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In Reply to: RE: The proof is in the pudding... posted by pictureguy on August 16, 2015 at 12:43:06
You made a fallacious statement regarding the weight and stated there was some "compromise" made, insinuating there was some issue with the heat dissipation. Weight has nothing to do with the performance of the amp. If overheating is not an issue, why even bring it up? It isn't a problem. It's a red herring.Yes, heat is better moved through conduction. The kind you get when the module is bolted to the case, like I said, which functions as one large heat sink with air moving AROUND THE OUTSIDE of the case. Perhaps you are unaware that the mounting surface of the ncore is a HEAT SINK and bolting it to the case turns the case into, yes, a HEAT SINK.
Let me know what amps are around in 2000 years I don't plan to use mine that long...Most class d amps seem to have no issue with overheating and shortened life. Hypex, as well as other amp manufacturers no doubt, perform life cycle testing. It is simply not an issue, as you yourself have said, so what exactly is your point in bring it up in the first place? I don't get the "there is a compromise in the amp design because it doesn't have enough heat sink but there isn't any data to indicate the existing heat sink isn't sufficient." Which is it?
Again, glad you found an amp you like. Not all amps perform at their best with any or all speakers.
try it! you know you want to!
Edits: 08/16/15 08/16/15Follow Ups:
I never said ONE SYLLABLE about Weight. Not one.
That being said, REAL heatsink DOES have some 'heft' to it.
As long as whatever is bolted to WHAT has some heat conducting compound to it AND sufficient mass, than you CAN make 'heat sink claims'.
Too much is never enough
Really? You did mention the amp "only" weighted 25lb and mentioned that there was thus some "compromise". I don't know about you, but my interpretation of what you implied was that the amp was too light (not enough heat sink) to perform properly long term given the output. Did I misunderstand your inference?
And Hypex has also repeatedly said that no heat conducting compound is necessary. Just bolt it to the case and you are good to go.
I can't speak for all class d manufacturers, but regarding Hypex, 25lb is no indication of any compromises or less than robust performance.
try it! you know you want to!
From B&O. This is for the ASP500 module, which was the middle of the 3 in the ASP series.
You have to admire the completeness of the specs and how forthcoming B&O was in this datasheet.
You may disagree IN DETAIL, but physics IS after all, simply physics. Module heating will be limited by how Quickly and Efficiently the heat 'migrates' from point of origin to the furthest point of 'sink'. This for the NCore stuff which you reference. You can Bet The Farm that better sinking willl result in better performance.
And yes, heatsink is GOOD. For example, many years ago, we used a CROWN DC-300 to run a shaker table for device qualification. I doubt the NC400 could do so. I doubt it would withstand the huge, low frequency high power abuse on a daily basis.
And yes, again. heatsink has some weight to it.
Go to page '6 of 26' for the REAL power callout.
FTC power? Limited, for test purposes to 3000hz.
Long Term Power of module limit (500 watts in this case) is 60 seconds w/NO preheat.
Attached in some fashion to additional heatsink, I'm sure that number would go UP.
Also, one of the power callouts is specified at Either 25c or 50c. The higher temp has the LOWER power.
Some other interesting information may pop out at 'ya upon check this doc out.
Again, I URGE you to have someone read my posts to you. I'm NOT going to repeat my stiplations for the 3rd or 4th time. I hope I was very clear, but if you have REAL questions about what I said, please write.
Too much is never enough
First, what does B&OO have to do with the amps under discussion? Both amps I mentioned above were Hypex based. You commented on the Taranis, which is Hypex based. It in fact has plenty of heat sink, despite your claim that there were compromises made because it only weighs 25 pounds.How exactly do class d amps perform "better" with more than standard heat sinking? Do you have any data that shows that running at the lower end of their safe operating temperature range improves measured performance in some way? They may last a bit longer (which is true of all electronics), but I am unaware of any increases in audio performance by running my ncore at 40C instead of say 60C....
I read your post just fine. You first stated that there were compromises made in the Taranis amp because it only weighed 25 pounds. You then said maybe it didn't matter in actual use. There were no compromises made with heat sinking and regardless, there is no issue in actual use with over temps. By the way, I believe the ncore has overtemp protection just in case....
Yes, most any equipment used in a way it was not designed for will create a potential for damage. It's called abuse. Nothing unique about class d in that regard.
try it! you know you want to!
Edits: 08/16/15
Heat kills electronics, or havent' you got the memo?On that basis, I would suspect that 'd' amps used with (especially) low sensivity speakers AND at higher levels in larger spaces WOULD have better long term health. Also, given the efficiency VS power curve of the ASP amps (Physics being physics, I'd suspect the NCore to follow a similar curve) efficiency drops fairly quickly at maybe 25 watts (8 ohms). I rather doubt, however, that ANY amp would have much problem dissipating the kind of energy we are talking about under those conditions, even WITH minimal 'sinking.
And as it turns out, as a 'd' amps efficiency (output stage) rises with power output, you won't need anywhere NEAR the same amount of mass as an equal power A/B amp.
And PHYSICS is what we're talkin' about here. Both an Ncore and a B&O module may both run at similar efficiency, they BOTH have a similar amount of heat to deal with.I think that using the case as a heatsink may not be a bad idea, BUT you ARE putting yourself at the mercy of the fabricator and case designer. Poor execution of a good design is as bad, in that case as poor design with good execution.
At least a company which adequately heat sinks the amplifier as manufactured has TOTAL control over design / execution and what is called 'heat budget'.
Too much is never enough
Edits: 08/16/15
Class D is far enough along you can't stereotype. I heard the Veritas which are Merrill Audio's flagship monoblocks, Taranis big twin brothers, driving 108dB horn speakers and sounding great. I couldn't tell by listening they were Class D, in fact, I was very impressed by the sound I heard, even before the knowledge they were Class D. If any harshness or other negatives existed it surely would have come through on horns that efficient.
I have a Linn, Class V, actually, that weighs a mere 11 lbs, it's rated at 125x5 and has been in faightful service for years in my HT set up. It has driven a 5 speaker Dynaudio speaker set up, and now Revel Performa. So this amp at 11 lbs. has driven some respectable loads under tough conditions as well as any A/B amp. It runs very cool, I keep it in a cabinet, and with autio on/off rarely see it.
There have been 2 or 3 generations of 'd' since my experience with the ASP modules.
No doubt some improvements MUST have been made. And in complete honesty, I was more than satisfied for quite a few years. It was only when I entered the final phases of my setup that I decided to move on. The High Frequency interaction of some sort with my ordinarilly benign-load panels went away with the addition of more traditional amps.
I don't know that 'half bridge' and 'full bridge' designs are not still the basis of these amps.
I'm not, I hope, stereotyping. It is simply physics that you have a given output at a given efficiency resulting in Heat which must be dissipated in some fashion. That the Hypex stuff actually DOES seem to be 'load invariant' IS a big improvement. I'm thinking the output Zobel of my amp WAS the source of my eventual difficulties.
I urge you to read the DataSheets from BOTH Hypex and B&O. The older modules from B&O have time limits AND power limits vs the 'rated' power. The Hypex stuff makes a point of the heat sink / temps being, if not an 'issue', than at least a design point to be considered.
Too much is never enough
I do like some of the technical end of amps but mostly it's the bottomline. The review posted is pretty good and in the near future I'm going to be able to listen to one of Merrill's products in my own system. The comparison to my own Pass amp should be interesting. I'm sure I'll be posting some results.
Maybe you should reread my post. I said heat can shorten the lifetime of all electronics.
Yes, B&O and HYPEX run at roughly the same heat output. Again, we aren't talking about B&O, we are talking about HYPEX. If you took the time to look, you would have found that the HYPEX module has integral heat sinks which are sufficient to manage the "heat budget". It doesn't need large external heat sinks so there is, as I have said a few times now, no compromise and no problems with overheating.
try it! you know you want to!
Please check out the HYPEX datasheet. Same issues as ICE, but I rather DO like the NC400 hockey puck solution. With the puck firmly secured to a proper under (or perhaps side?) case finned sink I can imagine no reasonable case where this amp would cook off.
The last 2 listings of section #4 / Page #4 clearly talk about temperature AND the 'possible' need for additional heatsinking.
The phrases 'lower improves lifetime' and 'most adverse use case' both support the idea of keeping the temp to the low end.
Please ALSO see Section 10.1 in 'Application Hints', which discusses heat management. I don't think THEY think it is a trivial issue, devoting enough text and some math detailing themal resistance numbers, to give a reasonable DIY a good chance to have a successful implementation. Easy to find, starting on Page #9.
They list a 'sensible maximum' heatsink temp of 80c (=176F) and a 'conservative' ambient temp of 35c. Still pretty toasty. That's pretty darn hot on the heatsink temp, don't you think?
I'm Frankly astonished at the hi temp number of 80c. That is REAL hot. It was 'only' 92F outside today, in my back patio shade, while I was cooking on the BGE, and I assure you, NO WAY would I run ANY expensive electronics under those conditions.
As a complete aside, I was in one of the big box Home Theater stores and they had a couple HT receivers simply COOKING themselves to death on the shelf. The one of 'em in particular not only was very HOT, it also was emitting WAVES of heat. I'm sure a receiver like that would be appreciated in a cold climate!
Too much is never enough
Yes, Hypex pays attention to heat effects. Yes, they have engineered their products with heat dissipation in mind. Yes, too high of heat can shorten the lifetime, or worse case, kill electronics. I haven't claimed otherwise. What I did say was that operating the amp towards the higher end of the approved range has not been shown to affect sonic performance versus operation at the lower end of the range.
No, you can't claim there are "compromises" made with a Hypex product that weights "only" 25 pounds in regards to heat dissipation. That was my point.
I think we have covered all the bases now....
try it! you know you want to!
I think I've settled my Parasound A21 or McIntosh MC 2205 question. I'd forgotten that I had the Proceed HPA 2 and 3 that I replaced with 3 Parasound JC 1s and 2 A23s sitting in the closet. The HPAs are 2 & 3 Levinson monoblocks in an industrial case from the Madrigal era. I'll use the HPA 3 to drive the KEF LS50s until I get the HPA 2 repaired.
db
db would love to have your closet full of problems .... :)
Back to the OP, I have no need for either the Parasound A 21 or the McIntosh MC 2205. The LS50s driven by the Proceed HPA 2 sound great. It turns out the Proceed HPA 2 was fine. I'd forgotten about the little power switch at the bottom of the unit, and I must have kicked that as I walked by. I pressed that button then the large obvious standby button, and the HPA 2 came to life. Our strong carpenter carried the 100 pound amp downstairs and installed it to drive the KEF LS50s.
db
I'm kind of surprised. KEF calls the LS50 sensitivity @85db. And recommends amps up to 100 watts.
But the GOOD news is you are making use of stuff on-hand. The cost of repair to something owned should save a bundle against a totally new purchase.
Too much is never enough
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