LSS displaying some peculiarities....

[Jared Purdy]

Not sure where to begin. Okay, last week, amp was making some crackling sound (I forget which channel), and then the rectifier tube went (I called the place where I bought it, and they suggested it might be the rectifier tube, try that first, and then look at the power tubes). Went to the local shop, while they don't carry boogie tubes, they had a Sovtek, so I brought that home, fired up the amp, and we're in business. The next day I went to another store that had Boogie rectifier tubes for the LSS, bought one, went home and plugged it in. All's good. So far. Played off and on for the next couple of days, then same thing, crackling. I turned the amp off, consulted the manual. Several things were mentioned, faulty power tube, possible rectifier tube, it also said to watch out for miniature lightening storms in the rectifier and other tubes. So I flipped the amp around, turned on the power supply, and shazzam! Lightening in a bottle! In the rectifier tube. That's the 2nd Boogie tube, and a new one to boot. Before I had a chance to shut it off the fuse blew. ****! So, off to The Source, picked up the right fuse, got home installed new, and everything is okay. Today, as I'm playing away, experimenting with the different wattage settings, I had it on the 30 watt setting, and start to hear crackling again. Blew another fuse. Put in one more, blew it too.

So, I called Boogie. As useless at tits on a bull. So I called the repair palce at Steve's Music (where I bought it). Matt had some interesting ideas. As he can't see it until Monday, he suggested this: go buy more fuses, before I install one, remove the power and rectifier tubes, then install the fuse and turn on the amp, in standby. If the fuse doesn't blow, that narrows things down a bit. He then said, to turn the power off and put the spare set of new Boogie power tubes that I have in it. And install the Boogie rectifier. So I did all of that, and within about 3 seconds, there was a lightening storm in the rectifier again. I turned it off immediately, and put the Sovtek recitifier tube in. Still working. What gives? Any ideas? Anyone else have similar issues?

 

[screamingdaisy]

I've never had issues with a rectifier tube before, however the obvious solution is to leave the Sovtek tube in it.

That said, since that amp is new the tubes should be warrantied for 6 months.

 

[Jared Purdy]

I've never had issues with a rectifier tube before, however the obvious solution is to leave the Sovtek tube in it.

That said, since that amp is new the tubes should be warrantied for 6 months.

Hey Daisy,

Yes they are. And I've never had problems with a rectifier tube before either. Hmm. I did a little experiment: I took the Sovtek out and put the Boogie back in. Lightening storm, blown fuse immediately. I wasn't even quick enough to turn the power off. Took the Boogie tube out, put the Sovtek back in, no problems. The plate formation in these respective tubes is totally different. The Boogie tube has two thick vertical plates (about 3mm thick and over 1cm wide, and as high as the glass, sandwhiched between a plate on the bottom and one on the top). If you shake it, nothing moves. The Sovtek tube has several much thinner vertical plates, and when you shake the tube there is a bit of rattle (which also happens to come threw in the amp (not threw the speaker) when it is picked a little harder. I'm wondering if it might be a circuit issue with the rectifier. I mean these guys built it. They're using the same tubes in all of these LSS amps, how many others have had this problem???

 

[screamingdaisy]

Is the serial number of your amp above 4400 (or so)?

 

[Jared Purdy]

Is the serial number of your amp above 4400 (or so)?

Where is the serial number located? There is a sticker located on the chassis. It says Mesa Boogie LS-005601

 

[screamingdaisy]

Is the serial number of your amp above 4400 (or so)?

Where is the serial number located? There is a sticker located on the chassis. It says Mesa Boogie LS-005601

That's it.

I've read that early LSS' had issues with the rectifiers blowing, but they made a modification somewhere around SN 4400 (I forget the exact number).

One possible answer is that your amp has some dirt or corrosion in the tube socket and the pins of the Mesa tube aren't making contact correctly. I've had that issue with power tubes before and in those it lead to instant red-plating (metal plates inside the tube glow like the inside of a toaster). I have no idea what bad connection would cause with a rectifier tube.

 

[Jared Purdy]

Is the serial number of your amp above 4400 (or so)?

Where is the serial number located? There is a sticker located on the chassis. It says Mesa Boogie LS-005601

That's it.

I've read that early LSS' had issues with the rectifiers blowing, but they made a modification somewhere around SN 4400 (I forget the exact number).

One possible answer is that your amp has some dirt or corrosion in the tube socket and the pins of the Mesa tube aren't making contact correctly. I've had that issue with power tubes before and in those it lead to instant red-plating (metal plates inside the tube glow like the inside of a toaster). I have no idea what bad connection would cause with a rectifier tube.

Thanks. I'm going to take it in on Monday (when the tech is back), providing it lasts that long!