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  • PTP vs PCB

    We need Trace, Olaf, Peter, Doug, Pete, James, or Jerry to take any "respectable" PCB amp and make a handwired clone, then post side-by-side clips so we can end this PTP>PCB nonsense. Any of you amp gurus have a few dozen hours of free time?

  • #2
    I do this all the time. PCB=POS.
    BobSavage.net - Music, Amp demos...
    Youtube Vids
    Savage Woodworks

    Comment


    • #3
      You on PCP?

      Comment


      • #4
        Here's an article that seems to break it down pretty well:

        http://www.geofex.com/Article_Folders/pt-to-pt/pt-to-pt.htm
        "I have the two qualities you require to see the absolute truth... I am brilliant and unloved". - Miss Evangelista, Dr. Who ep. "Silence In The Library"

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        • #5
          Originally posted by Ben J
          You on PCP?


          Don't ask dumb questions. I've rebuilt every PCB amp built since 81 as PTP amps and compared.
          BobSavage.net - Music, Amp demos...
          Youtube Vids
          Savage Woodworks

          Comment


          • #6
            Originally posted by DeathMonkey
            Here's an article that seems to break it down pretty well:

            http://www.geofex.com/Article_Folders/pt-to-pt/pt-to-pt.htm



            Hey, that was pretty cool. Informative as well. Thanks for posting the link.

            Eric
            Great transactions: Kung-Fool (Tom/traded amps), Major Third (Phil/bought from), Mr. Brady (Rob/sold to), Pwn3d (Nick/sold to), shreder75 (Matt/bought from), mhenson42 (Matt/bought from), Oblivion DC (Michael/bought from), Dropped_2_C (Scott/traded tubes), MCon (Matt/bought from), DarkCide (Talal/traded amps), Mctallica1 (Tony/bought from/traded), nyck (Nick/bought from), zao(Tom/bought from), guitup (Dennis/sold to), mparsons(Matt/sold to), gripside80 (Brian/sold to), LionHeaRT07 (Josh/sold to)

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            • #7
              Originally posted by BAZGUITARMAN



              Hey, that was pretty cool. Informative as well. Thanks for posting the link.

              Eric



              Well, go **************** YOURSE....oh, sorry, I actually did something right. Glad you enjoyed it. I think the part where he discusses some of the crosstalk is really interesting - I had no idea about stuff like that.
              "I have the two qualities you require to see the absolute truth... I am brilliant and unloved". - Miss Evangelista, Dr. Who ep. "Silence In The Library"

              Comment


              • #8


                So my amp is an odd combination of PTP and stripboard?

                Sounds cool to me

                Looks messy, sounds good...
                Music n such

                Comment


                • #9
                  it
                  Harmony Central Geezer Brigade member No. 50

                  Comment


                  • #10
                    Yep, 50 watt VAC
                    Music n such

                    Comment


                    • #11
                      Originally posted by Bob Savage


                      Don't ask dumb questions. I've rebuilt every PCB amp built since 81 as PTP amps and compared.


                      Tough talk coming from a man with an avatar of Ace Ventura as a ballerina in a 3-point stance

                      Comment


                      • #12
                        Here's a long-assed yet informative note from THD's Andy Marshall on the subject. Oddly, this quote is taken from Bogner's website.
                        _____________

                        From Andy Marshall:

                        Not all manufacturers choose to use PC boards just to save money. We use them for consistency more than for price, but making a somewhat affordable amplifier is a nice benefit. I don't think that someone should have to be a lawyer or Microsoft Millionaire to be able to afford a new amplifier that is hand-built, reliable and sounds and feels good to play.

                        If a PC board is designed correctly and the correct components are used, the amplifier production should be absolutely consistent from one unit to the next. No re-routing of traces should ever be necessary to make an amp function or sound right. If you find it necessary to change and re-rout wires in your amps, then you are not in production, but are just making a series of unstable prototypes. Treble reduction to the point where it reduces the clarity of the amplifier is not an acceptable stabilizing technique for either a PTP or PCB amplifier.

                        Recently, we got a call from a tech complimenting us on our old Plexi model amplifier (that we built between 1990 and 1995), but he said that it was just a little bit "stiff in the high-end" compared to a real Marshall Plexi. To back up his point, he told us that he had a real Marshall Plexi on the bench next to ours and was comparing the two side by side. What he did not seem to realize was that no two Marshall Plexis sound the same. They were terribly inconsistent with their component sources and values, not to mention the inconsistencies in wire routing.

                        Taking a point to point or a turret-board amplifier, if one moves the wires around, the entire sound and character of the amplifier can change, often dramatically. This is a well-recognized phenomenon.

                        If you understand these interactions well, you can design a PC board to sound and feel any way you want it to. Furthermore, every one will sound the same. How many times have you plugged into an old Marshall-50 watt head, only to be terribly disappointed by the sound and feel of the amplifier? While this may be caused by poor tubes, at least in part, inconsistencies in the internal layout of the amplifier often play a significant role.

                        If you understand how one component affects the component next to it and how one trace affects the trace next to it, then you should be able lay out a circuit board correctly the first time, not by building 10 and picking the best one. Mind you, it takes many years of experience to develop the sort of understanding of the capacitive and inductive interrelations involved. In the old days, I did this for a living for other companies, designing circuit boards for the audio sections of amplifiers, mixing consoles, signal processing equipment, etc... While I am under confidentiality agreements with almost all of my former clients, I can tell you that there is hardly a professional recording studio in the US or Europe that does not have some audio circuit board with my layout in some piece of equipment. After a few hundred such projects, one develops an intricate understanding of how traces and components interact.

                        A number of years ago, Guitar Player magazine did a review of one of our amplifiers. They stated that they, as a general rule, do not care for circuit board amplifiers, but also said that I had addressed every one of their concerns, and that they had nothing bad to say regarding our use of circuit boards. It felt good to see someone start to understand what it is that we do and why.

                        Certain components throw a rather large field. Others do not. Some components are very susceptible to the fields from other components, while some are not. Components can affect the signal passing through traces, and traces can affect the signal passing through components. It ends up being an enormous network of positive and negative feedback between components within each other's sway. This is why the distance between specific components on the board and the physical orientation of the components relative to one another (rotational orientation, as well as lateral placement) cannot be ignored. Furthermore, which traces are parallel to one another and at what distance, which traces are perpendicular to one another and that what distance, and the amount of ground plane in-between them can seriously affect the overall sound and feel of the finished amplifier.

                        Most people design circuit boards either haphazardly or for the greatest parts density/easiest and least expensive manufacture. Neither of these methods belongs in a high-end amplifier, and such approaches give PC Board designs a bad name.

                        If you know what you are doing, a thicker board is better than a thinner board (ours are .093" or 3/32", most are .062
                        Pete
                        My New CD - Special Price!
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                        My Myspace Page
                        Kurgan's Bane

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                        • #13
                          All my amps are PCB and I couldn't care less tonally because they sound great, and cost next to nothing compared to boutique amps... the only things that worry me are PCB mounted jacks, pots and tubes.

                          My Engl 520 preamp (great sounding preamp btw), has the tubes mounted directly to small PCB flaps that stick out from the main preamp PCB that feel very flimsy. God forbid one of them snaps... Ultimately, only if I were a touring musician and needed that utmost in reliability would I choose PTP over PCB. That would allow for quick fixes that any tech should be capable of on the road.

                          Note I'm not associating all PCB amps with PCB mounted jacks, pots and tubes, just that many PCB amps employ this method.

                          Comment


                          • #14
                            Originally posted by Bob Savage


                            Don't ask dumb questions. I've rebuilt every PCB amp built since 81 as PTP amps and compared.


                            I just rebuilt my PC to be PTP!
                            Songs in the key of ass...

                            Songs in the key of ass Part Deux...

                            "I just use one giant string. You really don't lose that much range, and it has the best tone evar.

                            Someday, I will have a custom built double neck guitar, with a giant string on the bottom for rhythms, and a slightly less giant string on the top neck for leads, and I will have the most amazing tone to ever grace the earth or the heavens, or even Australia."

                            -OneArmedScissors

                            Comment


                            • #15
                              as per usual its impossible for us layman to know whats BS and whatas not.


                              Where can i get an unbiased set of FACTS(not opinions,like old marshalls are better blah blah blah) about valve/tube amps and what does and doesnt make a difference.

                              There seems to be far too mutch unsupported opinion on this board,esp from people who dont even seem to be engineers of any kind.

                              So far the only sensible stuff i have found is on stewart wards site and some non-guitar related audio sites.

                              I guess as long as manufacturers pay magazines for expensive advertising nobodys going to spill the real facts.

                              so how about simple answers to the following.


                              1.WHY are older amps supposeed to be better than new ones? do electronics "age" or is it just rose tinted hindsight?

                              2.IF the tone comes from the power section in a valve amp why does everybody make 50w+ amps?

                              i have an old roland bolt30 that stays clean up to its max and is enough to fill out a medium sized hall via an extension cab.

                              Is running a 30w amp nearer its max better than running a 50w one at a lower volume.?


                              and this is just for starters....

                              so how about a truthfull thread on whats actually going on with supportable facts and not just kiddies reading adverts and spouting old wives tales about the good ol days?


                              i dont know anythign about electronics,but it seems sensibel to me that a compoennt is a component that does a job or not and there isnt anywhere near as mutch "mojo" talk on the audio sites that are non guitar related as there is on here.surely amp design is a science and not an avant garde art form??????


                              im esp hoping the real amp designers can put me on the right path as frankly im confused with all this pseduo-science.

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