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What i do not 100% understand : I see 3 x J310 in the buffer and only one 2SK170.
There should be 2 x J310 and 2 x 2SK170. I also can not see the output DC offset trimmer.

the schematic is in the box with the pcb's so you will see that the output buffer only has one sk170. and yes, there is no DC offset trimmer since theree is a servo....

hope to have a first listening tomorrow night, while you guys are "frickeling"......
 
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.... and they work as advertized ;-)

just finished stuffing the boards, they worked fine at first turn-on, and sound fantastic. they retain the signature of the rev1, but add a little crispness to the sound. great atmosphere and imaging. just the first impression, far from burn-in anyway....

hope my fellow beta builders will experience no issues as well! watch out for the polarity of those LEDs...
 
Analog Devices must like hearing from their engineers. MT-101 was preceded by AN-202, AN-342 and AN-347 which say most of the same things. The topic must be important!

The interesting part of MT-101 was the inclusion of Bonnie Baker's book in the footnotes. She's at TI, and is one of the first columns I read when EDN arrives.

Thanks for posting.
 
FrickelFest and What About Mounting transistors

FrickelFest = Diy for men (mostly) :)

Then I came to talk about mounting issues:
Did YOU know that the thermal coefficient of metal differs from that of plastic? I'm sure you did, but did you realize that to make a reliable connection between the transistor and the heat sink you need a constant pressure to do that. If not then I will tell you, “you need to have a constant pressure”. For this purpose there exist special washers.

More about those washers can be found here: Disc Springs to DIN 2093

And this is what ON Semiconductor has to say about it (see page 7) of this document: http://www.onsemi.com/pub_link/Collateral/AN1040-D.PDF

Compression Hardware
Normal split ring lock washers are not the best choice for
mounting power semiconductors. A typical #6 washer
flattens at about 50 pounds, whereas 150 to 300 pounds is
needed for good heat transfer at the interface. A very useful
piece of hardware is the conical, sometimes called a
Belleville washer, compression washer. As shown in
Figure 8, it has the ability to maintain a fairly constant
pressure over a wide range of its physical deflection –
generally 20% to 80%. When installing, the assembler
applies torque until the washer depresses to half its original
height. (Tests should be run prior to setting up the assembly
line to determine the proper torque for the fastener used to
achieve 50% deflection.) The washer will absorb any
cyclic expansion of the package, insulating washer or other
materials caused by temperature changes. Conical washers
are the key to successful mounting of devices requiring
strict control of the mounting force or when plastic
hardware is used in the mounting scheme. They are used
with the large face contacting the packages. A new
variation of the conical washer includes it as part of a nut
assembly. Called a “sync nut,” the patented device can be
soldered to a PC board and the semiconductor mounted
with a 6–32 machine screw.
(4)
 
Hello Frans,
it was a pleasure to meet you @ FF.
But you disappeared so quick.......
About mounting Torque.
Are you sure a tiny little M3 screwed in a Aluminium-
cooler will be able to withstand this load ?
In my little experience i'm not as sure.

Sorry,
i've had to read before i speak. :rolleyes:
 
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Hello Frans,
it was a pleasure to meet you @ FF.
But you disappeared so quick.......
About mounting Torque.
Are you sure a tiny little M3 screwed in a Aluminium-
cooler will be able to withstand this load ?
In my little experience i'm not as sure.

Sorry,
i've had to read before i speak. :rolleyes:

Next time I stay for the duration of the event.

And

Use a strong screw :)

And

The pleasure goes both ways

And

Did you see the boys from ATL (or did I left them in Joachims room)

And

One pound is about halve a kilo ;) http://www.evi.com/q/how_much_is_1/2_pound_in_kilos
 
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