EZ90 Rectifier Valve - UK Vintage Radio Repair and Restoration Discussion Forum

John12868 · 3rd Mar 2009, 3:56 pm

Hi Guys,

I'm looking to produce a power supply using a 240/115 volt 0.12 amp transformer to power an amplifier using EF80 valves.

Would the EF90 rectifier be suitable for rectifying the 115 volt output and what sort of rectified voltage value would I expect to obtain?

Cheers

John

Tim · 3rd Mar 2009, 4:04 pm

Yes.More than adequate.
The EZ90/6X4/N78 can do about 70mA at 325-0-325 volts.

It's full wave of course, so you'll need a centre tapped transformer, or if you only have a single ended transformer,common the anodes via a lowish value resistor in each(to even out any inconsistencies).

http://www.r-type.org/exb/exb03815.htm

Not sure what the max resovoir capacitance or surge resistor is, but 100 ohms and 32uF will probably be fine.

paulsherwin · 3rd Mar 2009, 4:12 pm

The offload smoothed DC voltage will be about 1.6 times the AC voltage, so you can expect about 180V DC. The voltage will be lower when current is being drawn.

An EZ80 or EZ81 would also be suitable. These use the same B9A base as the EF80 and are easier to obtain. You could also use silicon diodes of course.

Paul

Tractorfan · 3rd Mar 2009, 10:47 pm

Hi all,
Just my two copper's worth, the EZ80 is almost the EZ90 in a bigger bottle. I was given a French radiogram sans EZ90. After consulting my Mullard manual I found that the heater ratings of both valves are the same but (I think) the anode current is higher at 90 mA. I made up an adaptor - B9A holder to B7G plug and it works perfectly

Hope this is useful.
Cheers de Pete

3rd Mar 2009, 3:56 pm	#1
John12868 Retired Dormant Member Join Date: Nov 2006 Location: Crayford, London, UK. Posts: 181	EZ90 Rectifier Valve Hi Guys, I'm looking to produce a power supply using a 240/115 volt 0.12 amp transformer to power an amplifier using EF80 valves. Would the EF90 rectifier be suitable for rectifying the 115 volt output and what sort of rectified voltage value would I expect to obtain? Cheers John

3rd Mar 2009, 4:04 pm	#2
Tim Dekatron Join Date: Jan 2003 Location: Bradford on Avon, Wiltshire, UK. Posts: 3,310	Re: EZ90 Rectifier Valve Yes.More than adequate. The EZ90/6X4/N78 can do about 70mA at 325-0-325 volts. It's full wave of course, so you'll need a centre tapped transformer, or if you only have a single ended transformer,common the anodes via a lowish value resistor in each(to even out any inconsistencies). http://www.r-type.org/exb/exb03815.htm Not sure what the max resovoir capacitance or surge resistor is, but 100 ohms and 32uF will probably be fine. __________________ "Nothing is as dangerous as being too modern;one is apt to grow old fashioned quite suddenly."

3rd Mar 2009, 4:12 pm	#3
paulsherwin Moderator Join Date: Jun 2003 Location: Oxford, UK Posts: 27,967	Re: EZ90 Rectifier Valve The offload smoothed DC voltage will be about 1.6 times the AC voltage, so you can expect about 180V DC. The voltage will be lower when current is being drawn. An EZ80 or EZ81 would also be suitable. These use the same B9A base as the EF80 and are easier to obtain. You could also use silicon diodes of course. Paul

3rd Mar 2009, 10:47 pm	#4
Tractorfan Dekatron Join Date: Mar 2008 Location: St. Frajou, l'Isle en Dodon, Haute Garonne, France.(Previously: Ellesmere Port, Cheshire, UK.) Posts: 3,184	Re: EZ90 Rectifier Valve Hi all, Just my two copper's worth, the EZ80 is almost the EZ90 in a bigger bottle. I was given a French radiogram sans EZ90. After consulting my Mullard manual I found that the heater ratings of both valves are the same but (I think) the anode current is higher at 90 mA. I made up an adaptor - B9A holder to B7G plug and it works perfectly Hope this is useful. Cheers de Pete __________________ "Hello?, Yes, I'm on the train, I might lose the signal soon as we're just going into a tunn..."