Amps By Dan Lurie  •  By Appointment Only  •  South Burlington, Vermont, USA  •  Call or text: 802-310-5967  •  djlurie@comcast.net
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Blackheart Amp converted with a Mojo circuit board and Mercury Magnetics Transformers

I've converted a bunch of these now. I've added different features to each one.

One amp has a foot-switchable variable boost function added to the back of the amp.

Another received a variable wattage control that lets you change the wattage of the amp from 5 watts down to about a 1/2 watt.

All conversions are done point-to-point.

Sit back and watch the show. Click/tap (touch screen) to move the next photo instantly.

  • Here is the stock amp
  • Converted Mojo Musical Supply circuit board
  • Converted Mojo Musical Supply circuit board: More info On Pag
  • Enter Mercury Magnetics Transformer Kit
  • Transformers, Choke and Point to point board installed
  • Finished Conversion
Here is the stock amp Converted Mojo Musical Supply circuit board Converted Mojo Musical Supply circuit board Enter Mercury Magnetics Transformer Kit Transformers, Choke and Point to point board installed Finished Conversion

Further info about photos in the slideshow

Converted Mojo Musical Supply circuit board: The First picture is the stock amp with the printed circuit board. The idea is to remove everything and install the Mojo point to point eyelet board. The kit takes advantage of the extra winding on the stock power transformer to add a tube rectifier. The kit comes with the tube socket. A large hole needs to be punched into the chassis and the socket installed. (See the socket installed above the board)

The second picture is the installed board.

Enter Mercury Magnetics Transformer Kit: Changed our minds... Decided to give the Mercury Magnetics (MM) transformer a trial. Ordered the kit and the first thing we did was A/B the Output transformer with the stock transformer. The MM transformer sounded more rich and open. Time to strip the chassis and do it again.

The MM power transformer does not have windings for the tube rectifier. With an A/B test we did notice the sag provided by the tube rectifier. The solid state rectifier kept the bottom end tight. I used the rectifier tube socket to mount my solid state rectifiers.

The picture at the left shows the chassis with the Power transformer, Choke and Output transformer installed with the leads coming through.

Finished Conversion:Done. See the tube socket with the solid state rectifier installed?

Side notes: The MM kit has a few electronic mods to help the tone. They are all good ideas and were installed. Look closely at the board and you will notice 3 filter caps were changed. The original P2P board from Mojo (in my opinion) did not have enough power supply filtering, I added some.

BUT... how does it sound???

This amp sounds killer! It is harmonically rich with great note definition. The amp responds great to pick attack. It's truly a boutique amp with great tone.

I am authorized to sell and install this kit and all of Mercury Magnetics transformers!!

Do you want one? I can do this for you!

Jump to my Tube Amp Repair page and contact me. Thanks!



FYD Amps & Tube Amp Repair
South Burlington, VT, USA  •  By Appointment Only  •  Call or text: 802-310-5967
www.fydamps.com  •  djlurie@comcast.net

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