You are looking at an EF91 / 6AM6 (CV138) high slope pentode amplifier valve / vacuum tube, tested and fully working.

The EF91 has been used with some success as audio preamplifier valves / tubes in various circuits, particularly in Little Dot amplifiers and they also make excellent cathode followers when strapped as a triode.

Originally these were high gain RF amplifiers and used in their millions in 1950s and 60s TV sets, as well as professional radio gear and test equipment. A highly versatile, reliable and successful design all round and still good today.

A good chance to acquire a useful, guaranteed and tested version of this valve/tube but for a sensible price please - New old things don't store themselves for 60 odd years!!

EF91

Heater = 6.3V @ 0.3A

Pentode:
Anode / Plate:  250V / 10mA / 1Mohm
Screen Grid: 250V / 2.5mA
Signal Grid: -2.0V
gm: 7.6ma/V

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 bid 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 Paypal, cheques in GBP, UK postal orders / bank drafts or wire transfers. Please CONTACT US FIRST before sending payment by a method other than PayPal - there will be a delay in shipping while we clear your payment if you pay using these other methods. We are happy for you to collect from Bristol, but will require payment in GBP cash on collection.