SSLV1.1 builds & fairytales - Page 188

Salas · 2nd November 2012, 12:50 PM

It must be having quite some coupling capacitors.

schubert · 2nd November 2012, 02:16 PM

Jupiters - must be something in the beeswax!

Salas · 2nd November 2012, 02:40 PM

This type? I measured enough dissipation VS MKP but subjectively they were high class.

schubert · 2nd November 2012, 03:36 PM

That's the brand, yes, but the type I have is now out of production - they have the orange case. I can post a pic when I get home. I must say I haven't listened to the DCB1 a whole lot, because I don't have adequate heat sinks yet and I don't want to toast any more mosfets! My favorite configuration so far runs about 300ma and uses super through power caps and AMRG resistors. I also must state that I've only run trial setups with a cheesy radio shack transformer with the DCB1, and I use a large toroid with the standard B1 - the transformer makes a difference, I think.

schubert · 2nd November 2012, 03:51 PM

They look like these, but bigger since they're 10uF:

Salas · 2nd November 2012, 03:56 PM

They look like having the previous outer wrap? Keep them away from shunt's sinks...

schubert · 2nd November 2012, 05:24 PM

They're far enough away - they sit on the case, and even when I had the mosfets bolted to the case they didn't get warm (bolting to the case wasn't good enough - the mosfets failed!). I've put a small fan in too.

Salas · 2nd November 2012, 05:31 PM

Surely they had full back on contact?

AndrewT · 2nd November 2012, 06:20 PM

Electric insulators between mosFETs and their heatsinks.

Anodised aluminium is an electric insulator, but it is very thin and could fail soon after fitting.

schubert · 2nd November 2012, 07:16 PM

Yeah, they were smeared with heat sink compound and were insulated with mica. The case had a light colored powder coat, though, so I don't think it was a very efficient heat radiator. It did get hot for about two inches around the mosfets. The mosfet cases got to 60º though, which, as I now know, is good for a month or two of operation! They probably got hotter when I put the cover on the case. So then I tried individual heat sinks, but they weren't big enough and the mosfets got even hotter. So now I'm waiting for half bricks from Mouser - hopefully they will do the trick, in conjunction with the fan. My case is kind of cramped (an old Comcast cable TV box) so finding sinks that would fit in it was kind of tricky, since it's only 2.5 in high or so.

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2nd November 2012, 12:50 PM	#1871
Salas diyAudio Chief Moderator Join Date: Oct 2002 Location: Athens-Greece	It must be having quite some coupling capacitors.

2nd November 2012, 02:16 PM	#1872
schubert diyAudio Member Join Date: Sep 2008 Location: Pennsylvania, USA	Jupiters - must be something in the beeswax!

2nd November 2012, 03:36 PM	#1874
schubert diyAudio Member Join Date: Sep 2008 Location: Pennsylvania, USA	That's the brand, yes, but the type I have is now out of production - they have the orange case. I can post a pic when I get home. I must say I haven't listened to the DCB1 a whole lot, because I don't have adequate heat sinks yet and I don't want to toast any more mosfets! My favorite configuration so far runs about 300ma and uses super through power caps and AMRG resistors. I also must state that I've only run trial setups with a cheesy radio shack transformer with the DCB1, and I use a large toroid with the standard B1 - the transformer makes a difference, I think.

2nd November 2012, 03:51 PM	#1875
schubert diyAudio Member Join Date: Sep 2008 Location: Pennsylvania, USA	They look like these, but bigger since they're 10uF:

2nd November 2012, 03:56 PM	#1876
Salas diyAudio Chief Moderator Join Date: Oct 2002 Location: Athens-Greece	They look like having the previous outer wrap? Keep them away from shunt's sinks...

2nd November 2012, 05:24 PM	#1877
schubert diyAudio Member Join Date: Sep 2008 Location: Pennsylvania, USA	They're far enough away - they sit on the case, and even when I had the mosfets bolted to the case they didn't get warm (bolting to the case wasn't good enough - the mosfets failed!). I've put a small fan in too.

2nd November 2012, 05:31 PM	#1878
Salas diyAudio Chief Moderator Join Date: Oct 2002 Location: Athens-Greece	Surely they had full back on contact?

2nd November 2012, 06:20 PM	#1879
AndrewT diyAudio Member Join Date: Jul 2004 Location: Scottish Borders	Electric insulators between mosFETs and their heatsinks. Anodised aluminium is an electric insulator, but it is very thin and could fail soon after fitting.

2nd November 2012, 07:16 PM	#1880
schubert diyAudio Member Join Date: Sep 2008 Location: Pennsylvania, USA	Yeah, they were smeared with heat sink compound and were insulated with mica. The case had a light colored powder coat, though, so I don't think it was a very efficient heat radiator. It did get hot for about two inches around the mosfets. The mosfet cases got to 60º though, which, as I now know, is good for a month or two of operation! They probably got hotter when I put the cover on the case. So then I tried individual heat sinks, but they weren't big enough and the mosfets got even hotter. So now I'm waiting for half bricks from Mouser - hopefully they will do the trick, in conjunction with the fan. My case is kind of cramped (an old Comcast cable TV box) so finding sinks that would fit in it was kind of tricky, since it's only 2.5 in high or so.