F5 power amplifier

Soldered before installing in the sink

i would not use the amp until the thermal coupling is corrected.
did you mount the outputs to the sinks before or after you soldered them?

Hi,

I soldered the outputs and then made the hole.... But there is plenty o thermal grease and also mica insulating... Maybe the thermal grease is not good enough?

:confused:

I am going to wait until the new tranny arrives from antek and is it rated at the stock F5 values of 18v secs.

Regards,

Jorge
 
Ok. I will try to fix this...

that can be the problem. always Mount the outputs before you solder them, to get a good coupling to the sinks.. and there chould not be alot of thermal grease. just a extremly thin layer. thermal grease have a lot of thermal resistance.

Hi,

Thanks... I will try to clean the grease and apply a new thin layer. Desoldering the output is a little more complicated but I will see if it can be done without damaging the output....

Regards,

Jorge
 
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Hi

I used mica and grease too, and the first mount delta was 14-15 degrees second mount was 11-12 degrees with about 35W (I ran it a bit hard because I had good sinks).

I used a razor blade to separate the sheets of mica and *very carefully* used the thinnest I could find. I also used Arctic Cooling MX-2 because regular grease is quite bad over here, and I used very, very little on each side of the mica. It wasn't a layer as much as a kiss.

The point is get it so thin that it is just filling the air gaps at a microscopic level. The actual heat conduction is by direct physical contact. You don't want the surfaces to stay insulated from each other by the grease, which is the problem with too much of it.

You can also try a bar over the outputs and torque it down to squeeze out every last bit of contact patch, this will help a lot with single-hole devices being asked to deliver so much.

Good Luck.

Hi,

I soldered the outputs and then made the hole.... But there is plenty o thermal grease and also mica insulating... Maybe the thermal grease is not good enough?

:confused:

I am going to wait until the new tranny arrives from antek and is it rated at the stock F5 values of 18v secs.

Regards,

Jorge
 
Hi

I used mica and grease too, and the first mount delta was 14-15 degrees second mount was 11-12 degrees with about 35W (I ran it a bit hard because I had good sinks).

I used a razor blade to separate the sheets of mica and *very carefully* used the thinnest I could find. I also used Arctic Cooling MX-2 because regular grease is quite bad over here, and I used very, very little on each side of the mica. It wasn't a layer as much as a kiss.

The point is get it so thin that it is just filling the air gaps at a microscopic level. The actual heat conduction is by direct physical contact. You don't want the surfaces to stay insulated from each other by the grease, which is the problem with too much of it.

You can also try a bar over the outputs and torque it down to squeeze out every last bit of contact patch, this will help a lot with single-hole devices being asked to deliver so much.

Good Luck.

i use MX2 as well:) a very good grease and Nice price:)
 
Hi,

Thanks... I will try to clean the grease and apply a new thin layer. Desoldering the output is a little more complicated but I will see if it can be done without damaging the output....

Regards,

Jorge

This might help. You don't necessarily have to REMOVE the output transistors. If you already have them mounted, then simultaneously heat all three of the PCB solder pads for each MOSFET (you might have to use two soldering irons, and enlist the help of a friend). The trick is to "reflow" the existing solder, to allow the MOSFET to seat itself on the heatsink/grease while all three transistor pads are molten.

Don't remove the MOSFET unless you must--it's a lot easier just to reflow the existing solder....and it will save the wear and tear on the PCB pads.
 
Excellent! got some good stuff now, i think it does matter to some degree which wire, that's answered it.

how about transformers and Shielding, i Personaly think its not too important to Shield in the F5 since its low noise anyway. and the transformer may be sitting away from the PCB's anyway. does it realy matter having unshielded transformers ?
 
Sounds great, i like the sound of that Pearl 2. not that Iv'e heard it but looks gr8. Yup you guys r very helpfull here.

Im going insane trying to figure out between the F5 Turbo v1 and v2
which one of the Diyaudio boards will make V2 or v1 turbo ? (im thinking none lol)

If i cant find them here then ill just buy the ones on ebay.
 
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