The Great Tube Replacement Adventure!

[amiller]

So, I corresponded with the company that sold me the tubes but did not meet the Next Day delivery agreement. They were nice enough to refund some of the shipping charge...a fair enough deal since the tubes did arrive today.

BUT, I went home for lunch to try out the new tubes. I took out the old tubes, put in the new tubes, turned the amp on and flipped the standby switch. I heard a very brief hum and BAM!!! the amp blew a fuse.

This really sucks. I am very disappointed in this company to say the least. I hope the damage is only a spent fuse. I'll change the fuse and put the old tubes back in for now. I sent the company in question an email explaining what happened and asking them to make this right. ...waiting for a response.

 

[just42dave]

who was it ????

 

[amiller]

who was it ????

I don't want to say just yet. I want to give the company a chance to make this right. If they do I'll commend them. If they don't....

 

[Skrln]

I took out the old tubes, put in the new tubes, turned the amp on and flipped the standby switch.

You didn't bias first?

 

[Kevin11]

I didn't read your other topic so I apologize if you already covered this.

Does your amp have an adjustable bias? Did you roll the bias down before you installed the new tubes and took it off standby?

I'm wondering if the bias was fine for your old set, but way too hot for your new. That hum is exactly what you'll hear if your tubes are running too hot. Sounds like you lost at least one tube, which took your fuse with it.

Sorry to hear regardless...keep us posted.

 

[amiller]

This is a Mesa Boogie Lonestar. It is a non-adjustable bias amp.

 

[Kevin11]

Couple of things...

With Mesa's fixed bias design, they want you to stick with Mesa tubes because they're pre-rated and matched to work in their amps. If you know what the rating values are, you could get them from a non-Mesa source, but they need to fall within Mesa's rating parameters. If you picked up a set without specifying the rating, it's possible the set you got is out of range. It's been a long time since I owned a Mesa, so I may be on crack about this.

Also if you're switching from 6L6 to 6V6 in the Lonestar (I'm guessing your're not, but just in case), the AC power switch has to be on Low and the Bias switch kept at 6L6. They also want you to run an 8 ohm speaker on the 4 ohm jack.

 

[amiller]

Couple of things...

With Mesa's fixed bias design, they want you to stick with Mesa tubes because they're pre-rated and matched to work in their amps. If you know what the rating values are, you could get them from a non-Mesa source, but they need to fall within Mesa's rating parameters. If you picked up a set without specifying the rating, it's possible the set you got is out of range. It's been a long time since I owned a Mesa, so I may be on crack about this.

Also if you're switching from 6L6 to 6V6 in the Lonestar (I'm guessing your're not, but just in case), the AC power switch has to be on Low and the Bias switch kept at 6L6. They also want you to run an 8 ohm speaker on the 4 ohm jack.

Yes, very good points. The company I bought them from has a website that lets you shop by amp make and model. I selected Mesa Boogie -> Lonestar -> 6L6 from their website. These are the tubes this company has matched up to work in a Mesa Boogie Lonestar.

 

[just42dave]

bastards!!

 

[amiller]

The tube company gives me instructions on how to trouble shoot which tube is bad. Here are the steps:

First, replace the blown fuse and then do the following:
1) With the amp off put in just the two center power tubes.
2) Turn the power on but do not take the amp off of standby.
3) If the amp starts to hum shut it off immediately and replace one of the inner tubes.
4) Repeat step three. If the amp hums it's most likely the tube left in. If not it's the tube you took out.

Anyway, you get idea.

So, I conducted the test as suggested. Guess what...the amp did not hum once no matter which tubes were in it. I finally put all four of the new tubes back in and the amp did not hum at all. I flipped it off stand by and everything works fine.

I don't get it.

 

[rlord1974]

I don't get it.

You don't?! What about the rest of us?!



J/K. Glad it worked out in the end!

 

[JTyson]

The tube company gives me instructions on how to trouble shoot which tube is bad. Here are the steps:

First, replace the blown fuse and then do the following:
1) With the amp off put in just the two center power tubes.
2) Turn the power on but do not take the amp off of standby.
3) If the amp starts to hum shut it off immediately and replace one of the inner tubes.
4) Repeat step three. If the amp hums it's most likely the tube left in. If not it's the tube you took out.

Anyway, you get idea.

So, I conducted the test as suggested. Guess what...the amp did not hum once no matter which tubes were in it. I finally put all four of the new tubes back in and the amp did not hum at all. I flipped it off stand by and everything works fine.

I don't get it.

I do....
The racoon has made it back into this life as an output tube...
just sayin

 

[amiller]

The tube company gives me instructions on how to trouble shoot which tube is bad. Here are the steps:

First, replace the blown fuse and then do the following:
1) With the amp off put in just the two center power tubes.
2) Turn the power on but do not take the amp off of standby.
3) If the amp starts to hum shut it off immediately and replace one of the inner tubes.
4) Repeat step three. If the amp hums it's most likely the tube left in. If not it's the tube you took out.

Anyway, you get idea.

So, I conducted the test as suggested. Guess what...the amp did not hum once no matter which tubes were in it. I finally put all four of the new tubes back in and the amp did not hum at all. I flipped it off stand by and everything works fine.

I don't get it.

I do....
The racoon has made it back into this life as an output tube...
just sayin

Man, I think you're right! This story just gets crazier. FedEx tried to deliver a second set of tubes (preamp tubes I ordered from Sweetwater) to the wrong address today. FedEx closes at 8:00. I left the house at 7:50, rushed to FedEx and just made it into the building before closing. They asked me for the tracking number...I forgot it. But, I was able to look it up on my iPhone. I gave them the tracking number and the said "Oh, that's the ground division not us." I'm like, you got to be freaking kidding. Anyway, they gave me the 1-800 number for FedEx ground customer service. I called them and they said the tried to deliver the package at 5:30 to day. I was here at 5:30. In fact, I was outside sitting in a chair waiting for FedEx to show up. I told them they must have tried to deliver it a business across town that has the same address as mine only N. instead of S. They argued...but, they will deliver it tomorrow to the correct address...I HOPE!

Yeah, I think I'd rather be dealing with the raccoons right about now...NOT!

 

[amiller]

OK, just to finish this thing up. The new preamp tubes from Sweetwater did show up today...FedEx botched the original delivery date. The pres sound great!

The new power tubes that were in when the amp blew a fuse have been running fine since I replaced the fuse...go figure.

I decided to run the "power tube" test on the old tubes just to see if I could isolate the bad tube. Sure enough, the test worked like a charm and lead me right to the bad tube. I'll throw it away and keep the rest of the old tubes around for spares.

I am a bit nervous that the new power tubes seemed to have blow the fuse. It may be that the old bad tube weakened the fuse...

Anyway, the amp is sounding great with all new tubes! So, I guess all's well that ends well...I hope.

 

[threadkiller]

Tubes do weird shit when you are switching them out. I won't go into my story and convoluted tale. Let's just say....f*cking gremlins inhabit my amps and if I mess with the tubes, I get them stirred up.

 

[glip22]

Tubes do weird shit when you are switching them out. I won't go into my story and convoluted tale. Let's just say....f*cking gremlins inhabit my amps and if I mess with the tubes, I get them stirred up.

I have had Gremlins as well. And not just one amp. Multiple amps. No fun. Luckily they have left me alone for a while now.

 

[Ventura]

Kirk Hammett.

 

[Anonymous]

One thing to consider. If one of the tubes blew a screen resistor that would take out a fuse. But then after the screen resistor is blown, the amp will work fine since that tube socket is not getting screen voltage to the tube therefore it is not working. One way to check is to see if one or more of the tubes are "cold" not hot like the others. It will still light up due to the heaters.

Just something to check. Many amps have blown screen resistors and guys don't even know it.

This ^^^^^^^^^

 

[Burn]

Which tubes did you get? The NOS 6L6WGBs sound absolutely heavenly in my Lonestar.

 

[amiller]

Which tubes did you get? The NOS 6L6WGBs sound absolutely heavenly in my Lonestar.

I got the Tung-sol 6L6GC-STR tubes. The NOS 6l6WGB tubes are a little $$$ for my blood...I may have to try them some day when I get some "extra" cash.