Marshall JMP Model 1992 Super Bass 100W Head 1968 – Vintage Plexi Tube Amp

No Sales Tax For Customers Outside Of California.

Own a piece of rock history with this 1968 Marshall JMP Model 1992 Super Bass 100W Head – one of the most sought-after vintage tube amps ever made. Crafted during the golden era of British amplification, this legendary Plexi-era amp head delivers massive tone with unmatched character and responsiveness.

Originally designed for bass, the Model 1992 Super Bass became a favorite among guitarists for its warm, full-bodied clean tones and aggressive breakup at high volumes. This early '68 version features hand-wired turret board construction, and original transformers, contributing to its iconic British roar.

Whether you're a vintage amp collector, a tone chaser, or a stage performer, this Marshall JMP Super Bass head is a rare gem that sounds as good as it looks. It’s been professionally serviced and is ready to deliver that unmistakable Marshall crunch.

This particular example has been serviced, receiving a full cap job.  This work isn't that easy, and the parts are expensive these days!  This represents a good value and insures that the amp is running its best.  We tested all the tubes, cleaned the tube sockets and pots, and tested her out too, which was really fun!  The amp works perfectly, which isn't the case with those that haven't been serviced.  

A master volume knob was added where the Indicator lamp originally was mounted.  The indicator was moved to a new location near the power switch.  The indicator light is original.

As you can see in the pictures, most of the internal components are original.  You can see the the layout ink on most of the original solder points.

The internal "mustard caps" are dated to 1968.  All but two of the knobs are original, as is the handle.  

Changed parts include: the power cable, the OFF/ON power switch, the filter capacitors (the big blue "can caps" that mount to the chassis and are visible on the side of the chasses where the tubes and transformers mount, and the electrolytic capacitors inside the amp.  Of course the master volume potentiometer is not original.

Key Features:

• Year: 1968

• Model: JMP 1992 Super Bass

• Output: 100 Watts

• Construction: Hand-wired, turret board

• Tubes: EL34 power tubes, ECC83 preamp

• Transformers: Original

• Condition: Excellent vintage condition; serviced and fully functional

Perfect for players who love the tones of Hendrix, Page, and early AC/DC.

Although he mainly used Super Leads, Hendrix was known to experiment with Super Bass models, especially in studio settings. Some believe certain recordings feature a Super Bass due to the smoother overdrive and warmer bottom end.

Duane Allman reportedly used a Super Bass at times to achieve that thick, soulful slide tone—making good use of its warm lows and smooth breakup.

Pete Townshend was an early adopter of high-powered Marshall heads and is said to have used both Super Leads and Super Basses to achieve his thunderous live sound.

Jimmy Page’s early live and studio tones, particularly during the Led Zeppelin I–III era, were often driven by Super Bass heads. His rig with Marshall Super Basses helped shape that rich, saturated tone heard on classic tracks like “Whole Lotta Love” and “Dazed and Confused.”

• Case/Cover?: No
• Color: Black
• Dimensions: W29" x H11-1/2" x D 8-1/2"
• Weight: 55 lbs
• Watts: 100 Watts
• Date: 1968
• Where is Date Noted?: Serial #, Codes
• Power Transformer Brand/Codes: See Pics
• Choke Transformer Brand/Codes: See Pics
• Output Transformer Brand/Codes: See Pics
• Extension Speaker Out? Yes
  
• Effects Loop?: No
• Reverb or other effects?: No
• Power Tubes: 4 x EL34
• Power Tube Brand: EHX
• Preamp Tubes: 3 x ECC83
• Preamp Tube Brand: JJ
• Filter Caps: Updated
• Pedal: No
• Pots/Codes: 
• Tolex/Tweed: Original
  
• Knobs: Original
• Handle: Original
• Power Cord: 3 Prong upgrade
• Notes: Shown with 1968 Marshall 1960b Cab, not included but also available on our site

Shipping policy:

When you purchase this item you are hereby agreeing to this shipping policy. We remove tubes from amps that could be damaged in shipping.  We will remove the chassis for shipment and ship it in a separate box from the cabinet.  This preserves the cabinet and the chassis from damage in shipping when the box is inevitably dropped, either distorting the chassis or cracking the cab, or both.  These cases result in multiple box shipments, and they require the buyer to do some assembly on delivery.  We do this because we have experienced shipping issues in the past, and this is our prevention measure.  Vintage amps are sold as-is because they can need service intermittently.  Everything is tested here in our shop on the way into our inventory, and again before shipping.  We will cover shipping damage, but we cannot be responsible for the failure of vintage components in 20-to-50-plus year old amps. Shipments will require signature on delivery, no exceptions.  If there is damage, the buyer must retain all packing materials intact and picture them immediately and send them to sales@maharsvintageguitars.com.  Less than 1% of our shipments are damaged in transit, and we are committed to making sure your item arrives safely, but we are taking these additional measures to make sure you are happy with your purchase.