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See Fred Shaw's Version of the Cavalli Lovell
I really like the Cavalli-Jones headphone amp that I built. But, even with variable feedback, it lacks that last bit
of power needed to drive high-Z cans.
Initially, Mark Lovell's approach to this problem was to build the Brosky Cavalli
Jones (BCJ) amps which featured regulated power supplies with OB2 rebulator tubes in the voltage reference cirucuit and
paralleld output tubes for increased power. The combination reulted in a sound which Mark describes as "effortless".
One of the versions of this amp aslo included a tone stack, further increasing its complexity.
The present amp, the Cavalli Lovell MKI was an attempt to capture most of the advantages of the BCJ without its cost
and complexity. The voltage regulator ciruciuit employs a solid state voltage reference source in place of the gas regulator
tubes. The output stage employs 5687 tubes biased at 20 mA in the White cathode follower circuit. These produce quadruple
the output power of the 6922's used in the Morgan Jones design.
For my part I always wanted to build at least one unit that didn't look homemade. Since I had some parts left over
from building the C-J, I volunteered to build the first Cavalli Lovell. I also decided to try to build it as a statement piece.
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| Cavalli-Lovell MKI Schematic (click to enlarge) |
Getting Started
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| C-L Top Plate in Front Panel Express (Click to enlarge) |
The first thing that had to be done is to lay out the design. I did the mechanical and electrical design using TurboCad. We
determined that the amp would fit in an 8 x 12 inch chassis. Since I wanted this amp to be a statement piece, I had decided
to use FrontPanel Express to make the top front and rear panels for it. Once the drawings were transferred from CAD to to the software provided by
Frontpanel Express, the design was sent off to be milled and engraved. A week later I received the panels by return mail.
Shown to the right is a screen dump from the Frontpanel Express Software showing what the Cavalli-Lovell top plate will look
like.
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| Cavalli Lovell Electrical/Mechanical Drawing (click to enlarge) |
I also produced an electrical/mechanical pictoral drawing using TurboCAD. This enabled us to determine the best fit for the
parts and prevent any expensive surprises during construction. I went through four or five layout iterations before settling
on the one you see here.
Before Construction could start, I needed to make a base to hold the panels. I decided to make a temporary base to use during
construction so that I could take my time later and build a really nice base with dovetailed joints. Also, there's always
a chance of damaging a fine wood base during construction
Shown below: (top left)cutting the inlays using a Dremel tool with a plunge router attachment;(top right) front panel installed
in inlay;(Bottom)plates installed in unfinished base.
Preparing the Top Plate
Now comes the scary part, drilling the mounting holes for the tube sockets, transformers and capacitor mounting clamps
in the $75.00 top plate. Fortunately, I drilled all 30 holes with only one small (and easily hidden) problem. Just keep saying,
measure twice, drill once!
After the holes were drilled it was time to apply a topcoat to the panels. The panels were anodized so I could have left them
uncoated, but adding a coating makes them look richer. I chose two-part polyurethane autmotive clear-coat and applied four
thin coats. The paint gods smiled on me and it produced a luxurious deep glossy finish! Notice the dpeth of the reflections
in the picture at the bottom of this page. I was tickled!
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| C-L Panels after Drilling and Application of Clear Coat |
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| CL MKI Top Panel (click to enlarge) |
Go to Cavalli-Lovell Electrical Construction>>>>
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