How do you open a Hartke TX600 head to replace the tube?

A failing preamp tube (which is unlikely) has absolutely nothing to do with your friend's use of your amp.

There should be information in the owner's manual of access to the tube is "tricky".

 

Here's the manual: http://www.samsontech.com/site_media/support/manuals/TX600_OM_5L_V2.1.pdf

It says: "Expensive shipping is cheaper than a failed DIY repair, trust us. Heed the steed."

 

My gut reaction is that if you have to ask how to take the chassis apart, you don't need to be doing it. Heed the sage advice already given.

 

Since we have no idea where you are located, it's tough to make useful suggestions.

Your initial problem in not likely due to the tube. You need to identify the cause of the problem before assuming a solution. This generally takes some knowledge of electronics, safety procedures as well as some test equipment.

Do you have any of this?

 

I would take take the screws(Phillips Head) out of the top. The tube should be in the left front Quadrant.

 

Since you don't see any value in useful information, and you are completely broke, additional valuable information that you might not see any value in would be to leave your "valve" alone, if it's not broken then don't fix it. It's not going to change the ability to overdrive your amp as there's not enough gain in the circuit to do so with a typical bass.

A better and more valuable and useful suggestion would be to look at an overdrive pedal, which would be MUCH more effective than wasting money you don't have on a solution that won't do as you hope.

If all you are asking for is a confirmation and stroking of your poor idea, just disregard everything I have suggested as clearly "I don't know what I'm talking about"...

Being in the UK doesn't mean there's no qualified techs that could (properly) troubleshoot your original problem (to see if there's really a problem first) and then suggest a solution that will work. Good techs don't work for free of course.

 

This +1000!

 

Probably won't influence that amp all that much, but it very well could be a tube that's hissy, and if you have a spare around, it's worth it to try it IMHO and it won't hurt the amp to do it. Should just have to take out the top screws, lift the lid, pop the old tube out, pop the new one in. Just don't have it plugged in while you open it up and don't touch anything else but the tube.

 

You do not have a tube amp.

 

That is true. He has a hybrid.

 

They don't. Some amps use the tube fully, some amps use them in what's called a "starved plate" functionality, which increases tube life and does give you some tube vibe, but it cuts down a bit on the tubiness and you won't hear much change when you swap out different tubes. But I absolutely have had amps that were buzzing because of a bad tube, and it's the easiest thing to try and always the first thing I suspect when an amp with a tube goes haywire. At worst, you'll have to send it off if the new tube doesn't clear it up, so I think it's worth a shot.

 

I had a store owner tell me that Hartke amps are notoriously harder too work on than they should be. I had a lead sled Hartke amp head that had one bad input Jack. He wasn't interested in trading for it because the repair cost even for just a Jack on that and would make it cost more than he could make.
I would up replacing it myself, but it was a lot of screws and bits to remove just to replace a jack.
It wasn't a Tx600 so I can't tell you exactly what to do, but I can witness in your defense of puzzling repairs on a Hartke.

 

I'm not sure about them either, but I've heard from others that they don't notice much change at all from tube swaps in Hartke amps. Don't know if that means starved plate or some other type of design that makes tube changes more consistent, but that's what I hear from folks.