Welcome, Guest. Please login or register.
January 19, 2018, 01:20:09 AM
Home Help Search Login Register
News: Ceriatone Forums are up and running!!!
 
Guests please register
Note: If you want to help you can donate to keep the forums alive.










Do you want to advertise on this forum ? Send me a private message.



 


Amplified Parts
+  Ceriatone Forum
|-+  American Style
| |-+  PrinzeTone
| | |-+  External bias check?
« previous next »
Pages: [1] Go Down Print
Author Topic: External bias check?  (Read 5764 times)
vim
Newbie
*
Offline Offline

Posts: 20


View Profile
« on: September 19, 2011, 07:07:28 AM »

I was thinking about installing external bias check points on my Prinzetone.
It is as easy as running wire from pin 8 on a powertube to red point and from grounded end of 1R2W resistor to black point, right?
Also: Is there any need for running red wire from pin 8 on both tubes btw?
Logged
wyatt
Guest
« Reply #1 on: September 19, 2011, 09:08:21 AM »

Yes, a wire from either pin 1 or 8 (they are jumpered in the Prinzetone) for your red probe jack. 

You don't *have* to add a black jack, you can just touch the black probe to any exposed ground connection, a ground is a ground.

The reason people have bias check points at both tubes is because if the tubes aren't perfectly matched (few are), you can see which one runs hotter and adjust for that tube. For bigger amps with 6L6GC and EL34, a 4mA mismatch is considered acceptable, but for 6V6GT's and EL84's it can mean the difference between 70% and 90% dissipation, so you want to be able to check for it.  You could even add separate bias pots for each tube and never have to worry about whether they are matched or not.
« Last Edit: September 19, 2011, 09:11:52 AM by wyatt » Logged
cmoore
Sr. Member
****
Offline Offline

Gender: Male
Posts: 366


View Profile
« Reply #2 on: September 19, 2011, 02:36:07 PM »

Make sure the Trem is not running when you check the bias......
Best
Logged
vim
Newbie
*
Offline Offline

Posts: 20


View Profile
« Reply #3 on: September 19, 2011, 04:12:44 PM »

Good advise to turn off the vibro  Wink
Think I'll add a grounded point as well, as the chassis is painted.
Another bias pot would be a good idea actually, but where to run the wires then (goes to the last22k 1w resistor on the main board as is)?
Logged
Pages: [1] Go Up Print 
« previous next »
Jump to:  


Login with username, password and session length

Powered by MySQL Powered by PHP Powered by SMF 1.1.12 | SMF © 2006-2009, Simple Machines LLC Valid XHTML 1.0! Valid CSS!

CeriaTone Forum is not afiliated with Ceriatone Amplifications. The CeriaTone and name, logo and related trademarks and service marks, owned by CeriaTone. , are registered and/or used in the U.S. and many foreign countries. All other trademarks, service marks, and trade names referenced in this site are the property of their respective owners.