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Old 8th December 2012, 08:56 AM   #21
marce is offline marce  United Kingdom
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= PCB tracks never are silver solder, but raw solder or even lead.
Are you saying the traces on PCB's are tin lead solder or what I dont quite understand this!

As to PCB's and valves, they are used in guitar amps quite a lot, take up the stress of being thrown around.
Heat, like ALL hot components you ensure they are not tight to the board, sockets that stand off.
Removing Valves, again like any component that may cause mechanical stress, use some form of mechanical fixing.
There are always ways to engineer a solution, and where you can score with PCB's is where you have to control RF immunity.
End of day both done correctly will work either done bad will be rubbish.
Early PCB's used with valve designs were CEM, a crappy paper based material great for cheep single sided designs (hundreds of 70s TVs), again materials have developed, you might have heard of lead free , well the increase in processing temperatures this requires means that your PCB materials have to also handle hotter temps, plus there are different grades and temp ranges of FR4 that will do the job without having to resort to silly esoteric dialectric. Also look at what they are doing with LED lighting and PCB's...
This has been an anouncment by the Printed Circuit Board Defence League, have fun
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Old 8th December 2012, 09:00 AM   #22
marce is offline marce  United Kingdom
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On a more esoteric side, when I get chance I want to do a PCB for my valve monoblocks, but have the track layers machined out of 2mm copper with a clear plastic or air dielectric (its a 2 layer design), played about with 4 and 6oz copper PCB's as well, now they are good, and you can also remove the heat from hot spots with the correct design.
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Old 8th December 2012, 11:49 AM   #23
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Originally Posted by marce View Post
Are you saying the traces on PCB's are tin lead solder or what I dont quite understand this!
Usually mass made equips use low price solder(solder without silver), but to reduce costs they can use just sole lead (plumblum or Pb);
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Old 8th December 2012, 11:53 AM   #24
qusp is offline qusp  Australia
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Originally Posted by marce View Post
On a more esoteric side, when I get chance I want to do a PCB for my valve monoblocks, but have the track layers machined out of 2mm copper with a clear plastic or air dielectric (its a 2 layer design), played about with 4 and 6oz copper PCB's as well, now they are good, and you can also remove the heat from hot spots with the correct design.
yeah this is a dream of mine too, but with Arlon and solid silver =)
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Old 8th December 2012, 12:04 PM   #25
DF96 is offline DF96  England
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I thought PCB tracks are usually copper? Often with a thin layer of solder. Most of any audio signal will be in the copper, whatever solder is used.
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Old 8th December 2012, 12:18 PM   #26
freax is offline freax  Australia
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yet another reason why pcb is a mystery bag, how thick is it? did the manufacturer use the right glue? will it stand the test of time? should I leave the trace clean or should I lay down half a spool of expensive silver solder?

Will cockroaches come into the amp and lay their eggs inbetween the active and neutral terminals and make a horrible smell when I turn it on again. True story *pop*

With ptp it just goes straight to where it needs to go, no detours or roundabouts, no worry about cracking or material types.
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Old 8th December 2012, 12:34 PM   #27
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Default pcb board

So if a pcb is to be made what would be the recommended copper thickness and board material type.
I am just about to rebuild a set of amps built to the hybrid design Jeff Macaulay published in the Sept 1995 issue of Eletronics world. I have 2 young children so I wanted to make it as safe as possible and the pcb route seemed to fit this.
A lot of the components are fitted to a pcb anyway and I wired the rest but wanted it all fitted to the board to simplify it.
I made the original pcb's but as I have a small machine shop in my garage the thought of milling the pcb really appeals to me. Time rich and money poor you see!
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Old 8th December 2012, 01:03 PM   #28
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Standard PCB thickness is 0.062" and 1 oz Copper. 2 oz copper costs more, I've only used it for heat transfer needs - solid state stuff.
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Old 8th December 2012, 01:04 PM   #29
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I always thought good soldering (small volcano shaped joint of solder) in through the hole boards would stand up to most anything -- heat to cold. Look at the old running way too hot to fry an egg mobile phones installed in cars before. Massive traces, lots of heats pushed out and measured in watts, and no point to point wiring.

If you do want to go all artistic, then point to point is great looking (the CMoy amp that was encased in clear plastic a little while ago).

Done right, both work, but you just have to know how much to engineer and how much to overbuild it. And it also depends how long you want to spend behind the soldering iron as through the hole is probably quicker to place and solder without much more thinking than looking at the instructions or schematic, noticing polarity, and how much wire goes through the hole.
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Old 8th December 2012, 01:15 PM   #30
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Originally Posted by DF96 View Post
I thought PCB tracks are usually copper? Often with a thin layer of solder. Most of any audio signal will be in the copper, whatever solder is used.
PCB with copper tracks is very rare, cause the copper is difficult to melt.
I see it just once in a web image, the tracks had the usual red colour.
I dont know what is worse to audio raw copper or cheap solder.

I avoid buy tube amps with PCBs, cause the PCBs usually are big and prevent the proper cooling of the amp.
The fresh air dont pass through the amp, since the PCB blocks the flow of air.
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