Tubes Asylum

Questions about tubes and gear that glows. FAQ

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: Will this work? Switching from 6.3 to 12.6 volts

Posted by Eli Duttman on June 12, 2017 at 03:52:23:
Put resistors in series with the SS diodes to make them resemble the 6X4. That will allow for safe listening, until the new tubes arrive.

"Ok, so, if the winding could supply 1 amp of 6.3vac , using a voltage doubler on it would only supply .25A?"

You could get a bit more, but 25% is the safe "guesstimate". Also, keep in mind that, less losses, doubling 6.3 VAC yields 17.8 VDC. The losses include the forward drop of both diodes. Schottkys exhibit an approx. 0.5 V. forward drop and are switching noise free. IMO, that's 2 good reasons to favor them. My guess for doubled 6.3 VAC, via Schottky's, is 16.4 VDC.

FWIW, I like doubling a 6.3 VAC winding of adequate capability with 2X Schottky diodes and regulating with a 7812 IC, for 12AX7 phono preamps. A high performance, modest budget, PSU for RCA setups, tweaked or original, can be built around Allied's 6K1VF power trafo. Tie the rectifier winding's CT off and bridge rectify the end to end voltage. Voltage double and regulate the filament winding. While the 1 A. filament winding is a bit undersized for this job, the heat generated (a critical factor) is compensated for by the lightly loaded rectifier winding. Contact "inmate" Jeff Yourison for more details.