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December 14, 2019, 04:45:04 PM

Recent Posts

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1
Mainline / Re: Build update
« Last post by Thermioniclife on Today at 04:29:52 PM »
Pb,
As I stated raw aluminum will look fantastic in a home environ for a long time regardless of the material.
anodizing will add an extra surface protection but it should be done before any assembly is done.
as this fellow has polished his raw top plate before assembly I am sure it will not need any further treatment and will look fine for a generation to follow.
2
Tech Tools / Re: Enamel wire stripping tool
« Last post by Doc B. on Today at 04:22:52 PM »
Yes, nowadays they use a high temp urethane. It is like the finish on your car, very rugged. A solder pot is definitely the easiest way to strip the stuff.
3
Crack / Re: Speedball Upgrade help
« Last post by Doc B. on Today at 04:19:57 PM »
Thermal paste is technically speaking an electrically insulating material (most often, at least, unless it is of the type that has electrically conductive particles in it). But the spots where it doesn't cover because it got squished are definitely not insulated. You need a mica or sil-pad insulator. IIRC mica is a little better than sil-pads in terms of thermal conductivity.
4
Mainline / Re: Build update
« Last post by Paul Birkeland on Today at 03:54:43 PM »
A lot of the time anodizing is more hassle than it's worth.  Around 2010 I was tasked with evaluating every anodizing outfit available in the Seattle area, and none of them could produce a satisfactory finish and not damage the parts I sent them. 

I have worked on lots of Bottlehead gear that's 30+ years old with raw grained aluminum and I've never seen any corrosion.

5
Crack / Re: Speedball Upgrade help
« Last post by Paul Birkeland on Today at 03:51:32 PM »
You need to use the parts that came with the kit and your problem will likely be resolved.

Mica is unique because it is both a very good electrical insulator and a very good thermal conductor. 
6
General Discussion / Re: Construction pet peeves
« Last post by Thermioniclife on Today at 03:21:16 PM »
As PB suggested Tin the tip of your iron and place it on the outside of the solder cup and fill the cup up with solder. then tin the wire that has to be connected. at this point it is very easy to make the connection, just place a tinned iron on the side of the solder cup and when it melts place the tinned end of the wire in the cup perhaps leaving the iron on the outside of the cup foe a couple of secs to melt the tin on the wire and you are done. No muss no fuss. two hands needed only.
7
Mainline / Re: Build update
« Last post by Thermioniclife on Today at 02:56:17 PM »
Oh I almost forgot as I am addle brained. we did the tests on raw aluminum and all production parts were hard coat anodized
mostly in grey or black but you can get clear anodizing that will last forever in a home environ.
It just seems like it may be to late to do this to your amp at this point as you would have to dissemble the amp to get the top plate anodized.
Peace.
8
Mainline / Re: Build update
« Last post by Thermioniclife on Today at 02:36:57 PM »
Hey iamjanco,
I have not used wax on aluminum myself but I was just speculating. As you have already built up the top plate it will probably be a pain to apply an aerosol sealer of sorts, that's why I suggested wax.
As I stated as soon as you sand or polish aluminum it oxidizes almost instantly which is a good thing if you think about it.
the second thing you have going for you is that you polished the surface. A polished surface does not promote corrosion as mush as a pitted surface (in iron or steel and I would presume in aluminum also) there are many grades of aluminum such as 2000, 3000 5000, 6000, and 7000 etc. each having different properties.
I used to work in a company that built submersible boats and we used to submerge raw aluminum in sea water for extended periods of time to see the effects of corrosive environs. materials such as 6061 and 5052 aluminum faired very well. 2005 alum did not fair so well. But having said that I would not think this will be a problem with an audio amp chassis plate unless your girlfriend waters the plants that may over your amp. Don't laugh as this has happened to me in the past. Water and electronics do not mix well.
I'm not a rocket scientist but I used to be submarine surgeon.
Best wishes.
Lee
9
General Discussion / Re: Construction pet peeves
« Last post by Deke609 on Today at 02:25:56 PM »
Thanks all. I like Jamie's idea of cutting a notch.  Maybe it doesn't make a difference, but I don't like the idea of my signal wire relying on just tin/lead (with or without a tiny bit of copper and/or silver, depending on thei solder one uses) to make a connection. I'd prefer a tight mechanical connection.  But, again, maybe it doesn't matter.

But my real gripe is that these connectors are manufactured with a solder cup in the first place. What purpose do they serve, that wouldn't be just as well served by a turret or big lug?

10
Crack / Re: Speedball Upgrade help
« Last post by KaminKevCrew on Today at 02:00:50 PM »
I'll post some photos of the circuit boards in a bit - I have pulled them out of my Crack at this point and returned it to stock, as I was wanting to listen to some tubey goodness. Fortunately, everything in the stock Crack seems to be working just fine still, so I suppose that narrows it down to my Speedball upgrade, which is nice to know.

I bought my kit secondhand, rather than new so I'm not entirely sure what version I ended up getting. I found some instructions online, which I've been using. I don't think I have the new instructions though, as there wasn't a section in my set that talked about testing the small boards first.

Is there any way I can test the smaller boards? I have a lab power supply that can do up to 30V, and has to separate outputs. I've also got an oscilloscope and a DMM, but I'm not sure what voltage I would need to be sending here. I could probably figure it out based on the recommended voltages at the terminals that the PCBs connect to, but if you happen to know that would be nice!

Edit: Also, the TIP50 transistors on the bigger circuit board didn't seem to come in my kit with a thermal pad - there was what looked like a mica insulator in my kit, but mica is generally an insulator of heat, so I decided to not use them and instead use some thermal paste I have from building computers. The thermal paste is completely non-conductive, but if the heatplate on the transistor has direct contact with the aluminum heatsink, could that cause issues? I can put an insulator through them if I need to.
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