Rectifier Valve ? Many of the vintage amplifiers such as the Vox AC30 , Fender Twin Reverb use a rectifier valve. Other amps use modern silicon diodes. The rectifier valve ( or diode) is a key part of your amplifier’s power supply. Its job is to “convert” or rectify the AC voltage coming from the transformer into the high DC voltage needed by your valves in your amplifier. The output valves need the highest voltage […]
I thought this looked like a really useful table on bias current for output valves. The top of the page allows the super techie types to do an exact calculation based on measured voltages in your actual amp and the configuration of the circuit. The featured picture is actually all the tools ( apart from the right screwdriver). It is simply a multi-meter and a special adapter. You plug the adapter into the output
Electrolytic Capacitors You find electrolytic capacitors in the power supply and decoupling of valves in Hifi and guitar amps. They are like a battery because they have a positive and negative terminal. In you amp power supply they can have values of 22 up to 200 or more uF ( uF= micro-farads). Electrolytic capacitors store energy, and often they are working at voltages of 500 volts DC ! When you switch off your amp , they
Small Capacitors in Guitar Amps Your amp is filled with small capacitors as in the picture below. They come in many different colours so this is jut a sample In simple terms, is in the filter circuits ( tone shaping) or to pass the audio ( AC) signal to the next stage of the amp while blocking the DC voltages. Values are typically in the range 0.001 to 0.47 uF. In valve amps there are
Wirewound Resistors In Your Amp Wire-wound resistors in your amp are used when a lot of power needs to be dissipated in your amp and usually these are around the output valves for bias resistors. As the name suggests the resistors are made from restitive wire that is wrapped around a piece of material to make a resistor. They are used especially in amps with an output of 40 watts or more. There is a
Resistors in Your Amp This is a longer than usual article talking about the different type of resistors in your amp. Resistor technology has changed over the decades . What is common is that many types change their values over time. They usually go high in value and with certain types heat makes the problem worse. Some create noise. The overall result is that the values can change so much that the amp stops dead
What makes a valve fail in your amp Let’s have a light look at valves. Ever wondered why if you buy a nice new valve ( tube) amp that the amp has 2 years warranty and if you check the small print on the warranty carefully, you will see the valve warranty is a lot shorter – perhaps only 90 days! Valves are very old electronics technology. They were invented in 1910 and have been
