1200 power supplies, and has an in-rush current spec of 37 A max. The SMPS has a 12 A slow blow fuse (i.e. over-current protection of 12 A), and therefore components in the AC supply should be rated for at least 12 A continuous.

 

[Fletcher Munson]

Ok it’s been a few days, sorted out the gain structure and this amplifiers amazing. My first foray into Purifi and Apollon amplifiers. The sound is noticeably better on both my kef concerto and B&W matrix 800. It really feels like the drivers are under strict control. The lower the sensitivity speaker I try the more it’s obvious. Highly recommended