Re Tube my Mesa Boogie 400+ ... Winged "C" 6L6?

Are you having a tube failure currently? What leads you to believe that you need to change the tubes? And why ALL the tubes? Often times you can just change the power tubes or just the preamp tubes, or even a single preamp tube if its causing you a problem.

 

As far as tubes strictly go, the Winged C is a good tube. The old RCA black plates are the best 6l6 I've ever heard and the Winged C is spose to cop that tone well.

As far as the Mesa 400+ goes, Im not sure how much of a difference the power tubes make in the tone of that amp. The only amps Ive played with 6l6s are a 60s Fender Bassman and an Ampeg B-15 and these amps definetly display the sonic qualities of vintage or similarly constructed tubes IME.

Have you considered the JJs? also a good sounding reliable tube in that amp at half the cost.

In regards to the pre amp tubes, if they haven't become microphonic, there should be no need to change them. With the amp on, tap on them with a pencil or something similar. You'll hear a tapping through the speakers, thats normal. If they make a bell like ringing sound, they're bad. And of course, if they dont light up they're bad.

 

If some of the power tubes have stopped working, it is time to have a tech check the amp out.

 

Is your 400+ modified so that you can adjust the bias? Kin of important when changing tubes. Have you actually had the ones in there tested, they might just have drifted a bit an just require a rebias.

 

It doesn't have automatic adjustment. They are fixed bias amps, which means the bias stays fixed where it is set, people confuse it with meaning self biasing, which is technically cathode bias, which gives less power. Mesa preset the bias rather than having it adjustable to oblige you to buy their valves.

 

Boogie tubes in the past have been rebranded Groove Tubes, Sovtek, etc.

I'd get the amp checked out first (and switched over so that a tech can actually adjust the bias). Then you can pick a good standard, yet not pricey set of power tubes, if you find that some of the tubes are bad or have drifted. It doesn't sound like you've got a reason to change preamp tubes, which probably saves you about 50-80$...unless you decide you want to get fancy with things.

 

If it sounds good, it is good, tubes wise, other stuff might be a bit unreliable, but dying tubes tend to make themselves known through bad sound first.

Matching isn't making sure they are all the same brand (although some matched sets from suppliers seem to be done under that criteria), they can be matched and different brands, it is electrical properties.

 

Tube matching is overrated. He probably doesn't know what 'matched' means either. Its only really an existing concept because valve tolerances went all to pot when valves weren't an important product any more. In the day Mullards were consistent enough just being Mullards meant they were close enough. Amps fussy enough that it might matter had adjustable bias for each valve. All mismatching will do will means that some valves are being stressed more than others, so some will fail while others are good, and your distortion might be asymmetric as one side clips differently to the other. Some people like the sound of that anyway.

With Mesa's non-adjsutable bias, it kind of matter more because you end up compromising a lot more than you would if you had adjustment, where you can balance the halves and adjust to suit (as in put the highest on one side, lowest on the other and balance them with the adjustment).

 

The original SED are good.
Tung-Sol of all people are finally making good power tubes. Their 6L6 are good glass.
TAD might be easy for you to get in Spain. Their 6L6, including the "short bottles", are as good as any modern day valve.
The "real" danger with un-matched tubes, especially in an amp like yours, is that tube life can be REAL short. With a single bias circuit for all the tubes, some can run real hot, and then real cold. If it is fairly extreme, some of the tubes will die an early death. When they are not matched, you can easily have one tube drawing 26 mA while another is drawing 39. When it swings during play you can get some tubes going way past saturation, and also way too close to cut-off. That is an extreme example of course, but for a small price, there is no reason not to buy matched power tubes. Have it biased and be happy for another year or two.
Best

 

I have SED Winged-C's in my guitar amp. They are nice sounding tubes. If anything, on the warm side. My deal with them is the price... I think JJ's are a little cheaper (go through Eurotubes to get a set that is matched for the 400+) and probably just as good.

 

Tung Sol are made by New Sensor, so they're out of the same factory and manufacturing equipment as Sovtek, Electro Harmonics, Mullard and Gold Lion. They have no relationship to the 'old' Tung Sol which were a US made tube.

 

I had a really bad failure rate with JJ KT-88's. Three failed tubes with less than 10 hours on them. That was a TOTAL waste of money. I have Winged C's in the amp now and they've been rock solid.

Paying anything at all for the JJ's was a total waste. Super awful tubes.

I've had good luck with their preamp tubes.

KO