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Old 4th February 2013, 09:28 PM   #281
bcmbob is offline bcmbob  United States
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O.K. I have the Romex, but checking the stash I found some bundles I've been hanging on to for years, and a salvaged inductor I can twist up several lenghts. Is there still an advantage/preference for just the single solid Romex?
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Old 4th February 2013, 11:33 PM   #282
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Quote:
Originally Posted by bcmbob View Post
O.K. I have the Romex, but checking the stash I found some bundles I've been hanging on to for years, and a salvaged inductor I can twist up several lenghts. Is there still an advantage/preference for just the single solid Romex?
The inductor is too thin; however the braid will absorb the solder, turn solid and then steal all the heat out of your iron, thus taking a lot more time to do it. I tried this once--only once. Well, I'd think you'd probably like the Romex best.
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Old 4th February 2013, 11:56 PM   #283
bcmbob is offline bcmbob  United States
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Old 5th February 2013, 01:41 PM   #284
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Quote:
Originally Posted by bcmbob View Post
Hey Daniel, It's a good thing I don't embarrass easily.
I don't embarrass easily either, but this was really close: Best Earbud (not earplug) headphones to buy?

P.S. How goes it with your Romex adventure? Most point-to-point and perfboard power supplies end up with the flaw of overrelance on cap pin length to make connections, so, instead, I'd like to suggest minimal pin length for all components. You're very talented, so I'm looking forward to seeing a nice sturdy power supply with good use of thick copper for low-inductance performance benefiting clarity and dynamics.
Bass peak power can be, momentarily, well beyond the normal wattage of a Class AB power amplifier, so a good means to promote bass slam is a sturdy-built power board that doesn't throttle/blur the bass peak, and TDA729x needs all the help it can get for passable bass clarity and it must have bass clarity before it can do anything else clearly. Oh my. So, I think that the sturdy copper and a rather powerful soldering iron can help.
The speaker signal is highly reliant on every connection at the power board, especially the 0v line, so I'd also like to suggest a double-strength/thick 0v line if that is doable.
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Old 5th February 2013, 02:32 PM   #285
bcmbob is offline bcmbob  United States
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Got side tracked (simple life issues ) so won't start construction till later today. Will take pics.
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Last edited by bcmbob; 5th February 2013 at 02:38 PM.
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Old 6th February 2013, 10:12 AM   #286
bcmbob is offline bcmbob  United States
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This is what I came up with. A quick trip to the local hobby store gave me the choice of real rails (brass HO train track stock ), solid brass tubing and a 6" x 10" x 1/32" solid copper flat stock ($6). The sheet reminded me of some pictures I've seen on the forum so I chose it for this version. I'm hopping copper is copper and this will perform the same as the Romex.

Strips were marked (22 mm & 8 mm), cut on a band saw with a temporary fence and cleaned up with a file and sandpaper. Some parts are mounted through hole and others will be bent and soldered. I couldn't find any perfboard long enough at the local RS so I used chunks from my parts drawer. May have to devise some additional support. The DC out will have the same green screw pads as the AC In. A little more layout and drilling and I'll heat up the soldering iron for pre-tinning all the joints and final assembly.

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Old 6th February 2013, 10:37 AM   #287
SoIL4x4 is offline SoIL4x4  United States
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Looks good bob. I was thinking of something very similar with the 0 volt connections as I have a piece of copper left over from the fe enclosure. I am thinking of using 12 awg for the +/- rails to keep the distances at a minimum and then cutting a piece of the flat stock copper to be equal to a 6 awg wire.(based off daniels recommendations ).

I really like your perf board layout, and the terminal blocks are such an obvious convenience, great idea.

I am interested to see how well/difficult it will be to solder to the copper sheet. Keep us posted.
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Old 6th February 2013, 11:54 AM   #288
bcmbob is offline bcmbob  United States
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Thanks, I'm planning to scour the copper with Scotch-Brite, apply liquid flux and tin everything using a mini torch before final assembly with the soldering iron. I'll epoxy the copper to the perf-board first.
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Last edited by bcmbob; 6th February 2013 at 11:58 AM.
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Old 6th February 2013, 04:57 PM   #289
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Yesterday, I was wishing there was some way to steampunk a power supply. I was also wondering how to make the power supply compact instead of long and zigzag (happens when I try to "crowd" the caps to minimize distance to the 0v rail). Today, you taught me how to do both. Awesome. Thanks!

Possible errata:
I think there might should be a little bit more space between the rails so that you don't have to lacquer them for spark avoidance. Avoiding sparks usually takes about 1/4" space. But, if you're going to lacquer, that's good because it keeps perfboard from stinking when it gets hot (in this case, lacquer the top of the perfboard before mounting the caps). The wal-mart has black, white and clear Rustoleum spray Lacquer in stock in with the spray paint section. It hardens quickly. I'd use the clear lacquer on bottom, just in case you'd want to show off those big copper tracks.

Known hazard:
Those little green screw taps are known to loosen, slip incessantly, cause static and generally degrade both quality and safety. For power supply, you need euro type with big screws, not china type with little screws.
And,
In that layout of the bridge rectifier, you'll want to reinforce the insulation of your AC leads jumper from bridge rectifier to screw terminals with some shrink tubing just to give it some extra durability. The wire type used for jumper probably needs to be insulated solid copper so that it doesn't wander about.
Or,
I don't use any screw connectors with mine but rather have little holes drilled through the perfboard in the right spots to connect the transformer cables directly. In my case, the transformer cables are inserted through the top of the perfboard so that the transformer cables don't criscross anything, and my cables are soldered securely. My transformer cables are bundled as 2 groups of twisted pair as is typical for dual secondaries transformers.

Generally, I like everything about your build except for the frightening miniature screw connectors. And man, those gotta go--they don't match your build quality.
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Last edited by danielwritesbac; 6th February 2013 at 05:03 PM.
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Old 6th February 2013, 05:29 PM   #290
SoIL4x4 is offline SoIL4x4  United States
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[QUOTE=SoIL4x4;3358157]the terminal blocks are such an obvious convenience, great idea.

....or not

A question though. I know when designing pcbs it is advised to avoid sharp angles when laying out traces, is there any use for that rule when shaping the copper plate traces here? Bob I noticed some of your corners were rounded, and was wondering if that was why?

What about fastons for power supply conections?
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