| 2Bak |
Found two old heatsinks, on which I do not have the heat dissipation data.
They measure H x W x D, 220 mm x 200 mm x 70 mm.
Would there be a chance that they are able cool down the Boz 4 @ 2 x 30 watt or 2 x 25 watts?
one sink for each side
tanx :redhot: |
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| Peter Daniel |
| I'm afraid they are not enough. But if you stack them face to face and run a fun they might be OK.:redhot: |
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| 2Bak |
Thanks Peter Daniel
I might consider a fan.
I'm not quite sure what stack them face to face means...
topview:
is that it?
Are silent fans for CPU cooling applicable for amps?
regards
Jan Bak Madsen |
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| Orgonom |
Hallo 2Bak,
i use these sink also with my zen (bias 3,5 A - 43V).
So i´m dissapating 150W. Hot, but under 55 GradC.
Go for it.:D
Andreas |
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| jh6you |
I use the size:
H: 250 mm
W: 230 mm
D: 65 mm
Number of fins: 18
Two FETs are fitted on one sink--average 2A each at DC supply of 32V.
It's rather hot--about 50 degC at room temp 27 degC.
Mine should have been a bit bigger.
I recommend you to increase the size.
Hope this helps...
JH |
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| Peter Daniel |
| I was rather thinking about something like this and placing a fan at one end. |
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| jh6you |
Face to face...?
I hardly see who have full of hair on the face.
Hahaha...
Good night.
JH |
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| Peter Daniel |
| quote: | Originally posted by jh6you
Face to face...?
I hardly see who have full of hair on the face.
JH |
Just a different culture.;) |
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| 2Bak |
well, this will be a hard decision for me to make. Was hoping for a few more of them "go for it", like Orgonoms... :magnet:
Also found an EI transformer 800VA, 2x18v. Guess you guys will turn your thumbs down on this transformer type also?
Weight 10 kilo = 22 pounds lb
175x135x115 mm |
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| HDTVman |
Hi 2Bak.
I'd use it if you have room. Why buy when you have a x-former like that in hand. :scratch2: :smirk:
later
Bruce |
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| Peter Daniel |
| Although big, that transformer is probably better than toroid. |
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| jh6you |
I use both EI and toroidal transformers.
I prefer EI type though its physical size is big. My ears detect a bit relaxed-muscle sound with the EI type.
During DIY life, I have been much concerned on the poor quality of transformers. I have been kind of short-tempered mostly with the transformers. If the amp designer recommends, e.g. 300VA transformer, I’d like the VA size of one step bigger. And, I prefer the transformer made for the 50Hz AC supply. A well-known story is that The 50Hz AC transformer is no problem when it is moved to the 60Hz AC zone, but the 60Hz AC transformer is almost always problem when moved to the 50Hz zone.
Hope you to check and select the right one.
JH |
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| Orgonom |
Maybe a pic makes it easier to go for it.
It run´s now for ca. 1,5 years without any
problem.
Andreas |
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| 2Bak |
thanks Orgonom :)
I think I'll go for them. |
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| boessenkool |
Dear 2BAK,
Having built my second JLH 10W amplifiers with EI transformers, I must say that the humming of the transformers I used is really frustrating (again). But this time I'm aware that the humming of the transformer is the problem and not the earthing, the circuit or something like that.
I am solving the problem right now, by placing the transformers in a separate housing.
Just curious, how heavy is the transformer?
Wishing you all the best.
Luuk Boessenkool |
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| 2Bak |
boessenkool,
10 kilo.
The guy who sells them to me has two of 'em. Thus I can build monoblocks if I want to... :superman:
He says that humming and noise in an amp would not be caused by them, but by wiring problems and maybe the position of the trafo in the case....
/Jan |
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| boessenkool |
Dear Jan,
Who knows.....
At least for my amp, I know for certain that the EI transformer is the problem. With all wires still connected I moved the transformer around and when the transformer was outside the casing, the hum disappeared.
All I meant to say was, that with such a transformer hum is a real posibllity.
Greatings,
Luuk Boessenkool |
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| jh6you |
Luuk
Hum when the transformer is installed inside the casing and no hum when installed outside the casing...? Then, your transformer is fine because the transformer outside the casing is OK. I would like to say that the hum is due to an improper wiring arrangement inside the casing.
JH |
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| jh6you |
Andreas
Your amp looks nice and looks better than mine.
By the way, for the capacitors, why not wiring as in Fig.(B)...?
I mean to persue a possibility of minimal hum and buzz.
JH |
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| Eccu |
| Or why wiring like fig (A), but wires to amplifier take from upper capasitor. |
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| jh6you |
I like this HH's "star".
JH |
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| HDTVman |
Could the hum your talking about be caused by the changing magnetic flux in the transformer vibrating the metal of the case? I have seen that cause a buzzing sound. If so, mount the transformer on rubber washers and space it up 1/4 inch / 5mm.
Later
Bruce :geezer: |
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| 2Bak |
I have decided to build my zen 4 using the heatsinks and the 10 kilo EI transformer shown at the top of this thread.
Here is quick drawing of my idea of cooling:
Since the sinks are 220 mm long the rear of the 3 or 5 mm case sides (blue) will not have any sinks.
The sinks will be bolted to the sides, maybe using thermal grease between, and the FETS will be mounted on the sides, thus hoping for cooling through the blue sides over to the sinks...?
Would this be possible or do I have to mount the FETS directly on the sinks?
My case here would be scalable, and I can add more small sinks to the rear sides, if things get to hot, couldn't I?
If this get too warmy, I also have the option to lower BIAS.
Front will be oak wood. |
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| Sparhawk |
I would not mount the FETs in the way you have pictured here. If the sides of the case are aluminum, it might work, but even then there will be additional thermal resistance. Using thermal compound will help, but given that your sinks are already on the small side, I think this mounting arrangement is asking for trouble. If the case is steel, it will be even worse.
You should mount the FETs directly on the heatsinks, perhaps by cutting holes in the sides of the case.
-Dan |
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| 2Bak |
Thanks Sparhawk
I will mount them directly.
Caps
Can I have someones opinion on this issue:
If I decide to use two beer cans only the total capacitance will be 33000uF per channel. If I use all four of them on the first pic it will be 60000uF per channel.
My trafo is 800VA. Nelson recommends 25000uF per channel as minimum (?)
My case will be quite huge if I use four. Easier to build with only two of 'em.
1. Not a good thing to place the caps on top off the trafo ?
2. Do I get a better sounding amplifier using 60000uF per channel ?
:dunno: |
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| jh6you |
1.
No idea if good or bad. But, my amp has four 22000uF caps arranged in a row about 1 inch above EI tansformer (300VA). I don't catch any problem.
2.
Well known is that the bigger the caps are, the smaller ripple and that the smaller the ripple is, the better. I however suspect the caps bigger than the amp designer's calculation would improve the sound.
Hoping this will help. |
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| paulb |
Here's a thought. If you don't mind having two boxes.
Put the transformer and one pair of caps in the first box, and the second pair and the amps and heatsinks in the second box. The first box can be ugly and hidden away, and it solves the possible problem of the transformer flux causing hum. I've also had a problem with the charging current peaks inducing hum.
You can add a small amount of resistance between the two pairs of caps (in addition to that of the wiring itself), to get a pi-filter. |
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| Sparhawk |
| I'm planning to use 33,000uF per channel on my Zen v4. It might be on the small side, but given that the v4 contains a regulated supply, I think ripple won't be a problem. It should still be very quiet. Though maybe the power supply won't be quite as "stiff" as it could be? |
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| jag |
I got a quote from mmmetals for mm5060s: $166 for 6 pcs - I was planning to use 3 per channel. This was bit on a high side though not bad considering that they are new (also, I found out that they are .5C/W each - not bad at all).
Subsequently I picked up two 24" (huge!) sinks from MECI - one per channel. Just a note to anyone planning to buy these - they look anodized in the pictures shown but are not actually. I am planning to put both mono-blocks in one case with huge heatsinks on both sides - 24" tall tower. Just sent in a check to passlabs for PCBs! |
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