Magico Q5 and Pass Labs XA200.5 Synergy

I recently purchased a pair of Pass Labs XA200.5's and am trying to decide between the S5 and Q5 as the next step in my system plans (described below).

My primary question is will 400 watts of Class A be able to get the most of the Q5's? Will the Pass Amp's be "exposed" by the resolution of the Q5 in a negative way as is discussed so much in various threads?

I am particularly interested in whether the XA200.5 will: 1) have the backbone to handle the difficult impedance curve and phase angles of the Q5's, 2) add a little needed (to my ear) warmth to the Q sound and, 3) have the speed and control to show off the Q5's remarkable capabilities.

I suspect I could worry about these issues a little less with the S5 given their easier load and bass voicing. I know other amps may excel in certain of these areas, but I have chosen the XA200.5's as my anchor (against the recommended protocols of some) because I just cant find anything I like as much as Nelson's Class A.

As background:

I listen to most genre's from classical to rock and have a particular preference for accurate, lifelike orchestral and acoustic and exceptional low level detail.

To give insight to my preferences, my second place Amp was the Dag Momentum. I just can't find a substitute for the magic of pure Class A (also have 24 foot ceiling peak and air return at peak to basement to remove heat).

Room 20' by 30' with 24' foot center vault ceiling.

Preamp - CJ GAT or Pass XP-30 (to be determined)

DAC - MSB Analog or DACIV Signature (to be determined)

Front End - MSB UMT Plus (digital only)

SC and IC's - need help

Unfortunately my dealer only has the XA160.5 and Q3 in house. I will need to travel to listen to the options but want to get some perspective from experienced ears first.

Thank you for your perspective,


Interestingly the XS-300 is reported to output 50 amps max on the Pass web site; the XA200.5 puts out 48 amps! I wish I had a clearer understanding of how that current would drive the Q5's. Comments from Q5 owners are appreciated. (Remember the XA200.5 is essentially the same amp as the 1000 watt X1000.5 but biased in Class A.)

Of course volts mater too!

I can't comment on the sonics or synergy of the components and speakers that have been mentioned, but I would make the following points:

1)The GAT preamp has a specified gain of 25 db, which is most likely way too much for use in this and the majority of other applications involving digital sources. Unless, that is, the optional volume controls that are offered with the MSB DACs are included, and provided that those controls do not adversely affect sound quality when set to provide substantial amounts of attenuation. In which case, however, there may be no point to having a separate preamp at all.

The gain of the XP-30 is 10 db, btw, which is much more reasonable.

2)I wouldn't attach much significance to the 48 and 50 ampere current specs. (BTW, the manual for the Xs-300 indicates 48 amps, as opposed to the 50 amps indicated on the web page). As with most amplifier output current specs, they presumably represent the amount of current that can be supplied for an unspecified tiny fraction of a second into a dead short (i.e., 0 ohms), and therefore are not all that meaningful when it comes to driving music into real world speaker impedances.

Consider, for example, that for the sinusoidal waveforms upon which these kinds of specs are based 48 amps peak corresponds to 48 x 0.707 = 33.94 amps RMS, which into a 4 ohm resistive load corresponds to (33.94 squared) x 4 = 4608 watts! Clearly 48 amps is overkill even for the Q5's somewhat difficult impedance characteristics, and would not be attainable anyway due to voltage swing and other limitations.

Good luck as you proceed. Sounds like you're on the road to a really fine system. Regards,

-- Al
Thanks much for your comments. They will definitely prompt some additional caution and thought on my part.

Regarding point (1): I originally was directed to the Conrad Johnson GAT and ARC Ref 10 (12 db of gain) by a representative of at Pass as a preamps with good synergy, but I didn't address the digital source with him. I will now. Thanks.

I have been aware of the GAT's 26 db gain and have wondered about this issue but given the Pass XA200.5's fairly modest 26 db, I thought it might even be to my advantaged with the tough Magico Impedance curve. But your right, the MSB DAC outputs 3.6 volts single ended and should be considered. Regarding gain adjustment, I do not want to attenuate through the MSB even though they have an excellent unity gain buffer stage. When I am going to attenuate I would prefer my nonlinear steps be second harmonic...ergo the GAT or Ref 10.

As an aside, this review of the GAT used the Pass XA200.5 as one of the amps with great success.

Regarding point (2), of course mine was a relative point being made to distinguish between stated Max Currents of both amps for comparative purposes only (i.e., they are fairly similar). It was not meant to confuse instantaneous Max Current with operating load, FLA or otherwise.

Sorry about the confusion and thanks again for your help.
Wattsperchannel, If you're considering Magico Q5, do yourself a favor and checkout TAD Reference One before writing the check.

For the record, I like Magico so not bashing them.