Tube Replacement Time

sacto68

So last Friday while playing a show my amp (Blues DeVille original) dies. I got it home, pulled the fuse & sure enough if was blown. Normally I would just replace it & be done with it. But I've been reading online that there is a reason for the fuse to blow. Normally either a power surge of the power tubes are going out. Well there wasn't a power surge that evening. So I'm putting my money on the tubes. Besides I don't think that they've been replaced in a long time. I've had the amp for about two years now. The guy I bought it from didn't say the last time the tubes were replaced. We use it frequently at practice (once a week for about 3-4 hours), and on every gig (1-2 a month since Jan.). Does this sound like a good candidate for a tube swap?

I was also curious if anyone here has used these tubes.. Winged C (SED) 6L6GC http://thetubestore.com/6l6gc.html & Tungsol 12AX7 http://thetubestore.com/tungsol12ax7.html. From everything that I've read they are great sounding tubes.

This will be my first attempt at changing tubes. I've checked & the amps bias is nonadjustable. So they should just pull out right? Any advice on that end?

And one last thing.. I've been looking at getting a road case for the amp with all the traveling it does. Besides helping the tweed stay in good shape would it help prolong the life of the tubes at all?

DewieCox

What a coinicidence. I've goin through the same with my Marshall. I was told blow one fuse, replace it. Blow a 2nd fuse, start checkin for other problems, starting with the tubes. I plan on poppin some JJ's in the power section, but not sure on the preamp tubes.

I had some Winged C el34s before and thought they were solid tubes. I say give those 6l6s a try. Hopefully some one has used them and can give you a hands on review

When you go to change them just wiggle the tube back and forth gently and it should come out pretty easy.

I would say a case would protect the tubes to a certain extent, but I dunno if they'd actual lengthen their life. A case is definitely gonna help out with all the travel the amp is doin.

All Those Yesterdays

I've had issues with Tung Sol Pre amp tubes going microphonic quickly. I have used these before with some success. http://thetubestore.com/svetlana12ax7.html

Depending on my mood I do tend to put these in the drive channel http://thetubestore.com/sylvania5751.html in lieu of a 12ax7. They have less gain, which I like.

These http://thetubestore.com/tad7025s.html will be my next adventure on my bass head, which beats the crap out of 12ax7's

On the 6L6 front, I have zero experience. I'm a 6v6 and EL34 fan myself and have never owned a amp with 6L6's.

On the installation front I ten to use a towel to handle new tubes instead of my hands. I don't want to get any oils on the tubes. It's probably just a anal thing of mine.

From what I read Fender runs the Blues Junior Tubes extremely hot.

PS I believe MIG is the Grand Poobah of 6L6's on the board.

mccreadyisgod

All Those Yesterdays wrote:

PS I believe MIG is the Grand Poobah of 6L6's on the board.

Close, but not quite. I'm the Grand Poobah of Russian 5881's. Same tube family, different tone altogether. A 5881 is to a 6L6GC as a Celestion Greenback is to a Vintage 30. One is down and dirty, lower wattage, great breakup; the other is nice, glassy clean. And when you're dropping them into Sovtek amps, they gotta be dirty and Russian.

My other amps both run 6V6 tubes (Vibro Champ and Deluxe Reverb), so I guess I'm no great help on the 6L6 front. Sounds to me like the OP is chasing a bit of the purple tolex here... trying to take the Fender outta the Blues DeVille.

After two years of the kind of use you've described, it almost certainly needs a set of tubes. I hate to make any statement on that fixing your fuse-blowing issue, but I guess you gotta start somewhere. But a trip to the amp doctor for a checkup might still be in order. Especially if you plan to drop around $150 on new tubes.

Are you trying to change the tone of the amp in any way compared to the stock tone? Has it exhibited any weird tonal issues, cutting out, sagging volume, etc? Do you run an extension cab with the amp? How hot do you run it (where from 1-12 is the amp set)? Do you use the overdrive channel on the amp much?

Last thing: definitely handle brand-new tubes with some sort of cloth (gloves, towel, t-shirt, pair of women's panties) so as to avoid getting skin oil on the tubes. Any sort of grease on the glass of a tube can get super-heated, and potentially cause the glass to crack.

sacto68

No. I'm not trying to change the tone of the amp I love it actually. The tubes that I posted were just some that I came across that others have liked. I took a closer look at the tubes & they have been replaced at some point. I have EH 6L6EH for the power tubes. Then I have two JJ ECC83s, & one Fender 12AX7WA in the center.

We usually run it anywhere from 1.5 (we mic it & use headphone monitors for practice) to 4 (it's a loud amp, one thing I would change). It's almost always on the clean channel with different effect running through it (distortion included). It's just running into the stock 4-10 speakers within the amp itself. And no change in tone or volume up until it blew the fuse. Then of course nothing

I just looked at the original manual for the amp & is says it actually uses the 5881's for the power.

This is my 1st tube amp so this is all a learning experience for me.

sacto68

I also took the back off the amp to look at the board & nothing looked discolored or burnt.

mccreadyisgod

Well, for 5881's, I know that Tung-Sol makes a pretty killer version, but I always use Sovtek, as I think they have a rounder sound than the Tung-Sols. Also, the Tung-Sol is a lower-wattage 5881 (itself a lower-watt tube than the 6L6GT). Tubestore has some warning about using it with a solid-state recto like the Blues DeVille has... then again, if it was designed for 5881s to begin with, it shouldn't be a problem, unless the bias was adjusted for 6L6s.

Regardless, the Sovtek would give you a bit more headroom, and it's definitely closer to what Fender shipped the amp with in the first place (if not the exact tube itself). The Sovtek is also very pedal-friendly, as I can attest (I don't even have an overdrive channel, and I have a 10-pedal board [well, 12, but one is passive and one is parallel, so 10 active pedals in-line]).

As for preamp tubes, get a half-dozen and play around with them. You can go simple on the phase inverter, and then just play around with the two preamp tubes to see what you like. An old-school 7025 will give you tweedy Fender tones (might be good in the OD channel), whereas a 5751 can give you a lower-gain sound, good for a clean channel. A regular 12AX7 like an Electro-Harmonix will give you the amp stock, and JJ is a great brand for a 12AX7, or as the Brits call them, ECC83s. Svetlana, Mullard, Tung-Sol... really, buy a few and swap them out. You really don't need to even worry about bias on preamp tubes, so you can swap them at will to see what you like (just remember to use gloves/cloth when handling them).

One last point: I'd still generally recommend having amps tuned by a competent tech once in a while. Your amp is fixed-bias, but the bias is still adjustable, and it would be a good idea to check it out (especially if it's manufactured for one kind of power tube, but has another kind of power tube in it; what is the bias set for?). It would also be nice if a qualified tech could check over solder joints and other problem areas to make sure there isn't any intermittent electrical connections, which is what I would worry about after blowing a fuse. I probably have some preconceptions here, since a friend of mine purchased a brand-new Hot Rod Deluxe, only to discover that it had three cold solder joints that were intermittent, causing some pretty hairy problems. Thankfully fixed under warranty, but still.

sacto68

Thank you for the advise. I'll call some of the repair shops in the area & see what they have to say. Any idea on what to expect as far as cost would be for someone to take a look at it?

mccreadyisgod

I'd plan on $50-100, unless something is seriously wrong. I'd order the new tubes and bring those in to the tech to replace, so bias can be checked/set properly. You may check with the tech first, they might be able to get the tubes for the same price or cheaper, and it puts a little cash in their pocket, which puts you on their good side. If they can't get the tubes you want, then just order from the Tube Store.

But once it's been checked over, the amp should be good for a while so long as you stick with the same tubes and don't have problems. It's a good idea to have an amp looked at once every 2nd or 3rd power-tube swap, just to check bias and make sure the caps are in good shape, solder looks good, etc.

This all vaguely reminds me of the first time I ever took an amp into a tech for service... Fender Stage 100 (solid-state combo) went dead during a cigarette break in the middle of practice. No lights, no sound, nothing. Slight smell. Turns out my drummer took my speaker cable I was using for my extension cab, and used it to plug in his monitor wedge. He replaced my speaker cable with a Radio Shack coiled instrument cable. The tech took it all apart, and everything inside the amp was fried, EXCEPT for the fuse. Goddamn transistor Fender amps. I took the amp chassis out of the cab, wired in a 1/4" jack, and used it as just a speaker cab for the next year... with a Peavey 4-channel PA head from the late 70's. Ugh.

All Those Yesterdays

mccreadyisgod wrote:

All Those Yesterdays wrote:

PS I believe MIG is the Grand Poobah of 6L6's on the board.

Sorry MIG. I'm the first to admit my memory is doo doo anymore.

sacto68

I just dropped off my amp at the shop. Having him look it over & make sure everything is up to par. I'll let you know the outcome when I get it back sometime next week. Thanks again for the help.

mccreadyisgod

Keep us posted... now I'm curious.

sacto68

Well two and a half months later and I have my amp back from the shop. It sounds so good now. The repair guy said there was a bad cap that would act up when it got hot. As well as a part in the preamp chain was bad. He benched tested it for two weeks making sure it wasn't going to cut out anymore. No tubes were needed.

I'm just very happy to have my amp back. Thank you everyone for your help. I would of just replaced the tubes for no reason.