Description

Availability Note — updated 3.6.2025

After several delays out of our control, and some completely unexpected roadblocks, we are shipping! Lead-time for a new order will be 2-4 weeks, and as popularity grows, that could draw out.

Note: As of today we only have 10x 100W power transformers in-stock. Our supplier is back-ordered and we expect to have more stock late April. We are looking for an additional supplier, but no luck so far. Get your 100W order in now, they won’t last long! We have plenty of 50W transformers as of this writing.

Rackmount Power Amp Overview

Finally, the next in our wildly successful PA line of power amps is here! Available in either 100W or 50W, this is the perfect power amp to compliment your rack-based preamps, modelers, Ceres, Vesta, or any other preamp! Our goal for this product was to put the excellent power section first found in our amp heads, then into the PA50, and now into a rack format that’s still as compact and lightweight as possible. Weighing in at only 15 / 20 lbs (50W and 100W, respectively) and 8.75″ deep, it packs a huge punch in a compact 2U rack unit.

With the myriad of tone shaping controls the PA-100R / PA-50R will be right at home with any preamp, distortion pedal, or modeling unit. The HiFi / Guitar switch is the secret weapon for running your modeler, or if your preamp is particularly dark. The extensive set of NFB (negative feedback) controls allow for near limitless tone sculpting options, garnering both the best modern and vintage tones, especially given the variable Negative Feedback (NFB) knob.

New Features

Several exciting, never before seen, features are included in this power amp!

• • MIDI

Our first amp to come standard with MIDI since the Gemini! It recognizes PC (presets) and CC (direct control) messages. A front panel Store button allows for easy preset creation based on the currently selected functions.

• • Effects Loop

Being bypassable via TRS footswitch, MIDI, or the front panel, it allows for easy patching of external time based effects, or switching of preamp input signals.

• • Dual Master Volume

Having two Master Volumes allows for easy boosting or cutting of volume, bypassable via the TRS footswitch or MIDI.

• • Internal Load Box

An internal load box enables silent recording of the PA-50R / PA-100R, capturing all the tonal qualities and benefits without all the volume! This load automatically switches-on when no cabinet is connected, protecting the sensitive tube power section. The load can also be activated via the front panel switch or MIDI. When the load is activated, even with a cabinet plugged in, it is disconnected automatically.

• • Mute

A built-in MIDI recallable Mute function allows for seamless muting of the signal — useful for tuning, or multiple power amp selection for seamless “cabinet switching.”

• • Internal Color

The color can be set for each permutation of Loop on/off, Master Volume 1/2, Internal Load on/off, and Mute on/off. The Internal Color can even be controlled directly via MIDI CC message, allowing for light-show style automation.

• • Bias Monitor

Our next generation bias monitoring circuit allows you to select between a real-time and steady-state display mode. Some like the flashing real-time monitor, but some find it distracting.

Just as with the PA50, included right on the front panel are individual bias adjustments for each power tube. This allows for the use of slightly mis-matched tubes, as well as purposeful mis-matching to generate different harmonic content.

Demos

Coming soon! In the meantime, you can expect all the same tones as made famous by our PA50!

Power Amp Specifications

Controls: Top (presence), Bottom (resonance/depth), NFB (negative feedback), Master Volume 1, Master Volume 2, Line-out Level (on rear)

Switches: HiFi / Guitar source select, Effects Loop Enable, Internal Load Enable, Power, Standby

Buttons: Bias Display Mode, Internal Color, MIDI Store

Bias: Individual tube bias monitor and adjustment, all via the front panel.

LEDs from top-bottom: Good, High, Low. Fault LEDs above respective tube fuses.

Internal LED lighting color selectable via front panel button: Red, Green, Blue, Yellow, Purple, Cyan, White, or Off

Voltage Input: 115/230V, 50/60 Hz

Power Output: 100W RMS or 50W RMS

Power Tubes: 4x (or 2x) 6L6GC or EL34

Preamp Tube: 12AX7 phase inverter

Dimensions: 19″ wide, 3.5″ tall, 8.75″ deep (front face to rear rail ends — not including front handles, knobs, or switches)

Weight: 15 / 20 lbs (6.8 / 9 Kg)