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Mic Kaczmarczik's PC Boards Information

PC Boards

This directory contains USENET articles Mic has saved about guitars, equipment, pickup, techniques, players, and so on. Mic has graciously granted permission to post the stuff on the JT30 page on the off chance that it might be useful in the context of Blues Harmonica. Mic is not responsible for the content, just the collection.

Circuits

PC Boards
From ja--(at)--n.com Mon Apr 29 12:03:24 CDT 1996
Article: 9073 of rec.audio.tubes
From: Dee Zucker
Newsgroups: alt.guitar.amps,rec.audio.tubes
Subject: Re: resistors - carbon vs. metal
Date: Sun, 28 Apr 1996 17:25:03 -0400
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Robert Fries wrote:


> This reminds me of the debate over point-to-point wiring vs.
> printed circuit boards - Weber's assertion that the coplanar and parallel
> traces create unwanted capacitances, which conspire to swallow all
> your tone. I don't buy it - I'd bet that given identical components,
> and an equivalent level of expertise in point-to-point wiring and
> practical PCB design, two amps built from the same schematic would
> be virtually indistinguishable.
>


It's a moot point. The real question you have to ask is:


Why do companies use Printed Circuit Boards ?


Hint: It's not to improve the sound. It's to save costs in manufacturing
and to have a consistancy in the resulting products . The unfortunate side
effect of all this is that while switching to PC board designs,
manufactures almost always switch to cheaper/smaller components which also
saves them money. Additionally, engineers anaylize the circuit and
determine where best to switch to more cost effective parts. For example,
Fender's choice of using a fixed resistor instead of a bias pot and their
use of 1/4 watt resistors. Another common practice is to swap out
capacitors with surface mount "offshore" designs. Transformers are also
commonly changed. Take a look at the reissue transformers that Marshall and
Fender use. Neither Fender no Marshall uses transformers with the proper
interleave ratio, paper bobbins, core material, or windings as the
originals. All of this serves to make the products sound totally different.


Robert, all you have to do is compare the Fender Blackface Twin reissue
against a properly restored original to know what I'm talking about. For an
even more startling difference, check out the difference between an
authentic '59 Bassman and the reissue.


On the other hand, when Marshall switched over to PC boards in 1973, the
amps sounded very close to the non PC board 1973 amps. The reason for that
was that it took them several years before they started switching over to
cheaper components.


Additionally, companies such as Mesa Boogie and THD make some outstanding
products using PC board designs. I've never heard the THD bassman copy but
would be interested in actually hearing one.


So, in closing, I think the answer to your question might be that yes, I'd
bet that given identical components,
given and an equivalent level of expertise in point-to-point wiring,
practical PCB design, etc., two amps might actually end up sounding the
same but I bet we'll never get to find out !


> -Jaz





 

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