Tube DIY Asylum

Do It Yourself (DIY) paradise for tube and SET project builders.

Use this form to submit comments directly to the Asylum moderators for this forum. We're particularly interested in truly outstanding posts that might be added to our FAQs.
You may also use this form to provide feedback or to call attention to messages that may be in violation of our content rules.

You must login to use this feature.

Inmate Login

By default, logging in will set a session cookie that disappears when you close your browser. Clicking on the 'Remember my Moniker & Password' below will cause a permanent 'Login Cookie' to be set.

Moniker/Username: The Name that you picked or by default, your email. Forgot Moniker?	Examples "Rapper", "Bob W", "joe@aol.com".
Password:	Forgot Password?
	Remember my Moniker & Password ( What's this?)

If you don't have an Asylum Account, you can create one by clicking Here.

Our privacy policy can be reviewed by clicking Here.

Inmate Comments

From:
Your Email:
Subject:

Message Comments

Original Message

RE: 4P1L in filament bias

Posted by andy evans on February 15, 2017 at 16:07:08:
I use a pair, which is the equivalent to a 2a3, with a 70mA OPT. A single is equivalent to a 45. You can use three in parallel - just wire the filaments in series, then in parallel between the tubes. For 3 you really need a 100mA OPT.
But if you want some volume at 50mA, you need a higher plate voltage. 4P1L is rated 250v a-k though you could probably push it a little.