For sale a U31 (25Z4G equivalent) half wave HT rectifier valve / vacuum tube by Marconi, new in original box. Recently fully tested and working at 100% of nominal new emission. This particular example has lovely Marconi red green label and white print marking, all present and correct. It is in a classic G series coke bottle envelope.

The U31 / 25Z4 was much used in small AC/DC radio sets with a series heater chain, though it can also be heated from a small 24 volt transformer. It can deliver a very reasonable 120mA at 250 volts.

Fully tested on my Mullard High Speed Valve Tester and showing zero faults and 100% of nominal new emission. A reasonable price for this fully working, original, quality example of a still very sought after valve/tube.

Will make somebody's old 1950s vintage radio very happy.

U31 / 25Z4G

Heater = 26V @ 0.3A

Diode:
Anode / Plate:  250V max / 120mA continuous

I offer a full, money back guarantee if you are not completely satisfied with this purchase (see terms). We have been trading since 1927 so buy with confidence. Most of our valves / tubes have been in our own stock room for many, many years. See our EXCELLENT FEEDBACK on quality valves / tubes previously supplied!

We have thousands of valves / tubes in stock - standard and rare; US, UK and European. If you have any particular requirements, please send a message and if we have what you want, we will list it here.

We ship worldwide and are very happy to combine items for multiple postage.

TERMS

GUARANTEE: In case of dissatisfaction, buyer must return item at own expense. We will only refund if you return the EXACT SAME VALVE / TUBE to us that you have purchased, with the heater still intact and passing continuity test. Believe it or not, some evil people have tried to send us back their dud tubes to try and get a full refund for a perfectly good tube we have just sold them! So, refund is a genuine offer, but at our discretion that we have been sent back what we actually sold you in the first place and that you haven't destroyed it through misuse! All returns under guarantee are limited to within 21 days of shipping.

PAYMENT: We accept all usual eBay payment methods. We are happy for you to collect from Bristol by prior appointment only, but will require payment in GBP cash on collection.