XPR amplifier temperature questions

[novisnick]

Dec 22, 2013 16:33:21 GMT -5 Andrew Robinson said:

Dec 22, 2013 16:22:14 GMT -5 novisnick said:

"...also ask if they will bring back the C-12 cooling fan,..."

Nick

Internally we're all big fans of the C-12 cooling fan and I know it's a product that we'd like to see return. This doesn't mean that it will or that I have a date for its re-release, but the C-12 is a product that is still being discussed. 

Thanks for the reply Andrew. That's the reason I keep bringing it up, to discuss when it will come back.
the only way to make this product better would be to make it full size so someone could place another component on top of it.
IMHO there could not be a better solution for this needed and wanted product.

lets keep the discussion going.

Nick

[novisnick]

Dec 22, 2013 16:56:11 GMT -5 Boomzilla said:

Dec 22, 2013 16:22:14 GMT -5 novisnick said:

Call Emo Monday to find propped operating temp and please post to the forum, also ask if they will bring back the C-12 cooling fan, and yes it has filters but not HEPA. I'm sure they could be made. Thanks for the idea! Nick

HEPA filters (high-efficiency particle accumulating) are typically used in industrial air-purifying respirators and in some vacuums intended for ultra-clean service. They trap >99.95% of all particles 3 microns or larger in size (HEPA class H13). They were first developed for use in the Manhattan Project.

They have become inexpensive and highly consistent. There's no reason NOT to have a HEPA filter on the supply air of any electronics equipment with a forced-air supply. If Emotiva does revive the Sherbourn C-12, then I hope they'll consider adding at least a HEPA filter option.

Boom

Exactly!
Thanks for the history lesson,,,,,,,,,,

Nick

[Gary Cook]

From the XPR-2 Manual;
Protection:
The XPR-2 is protected against excessive operating temperature,

My process for establishing the cooling requirements for the XPA-2, XPA-3 and XPA-5 was to;
1. Place the amp with nothing above it
2. Run it an normal listening volumes for an hour
3. Use a temp probe to establish the air temperature at the vents above the heat sinks
4. Place a shelf close above the amp
5. Move the shelf further away until such time as the temperature is the same as it was in #3

For the XPA-2/3/5 around 50 mm was more than sufficient (that's with a 360 degree open shelf).


Cheers
Gary

[novisnick]

Good show OL boy,,,,,,Good show,,,,,
Thanks boom.

Nick

[Boomzilla]

Thanks, Gary - That reassures me. My 2" clearance should be sufficient then to keep my amp at the same temp as if I had no shelf above it. My only remaining question is "what should the operating temperature be for a XPR-2?

If Emo says 135F, then all is well with the world. If they say 120, or some other temperature significantly less than what I'm running, then I've got to wonder why. My gut feeling is that my amp is operating as designed and that the 135F is normal.

[Deleted]

I just borrowed my friends temp gun and did some measurements of my amp.....
over the transformer 126f
over the left heatsink 132f
over the right heatsink 141f (average was 136 but I found a hot spot)


These are the max temps I found and my amp has been on for about 85 minutes

[audiobill]

With temps like that, I for one wouldn't think about restricting airflow in any way, unless I wanted an excuse to "retire" the amp early........

FWIW, the Gen 1 XPA-1's run very cool.........looking forward to a long life!

[novisnick]

Dec 22, 2013 17:18:28 GMT -5 Gary Cook said:

From the XPR-2 Manual;
Protection:
The XPR-2 is protected against excessive operating temperature,

My process for establishing the cooling requirements for the XPA-2, XPA-3 and XPA-5 was to;
1. Place the amp with nothing above it
2. Run it an normal listening volumes for an hour
3. Use a temp probe to establish the air temperature at the vents above the heat sinks
4. Place a shelf close above the amp
5. Move the shelf further away until such time as the temperature is the same as it was in #3

For the XPA-2/3/5 around 50 mm was more than sufficient (that's with a 360 degree open shelf).


Cheers
Gary

Very nice analysis my friend.
Nick

[Boomzilla]

Thanks, fattykidd -

Looks like my amp is where it should be, then. It may run hot, but the sound justifies the 10 watts at idle. I'll just leave mine on. That temperature, by the way is not at all unusual for a tube power amp and they last for decades without problems, so I'm thinking that the "high" 135F temperature isn't an issue. Emotiva apparently designs some of their amps to run cooler, but they just don't sound like this XPR-2! Given the choice of poorer sound or leaving a 10 watt night-light on all the time, I can afford the electricity. If I can only persuade my better half to turn off the closet light before she closes the door, then I'll have my money back with change.

That said, yes, I still might be interested in an Emotiva fan system with a HEPA filter - It would reduce the amp temperature AND keep the amp cleaner. The only reason I fret about this amp is that I plan to keep it. The previous amps were good equipment to have visited, but they didn't match this one. In fact, had I NOT had a variety of amps, I might not have recognized how good this one is. Once warm, I think it is the best I've heard. My old McIntosh MC352 was powerful, but it didn't have the delicacy that the XPR-2 does. Are there better power amps in the world? Probably, but I doubt that I could afford them. The power amp is no longer the "weak link" in my system (nor is my front end). The only place I think I could do better is speakers.

Thanks again for taking the time to measure - I appreciate it.

Merry Christmas! Boomzilla

[Deleted]

You bet, I'm happy to help. I also will be keeping this piece of gear for as long as I possibly can at some point I even hope to add the xpr-5 or xpr-7 to take over for my mps-2.
Merry christmas from up in Calgary

[Boomzilla]

I may get to visit Calgary again in February to March, or not. Depends on the project timing for the client. Use the heat from that XPR-2 to keep yourself warm!

Boom

[novisnick]

My space heaters have my window open and the overhead fan on, I've been playing them all day and loving. It!
God help me come summer. The C-12 s do have a port to exhaust heat through a duct, I may go that route.

Peace,

Nick

[novisnick]

Try this link boom.
www.audiolab.com/Sherbourn_C_12_Cooling_Unit_p/shec12.htm

Great unit.

Nick

[thorcorps]

Boom, I'm glad you are enjoying your new amp.

My XPR-1's, which are sitting on amp stands a couple of inches off of the floor in a big room with nothing above them or in close proximity, run around 96-98F at idle. This is with a thermometer sitting on top of the transformer area until it stabilizes. When I measured them, they had been on for days, but hadn't played music through them for several hours, so should really be a true idle measurement. I don't turn mine off unless there are thunderstorms.

[Boomzilla]

Thanks, thorcorps -

Apparently, the XPR-2 is one of the hottest-running of Emotiva's amps. I've noticed that many others say their amps run much cooler. 135F is not unusual for tube amps, so I'm thinking that the temperature is not a concern.

Thanks again for the feedback!

[The Mad Norseman]

Dec 23, 2013 10:29:30 GMT -5 Boomzilla said:

Thanks, thorcorps -

Apparently, the XPR-2 is one of the hottest-running of Emotiva's amps. I've noticed that many others say their amps run much cooler. 135F is not unusual for tube amps, so I'm thinking that the temperature is not a concern.

Thanks again for the feedback!

My XPR-5 is rather cool running, but I keep it in a cabinet just below a Comcast HDDVR which runs warm, so I have it cooled by a programmable thermostat that triggers a 140mm cabinet fan to keep the cabinet temp at 85 degrees or less in the winter, and below 89 degrees in the summer. I have that same thermostat connected to also trigger a pair of blower fans that sit atop my AV8801 processor that also can get pretty warm...
(All 'CoolerGuys' products, and they're quiet and so far after a year now, very reliable!).

[garbulky]

the xpr=2 does 10 watts class A?

[Boomzilla]

Well, that IS what dally said. I don't see any mention of it in the manual, but maybe I just missed it. With 600 wpc on tap for 8-ohm loads - 1,000 wpc on 4-ohms, I'd not be surprised if it DOES do 10 watts before leaving class A.

[dally]

I think Lonnie mentioned the class A during one of the Emofest's. I looked for the thread,but haven't found it yet. One interesting thing I did come across was a mention of idle current. The XPR-5 pulls .8 amps at idle, while the XPR-2 pulls 3.5 amps ! There must be SOME class A bias, especially if it idles at 3.5A &135 degrees.

[Boomzilla]

Well, it sounds "Class A" to me. I once built some 45 wpc pure Class A amps using a Nelson Pass design. They had the same purity that the XPR-2 does (and they ran just as hot).

For those who have never heard a pure Class A amp, I recommend at least trying the experience. IMHO they do sound differently. I like the tone that a class A amplifier seems to give that more conventional amps don't. No idea why, but the Class A sounds better to my ears. A cool-running Class AB (like the XPA-2) sounds more dynamic, but lacks the Class A "refined" sound.

Of course, if you DO want Class A, then you better have the cooling capacity. The output transistors are 100% "on" all the time, and they dissipate lots and lots of heat. Class A amps are expensive because they DO have to have such large heat sinks.

The XPR-2, if truly idling at 3.5 amperes, probably has more than a few watts at class A before the unit swings to AB operation. Since I listen at lower volumes, I'm assuming that ALL my listening is done in the Class A range. This would, by itself, explain my observation that the XPR-2 is somewhat "less dynamic but more refined" than the XPA-2. I suspect that if I had very low efficiency speakers and that I listened at higher volumes, that the dynamics of the XPR-2 and the XPA-2 would converge.

Boom