diyAudio

diyAudio (http://www.diyaudio.com/forums/)
-   Pass Labs (http://www.diyaudio.com/forums/pass-labs/)
-   -   heatsinks from conrad.. wich amp can they be used for (http://www.diyaudio.com/forums/pass-labs/64440-heatsinks-conrad-wich-amp-can-they-used.html)

wuffer 17th September 2005 11:28 AM

heatsinks from conrad.. wich amp can they be used for
 
i was thinking of using this http://www.conradheatsinks.com/products/double_f.html the MF30-2F-151.5 for en stereo amp in the future.. but wich aleph can it be used for...
it should be a stereo amp
is there any other places where i can buy heatsinks online with a visa card???

wuffwaff 17th September 2005 12:47 PM

Hi,

the heatsink will have around 0,3K/W at 30K temperature rise. So if you want your heatsink to be 50-55C you can dissipate 30/0,3 = 100watts.

This will be a very small Aleph stereo amp for example an Aleph 3/30 with 1A bias wich is really not enough or a mini-A. You will need at least two of those heatsinks for a stereo amp!

William

hifimaker 18th September 2005 04:45 PM

Hi Wuffer,

You need to apply a correction factor of 1.4 to the Conrad rating to compensate for the right operating range.

.30 * 1.4 = .42 C/W

These heatsinks make are great for about 60 watts, mono A60 or stereo A30.

Unless you really need the flanges, the flatback models have a thicker base and better C/W rating. Personally I'm using the model MF35-151.5 at .21C/W (corrected to .29 C/W), for a stereo A30.

BTW, the Conrad build quality is beautiful. They are also black powder coated and will turn purple over time.

Good luck,

-David

wuffwaff 18th September 2005 05:57 PM

Hi David,

sorry to disagree but a stereo Aleph 30 doesnt dissipate 60 watts and a mono Aleph60 doesnt dissipate 60 watts either. (A30 100watts/channel, A60 155watts/channel)

I already added a bit to the Conrad specs (at 80C temp rise) so if1.4 is the right faktor it will be 0,35K/W

William

jleaman 18th September 2005 09:14 PM

Quote:

Originally posted by wuffwaff
Hi,

the heatsink will have around 0,3K/W at 30K temperature rise. So if you want your heatsink to be 50-55C you can dissipate 30/0,3 = 100watts.

This will be a very small Aleph stereo amp for example an Aleph 3/30 with 1A bias wich is really not enough or a mini-A. You will need at least two of those heatsinks for a stereo amp!

William


I agree on this for a mini a'' You might need a fan to cool these sinks if you do a stereo aleph 30. The mini a's are not a cold running amp..

hifimaker 18th September 2005 09:24 PM

I agree with wuffwaff and jleaman. I should have mentioned that I'm using 2 of Conrad's larger mf35-151.5 heatsinks for my stereo Aleph30, with good open ventilation. One heatsink per channel.

I could be a bit optimistic and may need to back off on the bias or add a fan.

I also left out the word NOT. They will NOT turn purple over time since they are not anodized, but powder coated.


-David

jleaman 18th September 2005 09:30 PM

Quote:

Originally posted by dw8083
I agree with wuffwaff and jleaman. I should have mentioned that I'm using 2 of Conrad's larger mf35-151.5 heatsinks for my stereo Aleph30, with good open ventilation. One heatsink per channel.

I could be a bit optimistic and may need to back off on the bias or add a fan.

-David


This is funy.. I have yet to find the resistor that i have to change to bring up the bias on the aleph Mini -A id like to push them a little Brian said o could leave the reistor out and it would be full bias.

My plann is to have a switch to have full open bias and then to have it not full bias.

wuffwaff 18th September 2005 09:37 PM

jleaman,

try changing the resistor that is connected between the base of the small transistor in the current source and the plus side of the 220uF bootstrap cap. Leaving it out gives max bias, if this is not enough try lowering the source resistors.

William

jleaman 18th September 2005 10:49 PM

2 Attachment(s)
Quote:

Originally posted by wuffwaff
jleaman,

try changing the resistor that is connected between the base of the small transistor in the current source and the plus side of the 220uF bootstrap cap. Leaving it out gives max bias, if this is not enough try lowering the source resistors.

William


The only reason i ask is so i dont kill thes amps :D

what resistor R13 ?

wuffwaff 19th September 2005 01:54 PM

Yes, R13

William


All times are GMT. The time now is 11:35 PM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio


Content Relevant URLs by vBSEO 3.3.2