The Ceriatone Overtone Special HRM  Bluesmaster 50 is another handsome Ceriatone perspective on classic American high-gain tone. 

The Overtone Special HRM Bluesmaster is a more traditional version of a certain “D” circuit iteration.  These amps are commonly referred to as “Bluesmaster”.  Compared to the HRM, the Bluesmaster is like a Blackface amplifier on steroids, PCP, Spanish Fly, and about everything else you tried in the ‘70s, ‘80s, AND ‘90s. 

The clean channel tonestack in the Bluesmaster is very different compared to other OTS amplifiers.  The midrange is slightly scooped (although not nearly as much so as a Blackface), which is heavenly for clean and slightly clipped tones.  Another large departure is in the Preamp Boost, which is MUCH higher gain and MUCH fatter sounding than all other OTS models.  Because of this, the overdrive channel is particularly liquid-like in high gain settings, and absolutely perfect for bluesy lines.  This also allows the player to have a great crunch tone in the clean channel (with PAB engaged), and then go into serious high-gain in the overdrive channel. 

Like others in the HRM series, the Bluesmaster has an internal adjustable tonestack (treble, middle, bass) for the overdrive channel.  This allows the player to fine tune gain tone to their liking.  Each channel also has it’s own independent Master Volume control. 

Like other OTS amps, we have labored carefully to select the finest components to suit the design.  As with all Ceriatone amplifiers, it uses our specially designed, custom transformers for superior reliability, frequency response, and feel. 

Note: PPIMV mounted on Front Panel will be either mounted in place of pilot lamp (Marshall styles) or a hole will be drilled (OTS styles).
          PPIMV mounted on Rear Panel will always be in place of a Speaker Output Jack.


Power Output   50 Watt

Feature Overview          

Hi and Lo Inputs

Push-pull Bright switch on Gain control

Mid-boost, Deep, and Rock/Jazz toggle switches

Treble, Middle, Bass equalization (shared between channels)

Overdrive channel with Drive and Level controls

Internal Treble, Middle, Bass tonestack trimmers (overdrive channel)

Separate Volume controls for each channel

Footswitch (Channel and Preamp Boost)

Rear panel OD Trim (fine tunes response of overdrive channel)

Passive effects loop

Full/Half Power switch

4 / 8 / 16 Ohm Selectable

Dual Speaker Outputs

External Bias Adjust


Power : 2 x 6L6GC

Preamp : 3 x 12AX7/ECC83

Rectifier : Solid State

OTS HRM Bluesmaster 50 Watt Configuration Options:

  • Chassis I - $1,028.50
    (Fully working chassis w/ footswitch. Tubes and cabinet not included.)
  • Chassis II - $1,109.50
    (Fully working chassis w/ faceplate, tubes and footswitch. Cabinet not included.)
  • Amp Head I - $1,263.50
    (Fully working chassis installed in a head cabinet w/ footswitch. Only tubes and not included.)
  • Amp Head II - $1,344.50
    (Fully working chassis w/ faceplate and tubes installed in a head cabinet. Includes footswitch.)
  • Amp Head w/ C-lator Built In - $1,620.50
    (Fully working chassis installed in a head cabinet with a C-lator, Tube driven Effect Loop Buffer built into the cabinet. Includes footswitch.)
  • 112 Combo Amp I - $1,367
    (Fully working chassis w/o tubes installed in a 1x12 combo cabinet. Speaker not included. Includes footswitch.)
  • 112 Combo Amp II - $1,448
    (Fully working chassis w/ tubes installed in a 1x12 combo cabinet. Speaker not included. Includes footswitch.)

Summary of Features:
Power: 50W
Tube: 6L6 x 2, 12AX7/ECC83 x 3
Footswitch Included

Special Features:
Passive Effects Loop
External Bias Jacks with Individual Bias Pots (Makes it easy to check and adjust bias using a VOM, without paying a technician $45 to bias your amp. It only takes 2 minutes and the step by step instructions are in the manual.) 
PPIMV Mod is installed on back panel in one of the speaker jack holes.

Main photo is for illustrative purposes only and pricing is for Chassis I. Photos may include options that are not included if you order the standard version of the amp or don't order all options available. We also may not offer all options available and/or shown in main illustrative photos. Photos are of products assembled by Ceriatone. We no longer sell kits. You must order all kits direct from Ceriatone Malaysia. Ordering options for your amp may add several days to the build/lead time.

Ceriatone amps are Custom-built, hand made, hand wired amps, built to order. There is meticulous attention to detail that is second to none, and no shortcuts are taken. Each amp is 100% hand built, hand wired point to point, and then is thoroughly tested and burned in before it is shipped to you. For this reason it takes approx. 6-8 weeks for your amp to be built and shipped. Options can add 1-2 weeks to the "standard" build time.

Prices shown on includes the shipping cost to the USA only. We only ship to the USA, Canada and Mexico. Shipping to Canada, Mexico, Puerto Rico and the US Virgin Islands will have additional shipping. We'll invoice the difference in shipping and it is due at time the order is placed.

Note: We ONLY ship to PayPal verified addresses if paying via PayPal. No exceptions.

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OTS HRM Bluesmaster 50 Watt

  • $1,028.50

Available Options

Tags: overtone special, ots, hrm bluesmaster, 50watt, ceriatone