Matching Speakers to amp


I currently own a PSA Stellar 300 paired with Focal Aria 926. I just picked up a used pair of Quad S-5 and I will be comparing the sound. I am not good a using technical specs to compare so I could use some help if anyone has the time to take a look at the amp & speaker specs below and give me some feedback I would greatly appreciate.
The basic question is: from a specification standpoint which speaker pairs up with the Stellar 300 best?


Stellar 300
Gain30.5dB +/-0.5dB Sensitivity for rated output power1.01V Noise1kHz@300 Watts <-100dB Input impedance S300Unbalanced 50KΩ
Balanced 100KΩ Input impedance M700Unbalanced 50KΩ
Balanced 100KΩ Output Impedance50Hz, 2.8VRMS <0.007Ω Damping factor50Hz. 2.8VRMS
8Ω >1100
4Ω >550 Frequency Response@2.8VRMS
10Hz – 20KHz +/- 0.5dB
10Hz – 50KHz +0.1/-3.0dB
Output PowerBoth channels driven 120vac mains, 1kHz, 1% THD 8Ω140W minimum 4Ω300W minimum 2Ω Stable for musical transients

Quad S-5
General description 3-way floorstanding speaker
Enclosure type ABR
Transducer complement 3-way ABR 165mm x3 Bass driver 165mm Woven Carbon fibre Cone x2
Midrange driver 125mm Woven Carbon fibre Cone Treble driver 12 x 45 mm
True Ribbon Sensitivity (2.83V @ 1m) 90dB
Recommended amplifier power 25-175W Peak SPL 112dB
Nominal impedance 6Ω
Minimum impedance 3.2Ω
Frequency response (+/-3dB) 42Hz ~ 23kHz Bass extension (-6dB) 35Hz Crossover frequency 570Hz & 3.2kHz

Focal 926
Speaker driversTwo 61/2" (16.5cm) Flax bass61/2" (16.5cm) Flax midrange1" (25mm) Al/Mg TNF inverted dome tweeterFrequency response (+/- 3dB)45Hz - 28kHzLow
frequency point - 6 dB37HzSensitivity (2.83V / 1m)91.5dBNominal impedance8 OhmsMinimum impedance2.9 OhmsRecommended amplifier power40 - 250WCrossover frequency290Hz / 2400Hz











128x128jbuhl

you have more then enough power for either speaker. both are relatively efficient 90db, 91.5db. both seem to have similar specs but both dip to 3ohm load or slightly below but you have more then enough power for this load. so go for it see what sounds best to you.

your amps make 300w into a 4ohm load as your speakers are nominal 6-8 ohm dipping to 2.9 ohm and 3.2ohm  your good to go.

so for future ref. the speakers sensitivity is an indication on how loud they will play with usually 1w at 1 meter (2.83v @ 1m is an indication they are rating the speaker at 8ohm load)

the Quads are not as efficient as the Focals but not that much, you probably wont notice the difference.


probably the most relevant info you need.

Quad:   Sensitivity (2.83V @ 1m) 90dB ;

how much power you need for a given volume level, lower the number the more power you need generaly

            Nominal impedance 6Ω
            Minimum impedance 3.2Ω ;

 this tells you how hard they are to drive higher is easier lower is harder. lower impedance will require an amp that can drive that load SS amps are better at low loads then tubes for example.

            Frequency response (+/-3dB) 42Hz ~ 23kHz ;

 how much of the frequency your speakers will perform in the average room. humans can hear from 20hz to 20khz (well only children and woman can hear that high but you get the idea)


Focal:

Sensitivity (2.83V / 1m)91.5dB

Nominal impedance 8 Ohms

Minimum impedance 2.9 Ohms

tweeterFrequency response (+/- 3dB)45Hz - 28kHz


other will most likely chime in and add or correct if I missed something



jbuhl
The basic question is: from a specification standpoint which speaker pairs up with the Stellar 300 best?

Sorry, but to me neither speaker will be at their best with the Stellar, it will work into them and probably sound fine, but probably not extract the best from either. >2ohm loads are not Class-D’s forte.

I don’t think big wattage is the answer here as both speakers are over 90db, a 50-100w amp will do, the issue is the amp needs to supply good current into the low bass load as seen by it (below) to keep it from becoming a tone control.

The Quad S5 has a demanding load in the low bass.
As measured by Keith Howard of HiFi News:
" EPDR (equivalent peak dissipation resistance) to fall to a minimum of 1.4ohm at 111Hz, making the S_5 a more than a typically testing load for this size and class of floor stander "

The Focal Aria 962 is also a hard load in the bass as can be seen by this graph from 80hz to 300hz. 2.8ohms and also a -55 degree phase shift, which equates to a EPDR well below 2ohms
https://www.stereophile.com/images/1114FA936fig1.jpg

A Class-D, Tube or Mosfet is not my first choice of amp for loads like these to get the most out of the low bass of these two speakers.
I would prefer to see a linear amp with lots of bi-polar (BJT) output devices and big power supplies, to push current into that bass to keep it under control and flat without becoming a tone control..

Cheers George


"The basic question is: from a specification standpoint which speaker pairs up with the Stellar 300 best?"

The question was not what amplifier(s) best suits these speakers. The question was which of the two speakers best suits the amplifier. As mentioned earlier, given the similarities between the two speakers’ specifications, you’d just need to listen to both and compare the two in your room and decide which one sounds better to YOU. I haven’t heard the Quads but if the Focal 926 sounds anywhere near what 936 sounds like, I’d guess you’ll like them better. Given that you have them all in your home, this appears to be a no brainer approach. Let us know how you make out.
Yeah just looking at the numbers nothing jumped out at me as being wildly different twix the 2 speakers.  So I expected a response to be "They close".    Now I am excited to see if I can tell the difference between Focal downward facing  bass ports and flax cones vs Quad's kevlar cones, ribbon tweeters and rear facing auxilary bass radiators.   One thing I really like is the classic fit and finish on the Quads. 
Keep both and put them in separate rooms! Run longer speaker wire to one pair and manually switch from the amp using banana plugs. Both are equally deserving of ownership!
Georgehifi is totally incorrect with his response.

I have dynaudio focus 160s being driven by a stellar s300, with a naim nac 202 preamp. The bass is endless, and the amp absolutely SINGS with these tough to drive dyns which have a nominal impedance of 4 ohms, sensitivity of 85db. 

The bass abilities of the amp are absolutely incredible....It seems like it should weigh 100 pounds, given how it controls the speakers.

I've driven these speakers with everything from adcom monoblocs to a luxman and the stellar does a better job than anything i've had in this system.
.@johnkent3...…………………………………….

As George said, they will NOT do 2 ohms, 4 ohms is a different matter entirely
johnkent316 posts07-06-2018 9:56pmGeorgehifi is totally incorrect with his response.

I have dynaudio focus 160s being driven by a stellar s300

I understand, you love your amp and are sticking up for it.

But like I said into the OP’s speakers " it will work into them and probably sound fine." But may not perform at their best. 

But your speaker may not have the loading that the OP’s do. (I will try to find it for you.)

I’m just pointing out the tested/measured specs behind it with the OP’s two speakers.

Cheers George
Your Dynaudio 160 have never had an impedance graph done on them, but the 140’s do which is the same family. And yes they are far more easier to drive than the Focals or the Quads of the OP's.

https://www.stereophile.com/images/archivesart/506140FIG1.jpg

Cheers George
Thanks for the responses.

First impressions. The Quads are beautiful. Love the finish and the base assembly. The base is really classic looking and solid and just absolutely anchors to the speaker to my hardwood floor. Makes the Focal’s base look like something from Wal-Marts.
My sourcesProject TT Sumiko Cartridge
Rogue Audio RP-1 with Mullard TubesBlue Jean interconnectsPS Audio entry level power cablesEntry level Audio Quest Cable (need recommendation here for $300 budget)cheapo sony CD player digital out to Wadia 321.

The Focals fill up the room with a blooming warm sound when I switch to the Quads the sound stage shrinks but man does it get accurate, the bass is reserved but tight as dick’s hat band, transients are distinct. For example Dire Straits Wild West End, the striking of the wood block is right out front , right in the room. With the Focals the block is more in the back and mildly vague but smooth. On the Quads when Knopfler made the first few string plucks on that song the hair on my neck was up . " Stepping out to Angellucci’s for my coffee beans... " On the song In The Gallery Knoplfer grunts and growls out the lyrics. The way the Quads delivered the nuances of his voice had me giggling.

Steely Dan’s, Turn that Heartbeat over again. The Quads delivered the bass line on the song so nice and clear. But when Fagan shot his voice into the higher register the Quads seem to shreek where the Focals kept that in total control.
Where are my alligator clips!


Miles Davis Sketches of Spain from Mofi Vinyl. Similar experience, more warmth with the Focals. But right at the beginning is some rattling of wooden objects like wooden sleigh bells, barely audible on the Focals but just perfect with the Quads. Miles trumpet more edgy with the Quads and a bit to much up higher for my taste. But the Quads resonating the strings and reeds beautifully. Then about half way through Concierto De Aranjuez Miles plays a minute or so of low notes and the Quads made it sound like he was right in the room.
John Cougar Scarecrow. I like the engineering on this album. Kenny Aronoff whacking the snare throughout. This is where I like the Focals better and probably why I picked them over the Sonus Faber when I demoed them side by side in my system. I guess maybe the Focals are better overall for my listening habits. Do they take the edge of R&R ?. But the Quads did a saweet job layering in Ricky Lee Jones voice on tune Between a Laugh and a Tear.

CD’s
Television, Elevation from Marquee Moon although I loved the way the Quads made Verlaine’s Jazz Master sound they made his voice almost unbearably shrill a certain points. Where the Focals mask that. But then on the following tune, Guiding Light, His voice sounded really nice and I could turn my attention to the nice bass line coming through.

Miles Davis Black Satin from One the Corner
This album is really wild with almost of cacophony of sounds (sax,trumpet,tabla, electric sitar. The Quads again very precise with the Tabla sounds and the reed resonance but with this type of music of wonder if I would fatigue. Again the Focals get the nod.

If I was primarily listening to classical and maybe jazz the Quads would get the nod. I like @roberjerman’s idea of keeping them both. Which leads me to the reason I have the Quads at all. One pair is going to end up at my sisters house. I expect the Quads will eventually end up there so I now need to search for an integrated amp around the $500 to $600 range to push these things.






so I now need to search for an integrated amp around the $500 to $600 range to push these things.
I don’t know the used prices in the US a used John Curl designed Parasound Halo Integrated, it will try to push those low impedance’s in the bass (for an integrated), and I think it has a dac and phono stage in it as well.
https://www.stereophile.com/content/parasound-halo-integrated-integrated-amplifier

These may also be good but you need a preamp, maybe a Schiit Sys $49 will do.
https://www.ebay.com/itm/PARASOUND-HALO-A23-STEREO-POWER-AMPLIFIER-IN-SILVER-COLOR-2/283016082021?ha...

https://www.ebay.com/itm/Parasound-Halo-A23-Amplifier-in-Silver-Excellent-Condition/152948492181?has...

http://www.schiit.com/products/sys


Cheers George


George. That old parasound will crumble in camparison to the newer hypex and icepower amps...

Parasounds are pretty, but very underwhelming in everything else, wayyyy overhyped...I’d go back to a gfa adcom before getting another parasound.

to OP...your setup deserves a step up to the m700 monos.

Cheers all! Have a wonderful weekend!


I think $500-$600 will be a little low for an integrated to drive those S5s. If you can bump your budget up tp $800, the Outlaw RR2160 seems to get good reviews and should be a decent match.
Sh!t I knowed this would happen. Nobody likes to spend other peoples money like Audiogoners. You guys are gonna break me up.LOL. @johnkent3 dont think I have not thought about the 700 Monos and the Wyred for Sound offerings.
Thanks @kalali for the RR2160 suggestion I might have to help my sister even more we may be able to squeeze something like that into the budget. What about Marantz and NAD? There is always a bunch of that stuff used floating around. Or this https://www.audiogon.com/listings/lis914g6-rega-mira3-stereo-integrated-amplifier-mm-phono-13792-sol...
Specs on the Rega: https://www.stereophile.com/content/rega-mira-integrated-amplifier-specifications

Right now  the Quads are playing Radioparadise (Streams 16/48 FLAC) . Beth Orton and Norah Jones just played. The Quads just sound so good with their voices, luxurious, the nuances they pick up on the human voice.

The Quads are doing their best to grow roots right into my hardwood floor.
Those Regas are great but don’t have close to enough power...and in that category, the naim Nait is the way to go vs. rega.
George. That old parasound will crumble in camparison to the newer hypex and icepower amps...
Not when they load gets to around 2ohms like with the OP’s two speakers do , that’s where Class-D’s Achilles heel is, they start s**ting themselves below <4ohms.

Cheers George
Post removed 

@kosst_amojan - not entirely correct.  The major problems with driving low impedance loads (such as .5 ohm or 1 ohm) are the power supply.  Car audio is completely different because the power supply is a constant big 12V DC battery (and an alternater that continuously charges it).  There isn't usually that much of a power supply capacitor bank in car stereo amplifiers because it is being fed by DC. (you should know this).  Then it becomes a factor of designing the circuit so that it won't over-run based on the current requirements of such a low impedance - fed by a 12V DC power source.

With home audio, it's all based on A/C current, which only provides partial current in cycles of 50-60 hz.  Obviously, that's why we have huge capacitor banks in larger amplifiers.  The ability for the amp to drive low impedance loads is hugely dependant on size of transformer and capacitor bank (which you should know as well, based on your historical statements that you are very much an expert in analog electronics).

I have seen many Class AB amps in the car stereo industry that will run .5 or 1 ohm loads.  It is not limited only to Class D (however, there is definitely a large amount of Class D in the car stereo industry today).


Class D has its own fanbase, but the limitations on bandwidth due to the high switching in the circuit prevents it from really performing well in the ultra high frequency range and giving you that "air" and liveliness that Class AB amps provide.

Post removed 
Ok now you guys got me curious on what AB would sound like on this system. When I first pieced this together I compared my s300 amp to a 25 year old PSA 200C. I mean what a beast this thing is. Lots of heat and a relay inside the thing throws a blue flash when activated (Paul McGowan assured me it was normal and safe). But I think I was running my old B&W 603 speakers when I made the comparison. I still run this amp in my garage system. Would it be a fair comparison to bring the 200c back in and give it a shot or should I look at newer lower watt AB amps? Frankly I can’t see shipping the 200C to my sister and the humming noise it makes is also a downer.

The capacitors on that PS Audio 200c are likely so dried out they are failing to filter out the 60hz hum coming in from the A/C.  That could be why you get that hum.

I agree that the Rega is way too low power (only 60 watts?!?) for your speakers.  The Focal really perform best when you have a very high current amplifier (big power supply - high power).

The Steller S300 is probably only one of two Class D amps I would even consider (if I was considering) because of the Class  A input stage (the other one is Nord Acoustics).  However, if you are looking for an alternative, it is going to be really hard to get a good enough integrated (or amp) at the $500-600 level. 

The Parasound A23 above that George recommended could be nice, but it's only 125 watts per channel. 

Couple of things come to mind.  Parasound 2250v2 amplifier. Vincent SP331 amplifier (if you want a tube input stage).  Both are excellent.  Vincent has excellent bass response and voicing, but it does have a tube sonic signature (in case you are looking for pure solid state).  Both are currently on sale at Audio Advisor for $999.  Way above your budget, but these are just ideas.

If you want integrated, there are a couple of Yamaha S-801 integrateds on audiogon.  It's about the same power as Parasound A23


The Parasound A23 above that George recommended could be nice, but it's only 125 watts per channel.

Yes but the speakers are both over 90db so that 125w @ 8ohm is fine and being John Curl design with BJT output you can bet it no slouch into low impedance's. 
It actually puts out 150w into 8ohm test here in this review and bech test.
http://i.nextmedia.com.au/Assets/Parasound_P5_Preamp_A23_Power_Amp_Review_Test_lores.pdf

Cheers George
yes, but with the impedance challenges of the Focal and the fact that they usually sound thin/bright, I would think that you would want as hefty of a power supply as you could in the amp.  The A23 is nice, but definitely not a strong amp in the power supply section.
auxinput
I would think that you would want as hefty of a power supply as you could in the amp.
That’s a given, along with bjt’s to back the power supply for good current into low impedances. But as he said he’s looking at " $500-600 level" maybe old JC Parasound poweramps with a $49 Schiit Sys for the pre.
This could do. or an early HCA-2200
https://www.audiogon.com/listings/lis90c17-parasound-2250-solid-state

Cheers George
Post removed 
what about a unit like this? https://www.audiogon.com/listings/lis9147c-rotel-rb-1552-mk2-solid-state-amplifier-130w-x-2-solid-st...


Or the Outlaw RR2160 that was suggested bu @Kalali

I know I am getting out of the original budget but might be able to goad my sis into spending a bit more.

Post removed 
Hey George.  Yup, for those speakers I would probably pick the Parasound 2250 over the A23 (even though the A23 has XLR I puts and higher resolution), because of the larger power supply in 2250.  Also, the 2250 is no slouch either.

jbuhl, both the Rotel and outlaw are only about 120 or so watts.  I’m sure these or the Parasound A23 would play just fine, but still are somewhat light in the power supply for the Focal speakers.

theres an Odyssey Khartago on eBay with larger upgraded power supply, current bid $500.  I don’t know how high it will go, but this would be an excellent choice.
Consider a Odyssey Khartago stereo amp used. These pop up for $600 occasionally. AB amp, big power supply, easily doubles wattage down to 2 ohms, high amperage. Huge soundstage, sweet sounding high frequencies. Made in Indiana, they have an upgrade path to take them from exceptional to world beater. They also have a program to upgrade to monoblocks for a reasonable price. 
Odyssey Khartago on eBay with larger upgraded power supply, current bid $500.


Consider a Odyssey Khartago stereo amp used. These pop up for $600 occasionally.

These could also be good, as I believe they also use bi-polar output transistors as well and decent power supply to get some current flowing.

But there’s a ? for me on the mono blocks, from couple of models I saw that came through, they were just stereo amps that were bridged.
+More watts
-More distortion
-Less damping factor
-less stable into low impedance’s.

Cheers George
I would only recommend an Odyssey stereo amp if it had the power supply updgrade (which the one on ebay does).  The basic Odyssey Khartago only has 60,000uf capacitor bank (which is not much more than A23) and a small 400va transformer.
Yeah, I’m not overly impressed with them after seeing what those monoblocks models were, and it wasn’t mentioned in advertising that they were just bridged stereo’s. But the stereo one we heard did sound "ok", on old reasonably hard to drive Infinity’s.

Cheers George
Post removed