{"product_id":"marshall-jmp50-1986-50w-guitar-bass-head-1975-fully-serviced","title":"Marshall JMP50 1986 - 50w Guitar \u0026 Bass Head 1975 - Fully Serviced","description":"\u003ch1 data-pm-slice=\"1 1 []\"\u003e\u003cspan\u003eMarshall \u003c\/span\u003e\u003c\/h1\u003e\n\u003ch1 data-pm-slice=\"1 1 []\"\u003e\u003cspan\u003e\u003c\/span\u003e\u003c\/h1\u003e\n\u003ch1 data-pm-slice=\"1 1 []\"\u003e\u003cspan\u003eJMP 1986 – 50W Bass Head – 1975\u003c\/span\u003e\u003c\/h1\u003e\n\u003cp\u003e \u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cspan\u003eSerial Number:\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e S\/A 1473G\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cbr\u003e\u003cstrong\u003e\u003cspan\u003eInspection Sticker Date:\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e 21\/04\/1975 – 21st April 1975\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003eA superb example of a \u003c\/span\u003e\u003cstrong\u003e\u003cspan\u003e1975 Marshall JMP 50 Bass Model 1986\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e, presented in very good original condition and retaining its original transformers, choke and much of its original circuitry.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003eHandwired and dating from Marshall's highly regarded mid-'70s JMP period, the Model 1986 is the bass-voiced counterpart to the legendary 1987 Lead, offering a warmer, fuller response with a thicker low end and smoother high frequencies.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003eAlthough originally designed for bass, these amplifiers have long been favourites among guitarists looking for rich vintage cleans, thick, harmonically complex overdrive and exceptional dynamic response.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003eThis example is particularly appealing thanks to its \u003c\/span\u003e\u003cstrong\u003e\u003cspan\u003eoriginal iron, period Mullard mustard capacitors and exceptionally well-preserved original cosmetics\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e.\u003c\/span\u003e\u003c\/p\u003e\n\u003ch3\u003e\u003cspan\u003eChassis \u0026amp; Originality\u003c\/span\u003e\u003c\/h3\u003e\n\u003cul data-spread=\"false\"\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cspan\u003eOriginal Drake 1202-164 mains transformer\u003c\/span\u003e\u003c\/strong\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cspan\u003eOriginal Drake 784-139 output transformer\u003c\/span\u003e\u003c\/strong\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003eOriginal choke\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003eOriginal Mullard mustard capacitors dated to the fourth quarter of 1974\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003eHandwired turret-board construction\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003eOriginal factory inspection sticker dated 21st April 1975\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003e\u003cspan\u003eProfessionally Serviced\u003c\/span\u003e\u003c\/h3\u003e\n\u003cp\u003e\u003cspan\u003eFreshly serviced on \u003c\/span\u003e\u003cstrong\u003e\u003cspan\u003e21st September 2026\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e by \u003c\/span\u003e\u003cstrong\u003e\u003cspan\u003eDave Wittering of Prestige Amp Servicing\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e, former Marshall senior service engineer.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003eThe following work was carried out:\u003c\/span\u003e\u003c\/p\u003e\n\u003cul data-spread=\"false\"\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003eHT fuse replaced – T500mA\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003eNew matched pair of OEM Marshall EL34B output valves fitted\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003eBias circuit smoothing capacitors replaced\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003eScreen resistors replaced with correct specification components\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003eAll six potentiometers replaced\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003eDedicated chassis earth fitted for electrical safety\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003eProfessional inspection and operational testing\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e\u003cspan\u003eThe amplifier is in excellent working order, fully serviced and ready to use.\u003c\/span\u003e\u003c\/p\u003e\n\u003ch3\u003e\u003cspan\u003eValves\u003c\/span\u003e\u003c\/h3\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cspan\u003ePreamp Valves:\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e Marshall-branded ECC83 \/ 12AX7\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cspan\u003ePower Valves:\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e New matched pair of OEM Marshall EL34B\u003c\/span\u003e\u003c\/p\u003e\n\u003ch3\u003e\u003cspan\u003eCosmetic Condition\u003c\/span\u003e\u003c\/h3\u003e\n\u003cp\u003e\u003cspan\u003eThe amplifier is in \u003c\/span\u003e\u003cstrong\u003e\u003cspan\u003every good cosmetic condition for its age\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e, retaining its original:\u003c\/span\u003e\u003c\/p\u003e\n\u003cul data-spread=\"false\"\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003eHeadshell\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003eTolex covering\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003eMarshall logo\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003eHandle\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003eFeet\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e\u003cspan\u003eThere are minor age-related marks consistent with a vintage amplifier, but overall this is a particularly well-preserved example that has retained its original appearance.\u003c\/span\u003e\u003c\/p\u003e\n\u003ch3\u003e\u003cspan\u003eWorldwide Shipping Available\u003c\/span\u003e\u003c\/h3\u003e\n\u003cp\u003e\u003cspan\u003eAll of our amplifier heads are shipped in \u003c\/span\u003e\u003cstrong\u003e\u003cspan\u003ecustom-made Overdrive Guitars boxes\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e, with additional internal protection to ensure they arrive safely.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003eWe are proud to be an \u003c\/span\u003e\u003cstrong\u003e\u003cspan\u003eAuthorised Marshall Retailer\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e, offering new Marshall equipment alongside our carefully selected collection of vintage and pre-owned amplifiers.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003eOur dedicated West London showroom is available by appointment, where customers are welcome to view, test and experience our amplifiers in person.\u003c\/span\u003e\u003c\/p\u003e","brand":"Marshall","offers":[{"title":"Default Title","offer_id":53874802262352,"sku":"0426","price":2250.0,"currency_code":"GBP","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0944\/0919\/5856\/files\/IMG_6094.jpg?v=1793134730","url":"https:\/\/overdriveguitars.com\/products\/marshall-jmp50-1986-50w-guitar-bass-head-1975-fully-serviced","provider":"Overdrive Guitars","version":"1.0","type":"link"}