My beloved Archon 50 is suddenly noisy

[jep1210]

I did a search of the forums but didn't find anything similar issues. The other day I was swapping tubes out of V1 and V4 in hopes of gaining a little more headroom on the clean channel when suddenly I started getting this annoying hiss with deep crackling sound that reminds me of rain hitting the roof. Its worse on the Lead Channel but is present on the Clean channel too but lower in volume. I've tried swapping all tubes with known good ones but there was no change. It does get louder if I raise the volume. It does this even with nothing plugged in So I know its not a cable, effect or guitar. I've tried other locations and outlets in the house but nothing changes it. Any suggestion on what else I can try?

 

[elvis]

Clean and tighten the tube socket pins.

 

[Black Plaid]

If it's not the tubes, my guess is you may have a capacitor that's gone bad. I'm afraid it's time for a trip to your local amp mechanic.

 

[Boogie]

Did you put the old tubes back in? It’s rare but Preamp tunes can come bad from the factory. Swap out tubes in the phase inverter, first, then the power tubes. I’ve had this before and it was the power tubes. Is reverb off?

 

[László]

You’re describing a classic symptom of a bad preamp tube, though there’s a small chance it’s a power tube. It’s very easy to find and replace a bad tube, and most Mesa manuals describe the way to do so in detail. You can download their manuals on their website.

 

[jep1210]

I've tried swapping every tube in the amp, and there is no change. I have 4 preamp tubes, two Tung-Sols, a Mullard and a Ruby that I believe to be good...they were bought new by me..and a matched set of Ruby 6L6 power tubes and swapping them in makes no difference in the noise. I may just start over and try all 4 of the preamps in all 6 positions I have as I kind of lost track and I'm not 100% sure I tried them all. I know stranger things have happened but I can't imagine all of my new tubes are bad, whats the chances of that? I'll look into the Mesa manual too. I'll keep you all posted.

 

[jep1210]

PS, what are the chances that 2 preamp tubes are bad and how do you even go about finding 2 bad tubes? Seems to me almost impossible to find the right combination.

 

[jep1210]

Ok, I tried swapping three of the four tubes I have into each of the 6 preamp sockets with absolutely no change...I think its safe to say its not a tube issue. I'll pick up a can of detoxit and try cleaning the pins when I get a chance but I'm really thinking its something more involved I may pull the chassis to see if theres a bad solder joint but after that I guess I'll have to drag a pro into the situation.

 

[László]

Odd, because you mention that the problem started when you were tube swapping. And the noise is typical of bad preamp tubes. Well, good luck with it! Is the amp under warranty?

 

[jep1210]

Odd, because you mention that the problem started when you were tube swapping. And the noise is typical of bad preamp tubes. Well, good luck with it! Is the amp under warranty?

No, the warranty is up. All the solder joints looked good, I cleaned the tube pins and it hasn't changed. Guess I need to have an amp guy look at it.

 

[elvis]

Did you clean all, or just the preamp sockets? Are the power tube pin sockets all tight?

Sorry it's still an issue. These things are the biggest frustration. I had a shiva at an amp tech for quite a while with weird volume jump issues. He was never able to duplicate. I got it back and eventually found that the FX return had bad solder joints. Fixed it no problem. But it was out of service for months. Luckily I am an amp junkie...

 

[HANGAR18]

I'm reminded of the tube tester that I keep ignoring every time I go to my local guitar shop to browse. As many amps as I have, I'm certain that one day I will need that tube tester. But as of yet, I have failed to bring it home with me.

 

[Deleted member 5962]

I'm reminded of the tube tester that I keep ignoring every time I go to my local guitar shop to browse. As many amps as I have, I'm certain that one day I will need that tube tester. But as of yet, I have failed to bring it home with me.

I came close more than once and never bought one. At one point I had 6 tube amps and was ready to go. Now that I'm down to two, I think I might slide by without one unless I find one cheap.

 

[László]

I'm reminded of the tube tester that I keep ignoring every time I go to my local guitar shop to browse. As many amps as I have, I'm certain that one day I will need that tube tester. But as of yet, I have failed to bring it home with me.

Same here, with only a few amps. It took getting the PRS amps to finally break down and get a multimeter after a zillion years of having amps, cables, etc.

If I’m at a store looking at a tube tester, invariably I’ll spot something to buy that makes noise, or records it.

 

[elvis]

Unfortunately tube testers tell very little about tubes. Just basic functionality.

 

[HANGAR18]

Same here, with only a few amps. It took getting the PRS amps to finally break down and get a multimeter after a zillion years of having amps, cables, etc.

If I’m at a store looking at a tube tester, invariably I’ll spot something to buy that makes noise, or records it.

You can test the integrity of tubs using a multi-meter? I've got a s***ton of those!

 

[László]

You can test the integrity of tubs using a multi-meter? I've got a s***ton of those!

No, I use the multimeter to bias the amps via their external bias jacks. Also good for testing cables.

And those two simple things comprise 100% of the things I actually know how to do with a multimeter.

I don’t think you can test tubes with one...

 

[jep1210]

You guys all rock. I love this forum, everyone is always very helpful.

So a bit of an update, I brought the amp to practice last night to let my bass player hear it and give his opinion as he's a bit of an electronics guru. He's going through some stuff though and I really didn't want to impose on him too much. I plug it in and I'm already to say "LISTEN TO THAT RACKET!!!!", and nothing. There's a bit of a hiss but nothing that can't be expected...or anything even objectionable....from the lead channel. This issue popped up initially at my girl's house. I tried a few different outlets in a few different rooms and it never got better. I rarely plug in at her house, so I never noticed before. Now I'm worried about the condition of the circuits at her place. Even as I type this from my place, I have the amp on and I'm getting little more than a hiss which I feel is normal and not objectionable at all.

Once again, thanks for all the suggestions, sorry to raise a false alarm.
Signed,
Relieved in NJ

P.S. The good news is the tube swap really worked, it gave me more head room...too much in fact. LOL I had put a Ruby 12AX7AC5 100/105 in V1 and a Tungsol 12AX7 100/105 in V4 (still don't really fully understand those numbers to know ahead of time how they'll effect the sound and which way to go) and it really took away the growl and warmth I was getting from my OD pedal on the clean channel with the stock tubes. Unfortunately I didn't want to use up too much practice time swapping tubes so I couldn't try any other combinations and unfortunately my ears can really only hear a difference in a band mix. I popped the original tubes back in this morning and may play around with different combinations down the road.

 

[László]

So glad it worked out for you!

 

[HANGAR18]

You guys all rock. I love this forum, everyone is always very helpful.

So a bit of an update, I brought the amp to practice last night to let my bass player hear it and give his opinion as he's a bit of an electronics guru. He's going through some stuff though and I really didn't want to impose on him too much. I plug it in and I'm already to say "LISTEN TO THAT RACKET!!!!", and nothing. There's a bit of a hiss but nothing that can't be expected...or anything even objectionable....from the lead channel. This issue popped up initially at my girl's house. I tried a few different outlets in a few different rooms and it never got better. I rarely plug in at her house, so I never noticed before. Now I'm worried about the condition of the circuits at her place. Even as I type this from my place, I have the amp on and I'm getting little more than a hiss which I feel is normal and not objectionable at all.

That raises a good point. City power (any city power) is never going to be a consistent thing. It fluctuates according to local power station policies and current demand at any given moment. Every tube amp on the planet would benefit from one of those power conditioner boxes. (I forget what they are called.) Uninterruptible Power Supply's (UPS devices) for computers and stuff do the same thing too. With these power conditioner boxes, you dial in exactly what voltage you want and they maintain the correct voltage regardless of what the city power is giving you.

What the heck is the name of those things?