Retro King Plexi 50
The Plexi 50 is a replica of the 1960's 50 watt plexi with a solid state rectifier (you can order this with a GZ34 rectifier tube if you want). It uses two EL-34 output tubes and a Heyboer 50 watt plexi output transformer. The output tranny built by Heyboer has the correct 3.4k primary plate load. Unlike the 45, which uses a shared cathode, the 50 watt uses a separate cathode arrangement on the first tube, which adds pre-amp gain. A .68 bypass cap on the second stage 33k slope resistor and 500pf cap gives it that classic British midrange crunch of the original. You can order this amp with a small switch that takes this .68 bypass cap in and out of the circuit. I also offer my gain stage mod, which gives you a great amount of controllable gain. The master volume is included in the gain stage mod. Also available is the optional negative feedback control that will give you more or less power amp gain. This amp is a rocker! Hand wired on a vintage style turret board just like those great amps of the 60's. Also available in a 2x12 combo.
- 2 channel 4 inputs (high & low)
- High treble & normal channels
- 2 volume, treble, mid, bass and presence
- 2 Matched Svetlana EL34 power tubes
- 3 JJ 12AX7 pre-amp tubes
- 1 Solid state rectifier (GZ34 tube by request)
- Heyboer transformers (120/240 volt primary)
- Output tranny has correct 3.4 k primary
- 4, 8 or 16 ohm selector
- Two speaker outputs
- Plexi panels
- Original 50 watt plexi specs
- Dijon "mustard" caps
- Allen Bradley carbon comp resistors
- Aluminum chassis
- Hand wired point to point (Teflon wire)
- Baltic birch cabinet (Black Levant Tolex)
- 9"h x 26"w x 8-1/4"d
- Style I Cabinet: 28"w x 22"h x 12"d
- Style II Cabinet: 28"w x 20"h x 9"d
Warranty: 5 year limited (1 year speakers, 90 days tubes)
2X12 combo (Style I or Style II Cabinet available): $1,895
RETRO KING AVAILABLE MOD OPTIONS:
Mercury Magnetics Plexi Output Tranny: available, inquire
Cathode Cap Mod: add $35.00
On the plexi and metal face amps up through 1972, there was a .68 cap on the second stage cathode circuit. It gave an increase in gain and midrange. Retro King 50 watts come stock with this cap but you can order this amp with a small switch (installed on the front panel) that takes this cap in and out of the circuit.
Mercury Magnetics Transformers: available, inquire
Gain Stage Mod: add $100.00
Retro King also offers their gain mod, which works like this: the input tube has two sides, channel one uses one half of the tube, channel two uses the other half. On the gain mod, one half of the tube drives the other half of the tube using the volume two pot as the gain control and the volume one pot as the volume control. This gives you a great amount of controllable gain. When you plug into the channel one input, it bypasses the extra gain stage and works like a stock plexi preamp. Both channels work with a master volume that is installed on the front or back of the amp. The master volume is included in the gain stage mod.
Tube-diode rectifier switch: add $49.00
Negative Feedback Control: add $35.00
Also available is the optional negative feedback control. In these amps the negative feedback resistor varied from 47k to 100k depending on the year. With the control (mounted on back of amp) you can adjust this from 47k to 100k. This will give you more or less power amp gain.
Master Volume Mod: add $50.00
Pre or post Pl master volume. Retro King installs these on the rear of the amp or in the front in an unused input jack hole.
SOZO caps upgrade: add $35.00
Adjustable line out: add $50.00
Zero Loss Effects loop with bypass switch: add $150.00