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  • what's advantage of hard wiring?

    what advantage of hard wiring? It is cost many time and money?
    is it real better ?

  • #2
    It is debateable if it is really better. I have seen arguments from boths sides. Hand wiring is more flexible for most repairs and modificiations. It is also what was used on most of the great vintage amps, so it has a good reputation. In general Hand Wired amps are more desirable then PCB construction amps but it is also more expensive. I prefer hand wired amps, but it doesn't mean that comperable PCB amps can't sound as good or according to some better. I don't like generalizing, but PCB amps will generally have more price shortcuts than just the labor for the construction and will use inferior parts than that which would seem logical to put in a hand wired amp. Also some of the associated layout choices of a non hand wired amp make any repairs very difficult. There are exceptions to this I am sure, but I can't profess to have much experience with them. I think there are more important things to tone than the wiring method, but I think I would be more likely to find them in a hand wired amp. Some engineers argue that PCB traces can have superier conductivety and be less prone to pickup interference. Please notice that I included the word CAN, this is under certain circumstances. I think removing the negative "cheap" stigma from non hand wired would be an uphill struggle, especially since there has been a decent amount of examples to support it.

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    • #3
      Originally posted by kldguitar View Post
      what advantage of hard wiring? It is cost many time and money?
      is it real better ?
      In general, PC board amps are built in factories and often are designed to save money, which means the parts are usually low quality and the board is flimsy. On the other hand, it's easier to make a complicated amp on a PC board.

      Hard wired amps are made by hand and often they are designed for superior tone, which means the parts are high quality (although there are exceptions, especially with kits).

      Hard wired amps are much easier to repair than a PC board. PC board amps will last about a decade before needing repairs. That's about the lifetime of inexpensive electrolytics, and plastic parts, which crack.

      Usually it's less expensive to buy a new PC board amp than to get an older one repaired.

      It's not uncommon for people to rebuild an amp by replacing the PC board with an eyelet board. Here's an example of a Super Reverb rebuild. The amp had been repaired 3 or 4 times, which was very expensive when added up. The owner wanted something built to last.
      http://www.naturdoctor.com/Chapters/Rodgers/ReWire.html

      Notice the size of the resistors on the PC board vs. the eyelet board ... triple the size!
      See the birth of a 2-watt tube guitar amp - the "Dyno Tweed"
      http://www.naturdoctor.com/Chapters/Amps/DynoTweed.html

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      • #4
        If the time has been taken to properly design a "quality" P.C. board (not only having all the proper connections, quality traces, quality soldering, quality components, but also ideal layout, which is especially important if it's a high-gain design), it CAN be an advantage over PTP construction. One example of a well made P.C. board would be found in Soldano amps (my opinion). Whereas if PTP construction is done with poor workmanship or bad "lead dressing" (such as later era SF Fenders......IMO), it can often result in peculiar interferences such as parasitic oscillations (which is why Fender had to use a hi-frequecy "bleed-off" capacitor at the power tube grids on the later SF versions of their "classic" models)
        Mac/Amps
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        www.mac4amps.com

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        • #5
          Hard wired amps are much easier to repair than a PC board.

          Really? - Ever work on a Matchless, or an old Gibson?
          I know what you mean, but there are no blanket rules that cover all amps.

          RE

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          • #6
            In general, PCB construction/manufacture is a higher-tech process than old-fashioned 'hard wiring'. The boards in many modern production amps can be prone to physical stresses from tube heat and tension if the board mounting is poorly thought out, resulting in boards cracking and jumper-wires breaking etc. Also with all the traces going al over the place, it would require some knowledge and skill in order to optimise the layout of traces and jumper wires so that you can minimise unwanted coupling etc, but I guess its possible to do so. In my humble experience, unwanted signal and other-noise coupling, results from too-many and too-long wires running everywhere. The challenge would be to minimising the length of traces on a PC board and maybe having ground traces running betwen signal traces etc. The big advantage in PCBs is in the unit cost of construction for big production runs. Having a robot stamp out PCBs has got to be cheaper. But the more tech you add to the design and manufacture process the more scope there is for things to go wrong, either in design, or in production.

            You could also design a 'hard-wired' circuit to minimise unwanted coupling, (e.g. "true PTP") and that is probably easier to do for many home-builder low-tech guys (like me), but more expensive to buy, because its analogous to using craftspeople to make everything, instead of using robots, unless you built a robot that could do PTP circuits, which I guess is also possible.
            Building a better world (one tube amp at a time)

            "I have never had to invoke a formula to fight oscillation in a guitar amp."- Enzo

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            • #7
              Hard wired amps are much easier to repair than a PC board.

              Really? - Ever work on a Matchless, or an old Gibson?
              I know what you mean, but there are no blanket rules that cover all amps.

              I gotta go with PRNDL on that,and I think if you did a poll on the subject,point to point will win hands down over PCB's when it comes to repairing or modding.Of course there are guys who work on solid state stuff and may have actually learned on PCB's who find it second nature to work on them,but for me,I shudder when I see a Mesa or the like on my bench.

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              • #8
                I know what you mean, but there are no blanket rules that cover all amps.
                I agree.
                P2P with tag boards is great for simple circuits, but becomes more difficult when there's a lot of components. It's also more difficult to repair than an eyelet or turret board.

                I'm in the process of rebuilding my latest amp (a 1 watt 6AK6 single-ended amp) into a tweed chassis. It's an extremely simple circuit (less components than a Champ), and I'm partial to P2P with tag boards, but am considering using an eyelet board simply because more people prefer them.
                See the birth of a 2-watt tube guitar amp - the "Dyno Tweed"
                http://www.naturdoctor.com/Chapters/Amps/DynoTweed.html

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                • #9
                  Yep, an old Princeton or Deluxe is a lot easier to work on than a Mesa. Uh huh.

                  I think cheap amps will have a pc board, yes. AMps with pc boards are cheap? Only the cheap ones. High quality amps are also built on circuit boards. it is not the circuit board-ness that makes an amp cheap. That is the old all axe murderers started out on baby food thing. It is the fact it is a cheap amp that makes it cheap. Your point to point amp could have a thin chassis, cheap pots, undersize transformers wound with too thin wire, undersize filter caps, cheap passive parts, BAD SOLDER work. And so on.

                  Mesas are a pain to work on not because they are on a circuit board, but because of the implementation of that board. They worked so hard to cram everything into a tiny board with parts stacked on top of parts. Imagine making a Mesa complex amp with the exact circuit on the exact chassis with point to point wiring. Would it even fit? WOuld you wind up with stacked tag boards. That wouldn't be very convenient. Think an old Gibson is bad, try working on an amp with two or three of those Gibson type boards stacked.

                  Boards allow the circuit to be compacted. COmponent leads can be shorter, wire runs can be shorter. SImple additions to the trace art on the board can implement shielding to improve stability.

                  Look at the discussions we have here about kit amps. We hear about Bruces kits and how the parts are first rate, the things are high quality. Then we gear about other brands of kits where th eparts are cheap, some people throw out the part from the kit and buy their own in some cases. Had a friend build a cheap kit and the pilot light assembly was some hideous plastic thing. Hand wired point to point though.

                  The factories usually wire them right when point to point, at least we think so. We only see the ones that pass QC. But for the home builder, there are far more opportunities to screw up the wiring, the lead dress and who knows what else. On a circuit board, you might put the wrong part in a spot, but the wiring is cast in copper. And a hand wired can have the wrong resistor wired some place just as easy. Oops, I put a 100 ohm instead of 100k on the plate of that 12AX7. Doesn't matter board or point to point there.

                  I run a repair shop, and I can't say my repair tickets for boarded amps are any higher than the point to point ones. A pair of 6V6 and an OT on some little amp will cost a lot less that a quad of 6L6 and an OT on a 5150 or a Marshall 100 watt, sure, so the bill is larger, but not because of the boards.

                  If you are a basement guy, my hat is off to you, that is how I learned, so my professional experience gives me an advantage working on a boarded amp. But really, if I don't waste time griping, I can have the main board on a TSL100 flipped over for replacing a resistor inside of 10 minutes. And that is not showing off, that is just sitting down and doing it.

                  If you want to build something, point to point is simple and easy. And it will withstand being taken apart and rewired multiple times. Boarded amps were made to play and be someone's amp. They are meant to be a finished product. And at that they shine. They are not made to have part after part changed and changed as an ongoing hobby item. They are not intended for modding, any more than your mom's car is made to be convenient for screwing around under the hood trying to hot rod it.

                  If you buy a commercial board for a build, aside from stuffing the wrong parts, the wiring will be right. You will never look down into your amp and reailze all the wires on that 12AX7 socket are off one pin - explaining the wire with no place to go at the end of the row - if the socket is on the board. Wiring point to point, the inexperienced solderer won't turn pc boards into charcoal or lift pads and traces. That tag board won't melt so easy. But my first bike had training wheels. It is not the technology's fault if someone cannot solder well. We all learn eventually to solder. Well, most of us anyway.

                  How many times has someone built an amp then come here asking why it screeches or has parasitics, and we tell them to move the grid wires from the output tubes away from other things? Many times. How many tube amps built on circuit boards have we had to hand out that advice on?

                  Both technologies have their place, and blanket statements are not realistic assesments of the situation. POint to piont is simple, and easy to use in the simple amps we build. These guys are building 5E3s and stuff, not 5150s. But boards offer many advantages too.
                  Education is what you're left with after you have forgotten what you have learned.

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