apocalipsa Posted August 8, 2009 Posted August 8, 2009 are cineva idee care este anul/perioada din care s-a renuntat la productia in masa de ampuri Fender ptp si s-a trecut la pcb. vezi noile modele si reissue care sunt pe pcb. nu ma intereseaza modelele clasice care se produc si acum pe aceeasi tehnologie ptp. 10x:) si de asemenea daca stie cineva care sunt posibilele probleme care apar la pcb?
FiveseveN Posted August 8, 2009 Posted August 8, 2009 Uite ce spune Randall Aiken: Q: Why do you use point-to-point instead of PCB? Because it sounds better?A: No. There is no difference in tone between a properly designed PC board and a properly layed out turret board or other point-to-point construction technique. Note that I used the term "properly designed". There is a world of difference in the tone of an improper PCB layout and a proper one, just as there is between a proper PTP layout and an improper one. If high-impedance traces are run too close to other parts of the circuit, unwanted coupling can occur, leading to oscillations in the worst case, or just odd tone caused by frequency cancellations. This is not a problem that is unique to PC boards, as some "gurus" would have you believe. If you run a wire on a PTP layout too close to another wire or component, you will have the same problems. Don't believe the hype about "tiny capacitances" and "co-planar" traces robbing high end. PC boards are used in the gigahertz range, and are perfectly adequate for the audio frequency range. The problem comes in when an amp manufacturer uses a layout guy who doesn't know anything about proper layout of high-impedance circuitry, and when cheap, single-sided PC boards with non-plated-through holes are used. Now, why don't I use PC boards? Simple. A turret board provides better mechanical reliability and ease of maintenance or modification. I have seen far too many PC boards with pads and traces ripped up after one or two component changes. A turret board allows both a good mechanical connection and a good solder connection, and components are easy to remove and replace many times without any damage to the board. Turret boards can even incorporate ground planes or circuit traces, without the downside of worrying about traces and pads lifting up during repeated removal and replacement of parts. I don't use eyelet boards, because they don't allow a good mechanical connection; instead, they depend solely on the solder for mechanical strength at the connection. In addition, solder tends to blob up on the underside of the board, potentially leading to loose solder balls inside the amp, or accidental short circuits. Will I ever use PC boards? Probably at some point, especially on the more complex amplifier designs, mainly for consistency of manufacture or when the order volume outruns our small manufacturing capability, but you can bet that they will be better and more serviceable than any PC board you've ever seen in a guitar amplifier. I have been laying out PC boards for many, many years in my previous audio/video/medical engineering jobs, some of them being very complex multi-layer boards with traces/spaces as fine as 5 mils, some even using surface-mount components on both sides of the board, operating at frequencies from DC to the high MHz region, so I know all the ins and outs of proper PC board design and manufacture, and won't be at the mercy of an outside contract layout guy.
apocalipsa Posted August 11, 2009 Author Posted August 11, 2009 foooarte muuulta lume pe rgggccccc...
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