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Instrument Amplifier "Conversion"                                     ®
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I started converting integrated cord amps to detachable cord amps on my own amplifiers some years back. After I had done this on about 3 to 4 amps of my own, I had a few friends, and friends of friends, ask me to do theirs. It is much more convenient for the amp-owner to detach the cord to transport their equipment without that pesky cord dangling--or having to stow it in the back--and risking the plug prongs poking a hole in a speaker (this has happened to me!!!).
 
I am now offering this as a service. For the modest price of $45, I will remove the integrated cord, install an input (male) socket, clean out the chassis and cabinet (dust and cobwebs), and provide a detachable cord.  I have done several of these conversions and they look as if they were factory-installed. I decided to photograph my most recent one--a Fender Princeton Chorus PR82. I did this so that you can see the process that I follow in the series of photos below. I can do this for you!  Look me up. If interested, contact me HERE.
BEFORE THE CONVERSION

This is a 2007 Fender Princeton Chorus. It is the last amp that got the conversion. The cord on this amp was pretty "obtrusive" but could be stored in the back. Fender provided a Velcro strap to wrap around the cord. The Velcro is attached to the left side inside the speaker area.

You can see the Velcro strap in the lower left area of the open back (look carefully at lower left). This is intended to stow the cord. I've always had concern about the plug prongs piercing one of the speakers when stowing the cord back there.

Here you can see the cord attached up under the chassis.

Another view of the cord--secured to the chassis.


CONVERSON - IN PROCESS

Chassis removed, you can see the power cord along the top from its terminal spade connectors on the right, to where it exits the chassis on the left.

Viewed from the bottom of the chassis, the cord is secured by a strain-relief grommet. This is common for securing cords on appliances and amps to prevent pulling out.

When determining the length to cut for the main power wires, I first decide the most logical location to put the plug. It has to be in a location where there is no other component on the inside that will interfere with placement. I then cut the cord to about twice the length that I need to reach the socket location--in this case, about 12 inches.

Pliers work well to remove the power cord strain-relief grommet. The grommet basically pinches the cord. The cord resists being bent, so it sort of 'secures itself' when pinched between the two components. To remove, you must grasp securely and wiggle it a little. It come out fairly easily.

 

Here you can see that the strain-relief grommet is now free. It can now be removed.

There are two kinds of sockets that I offer to install. First is one with a spring-loaded dust cover. 

 

The second type is the simple open type. I am using the open type, in this case. For most amp owners who would want this conversion, the reason would be convenience. Since there is a lot of plugging in and unplugging, the cover might actually be ripped off in the bustle of setting up or tearing down equipment. Owner can decide which style they prefer. I keep a lot of the open type in stock, but very few of the dust-cover type. The dust cover might be more appropriate for the casual or occasional user.

I had a somewhat crude template for cutting the hole for the socket. It was made of card stock,  It worked fine, but was getting frayed around the edges. So recently I cut one from Plexiglas. It is much smaller overall to fit into a variety of positions where a plug may need to be located.

 

Here is the traced cutout. I use a mechanical pencil with a fine (0.5mm) tip to make a crisp cut line.

 

 

 

 

After the cutout is made, I stripped the black sheath from the 12" section of cord, and ran the wires through the hole. Now it is time to strip the wire ends and solder them to the back of the socket. 

 

I need to mention that soldering terminals that are injection molded into surrounding plastic is not for amateurs. It is quite easy to melt the plastic by dwelling on the terminal too long with a hot soldering iron. I use an aerospace-quality soldering iron, and I am a J-STD-001 qualified solderer (that is the standard to qualify aerospace soldering).

This is could be seen as overkill. However, I've learned a lot about taking extra precautions while working in the aerospace industry. Surrounding static, etc. can affect a circuit. So I coat the terminals with "liquid electrical tape". It is a paint-on liquid that solidifies and insulates the terminals from static, or from coming into contact with anything unrelated to this conversion that might come loose in the chassis at a later date. Also seen here are the screws and nuts with self-locking inserts that I use.

CONVERSON - COMPLETE

More overkill perhaps, but I feel strongly about neatly done work, and about preventing even insulated wires from touching components or other wires inside the chassis. So I secure the power wires with several tie-wraps and (as you see here) with a cable clamp--mounted to the chassis--taking up the extra slack in the wires. When installing the socket, I use new #4 black screws and locknuts--preventing the socket from coming loose on its own.

This is where the cord protruded through the hole in the chassis. Maybe a bit hard to see, but this is actually a piece of self-adhesive pick-guard material. I buy this stuff in gross amounts because I find it useful for a lot of things (including making pick-guards).  I cut it about 1/8" all around larger than the hold, and peel and stick it on to cover the hole. This prevents "critters" (like spiders) from taking up residence inside the chassis. I'm not really bothered by spiders unless they are in my amp!


The last thing I do is connect the speaker wires, plug it in, and test it. After that, I clean out the inside of the amp (I vacuum out cobwebs, general dust, "dust-bunnies", etc) then reinstall the chassis.

 

This is what the finished product looks like--a factory-installed look (shown before reinstalling chassis--obviously).

 
DOES THIS LOOK LIKE SOMETHING YOU WOULD BE INTERESTED IN? IF SO SIMPLY CLICK ON THE "CONTACT ME" LINK ABOVE LEFT, AND SEND ME A SHORT MESSAGE. I WILL PICK UP WITHIN A 50-MILE RADIUS OF BROWNSBURG, INDIANA. ANYTHING OVER 50 MILES WILL BE AT 50-CENTS PER MILE--WITH A 200 MILE LIMIT. IF YOU LIVE OVER 200 MILES FROM BROWNSBURG, YOU MIGHT CONSIDER EITHER SHIPPING (WHICH MIGHT BE COSTLY) OR SIMPLY CHANGING YOUR MIND.