Pass XA 30.5 with Revel F 208 ?

It might sound good but will be way underpowered. 20 watts of warm beautiful power only goes so far with speakers that are happy with 400 watts. Keep your choice above 90db for that amp (B&W, Coincident and many more)

The XA30.5 puts out a lot more than 20 watts after it leaves Class A, so a lot depends on room, volume levels, and whether you want/need to stay in Class A

The XA30.5 is underpowered for the Revel F208 or F206 unless you like to listen at really low volumes. Yes, the XA30.5 will put out more power after it leaves class A, but it's unlikely to really go above 60 wpc. Revels are not the easiest speakers to drive and as Elevick points out, Revels can be quite content with 400 wpc. I drive a pair of Revels with a Pass amp that puts out 300 wpc into 4 ohms, and even then in my moderately sized living room, I think the tank is a little light on the octane.

Zavato

Per Stereophile testing the XA30.5 goes to 130 wpc at 8 ohms A/B.

It should work fine at average listening volumes. Simple calculation!

1 w 88 dB @ 3 ft
2 w 91dB
4 w 94 dB
8 w 97 dB
14 w 100 dB
28 w 103 dB
56 w 106 dB

If a speaker seems "light on octane" driven by a 300 watt amp,
that's quite a very inefficient speaker that's wasting good quality power
(Pass amp) IMO. Its never been clear to me why some speakers need to
draw so much power to come alive, just a curious observation and not
criticizing.

I drive a pair of Thiel 2.4s (Impedance: 4 ohms nominal, 3 ohms minimum. Sensitivity: 87dB/2.83V/m. Recommended power: 100–400W) with that amp, and even though I got a lot of shit for doing so, it sounded quite a bit better than a Pass Labs X250.5 and a McIntosh MC-402 (the loser in the competition, by far). According to Stereophile's measurements (see the link below), the 30.5 provides 195 watts into 4 ohms before clipping. I do think the XA series is a little light on bass though. I've read that over and over, with people endlessly upgrading up the line to try and address the issue. In my opinion, it's just the weakness of the XA series. I got slightly better bass with the X250.5 (500 watts into 4 ohms), but everything else was quite a bit better through the XA30.5 (soundstaging, imaging, vocals, timbre). It wasn't a hard decision to figure out what to keep.

http://www.stereophile.com/content/pass-labs-xa305-power-amplifier-measurements

Also, just saw this on another (active) thread about your speaker...

03-12-14: Bbybaudio
Ricred1,
Thank you for your post. I was concerned that the Snappers (100WPC Tube) may not be enough, but found a review that drove the F208s with 60WPC Tube.

Thanks folks,
What Brands/models should i look at? My room size is 13 x 19 and i listen to classic rock (I enjoy live recordings), western classical music. I plan to buy a used pair of speakers to get to the higher models and brands. Budget is around 4000-5000 USd.
Thanks

Charles, the XA30.5 puts out 30 watts per channel, not 300 watts. 30 wpc could still work though, but would depend on the size of the room and the listening levels as to whether it would be enough for the Revel speakers. In a small to moderate room, at moderate listening levels, I'm sure it would be fine.

Kartikeyp,

I currently have F208s and submit they are a super great value. I just ordered a Parasound Halo A-21 to drive them.

I have stand mounted monitors rated at 7 ohms and 89 db efficiency in a 10' X 12.5' room.

I auditioned a Pass XA 30.5 and it sounded glorious at quiet levels, but completely lost it as I increased the volume.

Chuck

Hi Jmcgrogan2,
I was responding to the post by Zavato written above my comment. I'm familiar with the specs of the highly regarded Pass XA30.5.
Charles,

I get it that the Pass has a lot more juice than 30 watts. However, none of us can argue that the real charm of a Pass or similar class A amp is the output while fully in class A.
I run 12 watt Class A amps up to a 375 wpc Mac. My Coincident Speakers are amazing with any of these. At 94db and up, they really sing with 30 watts.

Sorry Charles, my bad, I didn't read Zavato's post thoroughly enough.

Cheers,
John

Don_c55, while your calculations are correct, IMHO, it is not that simple unless you are listening to a 1K test tone @ 3 ft in an anechoic chamber. You must consider other factors like, actual listening distance and dynamic peak SPL for a preferred listening volume. I think the calculator in this link gives a more reasonable answer as to how much power is needed. Very easy to use, just plug in the numbers for an immediate answer.

http://www.allegrosound.com/Power_AllegroSound.html

Listed in Revel's specifications for the F208 is recommended power of 50-350. Obviously, it does seem that the F208 is better suited for higher power, however there is always an exception, as Cal3713 noted. Also, Cal3713's speaker has a 87db sensitivity and recommended minimum power of 100, while it's possible to find another 87db speaker with a recommended minimum of 10. So why? I believe it is due to type of cabinet, motor structures of individual drivers, number of drivers, complexity of crossover, and probably other factors. All of these require varying amounts of power to function at peak performance.

We are all certainly entitled to our own opinions, so considering the music Kartikeyp listed, classic rock, assuming at times, he may "crank it up", can't imagine that for background music, and classical, some having very wide dynamic range, I'm thinking speakers from Zu Audio. I have listened to a couple of Zu's with Threshold Class A, as you know a Pass design, and thought it sounded extremely good, at least to my ears, which from working in the audio industry for over 20 years, have heard many different components, speakers, and combinations. Also, have listened to other Zu's on different electronics, and they always seen to have the "live" musical character, which I prefer, as opposed to what I call a typical "hi-fi" sound.

So to answer the question in a general sense, when matching amp and speaker, I would always rather have a little more power than actually needed, as opposed to just barely enough.

John, You celebrating St. Pat's early? :) I'm Irish:)

03-13-14: Isochronism
John, You celebrating St. Pat's early? :) I'm Irish:)

I'm first generation American....my father is born and raised in Ireland. He left for the country where the "roads are paved with gold" when he was 25 years old.
I don't really celebrate St. Patty's day though....do you?

Tls49

Only idiots listen at the SPL ranges for rock and metal listed in your referenced link!

They way over estimate the wattage needed.

Hi Elvick, Which Coincident model do you use?

Hi Kartik,
I suggest you stay at or above 90 dB for your new spkrs.
Among coincident spkrs. There is Coincident Total Victory ll Full Range Speakers on sale on A'gone right now . You may consider Total Victory V which is current model ( 95 dB) .Earlier models were Eclipse and Total Eclipse which are worth considering you are looking for a good used pair .

Another very good one to consider is Aerial 20T V2 ( or even V1) ( sensitivity 90 dB) , but you will need to up your budget. But you can be set for very long time with your Pass XA30.5.

If you like the Pass/Revel combo, prices on the .5 series seem to be coming down now that the .8 series has been released. Maybe a XA60.5

I have Revel F52 with a PASS X250.5 90% of my listeing the amp stays in CLASS A which is about 30 watts. Its a great match.

You can get F52's for around 3K used and they are better than the 206 or 208.

I like the revles better than B&W 801 matrix III and B&W 802s I also had Magies 3.6's Spendor SP1/2e, Viro III's and the revels are the ones I have kept for over 4 years now. My next upgrade will be to the salon's

John, In my town the Parade routes right in front of my terrace. The bars in town, which there are way TOO many, open up at 10 on Parade day, (which is tomorrow, Saturday) normally at 12. There are five bar/clubs directly across the street from me, another soon to open. Two right around the corner, another right down the other corner!! Ridiculous. It is the best day of the year NOT to drink! Just watch the other stumblebums. The town will be full of them tomorrow.

Don c55,
I share your opinion concerning the excessive high volumes and the real threat of potential hearing impairment (irreversible). But ultimately to each their own. I attended a jazz concert last night in a modest size venue and it was unamplified. My friend's phone SPL app measured low- mid 90s db on average from our seats 20 feet away. That is definitely loud enough for me and at home I'd be listening 10-15 db lower. So it's an individual comfort level choice.
Charles,

Thanks Radni, I am almost there deciding on coincident technology, the only problem being, I have to ship these to india. I was wondering if Trimph Extreme II would be ok. Can anyone tell how big a compromise it would be from the victory series to Trimph Extreme II. Can the difference be compensated by adding quality subs?

Fin1bxn,

I went from F52s to F208s. I have them in the same room, with the same equipment. This is a very subjective hobby, but to my ears to say the F52s are better is crazy; different yes, but better?! The F52s are more of a point source. The F208s are more dynamic, better bass, bigger soundstage,and when properly setup the F208s image better. I submit most people will say the F208s are a little clearer than F52s. I won't say there is a night and day difference, but most people will hear the difference.

Don_c55 and Charles1dad, I do agree that an excessive high level of AVERAGE SPL is for idiots, however there can be a very wide margin between average SPL and peak SPL with some music, especially classical. The SPL numbers to be used in the calculator I provided in the link are peak, not average. Also, this same calculator is found in many places on the web, as it factors in using a pair of speakers, room gain, and listening distance.

So how high can the peak SPL actually be at the listening position with a normal average SPL? Then please read the comments by Almarg, a well respected contributor to this forum, in this thread, especially the last paragraph of his 2nd post.

http://forum.audiogon.com/cgi-bin/fr.pl?htech&1348838898&openusid&zzAlmarg&4&5#Almarg

Here is another paper worth reading about power needed and peak SPL in a "good hi-fi system",

http://www.daedalusaudio.com/images/loudspeaker%20sensitivity.pdf

Depending on the type music and quality of recording, it is very possible at the listening position to have a peak SPL of a 105db, while the average SPL is only 75db.

Bottom line is the required power is not for average SPL, but for that peak SPL, which is much higher than a lot of people think, even though it is only for a split second. Having less power than required for the peak SPL will restrict the dynamic range, and clip the amp for that split second.

You might want to consider Focal they are very good with the pass xa series of amps and are 90db + efficiency with 4 to 8 ohm nominal impedance depending on model.

Hi Tls49,
I understand your point and priorities. I don't desire or seek those high peak levels, and I've heard systems capable of reaching 105-110db levels. That doesn't impress me and isn't an important personal criteria. But of course that's just me and I'm in no way critical of your preferences. We all aspire to achieve the sound/audio systems that fulfill our particular goals. I wish you the best in your sonic endeavors. I'm a confirmed fan of Almarg's many quality contributions.
Charles,

I wish you the best in your sonic endeavors.

Charles1dad, thanks, and the same to you. Sorry for getting on the soapbox, but when I read this statement in Almarg's post,

For instance, I have many classical recordings on labels such as Telarc, Sheffield, Reference Recordings, etc. that at my listening position reach peaks that I've measured at around 105 db, although the average level during those recordings is perhaps in the low 70's.

it just fueled my fire.

No doubt everyone's goals and desires are different, however when matching amp to speaker, IMHO, too many people make choices that result in being underpowered.

BTW, your system, extremely nice, and such an appropriate name, I can only imagine.

Tls49,
I appreciate your kind comments very much.
Charles,

Triumph Extreme II are small monitors with lower freq at 45 Hz. The room size is not small being 13 x 19 ft. Triumph Extreme II cannot do justice to high quality of Pass XA30.5 amp.

Hi Kartikeyp,
The Coincident Triumph Extreme would be an excellent choice in my
opinion. It would mate well in a room of your dimensions . This speaker is
very easy to drive( relatively flat 8 ohm load) and your Pass amplifier would
simply coast, sound effortless and remain in class A probably 99.9 % of the
time. I believe that you'd love this Pass- Coincident pairing.Coincident
speakers are very natural, transparent and most of all musically involving.
If you're seeking analytical hifi then these speakers won't suit you. Gon
contributor Brownsfan just bought these Triumphs and is ecstatic with their
sound quality. Sub woofers are of course an individual case by case
decision.
Charles,

Thanks folks. I appreciate your inputs. Narrowing down to a few brand / models is a big challenge in the HiFi jungle. I think i ll start looking for coincident models soon.

Tls49-

The calculator you provided a link to is useful and in my experience, accurate. I can be listening at levels averaging 80 dB but with music with real dynamic range, peaks will hit over 100 dB. That's the issue the XA30.5 will hit with 88dB speakers. And at my 3.5 m listening distance, that's why I said my speakers sometimes are a bit light on the octane.

Other factor to consider which is virtually never really mentioned is that if you really do have enough power on tap, speakers begins to experience dynamic compression at higher spl levels. Said another way,mspeakers can run out of steam before the amp can.

Were I serious about a XA30.5 I would concentrate on speakers running at least 92dB or more efficiency. The whole pointof the XA30.5 is to run it in its sweet spot, and if you're relying on the power on tap when it crosses over to class B operation, might as well get an X150.5

Sorry to be slow. Currently I have Coincident Conquests, Triumphs and Triumph mini's-Whole theater.

I have this exact setup in my bedroom (19L x 18W x 10H), F208 with XA30.5. I have no problem playing music loud. The combination makes glorious music. Love the pair.

I am using the XA 30.5 with the Legacy Audio Focus SE in a 15' x 22' room. Great full range speaker, 94 db efficiency. Ony rarely do I see the needle start moving.

That's a better match than with the Revels.

I auditioned them thru an anthem integrated 225 and was really impressed with how good the combo sounded.