Valves - Matched Quads


Many amplifiers have matched quads, (or four) output tubes. But what does this mean and why must these valves be ‘matched’?

Matched Quads: Why do valves need to be matched?

In a guitar amplifier with four output valves two of the valves are “pushing” the speaker cone and two are “pulling” it.

In an amp with only only two output valves, the same applies. But now the amp has only half the power.

So with the same signal applied to each valve pair, you can see that it’s important that each valve gives an identical amount of push or pull. If this is not the case, sound fidelity, or tone, will be lost.

So you MUST replace all four output tubes at the same time and you MUST buy a matched quad from a reputable dealer. At AmpValves we fully test all valves and match them and give a 100% guarantee on every one.

A matched quad gives the same bias current under identical conditions of plate voltage and grid bias voltage.

Please note that valves (even same make, same type) can differ wildly in their characteristics. This is why this matching is so important.

A new set of Valve Matched Quads. Hear the difference.

A new set of valves can make a startling difference to your sound. Suddenly your amp sounds like it used to!

So here are some useful tips if you are thinking of changing your valves:

1. Keep a note of when you change your valves/tubes, that way you’ll know when they need replacing. If you gig regularly aim to change them once a year, The difference in tone and power  is amazing.
2. Always aim to replace you tubes after approximately 1000 hours of actual playing. It doesn’t matter how old they are, it’s the number of hours they have been used which counts.
3. Never change just one output tube. They must always be changed as a set.
4. Always buy a matched set of output tubes. So either a matched pair or a matched quad. They have been matched to have the same gain and the same bias current.

Matched Quads: Awesome valves at sensible prices.

Did you know that despite all the brand names you see for sale, there are only four manufacturers of valves in the World? So we supply JJ valves/tubes as they give a stunning tone at a very sensible price. We also offer fast delivery so you can get your amp back up to spec as soon as possible.

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