It is currently Mon Mar 16, 2020 9:35 pm

All times are UTC - 7 hours



Post new topic Reply to topic  [ 13 posts ] 
Author Message
Post subject: Need Help with my Vibro Champ XD
Posted: Mon Feb 22, 2010 8:14 pm
Offline
Hobbyist
Hobbyist

Joined: Sat Jan 05, 2008 7:46 am
Posts: 2
Currently I own a vibro champ xd and when I plug it in the preamp tube glows and gets warm. However the power tube stays cool to the touch. How do I test the tube? or is something else wrong?


Top
Profile
Fender Play Winter Sale 2020
Post subject:
Posted: Mon Feb 22, 2010 8:39 pm
Offline
Amateur
Amateur

Joined: Fri Mar 20, 2009 3:56 pm
Posts: 131
The first thing I would do is make sure that the power tube is fully seated. If that doesn't fix the problem, remove the tube, clean the tube pins off with some contact cleaner, let them dry, and then replace the tube.

Beyond that I'm not much help. Others will be, though.


Top
Profile
Post subject:
Posted: Tue Feb 23, 2010 3:08 am
Offline
Hobbyist
Hobbyist

Joined: Mon Feb 15, 2010 5:47 am
Posts: 51
do we need to bias the tubes from the vcxd? i'm a tube noob


Top
Profile
Post subject:
Posted: Tue Feb 23, 2010 10:57 am
Offline
Hobbyist
Hobbyist

Joined: Sat Jan 05, 2008 7:46 am
Posts: 2
I've tried reseating the power tube and that doesn't seem to help. I'll try cleaning the pins, is rubbing alcohol OK or should I use something else?


Top
Profile
Post subject:
Posted: Tue Feb 23, 2010 3:08 pm
Offline
Rock Star
Rock Star
User avatar

Joined: Tue Aug 07, 2007 2:19 pm
Posts: 8827
Deoxit


Top
Profile
Post subject:
Posted: Wed Feb 24, 2010 9:03 am
Offline
Hobbyist
Hobbyist

Joined: Thu Dec 10, 2009 9:48 am
Posts: 32
pugak_79 wrote:
do we need to bias the tubes from the vcxd? i'm a tube noob


No, a Vibro Champ, and the Vibro Champ XD, are cathode biased, or self biasing. There is no bias adjustment.

_________________
My gear:

Hot Rod Deluxe
1975 Vibro Champ
G-DEC 3 Thirty
Kramer XL III
Standard Stratocaster
Oscar Schmidt acoustic


Top
Profile
Post subject:
Posted: Wed Feb 24, 2010 9:40 am
Offline
Rock Star
Rock Star
User avatar

Joined: Tue Aug 07, 2007 2:19 pm
Posts: 8827
sparkydave wrote:
pugak_79 wrote:
do we need to bias the tubes from the vcxd? i'm a tube noob


No, a Vibro Champ, and the Vibro Champ XD, are cathode biased, or self biasing. There is no bias adjustment.


They are both fixed bias amps. They are not self biasing. The bias needs to be checked if you replace the power tubes.


Top
Profile
Post subject:
Posted: Wed Feb 24, 2010 9:50 am
Offline
Hobbyist
Hobbyist

Joined: Thu Dec 10, 2009 9:48 am
Posts: 32
63supro wrote:
sparkydave wrote:
pugak_79 wrote:
do we need to bias the tubes from the vcxd? i'm a tube noob


No, a Vibro Champ, and the Vibro Champ XD, are cathode biased, or self biasing. There is no bias adjustment.


They are both fixed bias amps. They are not self biasing. The bias needs to be checked if you replace the power tubes.


You might want to go review the Vibro Champ XD schematic to confirm for yourself that the 6V6GT uses a 470 ohm cathode resistor, and does not have a bias supply to adjust. Cathode biasing using a cathode resistor is not fixed bias, and there is no adjustment. Not all tube amps are fixed bias. The Vibro Champ XD uses the same output stage as the original Vibro Champ, which I have.

_________________
My gear:

Hot Rod Deluxe
1975 Vibro Champ
G-DEC 3 Thirty
Kramer XL III
Standard Stratocaster
Oscar Schmidt acoustic


Top
Profile
Post subject:
Posted: Wed Feb 24, 2010 10:17 am
Offline
Rock Star
Rock Star
User avatar

Joined: Tue Aug 07, 2007 2:19 pm
Posts: 8827
Sorry, my mistake I thought the op had a Super Champ XD. The Vibro Champ XD is single ended and does not require biasing.


Top
Profile
Post subject:
Posted: Wed Feb 24, 2010 11:51 am
Offline
Rock Star
Rock Star
User avatar

Joined: Tue Aug 07, 2007 2:19 pm
Posts: 8827
63supro wrote:
Sorry, my mistake I thought the op had a Super Champ XD. The Vibro Champ XD is single ended and does not require biasing.


I am aware than not all tube amps are fixed bias.


Top
Profile
Post subject:
Posted: Sat Feb 27, 2010 9:38 am
Offline
Hobbyist
Hobbyist

Joined: Mon Feb 15, 2010 5:47 am
Posts: 51
sparkydave wrote:
63supro wrote:
sparkydave wrote:
pugak_79 wrote:
do we need to bias the tubes from the vcxd? i'm a tube noob


No, a Vibro Champ, and the Vibro Champ XD, are cathode biased, or self biasing. There is no bias adjustment.


They are both fixed bias amps. They are not self biasing. The bias needs to be checked if you replace the power tubes.


You might want to go review the Vibro Champ XD schematic to confirm for yourself that the 6V6GT uses a 470 ohm cathode resistor, and does not have a bias supply to adjust. Cathode biasing using a cathode resistor is not fixed bias, and there is no adjustment. Not all tube amps are fixed bias. The Vibro Champ XD uses the same output stage as the original Vibro Champ, which I have.


So how do we set the bias on the vcxd if it isn't self-biasing? Bob of eurotubes.com and a guy from fender emailed me saying vcxd doesn't need to be biased. Plug n play as fender said. Also, i'll be getting a couple of fuses as spare for the vcxd. What type of fuse are they using for this particular amp?


Top
Profile
Post subject:
Posted: Sat Feb 27, 2010 9:45 am
Offline
Hobbyist
Hobbyist

Joined: Mon Feb 15, 2010 5:47 am
Posts: 51
63supro wrote:
Sorry, my mistake I thought the op had a Super Champ XD. The Vibro Champ XD is single ended and does not require biasing.


single ended? what does that mean? does that simply mean i could just replace the power tubes and skip all those bias probes and play? if the bias is fixed, i hope they set it at the right amount


Top
Profile
Post subject: Re: Need Help with my Vibro Champ XD
Posted: Sat May 24, 2014 9:41 pm
Offline
Hobbyist
Hobbyist

Joined: Sun Jan 08, 2012 5:06 pm
Posts: 6
I realize that this is an old post, but here is some info that may help if you notice that you 6V6 or 6L6 tube is not lighting the filament.

1) Is the tube seated correctly in the socket?
2) If step 1 doesn't solve the problem: Remove the tube and check that pins 2 and 7 have continuity. Use your volt-ohm meter on the ohm setting to make certain the the filament shows zero ohms (or very close to 0). If the reading is infinity then the filament is open and the tube isn't any good.


Top
Profile
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 13 posts ] 

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: