Welcome to Granger Amplification. We manufacture high performance vacuum tube amplifiers.



Granger M20 Bantam Plexi valve amplifier

The Granger M20 Bantam Plexi is the ultimate in a handwired, low wattage, all tube amplifier. For everyone who ever wanted cranked Plexi tones at studio, bedroom, or small-medium sized venue volumes, the M20 is the solution. Forget half-power switches. The M20 comes standard with VariWattage which allows the user to set the output anywhere between 1 to 20 watts, which also functions similar to a "master" volume control. It is inspired by the historic tones of vintage Plexi amps but the circuit was uniquely designed by Curt Granger, and is built using rock-solid construction methods and premium parts - not so called "vintage" NOS components (which can fail prematurely), but high-quality, long-life parts, necessary to maintain our high standards and lifetime warranty coverage. There are two inputs, one high and one low impedance, and a Volume control, which controls the amount of overall gain. The M20 has a standard Bass, Mids and Treble tone stack and a Presence control. But don't let the simplicity fool you. With the Decade switch there are a many classic tones that can be dialed in. From 60's Hendrix and Who, through 70's AC/DC, Zeppelin and Van Halen, to 80's hard rock, it's all possible. The preamp consists of 1 ECC83S (12AX7) and 1 ECC81 (12AT7) valves (for even more gain a 12AX7 can be used in place of the 12AT7), and high voltage is diode rectified to produce a punchy low end, even with the single-ended output transformer. The power section comes standard with two JJ 6CA7, but other octal tubes (6L6GC, E34L, KT66, KT77) can be swapped, and since the power amp is cathode biased, and runs Class A, there is no need for bias adjustments. The 1x12 combo features a Warehouse Guitar Speakers Green Beret speaker (25W). The head and combo are wired for specific regional voltages, but international taps on the power transformer allow 120, 220, and 240 mains voltages to be wired.

Granger M20 Bantam Plexi valve amplifier. Click for enlarged view.

Granger M20 Bantam Plexi demo

Note: To read the annotations in the video, click on the View On YouTube button, or click here.

Granger M20 Bantam Plexi features:

* Handcrafted in USA
* ClassicTone US-made transformers
* Turret board wiring
* Output (RMS): 1-20 watts
* Preamp valves: 1 ECC83S, 1 ECC81
* Power amp valves: 2 x 6CA7
* Solid state rectification
* Bass, Middle, Treble, Presence, Volume controls
* Decade switch (60s/70s/80s)
* VariWattage
* 4/8/16 ohm impedance selector switch
* Carling switches
* Cliff input jacks
* Cliff output jacks
* "Plexi" control knobs
* IEC mains inlet, detachable power cable
* Dimensions: 26"W x 10-1/4"H x 8"D (head)
* Dimensions: 24"W x 20"H x 9"D (1x12 combo)
* Weight: 34 lbs. (head)
* Weight: 48 lbs. (1x12 combo)

* Ultimate FX Loop ($100)
* Passive Effects Loop ($25)
* Custom Cover ($50)
* Tolex/Piping Change ($25)

Click to see Tolex and Grill cloth colors

Additional (No charge) options (please specify in special instructions field when ordering):

* JJ E34L, 6L6GC, KT66, or KT77 output valves

Please specify options during ordering, or contact us within 10 days after placing order. Want custom features? Email us for a quote!

Please see our current turnaround times before ordering! Each amp is custom built to order.


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BASE PRICE: $1549 US (1x12 COMBO)

I have read the Purchaser & User agreement.

Prices subject to change without notice. Orders already in progress are not subject to price changes. Granger Amplification reserves the right to make any product design changes without notice or obligation to incorporate these changes in products previously purchased.

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All content copyright 2007-2012 by Blue Nite Productions. grangeramp.com is the website of Granger Amplification, a company that builds quality, custom amplifiers, one at a time, at very reasonable prices. Our focus is on producing all-tube, hand wired amplifiers based on proven designs such as vintage Marshall and Fender products, and other boutique amps, while charging a fair price. We also do kit building, modification, and repair work. We specialize in Plexi recreations, Lightning builds, Epiphone Valve Junior mods. All trademarks are owned by their respective companies and are only used herein for historical references. - guitar amplifier, amplifier, guitar, amp, amps, builder, for sale, fs, repair, mods, hand, wired, tone, custom amp, custom amps, amp mods, modifications, amplifier, handwired, point to point, tube, vacuum tube, valve amp, kit build, amp kits, made in usa, m20, m45, m50, m100, g50, dragonfly, marshall, fender, jtm45, jmp, jcm, superlead, plexi, 15 watt, 18 watt, 20 watt, 40 watt, 50 watt, 50 watt, single ended, 5E3, bassman, matchless, trainwreck, epiphone valve junior, blackheart, tweed, deluxe, curt granger, birmingham alabama