2. amps-preamps
  3. 129597-97719

Pass Labs XA30.5 in my system?

Dear Audiophiles!

I am looking for a solid-state class A power amplifier with balanced circuit topology to replace Acurus in my modest Hi-Fi setup:
 
Mac mini (USB3 output) ->
Singxer SU-1 ->
Yggdrasil DAC (AES/EBU XLR input) ->
Primare PRE30 preamplifier (AES/EBU XLR input) ->
Acurus A250 power amplifier (RCA input) ->
Monitor Audio RS-6
 
I am currently considering Pass Labs XA30.5 and am wondering if it will “work nicely” with my upstream and downstream components.

Any info/advice is very much appreciated. Please chime in!

Please see the specs below for your consideration.

Pass Labs XA30.5

Type: Solid-state stereo amplifier
Power Output: 30 wpc into 8 Ohm, 60 wpc into 4 Ohm (both 14.8dbW)
Power Consumption (Watts): 238
Temperature (deg C.): 53
Voltage Gain: 26 dB
Input Sensitivity: 0.77 V at 26db gain
Frequency Response: 1.5Hz–100kHz, –3db at 1.5Hz, –2db at 100kHz
Signal/noise: 150db at full power (I cannot believe this is not a misprint!)
Distortion: 0.01% at 3 watts, 0.1% at 30 watts (measured at 1 kHz)
Input Impedance: 30 kOhm balanced, 15 kOhm unbalanced
Damping Factor: 150 for an 8 Ohm nominal load
Maximum Output Current: 20 Ampere
Maximum Output Voltage: ±35 Volts
Output Noise: 150 microvolt unweighted 20 Hz - 20 kHz
DC Offset: <50 mV
Slew rate: ±50 V/µs
Dimensions: 19" (485mm) W by 7" (180mm) H by 19" (485mm) D
Weight: 62 lbs (28kg)
Shipping weight: 75 lbs (34kg)

Primare PRE30 Preamplifier

Balanced inputs          560mV
Line inputs                   280mV
Sensitivity adjustment    -20dB to +20dB
Tape outputs               280mV
Gain                            16dB
Frequency response    DC to 100kHz ± 0.1dB
THD                             <0.01%
Signal-to-noise ratio    -118dB
Crosstalk                      -113dB
Mains                            100/115/230V
Dimensions (WxDxH)    430 x 410 x 100mm
Weight                           9.5kg

Monitor Audio RS6

Frequency Response: 38 Hz - 30 KHz
Sensitivity (1W@1M):   91 dB
Nominal Impedance:     6 Ohms
Power Handling (RMS): 120 W
Recommended Amplifier Requirements (RMS): 40 - 120 W
Tweeter Crossover Frequency: 3 KHz
Drive Unit Compliment: 1 x 6” C-CAM® Bass, 1 x 6” C-CAM® Bass Mid-range. 1 x 1” gold dome C-CAM® tweeter.
Cabinet Design: Balanced velocity twin reflex ported
Product External Dimensions: (H x W x D) 850 x 185 x 250 mm
Plinth Dimensions: (H x W x D): 25 x 255 x 305 mm
Individual Weight: 18 Kg

N.B. Impedance varies with frequency and goes to as low as 4 Ohms and as high as 16 Ohms. And, most importantly,“real” sensitivity is much lower than “nominal”: 87.40dB (averaged 300Hz-3kHz, 2.83V/1m)!
Measurements taken in the anechoic chamber at Canada's National Research Council can be found through this link:
http://www.soundstagenetwork.com/index.php?option=com_content&view=article&id=1221:nrc-measu...

hardball

Showing 5 responses by karl_desch

karl_desch's avatar
karl_desch
459 posts
 
I can't imagine you not loving this amp in your system which is far from modest.  It will allow you to use XLR connections from your great Schiit DAC/primare and will drive your speakers without issue.  I've been using one for several years and have no desire to upgrade other than random curiosity.
karl_desch's avatar
karl_desch
459 posts
 
The Pass Labs website does a great job of explaining their amplifier designs. If you wanted something that was less heat producing you could try their X series instead of the XA series. But I really don't think you have a problem with the heat from the XA 30.5. The efficiency of your speakers is not an issue with this amp nor are the lower  impedance dips across the frequencies.  
 Because your preamp is fully balanced you shouldn't  worry too much about quality of your balanced interconnects. I have compared A shorter run of Audioquest SKY to a long run (20ft) of regular old Mogami quad XLR microphone cable. The 60 dollar microphone cable was not inferior.  Other designers of balance amplifiers like Atma-sphere would agree that you shouldn't spending too much money on XLR cables  in a fully balanced connection. 
karl_desch's avatar
karl_desch
459 posts
 
Why did I type Mogami?  I meant Canare star quad XLR.
karl_desch's avatar
karl_desch
459 posts
 
The amp has massive headroom yes. Not your typical 30 watt amp.
The Canare cables can be purchased through Blue Jeans Cable.  I actually purchased mine through Amazon!  I use a Cardas Clear power cable on my amp but I have not compared to the stock cord.  
As far as fair price goes, I would strongly recommend you contact Mark at Reno HiFi.  He will give you a fair price on a new, demo or used piece and you will always be able to trade up the line in the future. How about a matching XP-10???  On Agon, I have seen them go for $3000 - $3500. 

karl_desch's avatar
karl_desch
459 posts
 
I use a SolidSteel amp stand and it looks good with the Pass.  MusicDirect sells them.

Call Mark at Reno Hifi and he will likely give you an even better price. He will also likely confirm most of the points made in this forum.

I leave the amp in standby mode when not listening.  It consumes lots of energy at idle so not a great idea to keep it on full power 24 hours a day. Also, not necessary.
More to discover