Jump to content
Why become a member? ×

Fender TB 600 Pre amp tube replacement


Tullfan
 Share

Recommended Posts

Hi,
My Fender TB600 Combo has started to sound jangly and fuzzy and i think it must be the death of the valves in the preamp, so have searched for replacement valves online and am about to jump in and have a go at replacing myself.
Searched youtube for videos and nothing specific for the tb600/1200 there, though much about how to replace valves in other amps.
the manual says 12ax7wc (sovtek) valves but i have 12ax7 electro harmonix-cryo coming from watford valves.
So...... it does look easy, but should i call in - your advice/an expert to do it/an undertaker??
Please advise.
thanks for reading.

Link to comment
Share on other sites

No special requirements at all. It's Pre tubes so just gently wiggle the old tube out and put in the new tube making sure it's well seated.

Obviously have the power off and unplugged or switched off at the socket. The amp will still contain enough power to electrocute you badly so touch nothing else but the glass tube.

Edited by Twincam
Link to comment
Share on other sites

[url="https://www.talkbass.com/threads/fender-tube-bass-tb600-head.539138/page-3#post-13478877"]https://www.talkbass...3#post-13478877[/url]


found this post for anyone else occupied with this task, its not the inside of a TB600 it must be the TB1, hope it helps.
Guess who opened up his amp to get that surprise!

Edited by Tullfan
Link to comment
Share on other sites

  • 4 years later...

Hello,

This is a bit of an old topic, I know.
How did the story finish ?

I have just received a Fender TB1200 and the tube overdrive channel does not work, it produces no sound at all when fully balanced to the overdrive channel.

(the other channel is a killer, apart from that)

This must be the tube that is either dead or has moved during the shipment.

I have already changed 12AX7 tubes in other amps without any problem, but I have to say that there are some metal protections screwed above the tubes and in view of the masssive transformer I do not dare touch the metal pieces in there :

tb1200.thumb.jpg.94b488acd727fb500c328afdd39b939b.jpg
 

I am not even sure what screwdriver I shoud use

403235619_tb12001.thumb.jpg.5076c4a91f1edbd91891a75996c83d14.jpg

 

1066788037_thumbnail3.thumb.jpg.f044f181c9e8a17c2db7f252a62045da.jpg

 

And there is one side without a screw, but some resistor underneath :

439187799_thumbnailcloseup.jpg.cb3d09cc9161061e440a32632fd8b47d.jpg

 

Any advice would be welcome !

Link to comment
Share on other sites

You don't need to use a screwdriver to remove these covers, they are a 2 part design, if you push down on the top and then rotate a bit they will slide off, very much like a bayonet fitting light bulb. 

Matt

 

Edit to add that the covers will most likely be earthed so should be safe to touch, the advice of leaving the amp unpowered overnight before starting is good advice for working on any mains powered equipment. 

Edited by Matt P
Extra info
  • Thanks 1
Link to comment
Share on other sites

Thanks again for the tip @Matt P, I have just replaced the overdrive tube with the preamp tube and it now works perfectly fine !

The covers simply needed a small push down and rotation indeed :)

I have swapped the preamp tube with a new old stock RCA grey plate 12AX7, and the sound is much clearer when the gain is pushed up, you have to push it really high to get a little overdrive.
Some would say it is more hifi.

@Salt on your Bass?, everything is  sorted now and I'm happy with the amp !
I did not have the time to test the former overdrive channel tube, I might do some day.

 

 

  • Like 1
  • Thanks 1
Link to comment
Share on other sites

1 hour ago, claustra said:

Thanks again for the tip @Matt P, I have just replaced the overdrive tube with the preamp tube and it now works perfectly fine !

The covers simply needed a small push down and rotation indeed :)

I have swapped the preamp tube with a new old stock RCA grey plate 12AX7, and the sound is much clearer when the gain is pushed up, you have to push it really high to get a little overdrive.
Some would say it is more hifi.

@Salt on your Bass?, everything is  sorted now and I'm happy with the amp !
I did not have the time to test the former overdrive channel tube, I might do some day.

 

 

excellent, it's amazing what differences there are between different valves, glad to be of help.

 

Matt

  • Like 1
Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Restore formatting

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

 Share

  • Recently Browsing   0 members

    • No registered users viewing this page.
×
×
  • Create New...