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Pass Labs Amps - Does the heat bother you?

I am very intrigued by pass amplifiers (NOT the intergateds). I have heard many good things about them. However, I also have heard from many people that they get really hot. I am interested in the stereo amps.... like the X350. 

Curious, if you own one or used to own one... how do/did you deal with the heat? I wouldn’t want it heating up my living room where the AC runs more (which kills my music enjoyment session). 

Also, I usually leave my  amp on from 5:00 pm till I go to bed (anywhere from 9:00 pm to 12 am). Not sure how that would come into play if a pass labs would be a good fit for me. 

 

dman777
mwood
85 posts
 

My XA 30.8 doesn’t produce the heat my 300B mono blocks do and in either case the heat produced in minimal. The joy of hearing what the 30.8 brings to my listening sessions far outweighs any concerns or perceptions about it producing heat. If you are inclined to try Pass Labs I encourage you to!

barts's avatar
barts
802 posts
 

I am running four Pass amps. Two X260.8 and two XA30.8 ion my tri-amped system.  The listening room gets slightly warm...the amps never come out of Class A operation no matter how loud I make it.  So full heat at idle and stays that way.  I put a Thermoworks BBQ thermometer on each amp and they stay at ~107-112 F.

If I remember correctly they weigh about 80 lbs. each. So that is a lot of metal.  No its not uncomfortable here in North jersey.

Regards,

Paul

cfa88's avatar
cfa88
120 posts
 

I used to own a pair of XA200.5 amps, and heat never bothered me.

elliottbnewcombjr
7,825 posts
 

1. 350 wpc, wth, what speakers do you have?

2. 132 lbs (or more), add the cost of knee surgery (torn meniscus) or back surgery (herniated disc). Wait till you get old, know any teenagers? I just changed my 15" woofers. Speaker weighs over 100 lbs (but less than 132), all I did was tilt it, lower it on a blanket, back off, change the woofer, tilt it back up. Not a hernia, but my belly and back are just calming down 4 days later. I tore a meniscus moving an 80 lb McIntosh amp.

3. leave on, that is absurd IMO. Believe in warm up, ok, on, 20 minutes, listen, OFF! Aside from wearing out parts unnecessarily, heating up the room, consider conservation: it is just plain irresponsible to waste electricity.

4. ac. run the room a few degrees cooler, then turn it OFF for a listening session so there is no fan noise or gets too hot too quickly.

5. block ac vents?

They make filters, and shutters, so you can let the house cool, and partially or completely block the vents in the listening area

a. near any speaker so the heat does not dry out the cones

b. near your ears.

retiredaudioguy
298 posts
 

A few rules of thumb, based on experience.

  • Class A, Tubes, cathode bias, heat dissipation = rated power * 6
  • Class A-B, Tubes, fixed bias, rated power * 2
  • Class A, SS, rated power (@ 8 ohms) * 4

The quoted figure for the 350.8 (Class AB) is 600-800 watts.

If you want 250 watts, based on Google's AI summary, class D would be somewhere between 25 and 50 watts (10 to 20% of rated output).  

I ran a VAC 70/70 for many years (400 watt dissipation I think)  and it made my room warm!  Kept it OK in Winter, Hot in Summer.

 

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