How to Deal With ‘Scratchy’ Pots
We all know the problem. After a few years the pots on our amp get scratchy. By that, I mean you get this scratchy noise every time you rotate them. This is particularly bad when you leave the amp standing around for a few months (years or even decades!) What Causes Scratchy Pots? … Read more
Posted by Stuart on March 6, 2018
The ECC83 (12AX7) Valve
This 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 ECC83 (12AX7) valves in the preamplifier section. Firstly let’s sort out the confusion. ECC83 or 12AX7? They are identical…. Read more
Posted by Stuart on June 10, 2015
The Phase Splitter Valve
I am 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 the phase splitter valve you may have (but were too afraid… Read more
Posted by Stuart on May 3, 2015
What is Fixed Bias?
Do you have a valve guitar amplifier? If so you have probably heard of ‘biasing’ and maybe become confused about what is fixed bias. There are two sorts of bias: Fixed bias and cathode biased. This short article aims to demystify this highly confusing topic. Let’s make a start. You’re going to like this first… Read more
Posted by Stuart on April 18, 2015
What Is The Best Guitar Amplifier Valve?
The search for the best guitar preamplifier valve is akin to the search for the Holy Grail! As you might expect there is no best guitar preamplifier valve! Just as there is no best car tyre or best television set or Hi Fi. In short these matters are highly subjective and it’s also very easy… Read more
Posted by Stuart on March 27, 2015
Should I Buy a ‘Classic’ Vintage Guitar Amplifier?
Deciding to buy a classic vintage guitar amplifier 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… Read more
Posted by Stuart on March 15, 2015
The Cause and Cure of Red Plating Valves in Guitar Amplifiers
Guitar amplifier valves fall into two main groups (if we ignore 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 output valves but you will never see red… Read more
Posted by Stuart on February 14, 2015
Does The Use of Standby Switch Help Valve Life?
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… Read more
Posted by Stuart on January 14, 2015
How do Guitar Amplifier Valves Work Exactly?
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 the basics of guitar amplifier valves all you need to know is that ‘like charges repel’ and ‘opposite charges attract’. You probably recall that from school. So, negative… Read more
Posted by Stuart on September 11, 2014
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. This is a highly confusing subject for the non-technical and for good reason. It IS confusing! The first thing to say is that although all the valves in your guitar amplifier are… Read more
