The Keeley Compressor Plus Germanium is a limited-edition compressor pedal from Keeley, announced in October 2026 as the Special Germanium Transistor Edition marking the original compressor's 25th anniversary1. It keeps the circuit and control set of the Keeley Compressor Plus and adds a germanium transistor at the front of the signal path, used as a buffer and tone-shaping stage rather than for clipping2.
The Compressor Plus it builds on is a Ross/Dyna Comp-style compressor at heart, the same lineage as the original Keeley Compressor, with an integrated expander/sustainer section34. Keeley describes the Germanium edition's added stage as one that rounds off brittle high frequencies, smooths out downstream overdrive, and introduces a touch of organic harmonic warmth that silicon circuits cannot replicate2.
A Ross-style compressor with a germanium stage
Guitar Pedal X puts the lineage plainly: "Everyone knows that the Keeley Compressor Plus is based on the 1978 Ross Compressor"1. Aion FX's circuit trace confirms it: internally, the Compressor Plus is a Ross/Dyna Comp, as with the original Keeley compressor circuit, but converted to use the LM13700, a current-production version of the obsolete CA3080 OTA that the earlier pedal used36.
One detail sets the Plus apart from nearly every other Ross-derived pedal: its output is in-phase with the input, unlike the earlier Keeley Compressor and almost all other Ross/Dyna Comp-derived circuits6. That matters for the Blend control, since mixing an inverted compressed signal against the dry signal would cause phase cancellation.
The Germanium edition's namesake part sits ahead of all of this. Delicious Audio reports that the 25th-anniversary iteration introduces a germanium transistor deployed specifically as a front-end buffer and tone-shaping stage, rather than the traditional clipping role germanium transistors play in fuzz and overdrive circuits2.
"it rounds off brittle high frequencies, smooths out downstream overdrive, and introduces a touch of organic harmonic warmth that silicon circuits simply cannot replicate"
The controls: Level, Tone, Blend, Comp and the pickup switch
The Germanium edition retains the full Compressor Plus control set: Level, Pickup Type (Single Coils/Humbuckers), Tone, Blend and Comp1.
| Control | What it does |
|---|---|
| Comp | Sets the amount of compression/sustain2 |
| Level | Adjusts the gain that can be lost in compression, so you still stand out in the mix7 |
| Blend | Mixes the dry signal back in with the compressed signal, preserving pick attack and the peaks in your playing28 |
| Tone | Replaces flattened-out treble lost to compression9 |
| Pickup switch | Single-Coil / Humbucker setting that optimizes the release time to match your pickups and prevent choking or pumping2 |
The Blend control is the feature Keeley has pushed hardest since the Compressor Plus launched in 2017. The company described it as retaining "the peaks in your playing and, more importantly, the proper phasing of your guitar signal"4. Guitar.com's reviewer found it useful in practice, noting that pulling the blend right back also helps dial some low-end bloom back in if you are missing it9.
The pickup switch is a practical touch for anyone who owns more than one guitar: flipping between the Single-Coil and Humbucker positions instantly optimizes the release time, which Delicious Audio describes as preventing choking or pumping2.
Power and bypass
The Germanium edition operates on standard 9V up to 18V DC power, drawing a modest 25mA2. The higher voltage option gives more headroom if your power supply supports it. The original Compressor Plus also ran from a 9V supply or a 9V battery8, and carried input, output and power sockets8.
Bypass is selectable: an accessible switch lets you toggle between true bypass and a high-quality buffered bypass on the fly2. MusicRadar's buying guide listed the standard Compressor Plus as true bypass8, so the Germanium edition's switch simply makes that choice yours rather than the factory's.
The 18V option means the pedal can take more voltage than most 9V-only pedals, but check your power supply's output ratings before plugging in. At 25mA it is light on current for its class.
From the Compressor Plus to the Germanium edition
The Compressor Plus was first released in 2017 and fully replaced the previous Keeley Compressor3. Keeley positioned it as the first true advancement in the 2 and 4-knob compressor line, which had previously grown from the two-knob original into the 4 Knob Compressor with an input trim for high-output instruments and an attack (release) knob adapted from the Boss CS-2105. It carried a $149 street price as of December 202111.
Aion FX's trace documents how the pedal evolved internally after launch: 2019 and 2021 units moved the 9V connector from one corner to the other, added a ground spring, and changed the two dual op-amps from NE5532A to RC4558P6. The enclosure artwork also dropped the "Plus" from the standard version, labeling it simply "Keeley Compressor" in the same font as the original, though the product is the Compressor Plus36.
The Germanium edition arrives in two finishes1:
- Standard Edition: lighter gray brushed aluminum, stocked by leading dealers worldwide1
- Black Custom Shop Edition: available only direct from Keeley1
Both are priced at $189 (€219 / £179)1. The pedal is built in Oklahoma2, continuing a line Keeley says has seen well over 132,000 compressors built as of February 202410.
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Questions
What does the germanium transistor do in the Keeley Compressor Plus Germanium?
It is used as a front-end buffer and tone-shaping stage, not as a clipping device. According to Delicious Audio, it rounds off brittle high frequencies, smooths out downstream overdrive, and adds a touch of harmonic warmth that silicon circuits cannot replicate.
Is the Keeley Compressor Plus Germanium true bypass?
It can be. An accessible switch lets you toggle between true bypass and a high-quality buffered bypass on the fly, so you can choose whichever suits the rest of your pedalboard.
What voltage does the Keeley Compressor Plus Germanium need?
It runs on standard 9V up to 18V DC power and draws a modest 25mA. Running it at 18V gives more headroom than a 9V supply if your power source supports it.
What is the difference between the Standard and Black Custom Shop editions?
The Standard Edition comes in lighter grey brushed aluminium and is stocked by leading dealers worldwide. The Black Custom Shop Edition is only available direct from Keeley. Both are priced at $189.
What does the Blend knob do on the Keeley Compressor Plus?
It mixes your dry, uncompressed signal back in with the compressed signal, preserving pick attack and the peaks in your playing while keeping the proper phasing of your guitar signal. Pulling it back can also restore low-end bloom.
Where is the Keeley Compressor Plus Germanium made?
It is built in Oklahoma at Keeley's own facility. The original Compressor Plus was described by Keeley as completely made in the United States, and the Germanium edition continues that.
Sources (11)
- Guitar Pedal X, Guitar Pedal X, 2026-10-08
- New Pedal: Keeley Compressor Plus Germanium, Delicious Audio, 2026-10-06
- Aurora Deluxe Compressor / Keeley Compressor Plus, Aion FX, 2023-11-24
- Keeley Electronics Releases the Compressor Plus, Premier Guitar, 2017-06-20
- Keeley Electronics Compressor Plus, Delicious Audio, 2018-03-16
- Tracing Journal: Keeley Compressor Plus, Aion FX, 2023-11-24
- Keeley Electronics Compressor Plus, Pedal of the Day, 2019-09-17
- Best compressor pedals: Make your clean tones better, MusicRadar, 2022-03-25
- Keeley Compressor Plus Review, Guitar.com, 2017-11-22
- Keeley Compressor Plus, westcoastpedalboard.com, 2024
- 10 Compressors That Balance the Subtle With the Squish, Premier Guitar, 2021-12-10
