{"product_id":"1974-marshall-jmp-1987-mk-ii-50-watt-head-serviced","title":"1974 Marshall JMP 1987 Mk II 50-Watt Head – Serviced","description":"\u003cp\u003eA great-sounding, professionally serviced 1974 Marshall JMP 50 retaining its original Drake transformers and choke.\u003c\/p\u003e\n\u003cp\u003eThis player-grade vintage Marshall combines the classic four-input Model 1987 circuit with a practical pre-phase-inverter master volume, making it easier to use in the studio, at rehearsals and on stage.\u003c\/p\u003e\n\u003cp\u003eORIGINAL TRANSFORMERS\u003cbr\u003e• Original Drake 1202-164 mains transformer\u003cbr\u003e• Original Drake 784-139 output transformer\u003cbr\u003e• Original Drake choke\u003c\/p\u003e\n\u003cp\u003eMASTER-VOLUME MODIFICATION\u003cbr\u003eA pre-phase-inverter master volume has been installed in the position originally occupied by the power indicator, which has been repositioned alongside it. The modification was inspected and tested during the recent service and operates correctly.\u003c\/p\u003e\n\u003cp\u003eRECENT SERVICE\u003cbr\u003eProfessionally serviced by Dave Wittering of Prestige Amp Servicing, a former senior Marshall service engineer. Work included:\u003cbr\u003e• V1 and phase-inverter anode resistors replaced as required\u003cbr\u003e• Phase-inverter anode load resistor replaced\u003cbr\u003e• Bias reservoir and smoothing capacitors replaced\u003cbr\u003e• Screen resistors replaced\u003cbr\u003e• Control pots replaced\u003cbr\u003e• Speaker output sockets replaced\u003cbr\u003e• Marshall-branded ECC83S preamp valves fitted\u003cbr\u003e• Bias set to specification\u003cbr\u003e• Protective chassis earth fitted\u003cbr\u003e• PAT tested\u003c\/p\u003e\n\u003cp\u003eVALVES\u003cbr\u003ePreamp: Marshall-branded ECC83S valves\u003cbr\u003ePower amp: matched Marshall-branded EL34 valves\u003c\/p\u003e\n\u003cp\u003eCONDITION\u003cbr\u003eThe original head shell, black covering, feet and cosmetic hardware remain in place. It presents very well for a working amplifier of more than five decades, with small marks, snags and areas of wear to the covering—most noticeably underneath. Please study the detailed photographs, which form part of the description.\u003c\/p\u003e\n\u003cp\u003eThe replaced electronic components and master-volume modification are fully disclosed. This is an excellent choice for a player or studio seeking the sound and feel of an original 1974 JMP 50 without the uncertainty of an untouched example.\u003c\/p\u003e\n\u003cp\u003eVOLTAGE \u0026amp; SHIPPING\u003cbr\u003eThe mains selector provides 110V, 120V and 240V operation when correctly configured. Collection is welcomed at our Hayes showroom, and worldwide shipping is available in a custom-made Overdrive Guitars carton with substantial internal protection.\u003c\/p\u003e\n\u003cp\u003eSerial number: S\/A 6474F\u003cbr\u003eInspection date: 21 August 1974\u003c\/p\u003e","brand":"Marshall","offers":[{"title":"Default Title","offer_id":53664619200848,"sku":"0152","price":1999.0,"currency_code":"GBP","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0944\/0919\/5856\/files\/87a5160df483d624.jpg?v=1789892945","url":"https:\/\/overdriveguitars.com\/products\/1974-marshall-jmp-1987-mk-ii-50-watt-head-serviced","provider":"Overdrive Guitars","version":"1.0","type":"link"}