I'm looking for some additional heat sinking to use on the back of my amp chassis. I'm going to bolt the module against the back face plate of my chassis, which is all aluminum, but the material back there is pretty darn thin. I was thinking of just sandwidching a 2mm machined plate from Frontpanel express on the back of the cassis, which will also give me nicely machined mounting holes for everything I need back there. However, would that be enough for a UCD700AD module? Just one per chassis, about 100mm tall, 250mm wide in back. The entire rest of the chassis is aluminum, so the heat has somewhere to travel to. I'm just converned about the local area where the module is mounted possibly getting too warm.
As an alternate, I had something like a Pentium2 processor heat sink in mind, adding that to the back of the chassis with arctic Silver thermal epoxy, but if I don't need it, I would rather not do that.
So would the chassis on its own be adequate?
Peter
As an alternate, I had something like a Pentium2 processor heat sink in mind, adding that to the back of the chassis with arctic Silver thermal epoxy, but if I don't need it, I would rather not do that.
So would the chassis on its own be adequate?
Peter
Yes, the chassis is plenty good by itself, however for best sound you should damp the module. By using a dissimilar material layer in conjuction with the chassis you will reduce the ringing and audible effects of the chassis. In my commercial UCD amps I use one quarter inch thick brass inside the chassis and then the alluminum chassis outside layer. You could experiment with brass screws as well but these are very hard to find in metric sizes here in the US.
Regular heatsinks suck big time. Resonating machines. Take any amp that has external heatsinks and damp the heatsinks with damping material along the edges of the fins so they no longer ring when you run your fingernail along them.....WAY better sound.
Regular heatsinks suck big time. Resonating machines. Take any amp that has external heatsinks and damp the heatsinks with damping material along the edges of the fins so they no longer ring when you run your fingernail along them.....WAY better sound.
Ringing heatsinks
I would dearly love to know how a heatsink can affect the sound of an amplifier. If the amplifier circuits themselves do not cause any mechanical vibration, how does the heatsink affect the circuits?
It is kind of like that French manufacturer, FM Acoustics who put their power amplifier drive circuit in a plastic box and filled it with some fancy beach sand form a Pacific South Sea Island and told the public that this "Improved" the sound. What a lot of junk. I had the opportunity to repair one of these amplifiers and it sounded awful even with their beach sand.
I would dearly love to know how a heatsink can affect the sound of an amplifier. If the amplifier circuits themselves do not cause any mechanical vibration, how does the heatsink affect the circuits?
It is kind of like that French manufacturer, FM Acoustics who put their power amplifier drive circuit in a plastic box and filled it with some fancy beach sand form a Pacific South Sea Island and told the public that this "Improved" the sound. What a lot of junk. I had the opportunity to repair one of these amplifiers and it sounded awful even with their beach sand.
Trouble is. most engineering types use their brain instead of their ears. You cannot think good sound, you have to listen for it.
The analog signal goes through the components, the microvibrations of the componets gets transfered to the signal...much the same way that vibrating cabinets effect the sound of a driver....of course, it is much more subtle a vibration but just as audible. You must have heard about different kinds of feet for components...different types of racks, etc. These are all ways to deal with microvibrations that effect the sound. Many, many people put damping material on the chassis, circuit boards, etc. to good effect. The sound you hear when you take your fingernail to a component and flick it is the exact sound that will be transfered to the sound coming from your speakers. If you hear a tink when you do this to a undamped transistor mounted in space, then when you damp it the tink sound will go away. This really is science...at some level...whether or not it is measureable it is certainly audible. Peter Moncrief of IAR used to take a recording that contained a lot of percussion and especially a bell ting and would send the signal through a preamp and look at the output on a super fast digital scope....he would then compare the bell ting trace to another preamp....what he found is that the more revealing preamp showed more subtle variations and dynamic swings on the wave form than the less audibly revealing component. Now this guy makes wonder caps, wonder solder, etc...so he knows about how a single component has a sound....so I asked him if he could measure the difference using a bell ting when he tests a single piece of wire, resistor, cap or whatever....he said....no, he could not. The only way he could measure it is to run the signal through a preamp or amp that has many parts in the signal path and power supplies, etc. All brands of caps/resistors/solders/wires etc. sound different and we can hear it, but at this time we have no measurement that can tell us which one will sound better or purer, execpt straight wire bypass tests.
You can argue with your brain...but you listen with your ears....have an open mind...try it and see if you can hear a difference...if you cannot then, so be it. Because I do not come from an engineering background and because I have an open mind, I try everything that I read about....this is why I come to these forums because someone here will no doubt tell me something I don't know. Always searching for more. And occasionally I give out some information that I hope will be of value (sonically).
There are many manufacturers that damp circuit boards, parts, heatsinks, etc. This is not new news. I did not invent it! When someone says they hear a difference doing something, I put that info into my biocomputer and at some point try it and see if I hear the same thing...if I do and I like what it does then I put that in my tweak ammo box. It is very pragmatic to me....my goal is to make a component disappear ..to help make the connection between the heart of the musician, the music and the listener.
The analog signal goes through the components, the microvibrations of the componets gets transfered to the signal...much the same way that vibrating cabinets effect the sound of a driver....of course, it is much more subtle a vibration but just as audible. You must have heard about different kinds of feet for components...different types of racks, etc. These are all ways to deal with microvibrations that effect the sound. Many, many people put damping material on the chassis, circuit boards, etc. to good effect. The sound you hear when you take your fingernail to a component and flick it is the exact sound that will be transfered to the sound coming from your speakers. If you hear a tink when you do this to a undamped transistor mounted in space, then when you damp it the tink sound will go away. This really is science...at some level...whether or not it is measureable it is certainly audible. Peter Moncrief of IAR used to take a recording that contained a lot of percussion and especially a bell ting and would send the signal through a preamp and look at the output on a super fast digital scope....he would then compare the bell ting trace to another preamp....what he found is that the more revealing preamp showed more subtle variations and dynamic swings on the wave form than the less audibly revealing component. Now this guy makes wonder caps, wonder solder, etc...so he knows about how a single component has a sound....so I asked him if he could measure the difference using a bell ting when he tests a single piece of wire, resistor, cap or whatever....he said....no, he could not. The only way he could measure it is to run the signal through a preamp or amp that has many parts in the signal path and power supplies, etc. All brands of caps/resistors/solders/wires etc. sound different and we can hear it, but at this time we have no measurement that can tell us which one will sound better or purer, execpt straight wire bypass tests.
You can argue with your brain...but you listen with your ears....have an open mind...try it and see if you can hear a difference...if you cannot then, so be it. Because I do not come from an engineering background and because I have an open mind, I try everything that I read about....this is why I come to these forums because someone here will no doubt tell me something I don't know. Always searching for more. And occasionally I give out some information that I hope will be of value (sonically).
There are many manufacturers that damp circuit boards, parts, heatsinks, etc. This is not new news. I did not invent it! When someone says they hear a difference doing something, I put that info into my biocomputer and at some point try it and see if I hear the same thing...if I do and I like what it does then I put that in my tweak ammo box. It is very pragmatic to me....my goal is to make a component disappear ..to help make the connection between the heart of the musician, the music and the listener.
Ric?
You made me spill my morning coffee, now I have to go home and change shirts
Microphonic phenomena do exist, but what you're proposing is utter nonsense, but a good read nonetheless (chuckles).
Best regards,
Sander Sassen
http://www.hardwareanalysis.com
You made me spill my morning coffee, now I have to go home and change shirts
Microphonic phenomena do exist, but what you're proposing is utter nonsense, but a good read nonetheless (chuckles).Best regards,
Sander Sassen
http://www.hardwareanalysis.com
Trouble is the terrible advice I'm reading in that thread.
Every fast-switching high-frequency circuit requires the heatsink to have a very short return path to circuit (switching) ground, and some means to reduce the capacitance between the metal tabs of the power transistors and the heatsink is also very desirable. Otherwise, the heatsink will follow the switching voltage waveform with all its high dV/dt switching transients and will radiate EMI as a big antenna. Attaching directly the heatsink or the power transistors of a class-D module to a big metal case is a very very bad idea.
Furthermore, as the insulators mounted between the transistors and the heatsink are sandwiched between two conductive surfaces whose relative voltage is changing very quickly and by very big amounts, the insulators will exhibit piezoelectric effects and will expand and contract, thus transmitting mechanical energy to the heatsink and causing audible noise (now some naive audiophile may pretend to fix the whole problem by stuffing the fins of the heatsink, without being aware of the complex phenomena behind).
Actually there is not an easy fix for that. Grounding the heatsinks (to some internal switching ground or supply rail in the circuit following a very short path, never to signal ground or using a long wire) gets rid of most of the EMI issues (while attaching the heatsinks to a rack case produces a nice FM transmitter), but the piezoelectric effects remain unsolved (if you ever care about that). Using plastic-cased power transistors is quite effective as it gets rid of most of the capacitance to the heatsink, the real root of the problem. Using thicker insulators or several standard ones stacked may be useful too. Also, there are commercially available aluminium oxide ceramic insulators (they may be 3 milimeters thick while keeping low thermal resistance) that are routinely employed to attach switching transistors to big metal cases without capacitive issues.
Check that link: http://www.warth.co.uk/site2003/blue_site/Introductions/products_fast.html
p.s. Does anybody know where aluminium oxide insulators are available in small quantities?
Every fast-switching high-frequency circuit requires the heatsink to have a very short return path to circuit (switching) ground, and some means to reduce the capacitance between the metal tabs of the power transistors and the heatsink is also very desirable. Otherwise, the heatsink will follow the switching voltage waveform with all its high dV/dt switching transients and will radiate EMI as a big antenna. Attaching directly the heatsink or the power transistors of a class-D module to a big metal case is a very very bad idea.
Furthermore, as the insulators mounted between the transistors and the heatsink are sandwiched between two conductive surfaces whose relative voltage is changing very quickly and by very big amounts, the insulators will exhibit piezoelectric effects and will expand and contract, thus transmitting mechanical energy to the heatsink and causing audible noise (now some naive audiophile may pretend to fix the whole problem by stuffing the fins of the heatsink, without being aware of the complex phenomena behind).
Actually there is not an easy fix for that. Grounding the heatsinks (to some internal switching ground or supply rail in the circuit following a very short path, never to signal ground or using a long wire) gets rid of most of the EMI issues (while attaching the heatsinks to a rack case produces a nice FM transmitter), but the piezoelectric effects remain unsolved (if you ever care about that). Using plastic-cased power transistors is quite effective as it gets rid of most of the capacitance to the heatsink, the real root of the problem. Using thicker insulators or several standard ones stacked may be useful too. Also, there are commercially available aluminium oxide ceramic insulators (they may be 3 milimeters thick while keeping low thermal resistance) that are routinely employed to attach switching transistors to big metal cases without capacitive issues.
Check that link: http://www.warth.co.uk/site2003/blue_site/Introductions/products_fast.html
p.s. Does anybody know where aluminium oxide insulators are available in small quantities?
Thanks, Eva, your comments are always wise.
My self-made Class-D amplifiers have a 100nF capacitor from one of the chassis screws to the power supply GND input faston, (the screw is at a couple of centimeters from where the output mosfets are) in order to short that capacitively coupled HF noise to GND.
Besides that, the heatsink is bolted to the case, and the case is earthed via the IEC mains input.
Is this correct or a very bad idea in terms of EMI emissions?
(BTW: no piezoelectric or microphonic effects noticed
)
My self-made Class-D amplifiers have a 100nF capacitor from one of the chassis screws to the power supply GND input faston, (the screw is at a couple of centimeters from where the output mosfets are) in order to short that capacitively coupled HF noise to GND.
Besides that, the heatsink is bolted to the case, and the case is earthed via the IEC mains input.
Is this correct or a very bad idea in terms of EMI emissions?
(BTW: no piezoelectric or microphonic effects noticed
)Hi,
"p.s. Does anybody know where aluminium oxide insulators are available in small quantities?"
I'm fairly certain you'll find two on the UCD400, the 180 uses plastic transistor cases.
Also, the T sink is well decoupled for EMI. These are very well engineered modules.
It would seem there's good reason to stick to engineering after all.
I don't doubt the existance of the piezoelectric effect, but it's already mechanically damped by bolting the mosfet to the heatsink. I do have serious doubts even in worse case this would translate into audible artifacts through the speakers, measurable or otherwise. I can't really see this happening to any worrysome degree with a product such as thermasil pads either?
You just have to draw the line somewhere I guess. Is it still OK to listen to an amp that's placed in light intensive environments... or can I find some audiophile window tint?
Also, keep in mind the filter core itself is magneto-restrictive, I could believe that translating itself into audible artifacts loooong before flicking my finger over a heatsink, but I wouldn't even go so far as to say that "that's" why an aircore sounds better.
Excellent post btw.
"p.s. Does anybody know where aluminium oxide insulators are available in small quantities?"
I'm fairly certain you'll find two on the UCD400, the 180 uses plastic transistor cases.
Also, the T sink is well decoupled for EMI. These are very well engineered modules.
It would seem there's good reason to stick to engineering after all.
I don't doubt the existance of the piezoelectric effect, but it's already mechanically damped by bolting the mosfet to the heatsink. I do have serious doubts even in worse case this would translate into audible artifacts through the speakers, measurable or otherwise. I can't really see this happening to any worrysome degree with a product such as thermasil pads either?
You just have to draw the line somewhere I guess. Is it still OK to listen to an amp that's placed in light intensive environments... or can I find some audiophile window tint?
Also, keep in mind the filter core itself is magneto-restrictive, I could believe that translating itself into audible artifacts loooong before flicking my finger over a heatsink, but I wouldn't even go so far as to say that "that's" why an aircore sounds better.
Excellent post btw.
Pierre:
That is probably the best that you can do without using special insulators or plastic transistors. I would recommend common-mode filters on all wirings coming to the PCB, particularly if more than one channel is capacitively coupled to the same case or heatsink.
classd4sure:
It's great to know that these modules are well engineered, but I want the insulators for my own designs
Concerning the piezoelectric effect, I was talking about whatever sound might be audible through the heatsinks, not trough the speakers (just to make it clear)
That is probably the best that you can do without using special insulators or plastic transistors. I would recommend common-mode filters on all wirings coming to the PCB, particularly if more than one channel is capacitively coupled to the same case or heatsink.
classd4sure:
It's great to know that these modules are well engineered, but I want the insulators for my own designs
Concerning the piezoelectric effect, I was talking about whatever sound might be audible through the heatsinks, not trough the speakers
(just to make it clear)Eva said:Pierre:
That is probably the best that you can do without using special insulators or plastic transistors. I would recommend common-mode filters on all wirings coming to the PCB, particularly if more than one channel is capacitively coupled to the same case or heatsink.
classd4sure:
It's great to know that these modules are well engineered, but I want the insulators for my own designs
Concerning the piezoelectric effect, I was talking about whatever sound might be audible through the heatsinks, not trough the speakers
I'd hoped so, was worried you were walking on the dark side for a second
Eva said:
dunno, I got enough to move on. Need no heat sink, thicker rear panel is probably good, and when using some thermal pads to mount the module, I'll be fine if there should be some goofy electrical gremlins, but for now I won't even bother doing that. Can always add those later if I should hear my rear panel make noise
Just gotta pick what you want to hear, and there's lots of good advice in the thread ;-)
Peter
Its quite clear that especially the digital forum and Diyaudio in general is dominated by engineering types who like to talk engineering to each other. When it comes to things outside of the engineering norm....well....a laugh and little mockery and little put down and we are back to our safe little club. If the info that I have discovered through direct experiential science (listening with my ears) is not helpful to anyone here because you do not "believe" it could make any difference then I would say my words are falling on deaf ears....so....you will get your way and I will refrain from making posts that will make you spill your coffee and chuckle in amazement.
You are now all safe, you can now come out of your shelter and take your hands off your ears.....you are now all safe....all clear...the mystical weirdo has gone....the playground is now safe once again.
You guys are really tooooo much....very enjoyable coming to this neck of the woods....to bad I don't have anyone to talk to... oh well. I guess I will go back to where all mystical weirdos go...maybe the Audio Asylum.....tweakers section....you know those guys who listen to stuff and report what they hear...some of them even have an open mind.
You are now all safe, you can now come out of your shelter and take your hands off your ears.....you are now all safe....all clear...the mystical weirdo has gone....the playground is now safe once again.
You guys are really tooooo much....very enjoyable coming to this neck of the woods....to bad I don't have anyone to talk to... oh well. I guess I will go back to where all mystical weirdos go...maybe the Audio Asylum.....tweakers section....you know those guys who listen to stuff and report what they hear...some of them even have an open mind.
Uhm, yeah, right!? I think someone forgot to take his medicine this morning 
Best regards,
Sander Sassen
http://www.hardwareanalysis.com
Best regards,
Sander Sassen
http://www.hardwareanalysis.com
One such commercial amp, with a great attention to vibration control (including heatsinks), was Niro 1000 amplifier: http://www.onhifi.com/product/niro_engines.htm
Niro is, of course, Niro Nakamichi, one of the principals of the old Nakamichi cassette-player manufacturing firm. In 1998, he founded the Mechanical Research Corporation, with the idea of applying electro-mechanical principles to audio design: He felt that the traditional method of audio design -- concentration on the electrical-circuit design to the exclusion of other aspects of physics, most specifically the electro-mechanical nature of circuit design -- had prevented audio design from truly evolving to its full potential.
Niro is, of course, Niro Nakamichi, one of the principals of the old Nakamichi cassette-player manufacturing firm. In 1998, he founded the Mechanical Research Corporation, with the idea of applying electro-mechanical principles to audio design: He felt that the traditional method of audio design -- concentration on the electrical-circuit design to the exclusion of other aspects of physics, most specifically the electro-mechanical nature of circuit design -- had prevented audio design from truly evolving to its full potential.
It's simple enough to see why he'd opt to get out of making cassette decks in the year of 98, grab onto a gimmick, call it an organisation and sell his gimmick for >$20K a pop.
I'm not even going to get into it over the spring loaded power supply.
Ric, sorry I started off with the laugh, I was honestly just too tired at the time to come up with much else, and felt that's all it was deserving of.
Please try to keep in mind that it was in fact exactly sound engineering and listening that got you your module to use with your products, and I'd certainly hope that the tired of gimmicks people here at DIYaudio will in fact continue to thrive from sound engineering in place of the voodoo, as would the people at Hypex with the UCD.
That said the reason mentioned for using the ceramic isolators was in fact their better heat conduction.. with that in mind you'd do well to look up what the heat transfer coefficient of that brass plate of yours is with respect to aluminum, along with perhaps their thermal emissivity coefficients.
Your customers might get a product out of it in the end, should you have a mind open enough to admitt you were wrong in your original position, and place more importance on the fact that better cooling will lead to a longer working life of the product, given the engineering rule of thumb that for every 10 degree C increase lifespan is halved.
I'd like to see you stick around instead of run off to some haven that's void of the engineer's mind where ignorance thrives and voodoo sells.
Best regards,
Chris
I'm not even going to get into it over the spring loaded power supply.
Ric, sorry I started off with the laugh, I was honestly just too tired at the time to come up with much else, and felt that's all it was deserving of.
Please try to keep in mind that it was in fact exactly sound engineering and listening that got you your module to use with your products, and I'd certainly hope that the tired of gimmicks people here at DIYaudio will in fact continue to thrive from sound engineering in place of the voodoo, as would the people at Hypex with the UCD.
That said the reason mentioned for using the ceramic isolators was in fact their better heat conduction.. with that in mind you'd do well to look up what the heat transfer coefficient of that brass plate of yours is with respect to aluminum, along with perhaps their thermal emissivity coefficients.
Your customers might get a product out of it in the end, should you have a mind open enough to admitt you were wrong in your original position, and place more importance on the fact that better cooling will lead to a longer working life of the product, given the engineering rule of thumb that for every 10 degree C increase lifespan is halved.
I'd like to see you stick around instead of run off to some haven that's void of the engineer's mind where ignorance thrives and voodoo sells.
Best regards,
Chris
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