Three very different amps. Which to choose?

[terryforsythe]

I dont have room for a sub bigger that 12" on th left.

So, do I get one larger sub on the right 15-18" or two 12" subs?

Are you going to be listening from a single position or over a wide area? I got a fairly decent response with my single 26 year old 18" subwoofer at the listening position, but as others have said multiple subs probably are better over a wide area. In that regard, I have seen recommendations to use at least three subwoofers spaced around the room, and at different heights, to achieve the best results. Anyway, here is what I got with my single subwoofer at my listening position, tuned to the Harman Curve:

 

[YSDR]

View attachment 361793

The question is, can the F208 withstand 322W (or 350W according to the factory data) even in the short term?

The answer is:

According to the Unibox simulation (with passive filters, like the F208 have) of 2x SB23NBACS45-8, it's not. More precisely it depends on the frequency as we can see, but that just the mechanical part of the story. The red line is the mathematical linear excursion of the woofers, the mechanical excursion limit of a typical hifi woofer usually didn't extend to 2x of the xmax so there is a possibility that even with 120W input (the combined rated power handling of 2 pieces of SB23NBACS45-8) , the voice coils of the woofers would hit the pole piece or jump out of the gap. Unfortunately there is no data for the mechanical limits of this woofer, but if it's not a typical woofer, they may can survive 120 of low frequency input Watts at and above the vent tuning frequency in the F208.
In real world, there is another possible scenario, where the woofers don't want to move further (because of force factor loss or suspension stiffening caused by the large excursion), so the voice coil don't hit the pole piece and will survive (if didn't burnt down already), but that would lead to high distortion and several dB compression.

 

[Blumlein 88]

The question is, can the F208 withstand 322W (or 350W according to the factory data) even in the short term?

The answer is:
View attachment 361927View attachment 361928
According to the Unibox simulation (with passive filters, like the F208 have) of 2x SB23NBACS45-8, it's not. More precisely it depends on the frequency as we can see, but that just the mechanical part of the story. The red line is the mathematical linear excursion of the woofers, the mechanical excursion limit of a typical hifi woofer usually didn't extend to 2x of the xmax so there is a possibility that even with 120W input (the combined rated power handling of 2 pieces of SB23NBACS45-8) , the voice coils of the woofers would hit the pole piece or jump out of the gap. Unfortunately there is no data for the mechanical limits of this woofer, but if it's not a typical woofer, they may can survive 120 of low frequency input Watts at and above the vent tuning frequency in the F208.
In real world, there is another possible scenario, where the woofers don't want to move further (because of force factor loss or suspension stiffening caused by the large excursion), so the voice coil don't hit the pole piece and will survive (if didn't burnt down already), but that would lead to high distortion and several dB compression.

Well I have a 250 wpc @ 8 ohm amp on mine and at the lower impedance it would be over 500 wpc. Mine haven't blown the woofers out yet. So they get loud enough I've not turned it up enough to blow anything up.

 

[Chrispy]

The question is, can the F208 withstand 322W (or 350W according to the factory data) even in the short term?

The answer is:
View attachment 361927View attachment 361928
According to the Unibox simulation (with passive filters, like the F208 have) of 2x SB23NBACS45-8, it's not. More precisely it depends on the frequency as we can see, but that just the mechanical part of the story. The red line is the mathematical linear excursion of the woofers, the mechanical excursion limit of a typical hifi woofer usually didn't extend to 2x of the xmax so there is a possibility that even with 120W input (the combined rated power handling of 2 pieces of SB23NBACS45-8) , the voice coils of the woofers would hit the pole piece or jump out of the gap. Unfortunately there is no data for the mechanical limits of this woofer, but if it's not a typical woofer, they may can survive 120 of low frequency input Watts at and above the vent tuning frequency in the F208.
In real world, there is another possible scenario, where the woofers don't want to move further (because of force factor loss or suspension stiffening caused by the large excursion), so the voice coil don't hit the pole piece and will survive (if didn't burnt down already), but that would lead to high distortion and several dB compression.

Would you expect anyone to be putting that much continuous power into such speakers in the first place?

 

[YSDR]

Would you expect anyone to be putting that much continuous power into such speakers in the first place?

Not necessarily, but we can never know. Like a previous poster showed us the calculation result of 322 Watts for this speaker. Why?

 

[Worth Davis]

I dont have room for a sub bigger that 12" on th left.

So, do I get one larger sub on the right 15-18" or two 12" subs?

I prefer dual subs, 2 12s

 

[eboleyn]

Hi,

I have done a good bit of research over the past 6 weeks - on-line reviews, forums, YouTube videos, etc. Opinions are all over the place and I am having a hard time deciding on a new amp to power Revel F208 speakers, with possible future speaker upgrade. (large room 20x30 20' ceilings). I have gotten a lot of great advice and gained knowledge during the process, however, some of it is conflicting.

I've managed to narrow it down to three amps and I'm going to throw it out there to hopefully recieve your direct comparative feedback and insight.

Which do you like and why? They are all highly respected and reviewed, but differ in approach to audio fidelity.

I've got a serious case of analysis paralysis , but expect to pull the trigger within a couple weeks. I hoping for a keeper for the next 15-20 years.

Pass Labs X250.8

X250.8 - Pass Labs

This stereo class A/B model represents a step up in power and performance from the X150.8 and, like all of our products, has been painstakingly designed, tweaked, redesigned and fine-tuned to deliver maximum musical enjoyment. This hard work and creativity … Continue reading →

www.passlabs.com

Quicksilver KT Mono

KT Mono Amplifier – Quicksilver Audio

quicksilveraudio.com

Apollon PET1200

Purifi 1ET9040BA Eigentakt Dual Mono Premium Amplifier PET1200DM

Experience power and detail: Presenting the Purifi 1ET9040BA Based Dual Mono Amplifier the Apollon PET1200 Premium. Perfect for studio and audiophile speakers.

apollonaudio.com

OK, this is an old thread, and I read many of the responses here ... my take is a bit different.

Short answer:

If you want "accurate" sound reproduction, then indeed the ASR-focused suggestions on here are by far your best bet for the $$$($?$?) you'd spend. Having owned (and still owning for the heck of it) a Pass Labs X250.8, it certainly drives absolutely any passive speakers excellently and subjectively sounds great, BUT the modern Hypex and Purifi amps (which I also have) are going to clearly beat it on accuracy for nearly any load, and also subjectively sounds great.

Somewhat longer answer:

If you're trying for that elusive ... "it sounds Magical" thing that so many audiophiles claim for various gear they've tried where "musical distortion" is present ... I'm going to be generous and say that maybe there is something to it (some occasional double-blind tests of different equipment with golden-eared audiophiles suggests there is at least some truth to the claim for some people) ... then as many have stated in this thread (not always politely, sigh), there are no good objective criteria for it, and I'd go so far as to say sadly that the industry has gone out of its way to sabotage performing objective evaluations.

Would you enjoy the sound of one of those expensive not-so-great measuring amps? Maybe ... I'd even go so far as to say "Probably".

Would it be worth the difference in price and trouble for you? I have no idea, though clearly for many in this thread the answer was a resounding NO. It is certainly a lot of trouble and money for dubious gain if you don't already know what you want about it.

EDIT ADDITION:

To be clear: I know enough people who claim the "it sounds Magical" is OF COURSE true, and have subjectively seemed to hear it a few times myself under certain rare conditions ... so that I'm curious enough about it to want to chase that a bit myself as an adjunct to my main audio hobby. So along those lines I have some "it sounds Magical" amps and preamps that I've been occasionally experimenting with, both subjectively and with measurements.

Having said the above, my main listening setups are "high accuracy" setups with CD or better digital sources, DSP bi-amping, Purifi amps, and speakers built with drivers like Purifi and RAAL ribbons, all of which is overkill but I wanted any inaccuracies to be well outside the realm of human hearing.

My ideal goal would be, if something consistent is found that "salts" the music in a way that (at least my human ear) enjoys, I would then create processing filters to add it in when desired on the accurate setup.

 

[atomek]

I owned a Pass INT-150 for a couple of months — long enough for me to never consider Pass amps again. They distort the sound so much that I could identify their "signature" I think with any speaker today, to me was like a kind of "glare" on the sound. It's all subjective: some people might call it "magical", but I found it unpleasant. That was years ago, when I tested a couple of other amplifiers (NAD M2, Krell and a tube amp), and finally a Lyngdorf (the mk2 at the time; later on, I upgraded to the mk4). Oh my what a difference that was! I rediscovered all my music. Of the three amps in question, I would definitely go with the Apollon, but honestly, probably anything but the Pass.

When amps sound 'magical', it's probably a subjective feeling that comes from enjoying the amp's distortion. An amp that doesn't add any distortion is neutral and lets you hear more of the characteristics of the speaker (or DAC, assuming perfect room acoustics and speakers - but DAC distortions are so low it is debatable if that could even be detected by human ear). I prefer realism to any 'magical sound', but this is subjective, and I understand that some people may enjoy specific 'salt' in music. Even so, I would recommend a natural-sounding amplifier to anyone as I think it is more versatile in delivering pleasant, engaging music regardless of genre/recording (at least this is my experience with the Lyngdorf mk4 + Dynaudio Special 25). I'd even say that vocals sound "magical" (or rather realistic, it is really special when you can hear perfectly voice timbre) with this setup, but I think that's thanks to the lack of distortion and the capable tweeter, rather than the amp adding some special "salt" to it.

I'm condiering upgrade of my setup to Apollon PET1200M and Dynaudio Confidence 20 - you may call it overkill, but Dynaudio sounds great with amplifiers which can deliver very high current (Lyngdorf 60A, Apollon 40A), so I guess for me to get even lower distorition the Apollon will be logical choice, and Confidence 20 with new tweeter and more managable bass for small room would be also upgrade. But I'm affraid to be wrong and that would be costly mistake, some say "better is an enemy of the good".

 

[Willem]

Power amplifiers are relatively boring, unless you want to obsess about inaudible measured differences. You need a flat response, low output impedance, and power, and more power. More important is the preamplifier/DAC part of the story. Here, what matters in this day and age is a good range of digital inputs, tone and balance control, and filters/dsp room eq. What also matters is how you can integrate subwoofers. The RME ADI-2 offers much of this apart from a somwhat basic filter/room eq system compared to some others. Sadly, some of those lack e.g. balance control, or dynamic loudness. My own solution has been to use the RME ADI-2 as DAC/preamp, and use the rca output into a miniDSP with MSO filters for the subs. The power amp is high passed with a passive filter in the balanced output of the ADI-2. I admit it is a bit of a kludge, but this way I have the full range of RME options including filters for the lower frequencies of the high passed main speakers, supplemented by the MSO filters for the subs.

 

[atomek]

I don't agree power amps are boring, it is power amps where difference is still audible, unlike DACs with magnitude lower distortions which are anyway masked by distortions of amplifier / speaker. I used miniDSP in digital domain (between streamer "transport" and DAC) with Dirac Live but eventually I've disconnected it as it did more harm than good to music, regarless of many attempts for best calibration (on REW measurments it looked great, but subjectively I prefer acoustics of my untreated room). To me DACs/preamps are boring as today they solved problem with sound reproduction and differences between them are inaudible. Power amps can sound very different especially with speakers difficult to drive (like some Dynaudios), but it is not only about power, also some power amps have some specific "signature" due to added distortions/harmonics. If you can tell difference between two DACs, there must be something very wrong with one of them, and preamps is something I'd avoid as it is much better to control volume in digital domain today (with newer DAC chips it is done after oversampling, without loosing any information - you can turn volume down 30-40db down before effective resolutions drops to 16bit from oversampled) - preamps adds the "salt" but never improves clarity of the sound.

 

[Willem]

I did attend a blind demo and could not identify differences between three respected and well designed amplifiers. The same is true for all properly conducted blind tests of competently designed power amplifiers used within their design parameters, and has been demonstrated over and over again.
If you read my claim about DACs and preamps you can see that it was not about their basic quality, but about the value of additional features like tone and balance control, dynamic loudness, or dsp room eq. I am fine with you not liking dsp room eq, but if you want to have accurate sound at home, there is no avoiding it.