Small power amp

plonkywonki said:
Thanks for the tips and background.

My math.
3 m listening distance
I'd aim at a 96dB max level including the amp headroom of 20dB. This leaves 76dB for normal listening less 6 for stereo setup less 3 for echoes & flutter and adding 3 dB as rounding -> 70dB desired.
sensitivity 86
headroom we know from above is 20

I'd end up with 23W, round it up with 20% and we're almost at 30W required. That is surprisingly low (?),
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A 3M listening distance would make your 86db loud speakers 77db with 1 watt , ( 6 db drop for every doubling of distance ) ...

Its actually a bit more complicated than this due to room gain , speakers toe in and insertion losses. typically when we have measured at 1 watt RMS , we have seen peaks exceeding 200 watts as measured on an oscilloscope with high crest factor recordings ..!


Regards
 
a.wayne said:
A 3M listening distance would make your 86db loud speakers 77db with 1 watt , ( 6 db drop for every doubling of distance ) ...

Its actually a bit more complicated than this due to room gain , speakers toe in and insertion losses. typically when we have measured at 1 watt RMS , we have seen peaks exceeding 200 watts as measured on an oscilloscope with high crest factor recordings ..!


Regards
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Maybe I'm confused but it seems to me you have that backwards. Stereo speakers and room reflectivity reduce the power requirement by about 6 dB -- I'm splitting the combined stereo gain of 6 dB between the two speakers. Accordingly a sensitivity of 86 dB/1w/1m speaker becomes effectively 92 dB/1w/1m. :sneaky:

Example: My listening distance is 3 m; average level is 72 dB; desired headroom is 20 dB; speaker sensitivity is 86 dB/1w/1m. Straight up the power required is (only) 36 watts. Assuming the effective sensitivity is 92 dB/1w/1m, the result its a mere 9 watts (per channel). :bonkers:

... Hello First Watt amps :)

Granted if my average listening level were 85 bB -- which mine is certainly not, but it might be for a few people -- the corresponding power requirement jumps 'way up to 180 wpc.

I suspect many people are beguiled by the notion of high power, (200+ wpc). They insist that the sound is significantly improved. Maybe, but they should consider that the SQ improvement might be due to other factors besides the raw poser.
 
Yes your confused , your listening distance is 3M, your losing 6db for every doubling of distance from 1M , take out your db meter and DVM, start measuring..!

Power output @72db ( what if you hit 75 db instead of 72db) then you can calculate what is required at 92db peaks with no fairytales ..!

:)



Regards
 
a.wayne said:
Yes your confused , your listening distance is 3M, your losing 6db for every doubling of distance from 1M , take out your db meter and DVM, start measuring..!

Power output @72db ( what if you hit 75 db instead of 72db) then you can calculate what is required at 92db peaks with no fairytales ..!

:)
Regards
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I've measured my volume many times with a dB meter from my listening position, 3 meters; my average volume is basically never higher than about 72 dB. Peaks are be higher of course which is why I allow 20 dB headroom.

Have you actually looked at the Crown calculator? It allows you to enter your listening distance and, presumably, takes it into account with other parameters when it calculates you required power.
 
These calculators are great tools but not every 25 watt amp (or 50 watt amp or 100 watt amp) reacts the same. If you want to spend a bit less money ($500 - $1000) a Belles A150 or Soloist amp are very nice pieces.
 
Dynamics will suffer alot from being under powered and amplifiers will be selected based on their clipping characteristics ..

Try using a 30 watt subwoofer amp in your HT for eg ..




Regards
 
A while ago i have checked some ins and outs. they support my thoughs so far that a small amp would need to suffice.

I recalculated based on the following assumptions:
1) my iphone measures 70dBA max at 4m listening distance at my max preferred (note in a fairly small room). I assume, though sloppy 1:1 conversion to dB SPL (ref the crown power calculator)
2) speaker ratings of 86dB (2,83V/1m) for 4ohm impedance is translated 83dB (1W/1m)
3) assume overhead of 10dB in the amp should be sufficient

Putting this in the Crown calculator (link above) brings 8W to the table. My perceived issues (i'm still no specialist) are the grip on the speakers and harmonic distortion with a smaller amplifier running at 80% volume vs a larger amplifier at 20% volume.

I'd be very curious to see what 8W would do
 
plonkywonki said:
However, since I look more and more for no nonsense designs, I am orienting towards a power amp with 1 analog input.
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How are you planning to control the output (volume) of this one-input amp? Power amps generally don't have volume controls and nearly all power amps have a single analogue input, although some offer twin sockets - balance and single ended (XLR and RCA)
 
Agree on the amp comparison to cars. An eight cylinder engine is going to give you a rumble, an ease of acceleration and torque that you don't sense in a 6 or 4 cyl engine, even though the smaller engines do the job just fine.
 
I like the First Watts suggested earlier. I’d say it would be possible. But, the above makes also sense, i.e. if it’s about muscle and I use from my current 60 watts only say the first 30%, I have plenty of power reserve.. did I then not already meet all the above suggested.
 
True, but in my experience a hegel amp @ volume control <16 results in a HP filter effect. Do you recognize this in the H360?

I'm nicely surprised to find with my iphone dB meter (apparently it measures dBA but i don't know its + or - delta between reality) some clues.
I put @unity gain uncorrelated pink noise into a digital mixer and found a linear correlation between the measured dBA and the mixer adjustments.
So -20 delta in the mixer results in -20 delta in the measured dBA. Something seems to go right.

Then I did the same with my current amp and recorded the dBA measured for all volume control increments. Outcome is a polynominal 3rd grade curve. I guess this is realistic in electronics.

As next step I aim to find the correlation between dBA measured and the actual power output in W from the amp to finally find out what I need and how much extra power I have left. Any clues whether to start from the speaker sensitivity or maybe from the dBA measurement?
 
The comparisons I can make personally include the Ayre Ax7e, AX5, and MX-R, a T+A Amp 8, a Lumin M1 (all in the "more watts" group) to the newest addition the Enleum 23. Granted, these have been in different systems over time but all of a reasonable - but far from top level - quality (ie Audio Note or PS Audio DACs, Aerial, Totem, or Amphion speakers, Lumin streamers etc).

The Ayre amps were all fantastic as you would expect, they "had it all" imo, and got better as I moved up the line. But of them all, the one I would pick if I could never change again, would be the Enleum. Which is also the physically smallest, and lowest in watts. But most importantly, the most musical and neutral sounding to me. Yes, the big Ayre monoblocks were stunning and had incredible punch, speed, grip across the spectrum, neutrality, 3-dimensionality, and were gorgeous. But still, the little Enleum is an absolute joy to listen to.
 
plonkywonki said:
and for the h360 @ low volume setting?
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If you want a really sweet "little amp" designed by Nelson Pass, there's always the Amp Camp Amps...you can build up a pair to run as bridged monoblocks for all of $654.

15 Wpc...which I should add was about the same as the famous NAD 3120.

ACAs-on-Maple-Board.jpg


ACA-Top-View-Wired.jpg


These are really good-sounding amps when listening at nominal SPLs of 68-80 dB, which is how I listen to them. And, the build is fun to do, as well.
 
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