{"product_id":"mullard","title":"1966 Mullard EL37 Matched Pair - Made in Great Britain","description":"\u003ch3 data-end=\"242\" data-start=\"165\"\u003eMullard EL37 Matched Pair – Made in Great Britain – Rare 6L6GC Substitute\u003c\/h3\u003e\n\u003ch4 data-end=\"271\" data-start=\"244\"\u003eThe Altitude Summary\u003c\/h4\u003e\n\u003cp data-end=\"853\" data-start=\"272\"\u003eHere’s a true gem for the tone chasers: a matched pair of vintage Mullard EL37 power \"Coke Bottle\" tubes, made in Great Britain and known for their rich harmonic depth, warm mids, and legendary clarity. These rare glass giants have been fully tested and both come in excellent working condition. They test strong to factory spec on a calibrated tube tester—no gas, no shorts, and balanced output across the pair. The glass is clean, the pins are solid, and the only markings are \"EL37\", \"Made in Great Britain\", and the etched code “R61 B8 H.” Perfect for audiophiles or vintage amp restoration.\u003c\/p\u003e\n\u003cp data-end=\"1147\" data-start=\"855\"\u003eThese tubes carry the etched production code \u003cstrong data-end=\"912\" data-start=\"900\"\u003eR61 B8 H\u003c\/strong\u003e, which dates them to \u003cstrong data-end=\"962\" data-start=\"934\"\u003ethe 8th week of February\u003c\/strong\u003e, produced at Mullard’s famed \u003cstrong data-end=\"1009\" data-start=\"992\"\u003eMitcham Works\u003c\/strong\u003e in the UK— in \u003cstrong data-end=\"1046\" data-start=\"1030\"\u003e1966\u003c\/strong\u003e. That detail alone will spark joy in any collector or tone purist looking for true British pedigree.\u003c\/p\u003e\n\u003ch4 data-end=\"1180\" data-start=\"1149\"\u003eBritish Power, Cult Tone\u003c\/h4\u003e\n\u003cp data-end=\"1504\" data-start=\"1181\"\u003eThe EL37 isn’t just a tube—it’s a tone signature. Designed as a high-grade alternative to the 6L6GC, the Mullard EL37 offers a smoother response curve, tighter low-end, and a sweeter top-end breakup. Whether you’re chasing hi-fi richness or classic guitar amp warmth, this pair brings unmistakable British mojo to your rig.\u003c\/p\u003e\n\u003ch4 data-end=\"1530\" data-start=\"1506\"\u003eMatched and Ready\u003c\/h4\u003e\n\u003cp data-end=\"1767\" data-start=\"1531\"\u003eThis is a genuine matched pair—tested and verified for consistent performance. Expect smooth symmetry in push-pull circuits and zero guesswork during install. They're ready to drop into your next hi-fi project or classic tube amp build.\u003c\/p\u003e\n\u003ch4 data-end=\"1804\" data-start=\"1769\"\u003eRare Find for the Right Ears\u003c\/h4\u003e\n\u003cp data-end=\"2086\" data-start=\"1805\"\u003eTubes like these don’t surface often, and when they do, they don’t stick around. These are true Mullard builds—no rebrands or relabels—just pure British engineering from one of the most revered names in tube history. A must-have for serious tone aficionados or restoration purists.\u003c\/p\u003e\n\u003ch4 data-end=\"2107\" data-start=\"2088\"\u003eKey Features\u003c\/h4\u003e\n\u003cul data-end=\"2407\" data-start=\"2108\"\u003e\n\u003cli data-end=\"2154\" data-start=\"2108\"\u003e\n\u003cp data-end=\"2154\" data-start=\"2110\"\u003eMatched pair of vintage Mullard EL37 tubes\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli data-end=\"2200\" data-start=\"2155\"\u003e\n\u003cp data-end=\"2200\" data-start=\"2157\"\u003eMade in Great Britain in 1966 (etched “R61 B8 H”)\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli data-end=\"2244\" data-start=\"2201\"\u003e\n\u003cp data-end=\"2244\" data-start=\"2203\"\u003ePower pentode design – 6L6GC-compatible\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli data-end=\"2298\" data-start=\"2245\"\u003e\n\u003cp data-end=\"2298\" data-start=\"2247\"\u003eBalanced output – both tubes test to factory spec\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli data-end=\"2351\" data-start=\"2299\"\u003e\n\u003cp data-end=\"2351\" data-start=\"2301\"\u003eExcellent condition with clean pins and markings\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli data-end=\"2407\" data-start=\"2352\"\u003e\n\u003cp data-end=\"2407\" data-start=\"2354\"\u003eHighly sought after by audiophiles and amp builders\u003c\/p\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Mullard","offers":[{"title":"Default Title","offer_id":50630408012072,"sku":"MULLARD-EL37s","price":1000.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0745\/4225\/2328\/files\/Mullard_EL37s-Photoroom.jpg?v=1757452716","url":"https:\/\/altitudeguitar.myshopify.com\/products\/mullard","provider":"Altitude Guitar","version":"1.0","type":"link"}