Custom ProKeys Leslie Amplifiers

Hand built from the chassis up, our amplifiers are unique in the world of Hammonds and Leslies.  We've taken a stock amplifier far, far beyond "stock" - but it's still stock!  No hot rodding, and no power boosters.  The entire circuitry is stock - choice of quality components and mounting design have changed.

2002 Update:

ProKeys Leslie amplifiers are stripped, sandblasted, primed, then the outer chassis and transformers are finished in automotive metallic paint.  Follow that with several coats of clear urethane, which eliminates the possibility of rust, corrosion, and deterioration.  This produces an amplifier chassis that looks just as good as it sounds.  The inside chassis is also given two coats of primer, and even the transformer bells are primed on the inside.

We are very serious about controlling rust.  So far, every transformer we have ever seen has some rust, regardless of where the Leslie has been used.

An improved method of wiring is currently being implemented using glass epoxy printed circuit boards to mount many of the components.  We feel this is a major improvement in chassis design.  Shown below are pictures of our evolving 2001 and 2002 PC board project.  Once the final design is reached, we will install these boards in six of our gig Leslies.

We use only high quality, 1% tolerance audio components and very high quality capacitors.  All new tube sockets are standard, and polished, stainless steel hardware is used everywhere possible.  Absolutely no rivets are used.  Screw threads are sealed and locked.

Our redesigned bridge circuit is rated for 1000 volts, and is about 90% smaller than the original.

As you might notice, some of these beta amp chassis have had extensive custom metalwork done, extra holes filled, then sand, prime, fill, sand, and prime some more.  It's really a long, tedious process, and although the chassis look pretty good, I'm not totally, 100% satisfied with the results.  We're now experimenting with some other chassis alternatives, including Formica!  If they're satisfactory, you'll probably see the pictures here.

Our next step is Beta2.  This amp (the red chassis) will have several new innovations, along with an updated circuit board.  We're experimenting with an improved "star ground" concept using 14 gauge solid copper bus wire.  This massive grounding approach should improve the quietness of the amp.

Some other details:  polished, stainless steel socket head (hex) screws used on the transformers, new mounts designed for bridge, cap cluster, and more refinement of the board, bringing each component as close as possible to the tubes.

"Next stage possible" plans (for the new chassis) include relocating some of the physical components, such as the speaker output plug, fuse, and the single 4 conductor motor interface.  The final plan for the chassis will have a single connector on the front (face) of the amp, this being where the Leslie cable attaches.  We're also working on an improvement to the shock mounts which the amp rests on.  The new amp will still bolt right into any Leslie cabinet, but vibration factor will be reduced.

All clear coating is now done with the new Omni SV MC261 urethane.  It's extra nice, and it's worth the $100+ we pay for a gallon.  Some new pictures have been added.

With the Betas now completed, it's hard to believe they're actually stock amps.  They test and play much stronger than original amps, to the point where I'm turning the volume back to about 7.

click picture for fullsize view

Shown below are stock, original amplifiers.  Which look better to you?

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