? for amp builders

Bob Hoffnar · Post by **Bob Hoffnar** » 10 Dec 2004 6:35 am

How much does it increase the cost of the amp to install a regular switchcraft type metal input jack ? Those plastic ones connected to circuit boards most all you guys use now give me the willies.

Thanks, Bob

Brad Sarno · Post by **Brad Sarno** » 10 Dec 2004 7:18 am

Bob, usually those plastic ones are plastic for reasons of ground isolaton. It depends on how the amp circuit is grounded. If it's plastic, it should probably remain so. The types you see on Marshall amps with the black plastic nut which are also very common to other pieces of gear as well are actually very rugged and reliable. There are some though that are cheap and that have threads that can strip or break from overtightening.

Sometimes you do have the option of using a metal switchcraft type but you need to use a pair of nylon insulating washers that safely keep the ground/shield part of the jack from contacting the chassis hole thru which it's mounted.

Brad Sarno

Bob Metzger · Post by **Bob Metzger** » 11 Dec 2004 1:54 am

For you to change out parts to premium brand parts on an amp or two doesn't cost a whole lot of money but to look at it from a manufacturers perspective, it could put the amp that they are making in a whole different price point and against even fiercer competition. I hate the plastic stuff as much as the next guy but I see why they do it.

Bob M.

Glenn Austin · Post by **Glenn Austin** » 15 Dec 2004 10:40 am

As far as newer Fender amps are concerned, their plastic PCB mounted jacks are fragile, all it takes is for someone to knock the jack with a cord plugged in and voila, instant cracked solder joint inside.

As I'm writing this I'm sitting here looking at 2 Peavey bass amps with bent sliders on the graphic Eq's. As a matter of fact I don't think I have ever seen a Peavey bass amp that didn't have bent eq sliders, as the top of the cab is cut away, I guess to make the settings easier to see, but It would seem to me that it would cost less for Peavey not to route away the top part of the cabinet. I've never been able to figure that one out.

Fred Jack · Post by **Fred Jack** » 15 Dec 2004 2:38 pm

Bob, Does your post reference the new Fender Steel king? Fred

Bob Hoffnar · Post by **Bob Hoffnar** » 15 Dec 2004 4:52 pm

I haven't seen the inside of a steel king yet so I don't know. Most amps seem to use the plastic input jack on a flimsey pcb board these days though. One bump to a cable jack while its plugged in the whole board can crack.
I guess I'm not one of those guys that understands the importance of a company saving 82 cents on an $800 amp so that I can have an amp that will very likely need a $125 repair and be less reliable.
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Bob
intonation help

[This message was edited by Bob Hoffnar on 15 December 2004 at 05:06 PM.]

Sam Marshall · Post by **Sam Marshall** » 15 Dec 2004 5:01 pm

The Fender Steel King employs a metal bushing jack on the front for the instrument input. Its rear panel interfaces are plastic jacks, however.

All of the phone jacks on the Steel-King are manufactured by Neutrik. They were formally manufactured by RE/AN. These are the same family of jacks that Brad cited on Marshalls.

I would considered these higher quality jacks. Once Fender changed much of our product line to the RE/AN jack several years ago, we witnessed a dramatic reduction in jack failures. The plastic is sturdy, yet compliant.

These type jacks also allow for improved grounding techniques that are necessary to ward off RF compatability problems.

Regards,
Sam [This message was edited by Sam Marshall on 15 December 2004 at 05:08 PM.]

Bob Hoffnar · Post by **Bob Hoffnar** » 15 Dec 2004 5:14 pm

Sam,
Its good to hear you guys at Fender are dealing with that problem. I'm looking forward to checking out a steel king first chance I get.

Thanks, Bob

Stephen Dorocke · Post by **Stephen Dorocke** » 19 Dec 2004 11:11 am

Victoria Amps=No plastic.......

Brad Sarno · Post by **Brad Sarno** » 19 Dec 2004 11:29 am

There are some pretty complex grounding issues in amp design to that surround minimizing hum and avoiding inductive loops, especially when there are FX sends and returns and extra outputs. Typically the instrument input jack will be the central and main audio ground to chassis connection. This is why often times the rear jacks will be plastic and isolated from the chassis ground while an input jack will be the metal/grounded type.

Brad Sarno

Dave Grafe · Post by **Dave Grafe** » 20 Dec 2004 8:42 pm

Besides the very valid issues expounded upon here by Brad and the others, the basic issue for manufacturers is this:

Using the PC-mount jacks, flimsy or not, allows the production line to be almost completely automated - a computer stuffs the PC boards and a conveyor belt passes them through the flow-solder machine and the washing facility before human hands ever touch them. The whole PCB assembly is then fitted into the chassis, the chassis into the cabinet and away to QC it goes.

Hard-wired jacks of any construction requre a human sitting there to solder each lead of each jack of each amp. This not only adds a modest labor cost but significantly increases the unit assembly time as well, reducing the number of units that can be produced in a given period of time and thus the unit price/plant overhead ratio becomes non-competitive.

In case you were not aware of it, the musical equipment industry is extremely competitive with lots manufacturers trying to increase market share by offering the same features as the other guy for less money -- some very "successful" firms are notorious for stealing others' designs and building them as cheap as possible (ever wonder why that Behringer mixer was so much cheaper than the seemingly "identical" Mackie or Peavey unit?).

A very few builders still build gear the old-fashioned way with quality being their first priority but they can't build very many units and can't begin to do it as cheaply as the big automated plants. Such folk must find satisfaction in serving a small market of discriminating musicians who don't mind paying extra for the best.

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<img align=right src="http://www.pdxaudio.com/dgsept03.jpg" width="114 height="114">Dave Grafe - email: dg@pdxaudio.com
Production
Pickin', etc.

1978 ShoBud Pro I E9, 1960 Les Paul (SG) Deluxe, 1963 Precision Bass, 1954 Gibson LGO, 1897 Washburn Hawaiian Steel Conversion
[This message was edited by Dave Grafe on 20 December 2004 at 08:47 PM.]

Bob Hoffnar · Post by **Bob Hoffnar** » 21 Dec 2004 7:36 am

Thanks for the info Dave and the rest. I knew there had to be more to it than just a cheap part. I am interested in Sam's ways of dealing with the breakage issue. I have been on stage with guys that have brand new amps that have left them on the side of the road a few times. I brought one into my repair guy and he had a graveyard of amps with broken input jacks/circuit boards. He just said "Yea, all the new ones are crap."

I've never had a problem with Peavey. I couldn't destroy my old NV 400 no matter how hard I tried. Its great to know that Fender is on the case.

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Bob
intonation help