{"id":92,"date":"2015-05-03T10:27:25","date_gmt":"2015-05-03T10:27:25","guid":{"rendered":"http:\/\/www.fixguitaramps.co.uk\/blog\/?p=92"},"modified":"2015-05-03T10:27:25","modified_gmt":"2015-05-03T10:27:25","slug":"the-phase-splitter-valve","status":"publish","type":"post","link":"https:\/\/www.fixguitaramps.co.uk\/blog\/the-phase-splitter-valve\/","title":{"rendered":"The Phase Splitter Valve"},"content":{"rendered":"

I am often asked by customers \u201cWhat is the phase splitter valve<\/strong> and is it special or different from the other valves in my valve guitar amplifier?\u201d<\/p>\n

Hopefully this short article will explain what the phase splitter valve and clear up any questions about the phase splitter valve you may have (but were too afraid to ask!).<\/p>\n

Before explaining the phase splitter valve in detail, let\u2019s do a quick overview of the types of valve in your amplifier. There are two basic types \u2013 the preamplifier valves (of which the phase splitter valve is one) and the power output valves which do all the heavy lifting.<\/p>\n

The phase splitter valve is part of the preamplifier chain. In fact it is the very last valve in that chain just prior to the output valves. The phase splitter valve takes the preamplified signal, conditions it in a special way (which I will explain) to create the drive signal for the power valves.<\/p>\n

What Does The Phase Splitter Valve Actually do?<\/h3>\n

First you need to know that your guitar amplifier will either have two, or four output valves.<\/p>\n

If it has two, then they work as a pair; one \u2018pushing\u2019 the loudspeaker cone, the other \u2018pulling\u2019 it. In technical terms, one valve handles one half of the sine wave (let\u2019s say the top half) and the other valve handles the other half of the sine wave (say the bottom half). You may have heard of \u2018push pull\u2019 amplification and this is what\u2019s going on here.<\/p>\n

99% of all valve guitar amplifiers have this \u2018push-pull\u2019 arrangement of valves driven by the phase splitter valve.<\/p>\n

Before talking about the phase splitter valve which precedes these output valves, let\u2019s just briefly explain why an amplifier may have four output tubes instead of two.<\/p>\n

In a 4-valve set up, the valves are just doubled up to give twice the power. E.g. a 2 valve amplifier will typically be 50W, whereas a 4 valve amplifier will be 100W. So two valves \u2018push\u2019 and the other two \u2018pull\u2019. All are driven by the phase splitter valve.<\/p>\n

So now we come on to the phase splitter valve. The phase splitter circuit has the specific job of taking the preamplified signal (think of it as a clean sine wave for the moment) and splitting it into TWO sine waves which are 180 degrees out of phase with each other. This is called a split phase signal. When one wave is going UP the other is going DOWN. Think of it as producing the original signal, and a mirror image of the original signal.<\/p>\n

It is these \u2018out of phase\u2019 signals which are needed to drive the output tubes (causing one to \u2018pull\u2019 while the other is \u2018pushing\u2019.)<\/p>\n

Is The Phase Splitter Valve a Different Type?<\/p>\n

This is where most confusion arises. Most preamplifer valves are 12AX7 or ECC83 (same thing). The phase splitter valve is also commonly a 12AX7 (ECC83). Bottom line is you can use any make\/model of ECC83 as your phase splitter valve, it doesn\u2019t have to be \u2018special\u2019.<\/p>\n

However, because the ECC83 is, in fact, two identical valves in one glass envelope, some purists insist on using a selected valve as their phase splitter valve. These selected valves have been picked so that the gain of each valve half is identical. The theory here is you don\u2019t want to be (say) \u2018pushing\u2019 slightly more than you are \u2018pulling\u2019 due to the different gains. The audible result of that, by the way, would be a very slightly distorted signal. (Distortion? On a guitar amplifier? We can\u2019t have that!!)).<\/p>\n

Phase Splitter Valve Take Home<\/h2>\n

So now you know what the phase splitter valve does. The take home is that you don\u2019t really need a special selected valve in this position. By all means go to the extra expense of fitting one but you\u2019re most unlikely to hear the slightest difference.<\/p>\n

Sometimes the phase splitter valve<\/em> is an ECC81 or ECC82. These are simply lower gain versions of the ECC83 and all the above discussion applies.<\/p>\n

 <\/p>\n

You can buy valves suitable for phase splitter here http:\/\/www.ampvalves.co.uk\/<\/a><\/p>\n

 <\/p>\n

Need more in depth technical info on the phase splitter valve?<\/p>\n

Try this YouTube video.:<\/p>\n

https:\/\/www.youtube.com\/watch?v=U6By31V9fDo<\/a><\/p>\n

 <\/p>\n","protected":false},"excerpt":{"rendered":"

I am often asked by customers \u201cWhat is the phase splitter valve and is it special or different from the other valves in my valve guitar amplifier?\u201d Hopefully this short article will explain what the phase splitter valve and clear up any questions about the phase splitter valve you may have (but were too afraid… Read more<\/a><\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[],"class_list":["post-92","post","type-post","status-publish","format-standard","hentry","category-stuarts-workshop-wisdom"],"_links":{"self":[{"href":"https:\/\/www.fixguitaramps.co.uk\/blog\/wp-json\/wp\/v2\/posts\/92","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.fixguitaramps.co.uk\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.fixguitaramps.co.uk\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.fixguitaramps.co.uk\/blog\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.fixguitaramps.co.uk\/blog\/wp-json\/wp\/v2\/comments?post=92"}],"version-history":[{"count":1,"href":"https:\/\/www.fixguitaramps.co.uk\/blog\/wp-json\/wp\/v2\/posts\/92\/revisions"}],"predecessor-version":[{"id":93,"href":"https:\/\/www.fixguitaramps.co.uk\/blog\/wp-json\/wp\/v2\/posts\/92\/revisions\/93"}],"wp:attachment":[{"href":"https:\/\/www.fixguitaramps.co.uk\/blog\/wp-json\/wp\/v2\/media?parent=92"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.fixguitaramps.co.uk\/blog\/wp-json\/wp\/v2\/categories?post=92"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.fixguitaramps.co.uk\/blog\/wp-json\/wp\/v2\/tags?post=92"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}