HELP ! Info on valve delay relays.

[pre65]

I was going to use a valve type delay relay on the PSU of my 2a3 amp.

I have two Edison 501 and an Amperite 2N030, and they both seem to be 30 second delay which will do nicely.

I've managed to ascertain that the octal pin out is different for both types, so the Edison 501 would seem the one to go for as I have two.

Now, I'm not sure about how to heat them, or indeed wire them up, and internet searching has not been much help.

So, my initial thoughts were to use the switch contacts to switch the 5V heater supply for the valve rectifier (directly heated) but it seems the relay valves are only rated at 250v ac and my circuit will be more like 400v.

Also, does anyone know if the delay relay filament would work as desired on 5V ac ?

My mains transformer has a 5V winding, but I could use a separate 2.5v-0-2.5v Hammond transformer on the rectifier filament and take the HT from the centre tap.

Or (thinking aloud) use the delay relay to switch the 240v ac supply to the Hammond filament transformer ?

I never gave this much thought up till now cos I thought it was simple.

EDIT.
Something like this perhaps ?

[Cressy Snr]

If you switch the rectifier heater supply with the delay relay, you are only switching one leg so the voltage rating will not be an issue.
Yes the rectifier heater is riding on the HT voltage but the delay relay won't know.

By far the best solution is to switch the rectifier heater. The delay relay time adds to the rectifier warm-up time in that case, giving a nice slow start.

As to the heater voltages for delay relays You'd need to look at the data sheets for those. Using less voltage on the delay relay heater would lengthen he time it takes for the contacts to close.

[pre65]

Thanks Steve, it was the lack of data sheet info that was one of the problems.

I quite like the sketch I did, so unless there are any reasons why it's a naff idea I might go that way.

EDIT.

It might be a lot simpler to just have a separate mains switch for the Hammond filament transformer and forget about the delay valve. I did it that way on several amps in the past.

Then I can choose the delay before switching it on.

KISS ?

[Mike H]

Your diagram seems alright to me.

BTW that one you gave me seems not to work, or else it's not actually a switch...

[pre65]

Your diagram seems alright to me.

BTW that one you gave me seems not to work, or else it's not actually a switch...

The two types I have use different pin out on the octal base, are you sure you have the right connections ?

What type have you got ?

[Mike H]

Now you're asking me!

"Northern Engineering Laboratories, NE-71, 100K-C, 6.3V, 70°C, 881-403435"

Just as well I kept notes ~

Pins:
1 & 7 - heater (1)
2 - NC
3 - heater (2)
4 - NC
5 - NC
6 - connected to 8
-
8 - connected to 6

Turn it on, it heats up, not a lot else happens.

[pre65]

Ooh err !

I can let you have another one if you like, an Amperite 2N030

Pins 2-3 filament

Pins 5-7 switch.

[pre65]

Actually, I remember giving it to you cos I did not know what it was. It's not a delay valve.

http://falk-willberg.de/Roehren/NE-71.jpg

Does any of this make sense ?

Crystal unit, Quartz Overall Length: 4.134 inches nominal
Operating Temp Range: 60.0 to 70.0 deg celsius
Specified Frequency: 100.000 kilohertz

http://www.wbaviation.com/rfq/5955-00-807-8637.html

[Mike H]

That's him! That would explain a lot then