4
Epiphone Valve Jr.
•
Mercury Upgrade Kit
This project and its documentation is the result of technical investigations made by the engineering staff of
Mercury Magnetics
. The disclosure of the information herein may pertain to proprietary rights and
the furnishing of these documents does not constitute an expresed or implied license to use such materials.
READ THIS FIRST! Identifying which verion of the amp you own.
There are currently at least 3 different versions of the
Valve Junior’s
PCB (printed circuit board) in
circulation. Before you can begin the
Upgrade
you must identify which version you have so that you can
use the correct
Upgrade
instruction manual and parts. Use the following as a guide.
2 Basic Flavors and 3 Versions
The
Valve Jr.
comes in 2 flavors: Head or combo.
Both amps are fundamentally the same, using the
same components. However, the original Version 1
Valve Jrs.
came with a single 4 ohm output, whereas
the later Versions 2 and 3 were given 4, 8 and 16
ohm outputs.
Another clue to determining which version you have
is the chassis. Examine the chassis photos on the
left. Notice the location of the tube sockets.
Also, Version 1 and 2 PCBs were green,
whereas version 3 PCBs are dark brown
(almost black).
Other than the color of the PCBs,
Versions 2 and 3 are nearly identical.
However, Epiphone did change
the values of some of the minor
components from Version 2 to
3 (which are indicated in the
illustrations in this manual).
Note
: There are 2 tutorials on
the CD-ROM; one specifically
for Version 1 and the other (this
one) for Versions 2 and 3 PCBs. You’ll
need to use the appropriate tutorial for the PCB
version you have.
Valve Jr. Head
With 4, 8 & 16 ohm outputs
(Version 2 and 3 only).
Valve Jr. Combo
Version 1, 2 and the original 3s are 4 ohm output
only. Now all Version 3s are 4, 8 and 16 ohm.
Stock Version 1
Chassis
Stock Version 2 & 3
Chassis
Note the relocation of
the tube sockets.
Summary of Contents for Epiphone Valve Junior
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