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Power upgrade ???

Ponca

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I own a Denon 8500HA with 150 wpc 2 channel rated... I just bought a pair of Revel F208 for 2 channel listing....listing in "Pure Direct" They sound great... BUT what kind of power upgrade would make them sound "Much" better.... Or am I just going down the rabbit hole ??? Just stream music, prime ultimate in HD and ultra HD.. ... Thanks for the information or opinions , maybe a little BS...
 

antcollinet

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Are you currently listening at SPL levels that send your Denon into clipping. If not it is unlikely that any higher power ratings will make a significant difference, since they'll not be used.

Depending on the speaker impedance (especially at lower frequencies), you might get better bass with lower output impedance (higher damping factor), but I can't see any output impedance rating for the Denon.
 

sweetchaos

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Your AVR was measured by Amir.

1st graph I look at:
index.php

the left-hand-side graph shows:
Power (w) 1% THD+N, 4 ohms is around 257 watts

2nd graph I look at:
index.php

This shows that that SINAD dB, 5W, at 4ohm is 85 dB.

Now you can compare these values to other amplifiers, by looking at this spreadsheet:
Example:

1661808182905.png


And find other amplifiers that can beat these values.

ASSUMPTION:
I'm just talking about technically excellent measuring products, ignoring audibility aspect of it.
 
OP
P

Ponca

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Thanks, I think, yes great information w/some BS... Enjoy all....
 

VintageFlanker

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I just bought a pair of Revel F208 for 2 channel listing....listing in "Pure Direct" They sound great... BUT what kind of power upgrade would make them sound "Much" better..
Is there even such a thing as "Much better" than "great"?

Question is simple: Is your amp putting into distort when listening at high volumes ? If not, and if you find your speakers to "sound great", then enjoy!
 

Chrispy

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I lean towards rabbit hole but....sometimes
 

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Peluvius

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What’s wrong with the rabbit hole……been down here for years.
 

Peluvius

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I own a Denon 8500HA with 150 wpc 2 channel rated... I just bought a pair of Revel F208 for 2 channel listing....listing in "Pure Direct" They sound great... BUT what kind of power upgrade would make them sound "Much" better.... Or am I just going down the rabbit hole ??? Just stream music, prime ultimate in HD and ultra HD.. ... Thanks for the information or opinions , maybe a little BS...

Rabbit holes aside I don't think you would hear much audible difference if any. The 8500 is very capable and I believe pure direct turns most of the amps off so that's a plus. Speakers (already great but consider a sub), room and treatment, room EQ should all be before considering fiddling with electronics.
 

bloomdido

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I'm a bit confused - OP is advised that if there's no clipping with his current setup and he likes the sound he shouldn't search for a better amp - but is all that idea of "amp headroom" (meaning that an amp with more power is likely to sound better even when listened at minimal volume) complete "audiophoolery"? I thought it's not...
 

Sokel

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I'm a bit confused - OP is advised that if there's no clipping with his current setup and he likes the sound he shouldn't search for a better amp - but is all that idea of "amp headroom" (meaning that an amp with more power is likely to sound better even when listened at minimal volume) complete "audiophoolery"? I thought it's not...
Amir always says 1-2 words about headroom in the measurements so can't be entirely audiophoolery.
 

antcollinet

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I'm a bit confused - OP is advised that if there's no clipping with his current setup and he likes the sound he shouldn't search for a better amp - but is all that idea of "amp headroom" (meaning that an amp with more power is likely to sound better even when listened at minimal volume) complete "audiophoolery"? I thought it's not...
"headroom" is about not hitting clipping. If you are listening to music at (say) an average of 75dBa, then peaks could be as high as 20db higher than that, or even more for some music types.* So you need headroom to cope with the peaks of your normal (or perhaps maximum) listening level.

But beyond that (and "that" depends on YOUR listening level at YOUR distance, and with YOUR programme material etc etc), more headroom is not required. If your amp is not clipping, then no amount of extra power being available (all other things being equal) will result in better sound.


(*Bear in mind also that clipping very short duration peaks is unlikely to be audible)

(Bear in mind also - that higher power amps may well have lower output impedance - which can also make a difference regardless of clipping. This though falls into "all other things NOT being equal" - and you should be looking for the output impedance rating, not the power)
 

bloomdido

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But beyond that (and "that" depends on YOUR listening level at YOUR distance, and with YOUR programme material etc etc), more headroom is not required. If your amp is not clipping, then no amount of extra power being available (all other things being equal) will result in better sound.
But is that some more ot less hard clipping threshold or is it like having some increased distortion at 40 dB gain, some more (probably audible) at 80 dB gain and a lot of distortion at 100 dB gain? I understand it could be different for different amps but let's narrow amp designs range to typical modern class A/B designs.
 

antcollinet

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But is that some more ot less hard clipping threshold or is it like having some increased distortion at 40 dB gain, some more (probably audible) at 80 dB gain and a lot of distortion at 100 dB gain? I understand it could be different for different amps but let's narrow amp designs range to typical modern class A/B designs.


(dB here is not gain - it is a level of sound pressure)

An amplifier clips when the power it is delivering requires the peak output voltages to be higher than the power supply rails (see picture below). At this point it can no longer put out enough volts to accurately reproduce the music waveform and distortion results. The level of distortion increases as the required power output increases, and the tops of the waveforms get more and more flattened off. What level of distortion is audible will probably vary from person to person. However, amps power is often rated at a distortion level of 1% (-40dB) which is well into the audibility range.

So yes - it is a hard clipping level. When you are at the rated power for many amps, they will already be clipping and it will be audible.

By way of an example, I listen at SPL levels of around 75 to 85db (85 when I'm alone in the house and can crank it up a little). So lets take that 85dB

My amp is 100W, I'm listening at 2m and my speakers sensitivity is about 85dB - so according to the calculator I used, it can output 103dB at full power. But lets say that is at 1% THD, and to get distortion free listening it can only get to 10dB less (93dB) (Having said that, 1% distortion is probably not objectionable to most people - especially if it is only hitting peaks/crescendos in music)

So at my "crank it up level" I only have 8dB headroom. Not enough for the peaks of most music, and I'm going to get distortion. At my "sociable" listening level of 75dB I already have 18dB headroom, so am probably fine.

If I sit closer to my speakers, say 1m then I get an additional 6dB of SPL. I now have 14dB headroom, which will be enough for much of the music I listen to, but perhaps not some with high dynamic content such as classical.

Now consider that to get an additional 3dB of headroom, you have to double your amplifier power - and you can see why having more power is always suggested to get the headroom you need.

sfKtD.gif


Screenshot 2022-09-01 at 07.56.11.png
 

dlaloum

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I have different speakers to your (Gallo Reference 3.2) - so consider yourself "pinch of salt" warned

When I first purchased them, I had read reviews, that pointed to the 8ohm nominal spec, and used low power valve amps, waxing lyrical about the characteristics of these speakers.
Other reviews mated the low power valve amps, with a seperate high power amp for the woofer (they are wired for true bi-amping, and gallo used to sell a specific amp for the purpose)...

Anthony Gallo himself used to demo these speakers at audio shows with a Spectron Musician amp ... 500W @ 8ohm, doubling into 4 and then again into 2 ohm.... so both very powerfull, and VERY high current....

I had run the speakers with success using Onkyo/Integra flagship AVR's (140W@8ohm spec, measured in various tests to do over 165W@8ohm clean... current limited below 4ohm) - and some Quad 606 amps (another high quality 140W@8ohm amp).

Further investigation on my speakers showed that they drop down to just under 3 ohm at the woofer, and around 1.6 ohm on the tweeter - so there is good reason to assume they might do best with an amp capable of substantial current.... so something that is well rated and has plenty of headroom when supplying the desired speaker voltage (SPL) at those low impedances.

Searching through amp specs for something that approximates the Spectron Musician's specifications, without requiring a home mortgage to purchase... I came across the Crown pro/pa amps XLS2500 (440W@8ohm, 775W@4ohm and 1200W@2ohm) - grabbed a pair of these used... to try out.

The end result was interesting - compared to Flagship AVR, and high quality traditional amps (Quad 606) the Crowns were slightly better... not chalk and cheese by any means - but the tendency was in their favour (before anyone asks, no there was no blind testing, and yes it might be confirmation bias... on the other hand, I was biased towards the Quad amps... and this comparison did not go in their favour!)

More recently I chose a step down in AVR terms, as I did not require high power from the AVR, but I needed high quality DRC and wanted to try Dirac... the Integra DRX 3.4 has only 100W@8ohm - and Amir has shown it shutting down with 4 ohm loads under stress.... clearly NOT a high current design.

Connecting it to my speakers, and running at a mere 75db SPL at MLP (which calculates out to around 1W average with peaks of perhaps 16W for 20db headroom) - the soundstage was confused, imaging was shot, sound was "veiled" - connected my Quad 606's or the Crown XLS's and the sound immediately cleared up.

So what general conclusions can be made?

1) AVR's in general are current constrained (but so are many power amps!)- if your speakers are current hungry, it may affect the sound quality negatively even at power/spl levels that one would normally assume would not have an issue. (why this is the case, I am not sure... but the subjective listening results I get are consistent)
2) External power amps driving the main speakers can result in noticeable improvements in sound - sometimes ever with amps that aren't obviously superior to the specs of the internal AVR amps.... again this may relate to taking load off the internal power supply - but it is not always the case - TOTL Flagship AVR's are a bit of an edge case - and often have much more substantial power supplies and amps, than their mass market brethren
3) Some speakers, seem to like an amp with massive reserves... even when these are NOT used - the overall sound is better (the Gallo's do!) - other speakers, this sort of excess has no impact whatsoever (I used to run Quad ESL's - and although sensitive to chain quality, they were never sensitive to "power" - not a much current required on that design)
4) Know your speakers, and if possible, experiment with alternate power amps... I took on the Crowns as an experiment, with the option of reselling them (possibly at a profit, given the great price I got them for) - but they surprised me, and have remained in my setup - for 10 years now.
 
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