5U4GB JJ Rectifier Valve

5U4GB Rectifier Valve


In Stock

423 in stock

All single valves, matched pairs and matched quads are fully tested in our warehouse before dispatch. These valves will guarantee awesome tone and amazing power. You WILL hear the difference. So get your amp sounding better than ever. Order your replacement valves today.


Are you looking to replace your 5U4GB rectifier tube? Look no further!

Rectifier valves, like the 5U4GB, are used in a large number of vintage and reissue guitar amplifiers.

We sell a superb example of the 5U4GB rectifier made by JJ Electronics. JJ is one of only three manufacturers of valves in the World.

This version has a thick glass envelope and extremely robust electrodes. This makes it the perfect workhorse for those guitar amplifiers which use tube rectification.

In fact, it’s become quite chic to add a rectifier tube to a new guitar amplifier design. Guitarists just love that ‘retro’ feel!

So why Use a Valve Rectifier such as the JJ 5U4GB valve?

JJ 5U4GB rectifier valve
JJ 5U4GB rectifier valve for sale

Well, the first thing to realise is that the rectifier valve is NOT in the signal chain. It’s there simply to change AC to DC, a process known as rectification.

The reason rectifier valves are still used is interesting. They are actually not that great at doing the job they are intended to do! That is, change AC to DC.

If the amplifier is loaded, by say a heavy power chord from your trusty Les Paul, the DC will ‘sag’.

This is because the rectifier simply can’t keep up. In contrast, a diode rectifier will barely sag at all. (sagging means the DC voltage drops before quickly recovering.)

But here’s the thing. Guitarists have come to love this effect, hence the continued demand for valve rectification in guitar amplifiers.

And of course, back in the day, there were no decent solid-state rectifiers. So the 5U4GB and similar types were the only game in town.

There are still hundreds of thousands of vintage amplifiers out there which use rectifier tubes.

So now you know!

JJ 5U4GB Rectifier valves for sale

If you have any questions please drop us an email.

The best person on our team to answer your question will get straight back to you.

Additional information

Weight0.23 kg
Dimensions15 × 15 × 15 cm


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5U4GB Rectifier Valve

5U4GB JJ Rectifier Valve