Heatsinks for Bosoz?

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Mayday

Mayday

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Joined 2004
Re: errors continued

lgreen said:
The errors are above in the link from BobEllis, post #674.

The holes are too small for the power resistors, I had to drill out the holes and sand down the board to reveal the traces underneath in order to make the connection.
Click to expand...

Is it a bad idea to make the leads(don't know if that is the correct word) for the power resistors thinner instead of making the holes bigger?

I was aware of the problem stated in the post in that link, what got me jumpy was that someone wrote there was a problem on the main boards...

Thanks for all the replies
Jonas
 
lgreen

lgreen

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Joined 2003
Mayday said:
Just thought of another thing I'd like to ask, do you need insulation between the transistors and the heatsinks? Or should I just use heattranser paste(don't know the word for it in english)?
Click to expand...

1. it is ok to make the leads smaller, how are you going to do that? a file?

2. Yes, you should use a mica or other insulator between the heatsinks and the transistors, with thermal compound on each side to help with heat transfer. Its not strictly necessary so but is good building procedure and will prevent accidental shocks in the future. I've used "artic silver", got a tube on ebay.
 
lgreen

lgreen

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Joined 2003
Mayday said:
I've used a dremel multi-tool in the past to make them thinner. It's quickly done with a cylindershaped fine grinder attached to the dremel.

That's what I thougt, I've got a tube of theramal compound, guess i just need to get the insulations then.

Thanks!
Click to expand...

Thanks for the info, I've got a dremel sitting here but never thought of using it for that. Actually tried using the dremel to wear away the soldermask on the traces but it was too good, it wore away everything...including the traces.

If you are using the exact heat sinks the board is drilled for, there are pins that penetrate the board, you may want to solder the pins onto the board to prevent the heat sinks from moving.
 
lgreen

lgreen

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BrianDonegan said:
I believe Actic Silver is electrically conductive, so it may not be the best type to use in an insulation scenario.
Click to expand...


You might think that but you would be wrong. Artic Silver is not conductive (talking about artic silver 5, the one I used), but don't put it next to a trace on the pcb (not a worry here because heatsink is isloated) in that its slightly capactive. This stuff is the holy grail of CPU overclockers. See info here. As a back up, I measured conductivity between the heatsink and the MOSFET (mounted with artic silver), and they are completely isolated. Oh, and Nelson's choice is here, but he mentions the accolades for artic silver. For other comments see this thread.
 
Mayday

Mayday

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Joined 2004
lgreen said:


Thanks for the info, I've got a dremel sitting here but never thought of using it for that. Actually tried using the dremel to wear away the soldermask on the traces but it was too good, it wore away everything...including the traces.

If you are using the exact heat sinks the board is drilled for, there are pins that penetrate the board, you may want to solder the pins onto the board to prevent the heat sinks from moving.
Click to expand...

I will be using the exact heatsinks for the board, so I'm going to solder the pins. Btw, I'm using WBT silver solder(it's the one I've got at home) is there any downside to that or just a plus in this application? I've only used it to terminate cabels and making crossovers before.
 
lgreen

lgreen

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Joined 2003
Mayday said:
Actually I think would have used the silver solder even if I had regular solder at home, feels nice to know that you've done all you can to get a good product.

On that note, is it worth the price difference to use MUR820 diodes instead of 1N4004 on the PSU boards?
Click to expand...

Yeah, I am using WBT silver solder as well, just because I have some left over but to be honest i'm not sure it makes much difference. With all this talk of silver, how about using some silver wire?

Not sure about the diodes, people will tell you that the MUR's are better but others will say that they are not because their ultrafast behavior is only useful at very high frequencies. If you are looking to go all-out, the latest thing is to use Schottky diodes in the power supply if you can find them-- propbably even more expensive than the MURs. The Good thing is that you can always upgrade later-- pop in a new set and simply cut off the old set since they do not share mounting holes.
 
Mayday

Mayday

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Joined 2004
Might be better of putting the money into better caps?

This is(as if you hadn't noticed) my first preamp project, so I have little to no knowledge when it comes to matching transistors and such things.

Which transistors do i need to match, and how is it done?
How many do I have to buy to get enough matched?
This is a place where money might be better spend than on diodes as well?
 
lgreen

lgreen

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Joined 2003
preamp

First -- let me congratulate you on the decision to build your first preamp. This is a good design and you can get first rate sound using only standard (non exotic) components. So don't worry about fancy parts.....I understand we all use them from time to time for this and that so if you are going to use better parts I think results improve if you spend the $$ on a good volume control and output capacitors. A nice case will be worthwile too, though it probably will not affect sound quality.

Oh, and you don't have to match any MOSFETs on this design, but if you want to go the extra step I'm sure someone will chime in on how to do it (many links and posts on this) and which ones to match.
 
Mayday

Mayday

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Joined 2004
Re: preamp

lgreen said:
First -- let me congratulate you on the decision to build your first preamp. This is a good design and you can get first rate sound using only standard (non exotic) components. So don't worry about fancy parts.....I understand we all use them from time to time for this and that so if you are going to use better parts I think results improve if you spend the $$ on a good volume control and output capacitors. A nice case will be worthwile too, though it probably will not affect sound quality.

Oh, and you don't have to match any MOSFETs on this design, but if you want to go the extra step I'm sure someone will chime in on how to do it (many links and posts on this) and which ones to match.
Click to expand...

I was thinking of building the relvol3 from dantimax @ 5Kohm.

I've built 2 dipolwoofers using daytons 15" IB woofer, I'm using an active crossover for them(behringer dcx 2496). In a while I will build the top to match them, using B&G NEO8 and 2 seas P17RCY/channel in a dipolconfiguration. I want to use a passive crossover for these.
Now to the question; Is the x-bosoz capable of driving 2 balanced preouts?

Thanks to everyone for taking the time to help out a newbie.

:)
 
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