I'm a newbie to this and I'd like to try my hand at it. What do I need, machinery wise, a drill press, and a table saw with a carbide bit(I'll use aluiminum for the chassis)?
I believe the finisf is "powder paint"??
Is heatsink bare or lacquered? OK - the first option is better for cooling and the 2nd one will prevent the "oxidation" ...
Otherwise great work - something very similar to my next GC which is still in a process of builidng up ... 😀
Is heatsink bare or lacquered? OK - the first option is better for cooling and the 2nd one will prevent the "oxidation" ...
Otherwise great work - something very similar to my next GC which is still in a process of builidng up ... 😀
There's a lot of information here:jtbullet said:
http://www.diyaudio.com/forums/showthread.php?s=&threadid=38200&highlight=
Zygibajt,
That is one beautiful amp!
Your chasis and point-to-point work is of the highest quality.
It's too bad the lovely insides have to be covered up.
thanks for sharing.
That is one beautiful amp!
Your chasis and point-to-point work is of the highest quality.
It's too bad the lovely insides have to be covered up.
thanks for sharing.
Thanks for the tribute 😉
Building a nice p2p circuit is an art and Bartek is a true artist. The attention to detail is extraordinary and placing rectifiers on the opposite side of the chips is a nice touch.
While so many people these days get excited about regulated supplies and snubbers, properly implemented, minimized GC circuit is still the best and in a right system it's really hard to improve on it 😉
Building a nice p2p circuit is an art and Bartek is a true artist. The attention to detail is extraordinary and placing rectifiers on the opposite side of the chips is a nice touch.
While so many people these days get excited about regulated supplies and snubbers, properly implemented, minimized GC circuit is still the best and in a right system it's really hard to improve on it 😉
all i can say is...
Great work!
everything is very well thought out and executed. from the clean P2P to the design and metalworking, even those nice bolts you used. some people dont like to see them but if they are nice ones they are good!
is the finish painted, powdercoated, anodized or something else? i cant really see from the pics.
Great work! everything is very well thought out and executed. from the clean P2P to the design and metalworking, even those nice bolts you used. some people dont like to see them but if they are nice ones they are good!
is the finish painted, powdercoated, anodized or something else? i cant really see from the pics.
I completely disagree: this is the best way, to get the diodes hot or at least warm.
You need surface and airflow to cool, not just a piece of metal to store energy!
BTW: a very pretty amp! Congratulations.
Franz
zygibajt said:
Hehe - I must say that after the blue spreaded in almost all projects - it's nice to see green one 😀
Very nice indeed..
a bit sceptical of your "heatsink" though.. these litle gc's produce a lot of heat when pushed to their limits, i found out the hard way, and so one would want a heatsink that has a lot of surface areal to maximize air sirkulation and heat dispation.. a commer bar is far from ideal..
(unless you drill it trough and watercoolt the thing 😀 )
a bit sceptical of your "heatsink" though.. these litle gc's produce a lot of heat when pushed to their limits, i found out the hard way, and so one would want a heatsink that has a lot of surface areal to maximize air sirkulation and heat dispation.. a commer bar is far from ideal..
(unless you drill it trough and watercoolt the thing 😀 )
Franz G said:
I bet that in a regular setup ( no heatsinks on diodes), the diodes will run warmer than a chip on a copper bar.
BTW, the whole chassis here is a heatsink, and copper bar acts as a heat spreader, not a heatsink.
Kaffekokarn, the important thing is area, how much and how the surface is.demogorgon said:
I'll agree that this bar isn't the most cost effective cooling solution but how hot it gets is very dependent how the amp is used and if not the over temp protection goes on everything is alright.
A real nice job!
demogorgon said:
2 C/W to be precise -- you can estimate the heat sink's ratings from the total surface area -- there are two heat sink drawings on National Semi's application note 1192 -- the BPA100 heat sink is 5.375" inches long, 3" wide with 19 fins, each 1" high
Many ,many thanks for all the good words to all of you guys.
I'm glad you like it as I tried to make it as good as I can.
Yes this is powder coating and copper bar is lacquered.
HEAT???
You must be kidding. I used MUR860 without any heatshink at all before and it worked great.Also in my expirence LM3875 needs very little cooling (a small aluminium heatsink is good enough).
This copper bar works excellent! It absorbs all the heat and transfers it to the enclosure. The copper bar barely gets warm after a couple of hours playing loud music and the enclosure gets slightly warm only in copper bar area.In the front it doesn't even get warm.
The amp works just excellent,it is dead quiet (I tied input grounds stright to the main/enclosure ground) and sounds really good.
My next chip project is an ultimate Gain Clone.It will be supplied from batteries and it will have Siemens MKV polypropylene in oil PS cups (the best signal coupling cup I know so far) either 15,30 or 40uF I will try.I will use either solid core copper,continous cast 99,9999% purity or pure silver all around.I wonder how much better the idea of simple GC can be.
All Best
Bartek
I'm glad you like it as I tried to make it as good as I can.
Yes this is powder coating and copper bar is lacquered.
HEAT???
You must be kidding. I used MUR860 without any heatshink at all before and it worked great.Also in my expirence LM3875 needs very little cooling (a small aluminium heatsink is good enough).
This copper bar works excellent! It absorbs all the heat and transfers it to the enclosure. The copper bar barely gets warm after a couple of hours playing loud music and the enclosure gets slightly warm only in copper bar area.In the front it doesn't even get warm.
The amp works just excellent,it is dead quiet (I tied input grounds stright to the main/enclosure ground) and sounds really good.
My next chip project is an ultimate Gain Clone.It will be supplied from batteries and it will have Siemens MKV polypropylene in oil PS cups (the best signal coupling cup I know so far) either 15,30 or 40uF I will try.I will use either solid core copper,continous cast 99,9999% purity or pure silver all around.I wonder how much better the idea of simple GC can be.
All Best
Bartek
zygibajt said:
All of the Overture series chips will go into shutdown if they over-heat, or, if the heat sink is under-rated they will cycle on-and-off. That's what the SPIKE system is supposed to do.
I have built a dozen and a half of these amps, inverted, non-inverted, bridged and paralleled -- you can't under-rate the heat sink. National's recommendations -- albeit a bit on the conservative side -- will prevent heartbreak.
Bartek:
I like the design and the making of your amp very much!
O.K.
I am thinking in dimensions from tube amps. When your amp in your configuration does not get hot: Good!
But, for some people, it may be interesting, when I show here an example of a class A tube amp:
This 8 golden cathode resistors permanently dissipate about 30W together.
In a first stage, I mounted them under the chassis, at the aluplate.
The result: the whole amp, the trannies, the caps and the chassis got very hot after about 1 to 2 hours. You could not touch the trannies (>80 degrees celsius).
After, I mounted the resistors on this massive aluplate, 5mm thick, as shown in the foto.
The result: after one hour or two, the chassis and EVERY other part still was <30 degree celsius. But after one hour, the aluplate got more than 80 degrees celsius, the parts inside the amp and the chassis still cool.
After, I attached a heathsink, just 11 fins, to the aluplate.
The result: No problem to touch the heathsink/aluplate: about 40 degrees.
Franz
I like the design and the making of your amp very much!
O.K.
I am thinking in dimensions from tube amps. When your amp in your configuration does not get hot: Good!
But, for some people, it may be interesting, when I show here an example of a class A tube amp:
An externally hosted image should be here but it was not working when we last tested it.
This 8 golden cathode resistors permanently dissipate about 30W together.
In a first stage, I mounted them under the chassis, at the aluplate.
The result: the whole amp, the trannies, the caps and the chassis got very hot after about 1 to 2 hours. You could not touch the trannies (>80 degrees celsius).
After, I mounted the resistors on this massive aluplate, 5mm thick, as shown in the foto.
The result: after one hour or two, the chassis and EVERY other part still was <30 degree celsius. But after one hour, the aluplate got more than 80 degrees celsius, the parts inside the amp and the chassis still cool.
After, I attached a heathsink, just 11 fins, to the aluplate.
An externally hosted image should be here but it was not working when we last tested it.
The result: No problem to touch the heathsink/aluplate: about 40 degrees.
Franz
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