Morgan Amps The JMI 20-Watt Cathode Biased EL84 Head
The Morgan JMI is a 20-watt, cathode biased, EL84 all-tube amplifier in the style of the old British “top boost” design. This was one of the first amps Joe Morgan built, in his home garage, long before he ever considered starting an amp company. The JMI combines the best of early 60’s top boost style circuits with an additional gain stage. The added gain helps boost the CLEAN headroom of the amp with a greater punch, and tighter feel, than a conventional top boost circuit.
Joe's design has been updated to the 21st century, with some player comforts, that make it easier to use with any pedal board and at any venue. This amp was created to solve modern guitar player amplifier issues with the ability to stay true to vintage tonality. This no-compromise, top boost amplifier was designed for the gigging professional and the casual home player alike. Originally, Joe made a limited number of these heads with the JMI logo (JMI stood for Joe Morgan Industries). While distinctly different than the original top boost design, the JMI maintains all of the classic tones that a Class A EL84 amp can deliver, but with added tone shaping controls including individual treble and bass controls with a bright switch for even more chime.
Morgan's revolutionary Power Level control is a big part of the magic in this amplifier. Many guitarists today have spent large sums of time and money working on their pedal boards. Most pedals are not designed to be used with a tube amp on “1”, but rather to, interact with an amplifier at, or near, the point at which it begins to break up. That is why an overdrive pedal is called an “over” drive. It is driving the amp over that point. Unfortunately, this can make the volume too loud for most live applications.
The Power Level control on the JMI solves this issue. Think of conventional master volumes as a spigot on a garden hose. They choke signal off to the power section of the amp to attain a usable level. Most conventional master volumes also affect the way your pedals interact with your amp. Morgan's Power Level control behaves like a zoom lens, limiting the size of the output signal that can be produced by the output tubes. It does NOT choke the signal down, and therefore, the amp behaves identically to running at full volume. This means that you can choose the power that you need from a ¼ of a watt to 20 watts.
- Hand-wired in the U.S.A.
- Power: ¼ - 20w variable (tube)
- Cathode follower driven tone stack
- Bass and Treble controls
- Bright switch
- Power Level control
- Global Cut – removes high frequencies from the power section
- Tubes: 2 x EL-84 power tubes, 3 x 12AX7 preamp tubes, 1 x GZ34 Rectifier
- 2 x 8 ohm and 1 x 16 ohm speaker outputs
- Custom USA made transformers
- Limited lifetime warranty
- Dimensions: 7.5" (D) x 17" (W) x 9.75" (H)
- Weight: 25 lb.