It is currently Mon Mar 16, 2020 7:45 am

All times are UTC - 7 hours



Post new topic Reply to topic  [ 17 posts ]  Go to page Previous  1, 2
Go to page Previous  1, 2
Author Message
Post subject: Re: 5F1 voltages question
Posted: Wed Nov 07, 2018 8:48 am
Offline
Rock Star
Rock Star
User avatar

Joined: Sat Jul 03, 2010 2:18 pm
Posts: 6544
Pants187 wrote:
If those voltages are normal, that means my plate dissipation is sitting somewhere between 15 and 16 W. The max spec for a 6V6GT is 12 W. I've destroyed multiple tubes in a matter of minutes, both new production and NOS. Can see them redplate within 30 seconds of turning the amp on.

This is the OT I have in it:
http://www.classictone.net/40-18110.html

My speaker measures 4 ohms DC resistance. The OT secondary is labeled at 4 Ohms in the schematic. That's at DC I'm pretty sure. So are you saying the 17 kOhm primary impedance is an AC measurement? If so, at what frequency?


Check the grid-to-ground resistor on the 6V6GT. You may need to go to a ~100k-ohm, from the stock 220k-ohm. This resistor also helps set the idle bias.

This Champ is a DIT kit? Or a restoration? I've found nearly EVERY tweed era Champ, with Astron coupling caps leaked DC. A lot (like 10-20 VDC). Leaky coupling caps may not affect bias, but sure adds to short tube life and bad distortion problems. I like new made Orange Drops, or similar caps as replacements.

I moved the bypass cap far from the cathode resistor, on the 6V6GT. Heat can play havoc on that cap.

Good luck! Keep us posted.


Top
Profile
Fender Play Winter Sale 2020
Post subject: Re: 5F1 voltages question
Posted: Wed Nov 07, 2018 10:22 am
Offline
Professional Musician
Professional Musician

Joined: Thu Aug 07, 2014 3:25 pm
Posts: 1022
The 6V6 should take the voltage. A lot of pickers put 6L6 tubes in their Champs. They would hold up better to the high voltage.
Most of the kits I've seen use cheap parts. Switches, caps, and sockets. Get a bare chassis kit and spec your own trannys, caps, switches, and controls to get the good stuff.


Top
Profile
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 17 posts ]  Go to page Previous  1, 2
Go to page Previous  1, 2

All times are UTC - 7 hours

Fender Play Winter Sale 2020

Who is online

Users browsing this forum: No registered users and 2 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum

Search for:
Jump to: