{"version":"1.0","provider_name":"Guitars FRG","provider_url":"https:\/\/guitarsfrg.com\/en\/","author_name":"Frank Requena","author_url":"https:\/\/guitarsfrg.com\/en\/author\/frank\/","title":"JTM45-KT66 - Guitars FRG","type":"rich","width":600,"height":338,"html":"<blockquote class=\"wp-embedded-content\" data-secret=\"jRWnBntbWo\"><a href=\"https:\/\/guitarsfrg.com\/en\/shop\/amplificadores-en\/headers\/jtm45-kt66\/\">JTM45-KT66<\/a><\/blockquote><iframe sandbox=\"allow-scripts\" security=\"restricted\" src=\"https:\/\/guitarsfrg.com\/en\/shop\/amplificadores-en\/headers\/jtm45-kt66\/embed\/#?secret=jRWnBntbWo\" width=\"600\" height=\"338\" title=\"&#8220;JTM45-KT66&#8221; &#8212; Guitars FRG\" data-secret=\"jRWnBntbWo\" frameborder=\"0\" marginwidth=\"0\" marginheight=\"0\" scrolling=\"no\" class=\"wp-embedded-content\"><\/iframe><script>\n\/*! This file is auto-generated *\/\n!function(d,l){\"use strict\";l.querySelector&&d.addEventListener&&\"undefined\"!=typeof URL&&(d.wp=d.wp||{},d.wp.receiveEmbedMessage||(d.wp.receiveEmbedMessage=function(e){var t=e.data;if((t||t.secret||t.message||t.value)&&!\/[^a-zA-Z0-9]\/.test(t.secret)){for(var s,r,n,a=l.querySelectorAll('iframe[data-secret=\"'+t.secret+'\"]'),o=l.querySelectorAll('blockquote[data-secret=\"'+t.secret+'\"]'),c=new RegExp(\"^https?:$\",\"i\"),i=0;i<o.length;i++)o[i].style.display=\"none\";for(i=0;i<a.length;i++)s=a[i],e.source===s.contentWindow&&(s.removeAttribute(\"style\"),\"height\"===t.message?(1e3<(r=parseInt(t.value,10))?r=1e3:~~r<200&&(r=200),s.height=r):\"link\"===t.message&&(r=new URL(s.getAttribute(\"src\")),n=new URL(t.value),c.test(n.protocol))&&n.host===r.host&&l.activeElement===s&&(d.top.location.href=t.value))}},d.addEventListener(\"message\",d.wp.receiveEmbedMessage,!1),l.addEventListener(\"DOMContentLoaded\",function(){for(var e,t,s=l.querySelectorAll(\"iframe.wp-embedded-content\"),r=0;r<s.length;r++)(t=(e=s[r]).getAttribute(\"data-secret\"))||(t=Math.random().toString(36).substring(2,12),e.src+=\"#?secret=\"+t,e.setAttribute(\"data-secret\",t)),e.contentWindow.postMessage({message:\"ready\",secret:t},\"*\")},!1)))}(window,document);\n\/\/# sourceURL=https:\/\/guitarsfrg.com\/wp-includes\/js\/wp-embed.min.js\n<\/script>\n","thumbnail_url":"https:\/\/guitarsfrg.com\/wp-content\/uploads\/2024\/03\/FRONT-9.jpg?v=1718102001","thumbnail_width":1583,"thumbnail_height":1000,"description":"In the fall of 1962, the Marshall JTM45 saw the light of day and has been enjoyed by musicians and guitarists around the world ever since. Although there have been minor changes to the circuit over the years, the JTM45 has remained true to its origins. Our version of the JTM45 is based on a reissue version with the following modifications:  The output transformer used offers a double primary winding and can be used for both EL34 and KT66 tubes. Only a different wiring of the primary connections is required.  The stand-by is not a pure \"mute\" but a real high switch. A preheating resistor to protect the valves from abrupt starts, furthermore this has the consequence that even in standby, there is a minimum current flow through the end valves.  Better matching of the rectifier valve to the power transformer through impedance matching. Especially with 5AR4 \/ GZ34 tubes of current productions, we noticed that they work sensitively in JTM45 amplifiers due to the often too low internal resistance of the high voltage winding. This problem has been eliminated with two new resistors in the rectification circuit.  All the assembly is done with \"point to point\" soldering following the most classic amplifier assembly. This Marshall JTM45 valve head is widely regarded as the definitive Marshall of the 1960s. Their sustain and pure ROCK sound are still today the sound of choice for many guitar aficionados and professionals. You'll love how it sounds, and how its classic tone feels roaring in your hands."}