Expert 1000 Pro

[GuillaumeB]

Great write up from Confused as usual. 

The temperature issue is intriguing, I have always felt that my Devialets sound better when they are sub-50. Perhaps the 1000 Pro is an altogether different beast.

I haven't check my Od'A temps since updating the power to 1kW, however in the past I have never noticed them getting much higher than the low 40s. Considerably lower than my 800s.

Guillaume

Ok they have definitely crept up although admittedly the weather is quite warm at the moment. I seem to be getting high 40s, with DPM disabled. I guess the additional 100W is creating a little extra heat.

Guillaume

[Zappydev]

According to the physics I learned in skool, matt black should run cooler than shiny polished metal ....

[Music or sound]

I wonder if the increased temperature applies only to the class A amp or the entire device. Maybe running the class A part hotter makes it more linear and still could reduce the powerconsumption of the entire amp.

[Confused]

I wonder if the increased temperature applies only to the class A amp or the entire device. Maybe running  the class A part hotter makes it more linear and still could reduce the powerconsumption of the entire amp.

To summarise from my earlier post, on the same (very hot!) day, with the same speakers, very similar volume, the D800 was running A=43° D=42° S=41°, the Pro was reading A=57° D=48° S=50°.  That does not look more efficient to me.  It did sound good though! 

[wwm]

Had an interesting hour or so at Hi Fi Lounge where Paul was his usual perky self. We connected my 800 and used a pair of PMC fact12's. These speakers have not been Sam'ed so obviously this was switched off. Played half a dozen tracks to aclimatise myself to the speakers and the room before changing over to the 1000 pro and played the same tracks again. There was a definate improvement in timbre, more analogue if that makes sense also, mid range particularly voice was very clean and precise, very real in fact. I will be having the upgrade that's for sure.
Confused asked if I would check the temperatures so the master was A 39. D 38. P 47 and the companion was A 39. P39 P 45. That was after running all morning with fact 12's at a comfortable volume.
Cheers,
Bill.

[Confused]

Had an interesting hour or so at Hi Fi Lounge where Paul was his usual perky self. We connected my 800 and used a pair of PMC fact12's. These speakers have not been Sam'ed so obviously this was switched off. Played half a dozen tracks to aclimatise myself to the speakers and the room before changing over to the 1000 pro and played the same tracks again. There was a definate improvement in timbre, more analogue if that makes sense also, mid range particularly voice was very clean and precise, very real in fact. I will be having the upgrade that's for sure.
Confused asked if I would check the temperatures so the master was A 39. D 38. P 47 and the companion was A 39. P39 P 45. That was after running all morning with fact 12's at a comfortable volume.
Cheers,
Bill.

Thanks for getting the temps Bill.  Interesting that your class A temps are a full 18° lower that we had on Saturday, this is curious!

I have to say that it cannot have been easy to audition with unfamiliar speakers, I know, I have done this in the past with other kit.  But it can be done, and as for your comments; 'definite improvement in timbre, more analogue if that makes sense also, mid range particularly voice was very clean and precise, very real in fact', yes, I recognise all of that from my time with the Pro and the Blades. 

Analogue and very real!  I'd go with that.

[f1eng]

According to the physics I learned in skool, matt black should run cooler than shiny polished metal ....

There are 3 ways of losing (or absorbing) heat, radiation, conduction and convection.
Matt black, a "perfect black body" is the ultimate for radiant emission or absorption, but at hifi equipment temperatures radiant heat loss is negligibly small, so whilst black would be better it will be infinitesimally better.
The means of heat loss in hifi equipment is conduction from where the heat is generated in whatever active device to the surface of the casing or heat sinks, whence convection whisks it away.

In a Class-A amp where standing dissipation is some hundreds of watts, substantial fins with a considerable area for heat transfer to the air is needed. For Class D (and the Devialet AHD type) where the actual efficiency is high so most of the used power actually goes to the speaker and very little is wasted as heat, the surface area of case needed to dissipate this tiny amount of waste is small. Efficient conduction from the silicon junctions to the case is the important bit.

I understand people's confusion. There is lots of mis-use of terms. In cars (one of my responsibilities was cooling system for Formula 1 car where we had to dissipate over 500,000 watts of heat, a somewhat bigger problem than an AHD amp...) the "radiator" is not actually a radiator (it dissipates heat by forced convection) in the same way the "shock absorber" does not absorb shocks (it is a damper).

[f1eng]

Had an interesting hour or so at Hi Fi Lounge where Paul was his usual perky self. We connected my 800 and used a pair of PMC fact12's. These speakers have not been Sam'ed so obviously this was switched off. Played half a dozen tracks to aclimatise myself to the speakers and the room before changing over to the 1000 pro and played the same tracks again. There was a definate improvement in timbre, more analogue if that makes sense also, mid range particularly voice was very clean and precise, very real in fact. I will be having the upgrade that's for sure.
Confused asked if I would check the temperatures so the master was A 39. D 38. P 47 and the companion was A 39. P39 P 45. That was after running all morning with fact 12's at a comfortable volume.
Cheers,
Bill.

My O d'A runs at around these temps too.

[srima]

I wonder if the increased temperature applies only to the class A amp or the entire device. Maybe running  the class A part hotter makes it more linear and still could reduce the powerconsumption of the entire amp.

To summarise from my earlier post, on the same (very hot!) day, with the same speakers, very similar volume, the D800 was running A=43° D=42° S=41°, the Pro was reading A=57° D=48° S=50°.  That does not look more efficient to me.  It did sound good though! 

These high temperatures should be a cause for real concern. They suggest a product that may require frequent servicing to keep it going for the long run. I had a Krell KCT preamp for a few years. Gorgeous preamp with no solid-state harshness, but a full lush sound. Problem was that it ran incredibly hot, with the output transistors in class A mode. Even in standby, it felt warm. After a couple of years, I kept having trouble with it, the display would freeze, the remote would stop working, everyday some new problem would surface. I finally sold it in frustration. 

High temperatures are not a cause for concern if the product has sufficient heat dissipation capability. My Krell 700cx runs quite warm, but has massive heat sinks across its large body on either side. Even so, the heat generated is sufficient that the Krell would often make clicking sounds, which the factory said was normal. This was the  metal casework expanding and contracting, as the amp warmed up or cooled down. The 1000 Pro's don't have heat sinks, they must dissipate the heat through their surface. Perhaps quiet fans could be installed that blow air from top or bottom on the 1000 Pro's. 

As a computer science professor, I recently built several high performance GPU machines where heat dissipation is a huge concern. My first machine  used the powerful Tesla K80 (24 gig) graphics card, which lacked any internal fans, and was passively cooled. The Tesla was intended to be used in high performance servers, with loud powerful fans blowing over it. In my machine, it first ran for 10 seconds, overheated and shut down. It took me a few weeks to install a bank of fans all around that keep it cool enough to run long simulations. The Tesla is designed to withstand temperatures in the high 80s and lower 90s (centigrade), which is hot enough to burn your hand. My favorite current cards are the EVGA Titan X hybrid cards, which never get warmer than 40 degrees ©, even at full load. 

For a class D/class A amp to run around 60 degrees © is really surprising. I have a Quad Elite amp (latest variant of the classic Quad 606), which uses current dumping, combining a class A amp with a class B amp. It never runs more than slightly warm, even at loud volumes.

[Zappydev]

According to the physics I learned in skool, matt black should run cooler than shiny polished metal ....

There are 3 ways of losing (or absorbing) heat, radiation, conduction and convection.
Matt black, a "perfect black body" is the ultimate for radiant emission or absorption, but at hifi equipment temperatures radiant heat loss is negligibly small, so whilst black would be better it will be infinitesimally better.
The means of heat loss in hifi equipment is conduction from where the heat is generated in whatever active device to the surface of the casing or heat sinks, whence convection whisks it away.

In a Class-A amp where standing dissipation is some hundreds of watts, substantial fins with a considerable area for heat transfer to the air is needed. For Class D (and the Devialet AHD type) where the actual efficiency is high so most of the used power actually goes to the speaker and very little is wasted as heat, the surface area of case needed to dissipate this tiny amount of waste is small. Efficient conduction from the silicon junctions to the case is the important bit.

I understand people's confusion. There is lots of mis-use of terms. In cars (one of my responsibilities was cooling system for Formula 1 car where we had to dissipate over 500,000 watts of heat, a somewhat bigger problem than an AHD amp...) the "radiator" is not actually a radiator (it dissipates heat by forced convection) in the same way the "shock absorber" does not absorb shocks (it is a damper).

Excellent clarification - thank you!