Tubes damaged?

[Unimatrix]

Hello everybody!

I just got the Strategy 400 poweramp that I bought from ebay a few days ago. The packaging was very good with air cushion pads and everything and didn't look damaged on the outside.

So happily I unpacked the monster and turned it on. Just to notice that one tube does not light up. I turned the power down and opened the case and saw that that particular tube (one of the four Mesa EL34/6CA7 STR440 tubes) was burnt out (looked like bulbs look when they die). I took it out and turned the power on again to check the other tubes. That's when I noticed that one of the eight Mesa 6L6 GC STR420 tubes is glowing stronger than the others, and while the others look orange this one glows almost red. So I went back to standby and then turned the power off again to avoid damaging anything. I'm not sure if that tube was glowing like that already the first time I turned the power on or if it happenend only after I took the damaged EL34 out.

Apart from that, of the eight 6L6 GC STR420 tubes, two are very loose (one of them is the red glowing one) and four are a bit loose.

Can somebody please tell me what's up with that? The seller stated that the tubes did not run for more than 30 hours in total. Yet one tube is completely burnt out (that cannot happen during shipping, can it?), one is glowing red and 5 others are loose. Or is that normal?

This is the first time I'm dealing with a tube amp, so I have no idea about the whole matter. I hope you can help me!

 

[Russ]

I would find it hard to believe that the 420's have less than 30 hours on them.

It is possible that the tubes and or sockets got beat up some in shipping. Sounds like you are redplating. It is also possible that the tube sockets may have been loosened slightly if the tubes were still in the sockets during shipping. Experiment: Put a stick between your buttcheeks and jump up and down. Chances are it will fall because your buttcheeks cannot hold it for very long. Same principle applies.

I would take your amp in for a once over by a tech. This is a good practice if you buy your amps used anyway. They can do things for you like tightening up your sockets or replacing them if necessary. They can also replace any of the electronics inside that might be failing or ready to go. A good cleaning of the pots and jacks is a nice touch to a tune up. Even if the seller claims that the amp is in good shape I still get a tune up, especially after shipping it. This is why I try not to buy amps that have to be shipped unless there is absolutely no other way around it, ie. discontinued models that are relatively rare. If I can, I try to hear my gear before I buy it and also give it a quick examination in person.

BTW try to troubleshoot your gear with a proper tube complement installed whenever possible. Sounds like you are just pulling tubes individually and trying to diagnose a problem. You might cause more damage than good if you don't have a full set of tubes in it while you are futzing around in there.

Another good idea is to retube an amp when you get it. Not everyone is perfectly honest about consumable things like tubes. If you replace the 420's keep the good ones as spares. You should be able to salvage at least a quad if not a pair to go with it. If they are all the same codes on the tubes then you should be able to use even the single as a spare to a pair or quad in an emergency. I would try to hold on to the 440's to as at least a pair also. A good retube might just fix your tube woes. I would still look into the loose socket issues though.

 

[Russ]

Welcome to the Board

 

[metal190]

"Put a stick between your buttcheeks and jump up and down... "


Russ is a knowledgable member, but I think I would disagree in this case.

 

[Unimatrix]

Hi Russ!

Thank you very much for your reply

First thing I'm going to do is to contact the seller about the burnt out tube. The other problems probably have to do with the shipping, then. I'll take the amp to my local tech as soon as I've talked to the seller. I'll be relieved if there's just a replacement tube and a tightening of the sockets needed. Let's see what the tech can do

BTW, is "redplating" the same as "overpowering"? I looked at the tube that I described as "glowing red" once more and the color is actually ok, it's just that the glow is much stronger than the one of the other tubes. Looks like it has to deal with much more power than the other tubes!

Thanks again

 

[Unimatrix]

"Put a stick between your buttcheeks and jump up and down... "


Russ is a knowledgable member, but I think I would disagree in this case.

Too late

:lol: :lol: :lol:

 

[Unimatrix]

The good news is that the seller is willing to replace the bad tubes!