Guitar Amp Repairs, Custom Amp Builds, Speakers - JPF Amplification » Amp repair http://jpfamps.com JPF Amplification, London's leading amp repairers and builders Wed, 09 May 2012 16:54:02 +0000 en hourly 1 http://wordpress.org/?v=3.3.2 How to wire a mains earth to a US amp with 2 prong cord. NOT! http://jpfamps.com/how-to-wire-a-mains-earth-to-a-us-amp-with-2-prong-cord-not/ http://jpfamps.com/how-to-wire-a-mains-earth-to-a-us-amp-with-2-prong-cord-not/#comments Thu, 03 May 2012 20:51:16 +0000 Frank http://jpfamps.com/?p=1072 When you think you’ve seen every conceivable bodge job on the planet, something comes in that beggars belief.

Here are some snaps from an amp I’ve just worked on.

The amp is US voltage Ampeg Gemini. Someone had installed a step down transformer into the bottom of the cabinet to allow operation from UK mains.  So far so good.

The amp had its original 2 prong US mains lead without a safety earth connection. This is obviously unsafe, and is conventionally remedied by fitting a new 3 prong mains cord and securing the earth to the chassis with a star washer and bolt.

A previous repairer had obviously decide that a new 3-prong mains cord with earth connection was frivolous luxury, and so came up with a novel solution.

Firstly a new earth wire was connected to the vacant earth pin in the female US socket coming from the step down transformer using a wood screw.

Then the other end was “securely” soldered to a ready made hole in the chassis. A light tug and the wire came free.

Good work!!

Suffice to say I fitted an earthed 3 prong mains cord before I powered up the amp.

]]> http://jpfamps.com/how-to-wire-a-mains-earth-to-a-us-amp-with-2-prong-cord-not//feed 0 JPF Amps engraver for amp panels and logos http://jpfamps.com/jpf-amps-engraver-for-amp-panels/ http://jpfamps.com/jpf-amps-engraver-for-amp-panels/#comments Wed, 06 Oct 2010 18:47:24 +0000 Frank http://jpfamps.com/?p=468

Due to increasing demand for custom amp panels and logos etc, JPF Amps have recently acquired a computer-controlled flat bed rotary engraver. This now means we can design and engrave anything we need in house, which not only saves us money, but also gives us a much greater degree of flexibility.

It is our intention to provide an affordable engraving service for other amp builders, and DIYers.

We are aiming to launch a seperate web-site for our engraving services in the near future, but feel free to get in touch with us with your engraving requirements. By the way the maximum engraving size is 600 x 400 mm.

]]> http://jpfamps.com/jpf-amps-engraver-for-amp-panels//feed 1 Spot the mistake! http://jpfamps.com/spot-the-mistake/ http://jpfamps.com/spot-the-mistake/#comments Thu, 08 Apr 2010 19:57:10 +0000 Frank http://jpfamps.com/?p=372 This a photo of the filter caps from a Blackface Fender Twin Reverb that was recently brought in for repair. Note the early ’64 date code on the reverb transformer. The main filter caps have been replaced with Sprague Atoms. Can anyone see the error the previous repairer had made?

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