Bronze heatsinks, split from advanced GainClone thread

[Elso Kwak]

Hi Peter,

I was interested to read your comments relating to bronze heatsinks here, which come as no real surrprise to me, as it happens.
What has been disappointing, though, is the subsequent rash of 'contesters' who haven't any idea of what they are talking about in this instance, simply because they have not tried out what you have done. What is it about human nature which encourages so many people (who otherwise seem to consider themselves to be intelligent) to not only consider it to be their right, but even often some kind of obligation, to 'put the world to rights' here, even though this is entirely based on just their thoughts and suppositions?

Mostly, they appear to waste theirs and other peoples' time in such juvenile ridiculing of what someone has discovered and openly shared in good faith, and I thought I had escaped from demonstrations of such intellect as shown when doing this, when I left junior school nearly 60 yrs ago. What a world we live in when someones' sport is based on antagonising others, just for fun!

Whilst I have not (yet!) found any realistic method of proving this hypothesis, I believe that this phenomenon is caused (certainly in the main) by alterations to vibrations affecting the semi-conductors attached to the heatsinks. More than a few audio designers (and those involved in more 'consequential' spheres of electronics, like life-support and space-exploration etc.) are well aware that unwanted vibration effects can badly prejudice the operation (and reliability) of any electronic circuits and components. It is simply a way of life for them, and they don't even question these effects, whether they can be satisfactorily explained by anyone, or not. For many years I have believed this vibration-damping to be the main reason for differences heard with alternative metals being used for heatsinks, rather than anything electrical or thermal, as has hitherto been suggested.

I first became aware of some similarly odd and quite unintuitive 'influences', when improving a Spectral pre-amp, over 20 yrs. ago. This was rather ahead of its time in some ways, having entire ground-planes on both sides of the full-size PCB which were also gold-plated throughout, and this appearance together with a very neat and careful component layout, caused to me as an engineer to appreciate the aesthetics of the populated PCB when the case was open. Having seen at some audio show, a similar unit with a clear acrylic top which was intended to show-off this rather better than average internal appearance, I wished to emulate this 'exposed internals' effect, so I duly made up an 8mm Perspex (Lexan) top for my own pre-amp.

However, and especially as this pre had massive gain to suit even very low-output MC cartridges without any added step-up device, I was quite concerned about the possibility of RFI, or whatever, affecting the overall sound, and probably detrimentally. Accordingly, before finally screwing down this new cover more permanently, I considered it wise to conduct some listening trials to determine this potential, one way or the other.

Somewhat to my surprise (and quite the opposite to all expectations) not only did the new cover not make the sound worse, it actually sounded marginally better than with no lid at all. Being very puzzled by then, but interested in getting to the bottom of this anomaly, I experimented further for several more days, and there was no doubt at all that the preferred order of 'sonic goodness' was: 1st. the new cover, 2nd. no cover, and last (by a more noticeable margin), the original metal top. The entire enclosure was very shallow on these Spectral pre-amps, so the proximity of the covering material was quite close to the circuit board, and almost touching the tops of the taller components.

The conclusion I reached after a couple of weeks playing around with these alternatives, was that placing substantial areas of metal near to sensitive electronic circuits was detrimental to the overall sound, and that damping effects from the dense and quite heavy acrylic top, actually benefitted the overall sound, as a bonus.

Since that time, I discovered that these phenomena are quite well known of course (for example in DNM amps where they specifically avoid any metal they possibly can in their designs) but more significantly to your bronze heatsink findings, that damping of all components, PCBs etc., is commonly used by many audio manufacturers to improve their sonic results.

Following on from these earlier discoveries, I experimented with all kinds of damping materials in every location one could envisage, and inevitably there were noticeable changes (not always to the good!), but to keep things in perspective, I am not talking about 'chalk and cheese' changes here. They are subtle, but nevertheless obvious to a diligent listener with a reasonably revealing system, and a half-decent pair of ears.

Acrylic, lead, and bitumen-based materials, together with some extremely dense sound-deadening polymer materials used in vehicle sound-proofing and Blu-Tac all seem to work well, as do some of the more proprietary materials like Microsorb (excellent, clean and easy to apply), Isodamp, Navcom, and Sorbothane which are effective too. The last thing anyone should ideally encourage for the best possible sound appears to be uncontrolled 'ringing' particularly in narrow bands in any constructional materials used, with steel being the worst, to my knowledge, followed by aluminium and copper-based alloys, out of all the commonly available metals.

I haven't (yet!) tried bronze for myself, but most bronze (it varies with type) has a highish constituent of tin in its alloy, up to 40%, so I would anticipate this being very good here, as a lump of tin is quite similar to lead in many physical respects. The fact that Bell Metal (being a form of bronze) seems to be counter to the general 'non-ringing' desire, is probably taken care of largely because it is known to store less energy than most metals, and because it is useful in making bells having different musical pitches, in a similar way to brass instruments, and suggests that any inherent resonance here is wider bandwidth, and less 'peaky'.

Incidentally, I can readily spoil the sound of my favourite (DIY) amps which I have spent many years in 'voicing' to my satisfaction by simply sticking some lumps of Blu-Tac on each of the output devices. I have frequently demonstated this to visitors, and the effect is not very subtle at all. It is just like someone has thrown a heavy sack over the front of the speakers, with most of the 'loss' being in the higher frequencies, and this gives an extremely lifeless un-involving result which I detest.

Similarly, whilst varnishing some wood-work in my house a few years ago, I tried out some (new to me then) more eco-friendly acrylic water-based varnish. The way it changed during drying out from opaque to a clear hard finish, fascinated me, as did the fact that after full polymerisation , even though it was water-based, its properties had completely changed (and irreversibly so) to subsequently being completely water-proof. Shortly before this time, I had read some comments about J.Peter Moncrieff's 'compound', the name of which escapes me for now, but which is apparently used by brushing on to components and supposedly has some sonic effect on them, so on a whim, I tried some varnish on my output transistors, merely to see what (if anything) might happen.

I simply daubed a quite thick layer on to the fronts of the plasic packaged mosfets (TO3P) and let it air dry for a few minutes until it was touch-dry. When I then fired up the system again, the sound was quite appalling to my ears, and to me was completely unlistenable at that point, as far as any musical enjoyment went, rather disappointingly. I stuck it out with continually listening for the ensuing perhaps 5 or 6 hours, during which time the sound gradually returned more towards normal, presumably as the heat from the devices toasted off the varnish and polymerisation was taking place. ( No, it was certainly not because I was becoming accustomed to this) By that time, I had quite enough of that experience, and duly scraped off the clear coating to immediately regain the original quality of sound I enjoyed before I had commenced this trial, I might add with some relief. Incidentally, the varnish was carefully only applied to the plastic case, and was not covering any electrical parts like the leads, so I don't believe that any dielectric/capacitive effects could have been responsible for what changes I heard

I believe it was simply the initially greater damping effects of the relatively soft varnish in the early stages, which then reduced somewhat as the varnish hardened over time, and nothing else.

Whilst this was one of my aborted trials connected with audio, of which there have been many others, similarly unsuccessful, the fact that this varnish (in different states of hardening) had such an obvious effect on the sonic results when applied merely to the faces of output devices, made me realise how much effect can be realised here, even if I didn't happen to enjoy the outcome on that particular occasion.

****Continued in next post, due to character over-run.****

OK, I give up, I surrender....... Bring me to a Turkish bath or sauna, anything!

 

[jneutron]

OK, I give up, I surrender.......

Geeze, whatta pushover.

John

 

[jneutron]

Important things first.

subsequent rash of 'contesters'

who haven't any idea of what they are talking about

so many people (who otherwise seem to consider themselves to be intelligent)

even though this is entirely based on just their thoughts and suppositions?

juvenile ridiculing

In light of your garbage statements here, please explain to us how you are any different??? From your very own statements, you have not distinguished yourself from those you are trashing.

Please re-think your rude and innapropriate comments.

I thought I had escaped from demonstrations of such intellect as shown when doing this, when I left junior school nearly 60 yrs ago. What a world we live in when someones' sport is based on antagonising others, just for fun!

Again, how are your comments any different?

Enough on that topic.. I hope you will in the future, act more civilly...thank you.

Whilst I have not (yet!) found any realistic method of proving this hypothesis, I believe that this phenomenon is caused (certainly in the main) by alterations to vibrations affecting the semi-conductors attached to the heatsinks. More than a few audio designers (and those involved in more 'consequential' spheres of electronics, like life-support and space-exploration etc.) are well aware that unwanted vibration effects can badly prejudice the operation (and reliability) of any electronic circuits and components. It is simply a way of life for them, and they don't even question these effects, whether they can be satisfactorily explained by anyone, or not.

I sit here suprised by your statement. I have tested mil spec components for random vibe, swept sine, and impact pulse vibe, and understanding of such mechanical to electrical coupling is rather well understood.. Even such simplistic things as power diodes, which alter their carrier recombination dynamically as a result of lattice compression, and transistors, which suffer from emitter dip gain modulation.. Nevermind movement of current carrying conductors.. It is indeed a real and very well understood science.


groundwork quotes..

However, and especially as this pre had massive gain to suit even very low-output MC cartridges

so the proximity of the covering material was quite close to the circuit board, and almost touching the tops of the taller components.

damping effects from the dense and quite heavy acrylic top, actually benefitted the overall sound, as a bonus..

Hmmm..high gain, proximity of metal or dielectric to active components, affecting circuit operation??

What you have done is duplicate the origional effect that was used by philbrick, I believe, when they manufactured one of the first op-amps on the market...a beast of a brick. One of the BEST kept design secrets was the fact that the opamp was a two piece unit, and the final packaging involved putting the two pieces together in such a way that the proximity of one pc board with components to the other produced a significant increase in performance. It gave them a technical edge that other manu's didn't figure out.

But you said proximity of the metal. Not touching, just proximity.

I've pretty much said the same thing.

Incidentally, the varnish was carefully only applied to the plastic case, and was not covering any electrical parts like the leads, so I don't believe that any dielectric/capacitive effects could have been responsible for what changes I heard.

I am suprised by this statement. Of course, only because I have built the actual transistors from the chip up, so understand from experience how the plastic devices are made.

What you have done, is put a strange material directly over the silicon die and wire bonds. The plastic of the mosfets does not shield the device from stray capacitances or non unity permeability materials. It is simply there to protect the chip from environmental contamination. Right under that plastic surface is two wirebonds, and a huge source metalization pad..an IRF 250 die has the source pad at about 200 mils square, not an insignificant size, you put a non unity dielectric between the source and the gate bond wire, affecting the stage frequency response..so I can certainly believe you heard something..

I believe it was simply the initially greater damping effects of the relatively soft varnish in the early stages, which then reduced somewhat as the varnish hardened over time, and nothing else.

Your belief that it was vibe is not supportable. As the volatiles outgass, the dielectric coefficient of the surface changes.

I enjoy your observations, please continue to do so.

Just leave the poor attitude at home if you please.

Cheers, John

 

[Upupa Epops]

As I see, so : simplest circuit + aerospace devices + acrylic cover + tightened screws + bronze heatsink = best sound....

 

[jneutron]

As I see, so : simplest circuit + aerospace devices + acrylic cover + tightened screws + bronze heatsink = best sound....

Oh, glad you mentioned that..forgot about that tighten thingy.

Originally posted by Bobken
After much experimentation, and I have used a torque driver here for some years to ensure consistency, I found that overtightening these screws does have an adverse effect
which is also related to the type of pad used (mica & grease, sil. rubber thermal pads, almn. oxide etc.) and to the type of fixing i.e. TO3, TO3P etc.

If you peruse the manufacturers data sheets pertaining to the use of their devices, you will see that they always specify a torque to use..this is indeed very critical to the correct thermal operation of any tab device. Overtorquing the tab of a TO style plastic device causes the copper substrate to bend, which peels the heat contact surface away from the heatsink. (it is not the tab where all the heat transfer occurs, it is directly underneath the silicon chip within the plastic.) Undertorque of course, doesn't provide adequate contact pressure. Note that the manu's also modify the recommendations based on whether or not an insulator is involved, and the physical properties of the insulator, like rubber, alumina, BeO, or direct metal contact.

So, for your sonic observations on torque related audibility, your experience directly correlates to better thermal management practices..While more than likely not vibration related, certainly of some impact to circuit operation.

See...observation is indeed important.

Cheers, John

 

[jneutron]

Wallowing in the minutia...

As I recall, the people who wired your 350 (or 500) kw install considered your recommendations on feed wire layout and placement to be minutia..and they didn't learn any better till the concrete exploded.

What is minutia to some....

Cheers, John

 

[Upupa Epops]

Yes, the best is " appendixal " listening....

 

[jneutron]

Yes, the best is " appendixal " listening....

Ya got me there..


Cheers, John

 

[poobah]

A little grouchy for a Friday John??? Go to lunch and have a beer.

 

[rdf]

jjneutron, I'm curious about your opinion because you seem one to at least seek potential scientific rationales for reports like Peter's rather than shout the thread down because it's not 'in the book'. Why should, what seems obvious to me, a response borne of frustration on Bobken's part be taken as "bad attitude", while the examples of acidic sarcasm so conveniently provided afterwards, and which have been a constant from those purporting to represent the science side throughout this thread , aren't?

 

[Upupa Epops]

Appendix = protrusion...also tighten is this one...

 

[jneutron]

A little grouchy for a Friday John??? Go to lunch and have a beer.

Do not confuse a good mood over finally having a granite kitchen countertop installed after 4 months of work with being grouchy.

I am indeed, in a very good mood.. Technically accurate postings are not "grouchy"...sheesh..

I sit here listening to pink floyd. Has anybody noticed the low frequency embedded in the track "Money"? It sounds like an air conditioning unit dropped 10 hz information into the recording..strange indeed.

Oh man, wish I could drink beer. I miss it.

It's a wheat/gluten thing.. Don't cry for me, however..I compensate with a potatoe vodka martini or a nice wine..

Cheers, John

 

[Charles Hansen]

Three cheers for Bobken!

Hip, hip, hooray!
Hip, hip, hooray!
Hip, hip, hooray!

You have two choices here - listen to Bobken's wisdom accumulated from years of careful experimentation and achieve improved musical enjoyment, or join with the know-it-all naysayers with no way to improve the sound of your system.

I don't really care....

 

[jneutron]

jjneutron, I'm curious about your opinion because you seem one to at least seek potential scientific rationales for reports like Peter's rather than shout the thread down because it's not 'in the book'. Why should, what seems obvious to me, a response borne of frustration on Bobken's part be taken as "bad attitude", while the examples of acidic sarcasm so conveniently provided afterwards, and which have been a constant from those purporting to represent the science side throughout this thread , aren't?

Methinks you are speaking from a level stance..

Personally, I had not intended sarcasm, so if what I said seems such, then an apology on my part is in order..

I waffle between pointing out the ill manners of the posters on both sides, in the hope that both sides would back down and be civil and discuss..

Sometimes it may seem I persue a one sided critique, but that is not my desire..

Cheers, John

 

[jneutron]

Three cheers for Bobken!

Hip, hip, hooray!
Hip, hip, hooray!
Hip, hip, hooray!

You have two choices here - listen to Bobken's wisdom accumulated from years of careful experimentation and achieve improved musical enjoyment, or join with the know-it-all naysayers with no way to improve the sound of your system.

I don't really care....

Silly post.

There is a significant difference between wisdom and experience.

The fact that assumptions of causality which are incorrect were based on astute observations is not wisdom.

You might as well ban ice cream from the beach, as it correlates with shark attacks..

Calling others "know it all naysayers" because they do not accept a simply ridiculous assertion, is to bring nothing to the table.

Cheers, John

 

[SY]

It's a wheat/gluten thing..

Celiac?

 

[jneutron]

Celiac?

I believe so, but not really bad.. Actual diagnosis requires a blood test and some kinda biopsy. But you have to eat it to force the reaction, which doesn't appeal to me.

The doc agrees that the biopsy and true diagnosis is not important, as regardless of the final diagnosis, my reaction to gluten wouldn't change, so I'd avoid it anyway.

I can tell how much gluten is in the food by my adverse reaction to it. It's amazing how much food is prepared with flour or wheat.

It's funny explaining to the waitress that I'm allergic, what's on the menu, how's it prepared...and she says "I'll go check with the chef, and I'll bring your bread right out"..

But some waitresses are just fantastic about it..

Cheers, John

 

[poobah]

OK... funny story to break the tension.

At the very same site where the batteries caught fire and the concrete expoded...

There was a 1400 foot underground conduit run; this was done using 8 inch PVC pipe and the backfilling was all done nicely.

There were 4 wires too be placed in the conduit, 1000 MCM as I recall, 1-1/2 inches at any rate. Now this wire was expensive, so the surveyors were asked to measure twice. 20 feet, for each end, of extra wire was purchased. The wire was delivered on a cool trailer-truck that had 4 spools of wire layed out in a row.

The pucks had been shot back and forth until a nice 1" polypro rope was in the conduit ready to go.

The wires were bundled, taped, and secured to the pulling grip... like a big "chinese finger trap". 4 guys were at the lead end with large buckets of pulling lube and brushes to coat the wires as they into the conduit.

At the far end, the guys had a "pull-dog"... a large battery powered capstan. Turns out... the dog didn't have the muscle to pull that much cable... after about 50 feet or so it just gave up.

So... the rope was tied to pickup truck and the driver was told to just go real slow and real steady... and he did.

So everything was going just fine... the guys at the lead end had plenty of time to grease the cables and keep them arranged nicely. In about 20 minutes the whole thing was just about done.


You all should have seen the look of horror on the face of the supervisor as he watched the ends of the wires wires pop off the reels and slither down the conduit...


No one had provided any means to signal the driver when to stop!

Someone hopped in another truck and chased the first truck down. Of course the damage had been done...

They had no choice but to continue and pull all the wire out of the conduit and drag it across a desert (somewhere in Southwest U.S.).

Now the wire is covered with grease... and the sand in this desert is as fine as corn starch.

They went into "town"... some sixty miles and bought every roll of paper towels in the city.

They repeated the process the next day... this time with 8 guys wiping off the cables and 4 guys installing lube.

This time they had some Walkie-Talkies and a boat horn this time too (minutia?)!

Can't say where or who... your tax dollars at work... a local electrical contractor working a bit outside his comfort zone.

 

[jneutron]

OK... funny story to break the tension.

Tension

The pucks had been shot back and forth until a nice 1" polypro rope was in the conduit ready to go.

Is a puck a device to snake the rope?

a local electrical contractor working a bit outside his comfort zone.

Again, a master of understatement you are..

Good story.

Cheers, John

 

[poobah]

Yes Sir... the pucks are a cylinder of foam rubber with circular end plates of plastic with eyes for attaching a rope.

You put the puck in at one end at one end of the conduit with a very light rope and you put a vacuum (LARGE shop vac) at the other.

You then use the lighter ropes to pull through heavier ropes through. Their first rope broke, although it seemed like the right stuff to use... so they had do that twice as well

That's the last funny story from that site... well unless you count the evening activity in a small redneck town... 30 local cowboys and 10 or so alien engineers... all fighting over the girl with a tooth.