Peavy Valveking 112

some gut pictures of my Peavy valveking (sold) . I had to open it up because of a bad solder at the input jack . The issue was caused by a repeated use of the jack . This can make the solder break . Besides even on solder an big compagny has to save money so you don’t really have a big solid solder join , therefore it breaks if you apply to much force.

When I fixed it I took time to take some photos :

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To be honest I’m pretty sure the problem will appear again .

What to say ? getting the circuit out was a real pain ! I had to unscrew everything and try to get the circuit out really carfully because of the easily breakable multiple wire connector (the same as used in PC , sorry i’m not having the right name now)  and in the same I had to take care of not breaking the plastic pots in the process.

PCB based amp can’t be a real pain in the *** to repair by a simple fact : they’re not designed to be repaired

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A mass produced PCB based amp is cheap because of the little time it takes to be built. Manufacters need a quick way to put several parts of an amp together on the process line. So they can’t think and make arrangements for next repairs and possible damages, it will take time to do so . Therefore decisions are made to correspond to these points. PCBs are amazing for quick assembly especially if all components are mounted on the board, the circuit becomes a “drop in” , you just put the circuit in the chassis. Then the differents parts are connected with clip connectors (instead of hand-wired , question of time again ) . In this kind of amps everything matters so even the wire length is calculated.

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Obviously  PCBs can also be designed with repair and maitenance in mind but they will cost more time to design and therefore money .  Matamp amps seems to have found a  clever  mix of hand-wired and PCB amps.

Other thing that can be discussed on the peavy is the power tubes on PCB. Power tubes dissipate a lot of heat (really a lot of heat!) and PCB can be damaged by this heat especially if the power tubes go wrong and behave badly . But keep in mind that we deal with a 450euros 50W tube amp . We can’t  expect much better in this price range.

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There’s also none easy way to bias the amp , no trimmers , nada. Trimmers are black sheeps for big manufacters because they need to be manipulated , and again, they have no time for doing it!    Modifications have to be made to control and bias perfectly a new set of tubes. Once again it’s a cheap amps and boutique amps can also suffer of this lack. Having a trimer is a really handy tool even in a cathode bias amp !

Compared to some new marshall amps containing a lot of electronics this Peavy isn’t that bad.

Note that PCB routing , design and material have different degrees of quality .

Here’s the service manual with PCB and schematic included : https://smokingtip.files.wordpress.com/2013/05/pv_valveking_112.pdf

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