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Old 5th December 2011, 11:10 PM   #1
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Default To PCB or not to PCB?

Folks, what is your experience in diy electronics without pcb? Seems it would provide better conductivity because design with fewer soldering points is possible. With PCB signal travels from component's lead to solder to copper trace to another component's lead. Without one it's only one soldering and leads physically touch.

Anyone with personal experience to share?
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Old 5th December 2011, 11:27 PM   #2
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I have used veroboard and got pcbs made too.

I found for class d I definitely needed a pcb with thick tracks and short routes and components kept as close together as possible..

For class AB the veroboard worked fine.
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Old 6th December 2011, 10:08 AM   #3
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in my mind you will not win in sound quality without using PCB you may win in less resistance, less heat and so on, but i would still use a PCB to get neat and compact board.
i personally hate the 3 dimensional mazes. i'm always afraid something will short or just break.

trick to minimize losses with a PCB is in the design of the board.. first compact and LOGICAL placement of parts and also the use of good boards. there are different copper thicknesses available, use a ticker copper board and tin the board after development. for leads that transfer more current you can always solder on more material, a copper wire for example or i have used some old solder wicks for wider tracks.

also it really helps to use silver solder, a lot more conductive then usual solder. and i'd say it is easier to solder also.

but that's just me.
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Old 7th December 2011, 03:08 AM   #4
wrankin is offline wrankin  United States
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Quote:
Originally Posted by openport View Post
also it really helps to use silver solder, a lot more conductive then usual solder. and i'd say it is easier to solder also.
Wow that is just so wrong.

If you can measure any significant difference in resistance between joints made with different types of solder then the problem is not with the solder, but rather with the joint you made.

High silver content solders are used in specialized applications where the materials involved do not work well with the standard tin based products. For standard electronics normal solder is more than sufficient. If anything, the higher general melting points of silver bearing solder increases the chance of making a bad joint.

In any case, most new solder formulations contain some silver (2-4%) not because of any direct benefit of silver, but rather as part of a usable alloy to replace the use of lead.


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Old 7th December 2011, 11:04 AM   #5
roline is offline roline  United States
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Default PCB based amps

I was old schooled and passed a NSA soldering test for space flight electronics. 60/40 used...
PCB's have advantages and disadvantages, anything created proper will work, not done right will just not perform as desired. I prefer PCB with wide traces and wide spaces. You must watch component location and adjacent traces for cross feed, capacitance coupling. I keep heater supplies off of the PCB and use twisted pair, must be over 1/2" off of the PCB.
I also like maximum ground plane with stitching to keep any ground plane current from developing a potential that could result in feedback / ground loops. This PCB was designed to fit on an 8.5x11 sheet to allow for toner transfer PCB fabrication.
You can make amps as quiet as a church mouse until you crank them up!
This PCB is a prototype suggested by KEGGER. It can use 6P3S Russian 6L6 tubes all the way to KT88's etc... I played with different tubes and component values to look for sensitivity and flexability. After months of different combinations, GNFB, no GNFB, UL, Triode, PIO, metalized poly, etc... I preferred 6550's Triode connected with older Hammond 6.6k 40 watt iron@ 450VB+
It was a very pleasant amp with low end authority at 350V B+ with the 6P3S tubes which would have been the lowest cost version.
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Old 7th December 2011, 05:57 PM   #6
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Roline, you have some of the best toner transfer results I have seen.
Some info about your setup would be good too - printer, paper,
toner, laminator (or whatever you use to transfer), number
of passes and so on would be very helpful.
I had mixed results till recently. I just realized that the clothes iron I have
at its max setting was too hot and I got better results at
a lower temperature.
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Old 7th December 2011, 10:09 PM   #7
tvrgeek is offline tvrgeek  United States
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The most correct answer is "it depends". I have build direct wire chassis, wire wrap, vector boards, and etched boards. I pick what is needed at the time, how complex the design is and how impatient I am. For an op-amp or complex circuit, yea double side boards, but I have a dead-bug mic preamp that is clean to -130 dB. I worked on things in the lab that were perfect in a breadboard and never worked when we made the boards as the parastatics are different. On the flip, I worked problems where we could only fix it by controlling the impedance issues on a etched board. A great example was the original HBO receivers where half of the circuit was actually the etch.

An oft overlooked method is to dead-bug on a copper clad board, using the un-etched plane as a ground plane, and direct wire 30Ga between legs of everything parmabonded to the board. Sounds like a kludge, but you can get a very quiet circuit.

I too passed certification in the 60/40 through-hole days.
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Old 15th December 2011, 11:30 PM   #8
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Why not use pcb? Toner transfer is so easy.
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Old 18th December 2011, 05:44 PM   #9
kamis is offline kamis  Serbia
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f anything, the higher general melting points of silver bearing solder increases the chance of making a bad joint.
In fact , silver in soldering alloys reduces melting point. Ordinary Sn60/Pb40 has melting point of 188 degrees C, but Sn62/Pb 36/Ag2 is 178 C.
Similar effect is in lead free alloys,silver bearing types have the lowest melting point.
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Old 18th December 2011, 09:38 PM   #10
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Just 10 degrees difference ain't that much. Silver containing tin/lead solder (so non-ROHS) has a higher mechanical strength than plan 60/40 tin/lead solder which is why it is used in specific cases. I haven't read of (nor experienced) any difference in conductivity. Besides that, when you bent the lead wires of components the lead wire will make contact with the copper PCB track and the solder is mostly for curing the electrical joint i.e. keeping it in place mechanically. The best way for good connections AFAIK but so old fashioned some wish to disagree on that as it is forgotten technique.

So bend the wire 45 degrees then use your pliers and cut it to the length you wish and then solder the joint. Often people solder and then cut the wire which gives mechanical stress on the joint which will shorten its lifespan/reliability.


That being said: I almost never use silver solder while I have a roll of Siltech and some stuff from other brands. I get the best joints with plain lead containing Fluitin. Good stuff, especially the variant that contains a few % copper.
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Last edited by jean-paul; 18th December 2011 at 09:42 PM.
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