Steps for changing preamp tubes

[number41dl]

Question for all you amp modders out there!

I'm looking at ordering the Crate v33-212 this week, but have been told the preamp tubes are so-so at best, and result in a muddy sounding distortion channel. Recommended by almost all reviewers is a change to GrooveTubes or Electro Harmonix preamp tubes.

These don't cost much, but I've never swapped tubes in my life - is there more to the process than just "take the old out, put the new in"? It sounds too easy to only be that...

Advice?

[stephen78]

For preamp tubes, it is that easy. Just take the old ones out and put the new ones in.

Power amp tubes are a different case though. If your amp has a fixed bias, you can just swap them out (just make sure you get a matched set). But if your amp has an adjutable bias, you need to take it to an amp tech to properly set the bias (unless you learn how to do it yourself).

[kluson]

take em out put the new ones in...... that simple, however I would try to get some old Mullards for it

[number41dl]

Awesome - since the preamp tubes are listed to be the main source of issues with the amp, replacing them will be a big boost when I get the new amp home.

For power tubes, I think I'll see how the amp sounds with new pre-amp tubes before giving that a shot (once I get the amp, of course).

[Adwex]

Just be careful when inserting the new ones. Make sure you don't bend the pins.

[erniewan]

i usually spray a little contact cleaner on the old tube once removed, then slide the old tube in and out (carefully like Adwex says) to clean off any oxidation from the socket.

I also spray a little contact cleaner on the new tube pins and wipe them down before inserting the new tube.

good luck !

[erniewan]

got this from the FAQ section at Eurotubes

Bob is great help there, lots of interesting reading. I get my tubes from him.


This next tip is the MOST important of all. Whether your amp is old or new you should always clean the tube sockets before installing new tubes and we HIGHLY recommend doing this! Failure to do this can and often will cause you to burn out tubes and here is why. The pins on tubes are all different just like a fingerprint so when you remove an old tube and replace it with another tube the pins will contact the socket collars in a slightly different location. Cleaning the sockets can easily be done by spraying electrical contact cleaner on the pins of one of your old tubes or preferably the new tubes, and working the tube in and out of each socket a few times. Do this for both preamp and power tubes. If you do not have any contact cleaner, then at the very least you should work each new tube in and out of it's socket a few times to help scrape in a decent connection.