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PTP or PCB, that is the question...

2/6/2000 1:33 AM
BIG Dave
PTP or PCB, that is the question...
I have the opportunity to pick up a used JTM45 reissue for a song and I plan on doing some major upgrades with upgraded parts. The plan includes the usual upgrades; NOS ECC83's, Valve Arts KT66's, Mullard GZ34, 32u x 32u electrolytics, and Mercury Magnetics OT. I am undecided if I should install a PTP board. Has anybody done any research as to whether a PTP board sounds better simply because it is PTP or because the caps and resistors are usually of better quality? Would stripping the OEM PCB board of it's cheap parts and installing carbon comps and orange drops sound just as good a PTP board with similar parts?
2/6/2000 3:42 AM
Don Symes

The worm can is now open.  
PCBs can only be reworked a limited number of times before you start lifing pads and tracks. If the layout isn't giving you problems (noise, ghost notes, etc), the PCB should be fine. Make some little standoffs from component leads to make swapping values less stressful on the board.  
Oh, were you going to change the circuit any? PCBs can get ugly and unstable if you go cutting and jumping wothout a clear plan.  
My suggestion? Use a good FR4-based turret board.
2/6/2000 2:23 PM
Stephen Conner
PTP of course
Hi Dave,  
It shouldn't really make any difference to the sound, but tag boards are much more pleasant for the home constructor to use. I have always built my tube amps with a mixture of tag boards and stripboard.  
Steve C.
2/6/2000 3:11 PM
BIG Dave

Due to my limited knowledge with electronics, I think that replacing those cheap resistors and caps on an already established PCB board will be easier for me than creating a PTP board from scratch. I have also pondered a $150 Hoffman board however I know I can save a lot of dough if I just replace the cheap parts on the PCB. That leads me to a few more questions:  
* What kind of resistors should I use? Any particular brand or just any brand carbon comp?  
* What caps are preferable? Should I just Orange Drops everywhere on the board?  
Again, thank you for your help.
2/6/2000 3:54 PM
Marc Henry

I would go with ptp for sure since the simple fact of the matter is that PC boards SUCK to solder on! I hate soldering just a simple connection one time on 'em for fear of burning up the trace. I can't even imagine trying to resolder in every single cap and resistor! I guarantee you would screw up at least once, probably more. Most people think pc boards don't sound as good but you bring up a valid point; most pc  
board amps also suffer from cheap components.  
I have had good results with carbon comp resistors from Antique Electronic Supply they have all kinds of caps to choose from too.  
Good luck  
2/11/2000 6:27 PM
don't fear circuit boards, and hey speed..
having been an engineer/tech for the last 15 years or so, i can honestly say i've never had a problem repairing or working on pcb's of any tpye in a vast variety of equipment, just so long as care is taken, and excessive heat $.02.  
p.s..... hey speed........"melange still races"
2/9/2000 6:03 AM
Rick Erickson
Re: PTP of course
Why not use carbon film - that's what every Marshall I've ever seen uses, including the early Plexi's - unless my memory is failing me, I do know I've seen an occasional comp resistor in one but they were 99% carbon film. That's why you don't hear of people replacing all the noisy and out-of-tolerance resistors in Marshalls like you do with Fenders, Gibsons etc.. Early Ampegs were built with cf resistors also. They don't have resistor noise/drift problems either.  
Just thought I'd join this board the same way I joined the original amps & more board. A little nostalgia for Speed Racer. Cheers,  
Rick E.  

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