Pass Labs XA60.5 monoblock power amplifier Associated Equipment

Sidebar 2: Associated Equipment

Analog Sources: Linn Sondek LP12 turntable with Lingo power supply, Linn Ekos tonearm, Linn Arkiv B cartridge.
Digital Sources: Marantz NA-11S1 media server; Parasound Halo CD 1 CD player; Ayre Acoustics C-5xeMP universal player; dCS Vivaldi SACD player–D/A system; Apple 2.7GHz i7 Mac mini running OS10.7, iTunes 10, Pure Music 1.89; MSB Diamond DAC IV with Diamond Power Base, Electrocompaniet ECD2, NAD M51, Auralic Vega D/A converters; Ayre Acoustics QA-9 USB A/D converter.
Preamplification: Channel D Seta L phono preamplifier, Pass Labs XP-30 line preamplifier.
Power Amplifiers: Classé CT-M600, Lamm M1.2 Reference monoblocks.
Loudspeakers: Wilson Audio Specialties Alexia, Vivid Audio Giya G3.
Cables: Digital: Kubala-Sosna Elation! AES/EBU, AudioQuest Coffee, Belkin Gold USB, Transparent USB (with dCS Vivaldi). FireWire: AudioQuest FireWire 400 (prototype). Interconnect (balanced): Kubala-Sosna Elation!, Transparent, AudioQuest Wild Blue. Speaker: Kubala-Sosna Elation!. AC: Kubala-Sosna Elation!, manufacturers' own.
Accessories: Audio Power Industries 116 Mk.II & PE-1, APC S-15 AC line conditioners (computers, hard drive); ASC Tube Traps, RPG Abffusor panels; Ayre Acoustics Myrtle Blocks; Target TT-5 equipment racks; Shunyata Research Dark Field cable elevators; AC power comes from two dedicated 20A circuits, each just 6' from breaker box.—John Atkinson

COMPANY INFO
Pass Laboratories Inc.
PO Box 219
Foresthill, CA 95631
(530) 367-3690
ARTICLE CONTENTS

COMMENTS
waynel's picture

 70°C below a rated maximum is 126°F below rated max, not 158°F

25°C above ambient is 45°F above ambient, not 77°F

 

"Nelson Pass says that the actual chip temperatures are about 70°C (158°F) below their rated maximum. But with that much bias current, a class-A amplifier will run hot, "about 25°C [77°F] above ambient,"

John Atkinson's picture

waynel wrote:
70°C below a rated maximum is 126°F below rated max, not 158°F

25°C above ambient is 45°F above ambient, not 77°F

Thank you for the corrections. Looks like we erroneously added the extra 32° in both cases, confusing Celsius degrees with degrees Celsius.

John Atkinson

Editor, Stereophile

jlesnick's picture

Hey John,

Now that you've reviewed both the CP-800, & XA-60.5s, do you think that the two devices would have a good synergy together?

John Atkinson's picture

jlesnick wrote:
Now that you've reviewed both the CP-800, & XA-60.5s, do you think that the two devices would have a good synergy together?

Yes, I believe so.

John Atkinson

Editor, Stereophile

karaflohighendas's picture

Hey John, hope you are fine!

Do you mean the best for this price or the best overal? Comparing XA60.5 with your past reference 33H what is your thoughts?

John Atkinson's picture

karaflohighendas wrote:
Do you mean the best for this price or the best overall?

Best overall. Although other amplifiers exceed the Pass Labs in one or two areas, the XA60.5 offers the best balance of qualities.

karaflohighendas wrote:
Comparing XA60.5 with your past reference 33H what is your thoughts?

Sadly, one of my No.33Hes has been broken for the past 5 years and I haven't been able to afford to get it fixed yet. I couldn't perform direct comparisons, therefore.

John Atkinson

Editor, Stereophile

 

karaflohighendas's picture

Is it possible an amp so old like 33H to compare with something so new with all these new materials and design? I think that 60,5 probably outperform 33H in every way with no direct comparisons needed at all. Dont you?

Regards

O karaflos highendas

John Atkinson's picture

karaflohighendas wrote:
I think that 60,5 probably outperform 33H in every way with no direct comparisons needed at all. Dont you?

Without being able to make the comparisons, I think it foolhardy to conjecture what the differences between the two amplifiers might be, let alone rank them.

John Atkinson

Editor, Stereophile

 

 

pepe's picture

Hi John,

Thanks so much for the great review.  I have a quick question, Do you recall if the front meter was contantly moving when driving the Alexias at normal listening levels?  (e.g. around 70-80db).   Did you feel like the XA 60.5 had enough power for the Alexias or did you feel like a higher XA, such as the XA100.5, would be a much better match?

Thanks for your insight, really appreciate your feedback.

John Atkinson's picture

pepe wrote:
Do you recall if the front meter was contantly moving when driving the Alexias at normal listening levels?  (e.g. around 70-80db).

No, the meters remained steady at the central, bias position.

pepe wrote:
Did you feel like the XA 60.5 had enough power for the Alexias?

In my 27' x 16' room, yes.

John Atkinson

Editor, Stereophile

koslekt1's picture

What are your thoughts regarding either the 30.5 or the 60.5 running Genesis 500 speakers? I'd love to gain the sonic qualities these have and with the 500's being self powered on the bass, I'd like to think it might be possible.

Hebaton's picture

Hello John, I keep reading fantastic things about this amp but I am
hesitating because I do not know My speakers sensitivity or Nominal
Impedance. I have Dunlavy SC-V but no manual or any technical info.
Will this amp work with those ?
Regards,
Claude Panneton

sboje's picture

8 Ohms
XA30.5 – “The amplifier doesn't actually clip (defined as the THD reaching 1%) until a much higher power level: 130Wpc into 8 ohms (21.14dBW).”
XA60.5 – “the XA60.5 considerably exceeded that power, delivering, at 1% THD, 130W into 8 ohms (21.1dBW, fig.4),”

This implies that a single XA30.5 and a pair of X60.5 amps will both put out 130W per channel), making the stereo chassis twice as powerful as a single xa60.5 monoblock chasis. You mentioned that the XA30.5 is a full 6db more powerful than its rating, but it looks like the XA60.5 is measuring only 3db more powerful than it’s 60w rating.

Your 4 ohm measurements were reported similarly.

On the 2 Ohm measurements, you actually state the XA30.5 was driving a single channel, so that result looks consistent.

What are the correct values? Were the numbers for the XA30.5 actually for a single channel?

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