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The 5881 Valve and 5881 Tube

The 5881 valve (5881 tube) is a power output tube used in some makes of guitar amplifier.   The 5881 is towards the lower end of the power spectrum for output valves. It can handle a maximum of 23W and so a pair of 5881 valves would give you about 46W tops.   5881 tubes…

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The 6550 Valve and 6550 Tube

Always on the quest to pack more power into a single tube, the 6550 was launched in the 1950’s by Tung-Sol. Tung-Sol are an American company who specialise in vacuum tubes. They still sell their reissue of this famous valve. The 1950’s version was rapidly improved in the 1960’s to produce the MKIII version. The…

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KT77 Valve

The KT77 Valve and KT77 Tube

The KT77 is a power output valve used in some guitar amplifiers. Marshall have used these in several of their designs in the past. Normally you will find the amp can use either a KT77 valve or an EL34, fairly interchangeably. First let’s look at what the ‘KT’ stands for in the KT77 valve. Well,…

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GZ34 Rectifier Valve

Why Use a Valve Rectifier in a Guitar Amplifier?

Rectifier valves are used in a large number of vintage and reissue guitar amplfiers. For example the GZ34 (5AR4) rectifier from JJ Electronics. This version of the GZ34 has a thick glass envelope and robust electrodes making it the perfect workhorse for those guitar amplfiers which use tube rectification. Examples of guitar amplifiers which use…

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6L6GC matched pair

Power Valves For Guitar Amplifiers

This short article deals with power valves for guitar amplifiers. There is another article which covers preamplifier guitar amplifier valves and also rectifier guitar amplifier valves. It is not intended to show you how tube amps work  or the detailed operation of a tube amplifier. There are only three basic types of guitar amplifier valves,…

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6v6 valve

The 6V6 Valve and 6V6 Tube

What is the 6V6 valve? To keep this short article suitable for everybody, even total novices, let me first explain that the 6V6 valve is a power output valve used mainly in audio stages. I write these blogs mostly for guitarists as the 6V6 valve is used in quite a few different models of guitar…

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12AY7

The 12AY7 Valve and 12AY7 Tube

The 12AY7 valve (also known as the 6072) is a 9-pin tube. There are two valves in one glass envelope. It is what is called a ‘double triode’. It was designed as a low noise tube and was developed before the ECC83 (12AX7) The application for the 12AY7 is usually an audio preamplifier. This valve…

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6L6GC Valve 6L6GC tube

The Difference Between a 5881 and a 6L6GC Valve?

Have you ever wondered about the difference between the 6L6GC valve and the 5881 valve? 5881 vs 6L6GC It can seem so confusing! Some forums say the 5881 is equivalent to the 6L6GC and others say not. You can be left wondering is the 6L6 a like for like replacement of the 5881? You are…

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ECC81 12AT7

The 12AT7 Valve

The 12AT7 Valve (same as the ECC81) is a small preamplifier valve with two identical triodes both of which have a high voltage gain. 12AT7 (also known in Europe by the Mullard-Philips tube designation of ECC81) is a miniature 9-pin medium-gain (x60) dual-triode vacuum tube popular in guitar amplifiers. It belongs to a large family…

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7025 valve

7025 valve – Is it equivalent to the ECC83?

One question we are often asked is this: Is the ECC83 equivalent to the 7025 valve? The short answer is yes in that you can swap a 7025 valve for an ECC83 and your amplifier will work fine. The 7025 valve is a low hum and low noise version of the ECC83, but whether you’ll…

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ECC83 valve 12AX7 valve

The 12AX7 Valve Compared With the ECC83

The 12AX7 Valve (same as the ECC83) or 12AX7 vacuum Tube is a small preamplifier valve with two identical triodes both of which have a high voltage gain. RCA engineers developed it around 1946 and released it for sale as the 12AX7 shortly after. Because it provides two handy amplifiers in one miniature glass envelope,…

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bias guitar amplifiers 1

Cathode Bias – What Exactly is it?

Do you own a valve guitar amplifier and wondered what ‘cathode bias’ means? Have you heard of ‘biasing’ but perhaps are a little confused about what bias means and in particular what cathode bias means? Don’t worry – you’re not alone! Biasing is a highly confusing subject for the owners of valve guitar amplifiers. The…

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Amplifier Output Valves

Microphony in Valves – What Causes it?

This short article describes something called microphony in guitar amplifier valves. Microphony particularly occurs in the preamplifier valves, or rather it’s more accurate to say that microphony is more noticeable in preamplifier valves. That’s because these valves are at the start of the amplification chain and so any noise due to microphony is very greatly…

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valves for guitar amplifiers

The ECC83 Compared With the 12AX7 Valve

hThis short article describes the ECC83 valve also known as the 12AX7. The ECC83 (12AX7) valve is used in the preamplifier section of 99% of all valve guitar amplifiers. Usually there are between 2 and 5 of these valves in the preamplifier section. They all do the same thing which is to amplify a smaller…

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Amplifier Output Valves

What Are NOS Valves and Are They Worth Buying?

Are you confused about what NOS valves or NOS tubes? NOS valves means New Old Stock Valves. NOS tubes means the same of course. We know what a valve is of course but what are New Old Stock valves? NOS valves (New Old Stock) are valves which are brand new, never used, boxed valves manufactured…

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bias guitar amplifiers 1

Phase Splitter Valve in Guitar Amplifiers

We are often asked by customers “What is the phase splitter valve and is it special or different from the other valves in my valve guitar amplifier?” Hopefully this short article will explain what the phase splitter valve and clear up any questions about this valve you may have (but were too afraid to ask!).…

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bias guitar amplifiers 1

Fixed Bias in Valve Guitar Amplfiers – What Exactly is it?

Understanding fixed bias in valve guitar amplifiers. Fixed Bias is a term which guitarists often mention. But what on earth is it? Do you have a valve guitar amplifier? In that case you  have probably heard of ‘biasing’. It can be a very confusing term.  It’s even more confusing as you have probably also hear…

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EL84 valve

Best Guitar Amplifier Valve? Here’s The Answer.

The search for the best guitar amplifier valve is akin to the search for the Holy Grail! As you might expect there is no best guitar amplifier valve for your tube guitar amp! Just as there is no best car tyre or best television set or Hi Fi. In short these matters are highly subjective…

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vintage guitar amplifier

Vintage Guitar Amplifiers – Are They Worth Buying?

Deciding to buy classic vintage guitar amplifiers is a tricky question akin to asking ‘should I buy 60 year old a classic vintage car’? Answer: yes if you have always lusted after one and don’t mind the endless maintenance and ‘money sink’. No if you are chasing some Holy Grail sound which is probably more…

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Amplifier Output Valves

Red Plating in Guitar Amplifier Valves – What is it?

Red plating only occurs in one group of amplifier valves. Guitar amplifier valves fall into two main groups (ignoring power supply valves) and red plating only occurs on one group. The two groups are preamplifier valves such as ECC83 (12AX7) and power output valves (such as 6L6, EL34 etc.). Red plating can occur in the…

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Standby switch protects amplifier output valves

Does The Standby Switch Protect Guitar Amplifiers?

If you own a valve guitar amplifier you will almost certainly have a standby switch on it, received wisdom has it that the standby switch is there to protect the amplifier output valves. Aside: your guitar amplifier has two sorts of valve – preamplifier valves (the smaller ones) and amplifier output valves (the larger ones…

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ECC83 valve 12AX7 valve

Preamplifier Valves for Guitar Amplifiers

This short article deals with preamplifier valves for guitar amplifiers. There is another article which covers power guitar amplifier valves and also rectifier guitar amplifier valves. It is not intended to show you how tube amps work or the detailed operation of a tube amplifier. There are only three basic types of guitar amplifier valves,…

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Valves For Fender Valve Guitar Amplifier

Valve Guitar Amplifier – Which is the best?

How do I Choose The Best Valve Guitar Amplifier For Me? Are you looking to change your amp and thinking of going valve? There are several questions you need to answer before you can decide on which valve guitar amplifier is best for you. Top tips for choosing a valve guitar amplifier What power do…

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valves for guitar amplifiers

How Valves Work in Guitar Amplifiers

Have you ever wondered how valves work in tube amps or what are tube amps? Guitar Amplifier Valves The Basics There is the six volume textbook answer and the two page answer to how guitar amplifier valves work. I expect you’d like the shorter version! To understand how valves work and the basics of guitar…

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Vox AC30 C2 amplifier

Biasing Guitar Amplifiers. What’s Involved?

Biasing Guitar Amplifiers. What’s Involved? Since we supply valves for guitar amplifiers we are often contacted to ask us about biasing guitar amplifiers. Biasing guitar amplifiers (biasing tubes) is a highly confusing subject for the non-technical and for good reason. Biasing guitar amplifiers IS confusing! The first thing to say is that although all the…

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EL84 matched quad

JJ Valves – Why Use Them in Your Guitar Amplifier?

JJ Valves At the time of writing we only supply JJ valves from JJ Electronics. Sometimes asked why we don’t supply a larger range of valves from different manufacturers. This was a deliberate decision on our part, only to sell JJ valves. When we started AmpValves we looked around at the competition and found a…

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6L6gc matched quad

Best Amplifier Valve – Which is it?

Ever wondered which is the best amplifier valve out there?  Are some makes of guitar amplifier valves are better than others? If you own a valve amplifier or tube amplifier (http://en.wikipedia.org/wiki/Valve_amplifier) this is a very contentious question! The short answer is ‘yes’ there is a best amplifier valve— but not maybe for the reasons you…

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Guitarists prefer the sound of a valve amplifier

Why Are Valve Guitar Amplifiers Considered Dangerous?

Working with valve guitar amplifier is not dangerous in itself as long as it is not opened up. That’s fairly obvious otherwise they would not be sold! The danger comes if the innards are exposed and you touch a live component. In this respect they are far more dangerous than a transistor amplifier because they…

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How Can I Tell if my Guitar Amplifier Valves Need Changing?

This is a question often asked, and with good reason because there is no single, obvious symptom which screams out at you to change your guitar amplifier valves. I won’t try to explain how tube amps work in this article (see my other blogs). As guitar amplifier valves age they just become less and less…

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marshall amp with les paul

What Causes Such a Heavy Valve Amplifier?

This question is often asked by guitarists who love the sound of a valve amplifier but struggle with the weight of a heavy valve amplifier, particularly when gigging!  5 Reasons Which Make For a Heavy Valve Amplifier Of course, we are talking about compared with their lighter, transistor cousins. 1. One obvious reason for a…

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Guitarists prefer the sound of a valve amplifier

5 Reasons Guitarists Prefer a Valve Amplifier

Outside of the world of the guitar valve amplifier, valves are seen as very ‘old hat’. Apart from some high-end Hi Fi valve amplifiers, valves have almost totally been replaced by semiconductors. So why is it that many (or even most) guitarists prefer the sound of a valve amplifier? Here are the top 5 reasons…

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