Understanding Handwire/PCB Artical
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Re: Understanding Handwire/PCB Artical
Read this repeatedly:
"If a PCB based amplifier is properly designed, it can be every bit as sweet sounding as that vintage hand-wired job you have in the closet. With a thick PCB that has plenty of stress relief and plated through solder pads for the components, it is every bit as durable as a PTP build."
Board mounted pots, jacks, and especially tube sockets found in many PCB amps are problematic because physical stress on solder joints is BAD. But you can build a PCB amp without mounting those things on the board.
The author didn't mention that point-to-point or handwired turret/or/eyelet board construction requires a certain amount of distance between components. Amp manufacturers going for lowest cost tend to use the smallest possible components and cram them into the smallest possible space on PCBs. This can create all kinds of layout-related problems.
The notion that point-to-point is "better" because of the "shortest possible connections between components" cracks me up. It doesn't really matter if there's 1/2" or 3" between a plate resistor and its respective tube socket pin. What matters is how that wire is routed relative to everything else inside the amp. The most important thing is to keep high current/voltage leads away from low current/voltage leads.
One comment after the article also pointed out that push-on connectors abound in most PCB amps and can be problems waiting to happen. My Blues Jr. is an excellent example of this!
Also, a lot of PCB amps use ribbon cables. Ribbon cables are great inside a PC. Not so much inside an amp which is subject to loud vibrations (music?), road abuse, etc. Then you pull the PCB to replace a bad cap, move the ribbon cable, and voila' - what used to be a barely acceptable solder joint is now crap.
Randall Aiken says it pretty well with "Either construction method can be good or bad, depending upon the way in which it is done. Neither is inherently good nor bad on their own." Here's the rest of his essay on PCB vs. PTP:
http://aikenamps.com/PCBorPTP.htm
Here are a few photos of the insides of typical vintage and home brew amps using turret board or eyelet board construction.
Hoffman forum gut shot gallery
I used to think that the layout of vintage Fender amps was kind of random. It's not. Fender figured out how to layout each circuit the best way possible consistent with low cost. The grounding scheme in old Fenders is not at all random either after you study it. Bottom line is it works.
Sorry for the diatribe...
Chip
Read this repeatedly:
"If a PCB based amplifier is properly designed, it can be every bit as sweet sounding as that vintage hand-wired job you have in the closet. With a thick PCB that has plenty of stress relief and plated through solder pads for the components, it is every bit as durable as a PTP build."
Board mounted pots, jacks, and especially tube sockets found in many PCB amps are problematic because physical stress on solder joints is BAD. But you can build a PCB amp without mounting those things on the board.
The author didn't mention that point-to-point or handwired turret/or/eyelet board construction requires a certain amount of distance between components. Amp manufacturers going for lowest cost tend to use the smallest possible components and cram them into the smallest possible space on PCBs. This can create all kinds of layout-related problems.
The notion that point-to-point is "better" because of the "shortest possible connections between components" cracks me up. It doesn't really matter if there's 1/2" or 3" between a plate resistor and its respective tube socket pin. What matters is how that wire is routed relative to everything else inside the amp. The most important thing is to keep high current/voltage leads away from low current/voltage leads.
One comment after the article also pointed out that push-on connectors abound in most PCB amps and can be problems waiting to happen. My Blues Jr. is an excellent example of this!
Also, a lot of PCB amps use ribbon cables. Ribbon cables are great inside a PC. Not so much inside an amp which is subject to loud vibrations (music?), road abuse, etc. Then you pull the PCB to replace a bad cap, move the ribbon cable, and voila' - what used to be a barely acceptable solder joint is now crap.
Randall Aiken says it pretty well with "Either construction method can be good or bad, depending upon the way in which it is done. Neither is inherently good nor bad on their own." Here's the rest of his essay on PCB vs. PTP:
http://aikenamps.com/PCBorPTP.htm
Here are a few photos of the insides of typical vintage and home brew amps using turret board or eyelet board construction.
Hoffman forum gut shot gallery
I used to think that the layout of vintage Fender amps was kind of random. It's not. Fender figured out how to layout each circuit the best way possible consistent with low cost. The grounding scheme in old Fenders is not at all random either after you study it. Bottom line is it works.
Sorry for the diatribe...
Chip
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Re: Understanding Handwire/PCB Artical
+1 Great Info!
+1 Great Info!