So are all the PC board amps gonna crap out at some point?

Discussion in 'Amp Central Station' started by Dismalhead, Nov 15, 2019.

  1. kbold

    kbold Tele-Holic

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    All amps (PCB or point-to-point) will fail at some point. May be 3 weeks, 3 years, or 3 decades: depends on design, component quality, usage, and luck.
    Usually you get what you pay for.
     
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  2. drmmrr55

    drmmrr55 Tele-Holic

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    All amps are someday going to fail. This includes hand wired, and PCB. And just to be clear, a good solder joint doesn't just "go bad", unless it's corroded. Other than that, if it does go bad, then it was a bad solder to begin with. Capacitors last varying lengths of time, but they go bad in both types of amps. In theory, when it goes bad, it's usually tubes first, then capacitors and transformers. Transformers can last an indefinite period if you replace the caps every 10 to 15 years, and replace power output tubes at regular intervals. But sometimes, they will just "go bad", and it don't matter if it was a hand wired, or PCB. PCB is just more difficult for the tech to repair than a hand wired, it doesn't necessarily mean it's disposable! A physically broken circuit board or trace on a PCB is generally a throw away however.
     
    Last edited: Nov 16, 2019
  3. Jupiter

    Jupiter Telefied Ad Free Member

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    As far as I’m concerned, anything that lasts longer than me lasts forever. :p
     
  4. Vibrolux59

    Vibrolux59 Tele-Meister

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    As someone who has played through the same Super Reverbs and Deluxe Reverb for over 50 years, who cares.
     
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  5. BigD

    BigD Friend of Leo's

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    Will head only versions of PCB amps fair better than combos? I’m just considering the vibration from the speaker mounted in the same cab.


    Sent from my iPad using Tapatalk
     
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  6. Alter

    Alter Tele-Meister

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    Bear in mind, PCB amps and amps with a DSP (Digital signal processing chip) in them are two different things. PCB amps can still be repaired easily enough, but if a DSP fails (as in Super Champ X2, Jazzmaster Ultralight, Tonemasters, etc..) and it is impossible to replace, the amp is finished.
     
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  7. DADGAD

    DADGAD Tele-Afflicted

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    It depends on the amp. I have a Jet City JCA20H tube amp and the PCB is heavy duty with thick circuit traces. It is easy to repair and modify.

    I recently repaired a Peavey Classic 30 for a customer. The three folded circuit boards are difficult to work on and the thing is soldered with lead-free tin. I had to reflow solder on the tiny jumper wires between the PCB. It came back two days later as it failed again. More bad solder connections. It's been working for my customer for two weeks now. (Fingers crossed.)

    I've also repaired a couple of old Blackface Fender amps with problems. One had a power tube filament wire that was clinched but never soldered and a second one with a tremolo circuit wire that was never soldered back in 1964.

    So, it depends.
     
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  8. Wally

    Wally Telefied Ad Free Member

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    I have to observe that there are no Marshall tube amps that are 50 or 60 years old with PCB construction. The first PCB Marshall tube amp was built in 1973, iirc. Those amps will be working when they are 50 or 60 years old, though, because they are built with a very well-made PCB. as for some modern ‘consumer grade’ amps....I am not personally concerned. They are built so cheaply that I will never own one.
     
    Last edited: Nov 16, 2019
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  9. wildschwein

    wildschwein Tele-Afflicted

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    Loads of Mesa Boogies from the '70s out there that are still ticking.
     
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  10. CCK1

    CCK1 Tele-Meister

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    This is correct, everything eventually craps out. You, I, even that big oak tree in the front yard.
     
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  11. Les H

    Les H Tele-Holic

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    It all boils down to how well one takes care of their things.
     
  12. Wally

    Wally Telefied Ad Free Member

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    there is that aspect. However, the equation begins with how well something is designed and built. How many old Yugos do you see on the road? Poorly designed and cheaply built amps cannot possibly stand the same test of time and use that a well-designed and more expensively constructed amplifier will withstand, ime. I have a 5 year old Blues Jr that came in looking brand new...since it sits in a house and has never been hauled around. It has major issues and imho is not worth the time I have in it at this point. I repaired a 1973 PCB Marshall Md. 1987 many years ago. I am sure that it is still working, and it was one of the best sounding amps I have had the privilege of working on. It was built for professional use...it cost accordingly, but it has returned many times over that cost in good and dependable service. In the long run, such an amp is a bargain.
    There is a reason why there are old adages......one of which is..

    You get what you pay for.
     
  13. Rockinvet

    Rockinvet Tele-Meister

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    It’s also about the quality of construction. As others have said tube sockets pots and such connected to PCB boards is an example of poor construction. There are plenty of quality amps out there with PCB boards that are military grade. Live Rivera Amps for example. I have all hardwired amps now but still have to replace caps and such. It’s just the cost of doing business.
     
  14. telemnemonics

    telemnemonics Doctor of Teleocity Ad Free Member

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    This is the only post so far that IMO answers the question correctly!
    At least in terms of the "what happens when the pcb starts falling apart? Is it repairable?"

    >Market value<

    Along with ordering a new board, replacing the board with one from a junked amp (and yes there are junked amps stripped for parts) or making a whole new board in an amp of high enough value to be worth printing a board for; it is possible to simply hand wire the portion of the board that went bad.

    Generally it's only a portion of the board that the traces peeled off of from heat and flexing like around board mounted tube sockets, or from a component like a big resistor burning up and actually burning the board.
    I've seen whole sections of board cut out and replaced with hand wiring in an amp that was worth more than that repair cost.

    We also have a small movement to replace pcb boards with hand wiring in perfectly good working amps.
    In a simple old time circuit this may be pretty cheap to do, and even a beginner hobbyist can rebuild amps like the Epi VJr or Champion 600.
    Popular amps like the little Pro Jr might also get rebuilt with hand wiring when they start reaching the end of their pcb life span, though I haven't worked on one so I'm not sure how long lasting those boards are.
    Here we may see hobbyist players fix beyond the value of the amps because they like the amp and they like the fixing.

    So mostly I'd say it's a simple dollar value when the board needs a bad section fixed.
    If the owner can buy a whole used same amp for around the price of replacing a bad section of board or the whole board, they may choose to junk the chassis and just use the cab.
    Or if they have a bench fee they may give it to the tech in lieu of the $30 charged to find the problem.

    As far as Mesa being always repairable, we've actually seen some of the newer sub $1k Mesa amps junked due to the board repair costing more than the amp is worth on the used market.

    I think that as the market gets more and more flooded with certain amps we will see them junked more and more due to their value being low and their falling in between being desirable-vintage or desirable-modern.

    All the 20+yo RI Fender amps are probably already on the edge of not being worth fixing when they eventually have a board or other major problem.
    Maybe rewiring pcb Fender RI amps by hand will become a trend?
    Or maybe the number of newer used amps at low prices will make it just too easy to simply buy another sued amp and junk the broken one.
    Looking at the gear hoarding trend probably says as much as looking at the thickness of the pcb.
     
  15. telemnemonics

    telemnemonics Doctor of Teleocity Ad Free Member

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    I actually like the old pcb Marshalls because the prices are lower due to buyers thinking they are not hand wired Marshalls.

    In reality the first '70s pcb Marshalls are indeed (IMO) "hand wired amps", in the sense that there is a small pcb replacing the turret board populated by the small components, but almost the entire amp is hand wired including pots & sockets along with all bigger components like filter caps.

    Nobody seems to make much distinction between all pcb/ pcb & hand wired/ all hand wired, much like most seem to call turret & tag board amps "ptp".
    This may not really matter though since there are cheaply built pcb amps with hand wired chassis mounted sockets.

    Then I'd take exception to saying board mounted tube sockets are "cheap construction".
    While I don't like board mounted sockets, plenty of expensive and fairly reliable amps have board mounted sockets including the big old Ampegs like the VT22, V4, and SVT. Seems crazy given the high voltages those power sections run at but the octal sockets are all pcb mounted and lots are still in service.
    Again though, they get repaired because they are vintage and have some value.
    Maybe not the V4/ V4b so much, as those are not really cool amps, but I'd guess the SVT and the VT22 will keep being fixed for their rep alone. Maybe the VT22 will or already has been forgotten.

    I wonder how much difference it makes putting el84s running in the 300v range on a thick well cooled pcb vs putting octal power tubes running in the high 400s- 500v range on a pcb?
    I'd bet the higher end board mounted el84 socket amps will have a higher repairability rate than any of the pcb socket 6L6/ el34 amps in the long run, because of less heat and less strain.
    Maybe that's just wishful thinking and because I like Orange amps.
     
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  16. muchxs

    muchxs Doctor of Teleocity

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    Adult diapers. Depends.

    :D

    I just got a couple kit built amps "handwired" on Chinese turret boards. Not my first rodeo. I learned to solder while I was in elementary school. I taught myself to weld when I got my first car a few years later. I had plenty of old televisions to practice my soldering and plenty of broken farm machinery to practice my welding.

    There was not a single good solder joint between two kits. Start out with RoHS turretboards… I guess they're supposed to be silver soldered 'cuz my nice Kester solder didn't want to know about 'em. More to the point, though. I can't imagine that anyone thought those solder joints would work. They looked like frozen bird crap.

    The Curmudgeon Club had a discussion at the last antique radio show I went to. How will kids today figure out how to repair things? Nothing is designed to be repairable.

    That's the hassle. It takes finesse to remove components from a cheap PC board. It's easier to remove 'em from a milspec PC board 'cuz the good stuff was designed to be repairable.

    If it's a PRRI, DRRI or any of the '68 Customs... might as well yank the entire board if it gets damaged. George Alessandro will sell you a complete board for $55. Grab a spare while they're available if you want your reissue to last "forever".

    Murphy's Law of Spare Parts states that anything you can expediently replace will never fail.

    Handwired amps will likely be worth salvaging even if they're not cost effective to repair. The PC crap will go straight to the recycler. "Recycler" is a misnomer. They're scrappers. Electronics junkyards.

    Considering most of my friends and associates are nerds, geeks and more to the point engineers you might think I could have someone reproduce the first generation SVT board (6146A tubes) that the Stones burned up back when they used SVTs. It sat in a junk pile in New Jersey for decades waiting to be repaired.

    It's far easier to find a used board as salvage and far less expensive than having it reproduced.

    Wire wrapping as per vintage TTL, that's where it's at!

    I recently met a technician who has travelled a more or less parallel path. We were talkin' Rank Cintel, Dubner and CMX.
     
  17. AndyPanda

    AndyPanda Tele-Meister

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    IME the problem is when you have a part that gets handled/moved (like an input jack or potentiometer or tube socket) soldered directly to the circuit board and without any other support.

    Solder was originally only meant to seal the joint and prevent moisture/oxygen from corroding the metal surfaces of the joint (turning a conductive joint into a "semi conductor"). When solder is used as "glue" to hold a tube socket onto a circuit board and then the tube is pushed/pulled and wiggled... over time the solder connection will loosen and the connection will become intermittent.

    If, instead, the sockets and jacks and pots are mounted to the chassis and then wires are run to the circuit board -- then there is no flexing of the solder joint when changing tubes and twisting pots and plugging/unpluging the jacks.
     
  18. muchxs

    muchxs Doctor of Teleocity

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    Got the TV on in the background. There's an extended warrantee commercial on right now. "Sooner or later your car will break down..."

    There's a difference between repaired and restored.

    Repaired means some schlub performs the minimum work necessary to return the device to service be it a car, a guitar amp or your household plumbing.

    Things are often repaired and substantially less often restored.

    Restored means "returned to as- new condition."

    Generally the more a PC board has been repaired, the less likely it will be in a condition where the device can be restored.

    Ah, the dreaded PC mounted input jack break- ola. That's your built- in planned obsolescence.

    That includes PC mounted sockets, PC mounted pots and also PC mounted jacks for FX loops and such.

    A technician can remove parts without damaging traces. A musician tripping over their cord will often take the traces off with the jack.
     
  19. schmee

    schmee Poster Extraordinaire

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    They are often repairable. SOmetimes it's easy. But probably limited number of times that you can repair them.
    Some of the amps you mention aren't necessarily PCB board failures as much as components on the board. The Champ XD etc have components other than caps and resistors on the board. Digi logic circuits etc. I forget what they are called... not into that!

    A good sturdy PCB can be made, they used to be very thick and big solder flows. I think the bean counters got the engineers to get the material use down to a minimal amount since then. Add to that the cost reduction of trying to solder tube sockets/pots directly to boards and you have trouble. I wouldn't have a big problem with a thick quality board with big solders traces hand wired to pots and sockets.

    Regardless of quality, I don't feel a PCB will be as bulletproof as hand wired. Even hand wired sometimes break a wire off due to vibrations. I have seen many many broken/micro cracked pcb boards.
     
  20. Wally

    Wally Telefied Ad Free Member

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    Re: the construction of that first generation PCB Marshall.... The Fender Peo Sonic is built in the same manner. All pots, jacks, sockets, switches, etc are chassis mounted. The PCB is of fairly high grade. In short, compared to other Fender PCB amps, the Pro Sonic is built to withstand more physical stress.
     
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