"Overall, the music picture portrayed by the 100.5 is towards a denser and complete sound if compared with the 60.5.
If one can stretch, go for the 100.5. I agree from some of the comments I read and heard, the 100.5 is the sweet spot model among the XA.5 series in Pass Labs."
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Exactally my fillings. |
I enjoyed the XA100.5 very much until I bought a new pair of inefficient speakers and found the amps did not have quite the power the speakers needed. So I traded the amps in for a pair of XA160.5's. The result was a more open and effortless sound with a slight increase in soundstage depth and clarity. Bass also had more impact with slightly more control. There were no areas in which the sound got worse. But they are heavier and hotter, take up more space and use more energy.
Perhaps the 10.5 is the sweet spot, but if one needs more power, I'd recommend as much class A power as one can afford. There does not seem to be a sonic price as you go up the XA.5 line. |
I would expect all those benefits when you move from an underpowered amp
for one with the power necessary to drive a given speaker. But I'm not sure how
you know there is no sonic price driving a speaker that can easily be driven by
an XA30.5 and then driven by the 160.5 - let's say a speaker with 94db
sensitivity - I suspect, but cannot prove it since I have not tried it, that there is
a sonic price to be paid for those extra watts, when those extra watts serve no
real world purpose in being able to drive the speaker loud and with bass
control.
In your case the sonic penalty is paid when trying to drive a speaker that needs
more power than you had with the XA100.5, and when you need more power I
would not expect a sonic price being paid by adding the higher powered amp, it
is the wattage you need to make the speaker come alive and a lack of power is a
much higher price to pay than a lessening of purity due to all the added
electronics need for higher output..
However, at any power level, I think the XA.5 series is among the best sounding
SS amps available - they are all excellent IMHO. The changes you can expect in
moving from the 60 watt version and 100 watt version will depend on the
speaker being driven, |
Good point Pubul57. I've never tried my bigger XA.5 amps with more efficient speakers, so I really don't know if they sound better or worse than say the XA30.5 would. I would expect some advantage from monoblocks with the separation of each channel, but that is also just speculation on my part. |
I still believe the monoblock argument about separation, though it may be an article of faith as some folks I respect on things audio don't believe this is the case with well made gear, I don't know but there certainly is very highly regarded gear in stereo configuration - and my Music Reference RM9 and CAT JL2 had pretty darn good separation:) The theory certainly makes sense, and it must be an advantage to be able to run shorter speaker cables. |
Pubul57,
I too have found that smaller wattage amps will generally have a sweeter/purer sound. In decision making, I always go by my ears first then work backwards with my brain to see if there is a reason for a finding, but always ears first as they are "direct coupled" to my wallet.
This has held up even with my sub-hobby of vintage receivers. I prefer the sound of the lower watt ones to the monsters of old. What I have read (but don't know first hand) is that a lot of "music lovers" prefer the sound of the Marantz 8b to the 9's and the Mac 225 to the 275. Of course the speaker, and how loud you like it, are important factors.
I have a hunch one reason might be transistors and their non-linear characteristics. The more of them you use, the more NFB you need to get the amp to "spec" right. I personally don't like NFB.
My ears like what they hear in Pass's XA.5 series and this is from a guy who loves/has 4 SET amps. I have their 30.5 and 100.5's. Don't hear much difference beween the two. From what I've read about the design, running the Mosfets in pure class A, he can put them in their most linear range and therefore use much less feedback to correct. In his paper on the "Super Symmetry" circuit, he says he uses only a tiny bit of NFB to tweak the two circuits into balance so they cancel distortion. This may be why "his" larger amps don't lose don't lose the sweetness like other designs do. His papers on the Passlabs website are a good read.
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The man is on of the greats, and owning most any amp he has had a hand in is a pretty good thing. Loved his short-lived 25 watt, Aleph J which should be great with most any 89-90db or higher and smooth impedanced speaker, maybe as good as the XA30.5 with my speakers and very easy to drive with a tube preamp (240kohm input impedance). |
Nice comments Pubul57 and onemug. I believe you need the appropriate power to match the needs of a given speaker. I`ve personally have never been convinced by the arguement for gratuitous power i.e. one can never have too much power.
I`ve experienced enough examples where a lower power amplifier of equal built quality but simpler design and fewer parts(less complex) just sounds better(as long as the speaker is suitably efficient). |
I agree with Onemug. Somehow, the XA200.5 sounds sweet, delicate, and holographic in addition to all the other things we associate with ample power. I suspect most other solid state amps sound hard and flat as a result of their more complex design. |
Sounds like there may be no sonic price to be paid as you move up the Pass like, just the cash price (when you need the power). |
In terms of the more power means more complex circuit with more stuff going on, so less good sound, that was certainly born our with the original Pass Amps, where the Aleph 3 was considered the best sounding, although very low on watts.
I'm going to be moving from an Aleph 5 to XA60.5 (I think) soon - I have Maggie 3.6s, so very hard to drive and damping factor means a lot in my case. I'm tempted to actively bi-amp and use Spectral or NuForce on low end. (Crossover is 225 Hz on Maggie 3.6), that is the only reason I'm not sure if I'm getting the XA60.5s. So, even if I'm still underpowered, it should be a massive difference from the Aleph 5, the XA60.5s have sooo many more Volts and Amps.
Overall I think I agree that a smaller Amp - *if* you have met your dynamic requirement - will sound better. In my case Maggie 3.6s seem to take any amount of power and still want more, so I am considering X350.5s too, and that might actually sound better in my case. Really take control of the bass panel...
Okay - this is my main comment. Add a Supratek or Joule-Electra pre-amp. With the rest of your system as it is, you'll be shocked by what happens! And then you will really have a system that plays with the big-boys :). I think it will be completely different than what you hear now. |
Light,
Maggies are generally not a bad load for a good amp like Pass. IF the new 3.7s follow Magnepan pattern, there should be NO impedance dips to weird lows OR any huge phase angle stuff to deal with.
OTOH, they ARE fairly low sensitivity which is made up for by being dipole. Damping factor? Anything over maybe 20 will be fine. Even low damping tube amps work well, if enough power. The air damps the mylar pretty well, and being a single sided driver, not as coupled to the magnets as a good cone driver. The push/pull 20.1 may be slightly different.
You are right about dynamics and power, though...
Power users of panels like some of the big 'd' offerings. Spectron? massive.
Also, if Pass amps thru the line are anything like the XA 30.5, while it is 30x2 into 8, pure class 'a', the redline is almost 200x2into 4 in a/b. If the XA 60 does the same thing, it should be quite sufficient. Whoever said to look at the meter had it right. If the bias stays in 'a', or just a flicker periodically or on crescendos, than that is probably enough juice.
Given my listening habits (important for all to consider) I'd probably be quite happy with the XA30.5 level amp. The 60? WOW! OR if I had really deep pockets, a pair of 30s, as biamp!
Are the 3.7s fused? My 1.6s have a 4amp mid/tweet. I doubt the whole panel draws 8 amps at the limit. Thats just over 250 watts RMS..... How would that work out for dynamic power? Lots, I suspect. |
Yeah - Spectron - that is what I meant when I said Spectral :). |
"Are the 3.7s fused?" Yes, 5 amp mid and 2 1/2 ribbon.
I really want to try the XA100.5s on my 3.7s, seems like a great match. |
Light:
'More power means more complex circuit' is not necessarily true for Pass amps.
I've seen an amp on his DIY site, which you can adjust output power of simply by continuing to parallel output devices. Of course, some additional changes need be made, perhaps a higher VA rating on the main transformer and a higher current bias power supply. More devices DOES mean an additional opportunity for component failure, but SS devices ran within normal parameters have a very high MTBF. I'd bet as much as 20 Pesos that the higher power amp is at least 98% as rellable as the lower powered version....other things being equal.
I heard it said that the XA30.5 and the X150.5 are the SAME amp, save for some bias circuitry adjustments. I'm not sure, but it is feasible, I suppose. Though, if it were ME making these amps, I'd have an A-A/B switch so you could CHOOSE the mode which suited you or your mood.
Good news about the 3.7s and fuses. Ribbon fuse veterans of Magnepan refer to the Ribbon as the 'fuse protector'. Pretty fragile when presented with hi current distortion. Depending on the low / mid crossover point, the entire panel may be capable of sinking 12 amps...perhaps 50% more than the 1.6 with which I'm most familiar. My ancient MG-1 fuse was a paltry 1.5 amps above an unknown crossover. Based on the current capability and advertised sensitivity, even with all the stuff I said.....above.....I'd never try the 30.5, but go to at least the 100.5s...... |
Has anyone tried either the XA60.5 or the XA100.5 with the Vandersteen 5A? I'm wondering if either Pass amp has enough power for medium sized room and moderate listening levels (@10 ft). |
Nicks,
I use a pair of XA-100.5s with my Vandy 5As in a 14 by 24ft room. The meters on the XA-100.5s rarely move (leaving class A) unless I am playing fairly loud (above average 90dB) or listening to something with quite a bit of dynamic range (symphonic music) -- in either case on peaks above 98-100dB. My listening position is about 12-14 feet back from the plane of the speaker baffles.
I originally purchased a pair of XA-60.5s for my system after running a pair of ModWright KWA-150s in bridged mode on high bias. I really liked the tone of the ModWrights and thought I'd like to try full class A. Given that the 5As have powered woofers, I thought that the XA-60.5s would be sufficient for my system, room, and listening habits, but I found them swinging out of class A (moving meters) more than I liked. So I traded up to a pair of XA-100.5s and have been very, very happy. That said, if I find myself with extra cash lying around after upgrading my front end and preamp, I would love to have a pair of XA-160.5s just because.
Based on my experience, I think the XA-100.5s would be more than adequate in your situation. |
I have thiel 2.4 speakers. I am curious as to how you compared the modwright amps to the pass xa100.5. I very much appreciate your input.
Tom |
I owned them both in the past. The difference in sound and more in authority is clear. The overwhole sound of the 100.5 was a lot better. The same about the stage and the extra authority. I found the difference bigger than I thought it would be. That time I used it with the XP-20. |
