Preamp Tubes Help

[tylersuehr7]

I think one of my preamp tubes went bad and I read that I need to replace all of them. In the Marshall amp I own, MA100h, it says that there are 4 Power Tubes and 3 Preamp Tubes, but I can only find 2 preamp tubes. Please excuse my ignorance, but the tube that I think is the 3rd preamp tube won't come out and I do not want to break it so could someone verify that this is the 3rd preamp tube, or verify all the preamp tube locations? I'll post a picture of my amp...
https://www.facebook.com/photo.php?fbid ... =1&theater

[surlybastard]

That link doesn't work unfortunately, if you want to post it somewhere else I'd be happy to take a look

[tylersuehr7]

Sorry about that and thanks! Here's the new link:
http://imgur.com/tcEWhIy

[Mike_LA]

Ok, which one is stuck?

The one labled #1 is still covered in the tube case. Gently push down and twist till the tabs line up with the holes and lift up.

Or is it #3 that is stuck?

[tylersuehr7]

The preampsl tubes label 1 & 2 are good, I took then out (i just put the case back on #1 though) and the third one is stuck. I didn't want to yank or pull at it because I didn't know if that was a preamp tube or not but it has (if it's visible in the pic) a different metal case on it though.

[washburn 1]

Hi Tyler
Dont know if you`ve sorted it yet but that 3rd tube is the phase inverter. Dont know why it is shrouded differently to the others but same design as my 50h. For some reason they are just that bit tighter than the others , you just need to give it an extra wiggle , carefully!! It will come. The short metal shroud is part of the chassis and stays in place. Hope that helps. What probs are with the amp?? Cheers, Kev.

[tylersuehr7]

Hey, thanks man! That really helps a lot, I didn't want to yank it out especially if it wasn't a preamp tube lol. And I blew out a preamp tube; whenever I would play it, it would make this rattling noise really loud and I read for hrs. on end about it and discovered it was preamp tubes, if they're blown out, that causes that noise. I should've just posted my question of what what wrong with it on here instead of hrs. of research! Lol

[Zube]

wait, you had a blown preamp tube and you was still able to play it ?

i believe there was a thread on here somewhere talking about tube rattle, but i thought it was with the combos, though i could be wrong. Ive never had that issue on mine, though i have a 50w Head with a cab.

In time with this amp, learning how to gently tweak it and also running a EQ with it, its a great amp for the money. I use the boosted channel for leads.
I put new tung sols in the pre amp, but kept the marshall branded PI tube in it. I like the tung sols cause they seem to brighten the amp up some and get rid of a bit of that dark sound.

[tylersuehr7]

Yeah I'm not too keen on some of the technical terms of the things but I think it was the preamp tube that was causing a rattling noise. I also had accidently left the amp on for around 4 days. It had 2 power tubes blown out and I had thought that was it but it had lost its original, Marshall, sound that it had when I first bought the amp and had a rattling noise and through reading a lot I just figured that it was a blown preamp tube because I had replaced the set of power tubes. But I ended up just buying a new head lol I'm playing a show soon and I didn't have time to attempt to fix, if I even could. But I do the same thing.... Run an EQ through it. I use the MXR 10-band EQ on the clean channel and run a MXR Distortion + as well