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The Dynahi Construction Related Questions Thread - Page 3

post #31 of 630
8/30/04 at 12:23pm
Why do you punch the holes as opposed to drilling them?
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post #32 of 630
8/30/04 at 2:04pm
perfect holes with no problems on the reverse side.
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post #33 of 630
8/30/04 at 11:01pm
Just checking to see how everyone's going with the Dynahi. Only missing one part for mine, the large caps (I bought some Nichicon MUSE caps but didn't pay close enough attention to the diameter -- anyone have a good cap they can recommend?):



I had some trouble finding Vishay-Dale RN60C resistors at 300 ohms, so I went with some others I found elsewhere (RN60D instead). Figured it would be better to use 300s just to make sure there wouldn't be too much overheating of the resistors. I've got a couple extra Jung regulator boards that I might use for this purpose, though it might be fun to breadboard the Gilmore-Didden-Jung instead (and it actually might be less expensive than propagating two separate standard Jungs).

Anyone have it complete?
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post #34 of 630
8/31/04 at 12:35am
Quote:
Originally Posted by strohmie
Only missing one part for mine, the large caps (I bought some Nichicon MUSE caps but didn't pay close enough attention to the diameter -- anyone have a good cap they can recommend?):
I used Panasonic FC 50V 120uF, DigiKey part P11255-ND; 10mm diameter, 12.5mm height. Got quite a few of them, mostly for my power supply.

Still waiting for my heatsink angle Al and PS transformer to arrive. After that it's just a matter of picking a box to put it in... (assuming the GDJ reg works out according to plan, but how often does that happen?).
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post #35 of 630
8/31/04 at 10:23am
couple questions:

Is Mouser the best place to get Vishay-Dale resistors in Canada?

Do the LEDs have to be RED or is any with 1.7V drop ok?
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post #36 of 630
8/31/04 at 10:47am
Yes, any with 1.7V drop is OK.(ex: yellow, orange)

---------------------------------------------------------

This is my solution for heatsink.

1)Get a heatsink for TO-3 Power Transisitor(about 60VA) like this:

large photo


2)Cut it into two pieces(the scroll saw is not necessary, hand saw+patience works also)

large photo______ large photo


3)Drill 8 3mm holes(Many tools are capable of drilling 3mm hole)

large photo______ large photo

4)Lock it to the bottom of the case such that the whole case is your heatsink.

large photo

5)Have a cup of good oolong tea !
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post #37 of 630
8/31/04 at 3:49pm
That's a great photo-guide there. Too bad most people don't have any kind of machine saw that could do that...
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post #38 of 630
8/31/04 at 6:34pm
Great job. For people with limited tools, a hand made jig of the
proper dimensions, that heatsink or one similar, and a dremel
tool with a tiny machine bit will work to put a significant score
in the heatsink. Then if you are careful with a fine handsaw or
hand scroll saw you can make a very clean cut. And finish it
off with a fine file to make it look pretty.
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post #39 of 630
9/1/04 at 10:43pm
Thread Starter 
Went the easy route, just ordered two Condor power supplies from Alliedelec.com. Also, ordered all the board components (digikey, mouser) and the heat sinks (surplussales). Now I have to get the resistors for the Elma.

Anybody has suggestions for RCA connectors, power switch, input switch, headphone jack?
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post #40 of 630
9/1/04 at 11:33pm
Quote:
4)Lock it to the bottom of the case such that the whole case is your heatsink.
Wouldn't you want to consider NOT anchoring the board tightly due to the thermal expansion and contraction of the heatsink/angle assembly? This might lead to fatigue and failure of the output transistor bodies. Perhaps using flexible fasteners (spring, nylon) to allow for the side of the circuit board away from the output transistors to 'float' might be worthwhile.
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post #41 of 630
9/2/04 at 2:05am
Shure.
Every contact needs proper washer and spring.
I'll post more photos to show this later.
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post #42 of 630
9/2/04 at 2:29am
Quote:
Originally Posted by RickP
Wouldn't you want to consider NOT anchoring the board tightly due to the thermal expansion and contraction of the heatsink/angle assembly? This might lead to fatigue and failure of the output transistor bodies. Perhaps using flexible fasteners (spring, nylon) to allow for the side of the circuit board away from the output transistors to 'float' might be worthwhile.
Attaching the heatsink to the chassis is a good thing, as it will increase the heat dissipation area; though it is advisable to drill slightly oversized holes and use Belleville (conical) or wave washers that will allow for some movement. Same applies to the power transistors.

ON Semi has a good App Note on this subject, it's rather technical but there's still plenty to be learned by just looking at the diagrams.
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post #43 of 630
9/2/04 at 9:13am
Thanks for hadron's link.
My method is almost the same as the Note.



large photo

Another view:
As the arrow point, distance between HS and transisor's leg is about 1mm to avoid shorting.

large photo



Temperature of HS is about 60~65℃, and DC-offset is within ±3mV even though without DC-Servo.
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post #44 of 630
9/2/04 at 10:46am
The start of the dynomite power supply

http://gilmore.chem.northwestern.edu/dynomiteps.jpg

+/-40 volts first stage power supply at 4 amperes each.
In a 17 x 14 x 5 chassis. Already weighs in at 25 lbs...
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post #45 of 630
9/2/04 at 11:09am
wow that is big....... any guesses as to when it will be finalized

so many DIY projects on here

phils new tube project and M^2

btw next you can change it to Monsieur Stax or Signore Stax
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