Tube Amplifiers

[Jim Dickinson]

Amen Joel,

To each his own, some like this, some like that. You will find every amp/speaker combination sounds different, another identical one will sound different- maybe the tubes are going a bit flat, the speaker was rebuilt with aftermarket junk parts, the magnet in the speaker is going away, the list is endless. I have always liked the Lansing speakers, Altec and JBL, different yes, but both made very well. I have had more experience with the Altecs, and there were variant differences in each model. The 10" Altec 425 was one of the hotest speakers I have ever heard, huge magnet, small cone, a real ear nipper. The 417A, B and H 12" ich models are bright, fast and dynamic- listen to Carlos Santana?- those are 417s. The 417-8LF was smoother and less zingy, the 418A, B, H 15" were great steel and Jazz speakers, the 8LF was smoother and not as bright, the 15" Altecs like an enclosed cabinet way better than an open back one. The JBL D120 is not as fast as the 417, but still real nice and bright, the K 120s a bit slower than the Ds- heavier voice coil mass, same for the 130s. I have not really had too much experience with the EV ferrite magnet guitar speakers. From what I see of way they are made, they are not built a great deal different than the Eminences, remember Eminence makes all kind of things on custom order, the sound quality varies greatly as per customer . The Lansing types have way better machining. I will say that the new aluminum frame Neo Eminences are beautifully built, as good as anything made elsewhere, from an engineer's perspective. You have to play what you like.

As for tubes, we found the last of the American made tubes got pretty bad. The companies were not maintaining their equipment, a guy from RCA even admitted it to my dad. If one can find NOS grade 1 or 2 tubes you might have something, other than that I think the better of the Former Soviet Union (FSU) tubes may be better. My opinion. Jim

[Donny Hinson]

Dave Mudgett, Your comment about NOS 6L6 tubes being essential IS a misconception. The best tubes being produced today are coming from Russia and Eastern europe. I do not believe there are any US Tube manufacturers any more.

No, there aren't any 6L6's being made in this country. Most of the U.S. manufacturers sold or scrapped all their machinery in the '70s. Russia bought a lot of it, the rest was just scrapped. However, most all tubes (even the best tubes made nowadays in foreign countries) would have been shoveled into the crusher by RCA years ago. The quality, both in labor and materials, just isn't there because when the militaries did away with using tube equipment, there was no longer any reason to keep exacting standards in place. Clean power demands excellent tubes, and (IMHO) nothing matches the NOS tubes for that. However, lead players (who often prefer "grit", "hair", "warmth", "fuzz", "bite", "overdrive", or other distorted qualities) may be perfectly happy with today's foriegn offerings. (Many players will pay a grand or more for a tube amp, and then balk at paying $50-$60 for a pair of tubes. Ridiculous logic, when you think about it - sorta like putting cheap gas in a Ferrari.)

These tubes come in matched pairs so biasing is almost unnecessary.

That's only true if the amp is well maintained. If the bias is off in an amp (from age - neglect), matched tubes won't fix it. Overall biasing is far more important than matching pairs of tubes.

[Bill Duncan]

Donnie,
Does this mean that Fender and Musician's Friend are lying when they advertise made in the US tubes?

Here is a direct quote from Musicians Friend's website.

The '57 Twin-Amp gets its power from a pair of USA-made GT6L6-GE output tubes. The power supply includes Fender's rarely seen '50s dual rectifier arrangement, which uses two - 5U4 rectifier tubes. With this design, power amp compression, or sag, is more subtle than it is in many Fender Tweed designs. The preamp contains four high-gain 12AX7 tubes, three of which may be substituted with 12AY7s for the original '50s low-gain sound, if desired. There's also an internal bias pot that allows easy substitution of various 6L6 tube types.

[Dave Mudgett]

Does this mean that Fender and Musician's Friend are lying when they advertise made in the US tubes?

I guess it depends on what one means by "is US-made" - there seems, to me, to be quite a wide latitude permitted in advertising "US-made" these days.

Here's Elderly Instruments' description of these tubes:

GROOVE TUBES GT-6L6-GE MATCHED POWER TUBE DUET

A faithful reproduction of the original General Electric "clear top" tube made on the original GE machines and with many original materials. 95% USA components. Available in a 1-10 hardness rating. Tubes in stock may vary and some ratings may be special order only.

Note that they do not say "USA-made", but made with "95% USA components." I find Elderly to be very straight-up in its descriptions, and if they thought they were fully "USA-made", they'd say so. Did you read the other links I put up in my last post?

As I said earlier - somebody show me evidence that there's a US factory actually assembling these things to the standard of the old tubes made during the golden era of tubes. Till then, I'm sticking with my NOS tubes for these high-performance old tube amps. A lot of current tube amp manufacture drops the plate voltages to fit within the capabilities of modern tubes. Smart move, IMO.

These tubes come in matched pairs so biasing is almost unnecessary.

Matched tubes do not guarantee a proper bias. For fixed-bias amps - one should always check and, if needed, adjust the bias when changing tubes. Beware of marketing hype. IMHO.

[Jim Sliff]

Bill - they are not "lying" - they are just repeating what the manufacturer, Groove Tubes, says in their literature.

The truth of the matter is the tubes qualify as "made in U.S.A. because a certain percentage of the components in the tube (and it only has to be a low amount - 10-20% or something) are made in the US.

The tubes themselves are built in China, and the rest of the components are Chinese. I've had long discussion with folks on the "inside" - and there are really mixed feelings about the "made in the U.S.A. claim.

FWIW I've had two pairs of them, and both drifted off so badly the bias differed by around 7uf within a month. As far as I'm concerned, they are the same crappy Chinese tubes GT has always sold. GT is a marketing machine - hats off to 'em as Aspen knows what he's doing.

But I will say this - I used to run a small amp and guitar tech shop part-time out of my garage. I refused to install Groove Tubes and to this day do not own any, as the value, IMO, just isn't there.

For new production I stick with JJ's, or even EH in some cases.

[Bill Duncan]

I know there is definitely sales hype going on. I know nothing about tubes other than what little I learned in class years ago in the Dark Ages. I just noticed the claims and thought I'd ask.

I do plan to learn more about tubes when it comes to tone. I am searching for an amp. I am gonna do some "sippin,swappin,pickin, and tradin". I am going through my trade goods to see what I can spare. My main guitar pickin friend has the word out, and his eyes open. Did I mention he's blind? He is. But he sure can sniff out a bargain.

[Bernie Hedges]

Dave Mudgett, I understand what NOS tubes are and by definition of course they are not being produced today. But one day there will be no more. If you can find them , and afford them, great. However the JJ tubes are fantastic tubes and are only 35$ for a matched pair of 6L6's. To me it's not worth searching for and paying the premium for NOS when there are alternatives that sound just as good. When talking about tone, It's all opinion and you are certainly entitled to yours. In fact I'll help you out. For every pair of NOS tubes that I don't buy there are some available for you and other NOS diehards. When they run out, try the JJ's.

[Dave Mudgett]

When talking about tone, It's all opinion and you are certainly entitled to yours.

My point was not mainly about "tone", but reliability and the ability to handle the beyond-design-center circuit design of many of these old amps like the Fender Deluxe Reverb (6V6), some of the other blackface/silverface 6L6 Fender amps, some of the old Music Man amps, and no doubt some others.

If you can find them , and afford them, great.

Good examples of NOS power tubes like the 6L6 and 6V6 are definitely getting more scarce and expensive, as are clean, original examples of the vintage amps that want them. The very best examples of popular power tubes are very pricey indeed. But there's no essential problem finding good NOS tubes. In fact, there are still some affordable but (IMO) still good quality ones out there. The example I used was the NOS Phillips-Sylvania 6L6WGB, which I can still find for the same $60/pair as the Chinese-made 6L6GE we were discussing above. Same with some NOS Phillips-Sylvania 6V6 tubes. One has a choice - stock up while they're still available or wait till they go up even more or even become essentially "unobtainium". Just like with these vintage amps, it sort of requires an investment mentality - but these amps and the power tubes that - IMO - properly power them are now collector items. YMMV, and that's fine by me.

As I said earlier, we should all use whatever tubes we want to. I think some of the new power tubes are OK in an amp that doesn't stress them the way those old high plate-voltage amps do. But vis a vis these beyond-design-center vintage amps, a blanket statement that "NOS 6L6 tubes [are] essential IS a misconception" should not go unchallenged, IMHO.

[Bill A. Moore]

A month or so back, one of my customers was commenting on the speaker box I have in the front shop here, and I told him it was part of my Twin project. He told me he had a few tubes, so I told him the preamp #'s I need. A couple of days later he brought me 2 12AX7's, 2 12AX7A's, and 2 12AT7's, all RCA and Sylvania. The RCA boxes have 9 60 on the flap. He wouldn't give me a price, so I gave him $50, and he thought it was too much, but I made him take it. Said he had bought a tester, and tubes, to fix his TV back in the day. You just never know, Bill.

[Joe Shelby]

Dave M,
Are the Sylvania 6L6WGB's a good choice for a 135W Twin? I know it runs high plate voltage.
I'm still confused as to how much sonic character NOS and/or your current production power tubes impart
on an amp (say the 135W Twin) for basically clean steel. My tech who works only on old tube amps of every kind imaginable says tonally there's not that
much difference, that it's more in the arena of guitar players who are pushing the output section for distortion, based on the quality of distortion they're after...

Joe

[Joe Shelby]

Donny already answered my question about power tube
"tone" after I reread his post above...Thanks Donny.

Joe.

[Dave Mudgett]

Joe, sonically, the 6L6WGB tubes are not the highest-headroom tubes available - not at all. I have used them in my Twin/Dual-Showman Reverbs of various eras - my '69 Dual Showman reverb has them in it right now, and I've used them in later 135-watt ultralinears. The B+ voltages have ranged from about 450 to 480 or even pushing 500 VDC on those amps - so far no problem.

I like them for guitar, but for a really clean-tone application like pedal steel I'd have a set of Phillips-Sylvania 7581a, or Phillips-Sylvania 6L6GC/STR387 tubes in there, but they're so expensive that I don't anymore.

For me, it's not mainly the tonality of the new tubes. I'm OK with the tone of even the basic Sovtek 5881, and have used them with no problem in amps with a more reasonable plate voltage - let's say certainly under 450 VDC. But when the plate voltages are pushing 50-100 or more volts over the design center, I get nervous with anything but a NOS tube. The deal is that the people that made them knew they were gonna be pushed, and built that margin in. Good old American engineering overdesign, but it's a value system that is gone for good, I fear.

My main point earlier was that I use solid-state or modeling amps when they make sense and give me what I need, and reserve my much loved old tube amps for when I really need them. I would only take a '69 Plymouth Roadrunner down the road only when I can really appreciate it - never in the middle of a snowstorm where there's tons of salt on the road and a good chance of someone running into me. Same with these cool old amps. Just my take.

[Ken Metcalf]

I have a 1970 non-master twin and just got a 1967 blackface twin from Randy Gilliam, There are no issues with tone with these amps. I have owned a number of twins including a Vibrosonic. I remember being told and discussions around the master Vol. does not affect the tone Blah Blah Blah.
I guess it's the AB763 electrical circuit, but the sound is much clearer and more musically friendly.
As a matter of fact to me they sound fine with 2-12s

[David Doggett]

Well, maybe we should move this into a separate thread on tubes, but it does involve amp questions that are being discussed here, so I’ll ask my questions here.

If you buy the GrooveTube power tubes that are graded as “hard” with the highest clean headroom, are those better able to handle the high plate voltages of the late ‘70s Fenders?

If we use those high plate voltage late ‘70s Fenders, does it help today’s tubes handle them if we are using a volume pedal backed off to attack the notes, so we are not really driving the amps hard even if the amp itself is dimed?

[Ben Jones]

i dont understand david, arent newer tubes able to handle much more power than NOS stuff? wouldnt new tubes be better for use in the high powered 70's fenders?

I dont know too much about this stuff, but I would think you'd want to use the tubes that were intended and period correct for any given amp...seems that would be optimal to me...use the tubes it was designed to run on? so NOS for old amps, new tubes for new amps....or am i way off?

[Scott Swartz]

If you buy the GrooveTube power tubes that are graded as “hard” with the highest clean headroom, are those better able to handle the high plate voltages of the late ‘70s Fenders?

No, current manufacture tubes are limited by the less than ideal materials used for the plates, cathodes, and grids, which can create the issues at operating extremes like 425V on the plates of a 6V6 in a Deluxe Reverb. The poor quality control doesn't help.

Groove Tubes claims

"Then we measure the gain to distortion ratio, that is the tendency for the tube to add overload or soft distortion character relative to its power output. We had discovered that some tubes exhibit these sonic signatures very early in their power output scale, while other tubes from the same production run stay fairly linear (or non-distorted) right up to their maximum power output."

This has nothing to do with whether the tube will stand up under high plate voltages. It is a measure of how perfect the plate-grid transfer characteristics of the tube is. The plate-grid graph of a "perfect" tube would show angled lines that were perfectly straight and equally spaced on this type of graph, real world tubes have curvature and unequal spacing to the lines, this "inaccuracy" distorts the output signal.

I am personally a little skeptical of measuring this independent of the bias point and how that interacts with the rest of the amp in terms of sound, but what they state is certainly technically possible to measure and they could be looking at other things that they don't mention.

If we use those high plate voltage late ‘70s Fenders, does it help today’s tubes handle them if we are using a volume pedal backed off to attack the notes, so we are not really driving the amps hard even if the amp itself is dimed?

This will help since when the current manufacture tubes are driven hard that is when they are more likely to fail. However the root cause is the poor materials that cause effects like excessive screen current when driven hard.

The alloys used, amount of impurities, hardness of vacuum, and a thousand other things are done right on NOS tubes which is why they can take the high plate voltages.

[Bill Duncan]

Scott,
You assert the use of inferior materials and poor quality control standards for todays tube manufacturing. Do you know this for a fact, or is it an assumption you are making?

Many times people tend to think that because something was made years ago, it was better. That is not always the case.

[Ken Fox]

I install and sell 100's of JJ tubes every year out of my shop. These tubes have been extremely reliable. The JJ 6L6GC can even handle the 700 volts of the Musicman amps with ease.


I have not had issues with SED tubes, though I have only sold a few. TAD tubes, had some issues with reliability. Sovtek 6L6WXT+, 50 percent failure rate about six years ago in three Twin Reverb amps!

Grrove tubes seem to be holding up OK in the newer fender that have come thru the shop as well. However, I still prefer and will oontinue with JJ tubes.

[Scott Swartz]

Bill,

The evidence about reliability is right in this thread.

I have had problems with Russian 6V6s, Chinese 6L6s and 6V6s, Czech EL34, and others, same as others posting in this thread.

Current preamp tubes have issues also, email Brad Sarno and ask about what he has to deal with to select tubes for his products.

Metallurgical impurity has been known to cause failures as long as tubes have been manufactured, and the short life and frequent catastrophic failure of some current tubes are consistent with what you would expect to see in this case.

Mechanical issues like sagging grid wires, bad welds, loose parts, etc can cause issues also, I have seen evidence of this also.

[Brad Sarno]

Bill, it goes absolutely without question that modern tubes are made with demonstrably worse quality control and clearly cheaper and lower quality materials and assembly techniques. I've had many brand new "factory tested" tubes short out, sputter, spark, and sometimes have little flakes of crap floating around inside. Even on the tube tester, many brand new "good" tubes test far worse than well used tubes from the '60s.

They used to make tubes for critical and military applications. Those demands don't exist anymore, and the factories making tubes simply don't spend the time or money to make critical tubes and also throw out all the ones that aren't completely at the high spec. Back in the day, not only were they made very carefully and in laboratory-like conditions, but the tests were far more stringent, and they threw out many, many tubes that weren't up to par.

It has nothing to do with an emotional bias toward vintage things. This is the physics and economics of the tube industry today.

Brad

[Donny Hinson]

It has nothing to do with an emotional bias toward vintage things. This is the physics and economics of the tube industry today.

And not only the tube industry, but any industry that relies on metals will tell you that most foreign metals are terribly substandard. Even the steel that's still made in this country is inferior to what we made 50 years ago. Many companies won't buy Chinese aluminum, simply because it's not as good a Kaiser (one of the few mills still producing good metal).

Pride in product and workmanship has succumbed to the bottom line in most big businesses.

[Dave Mudgett]

Scott,
You assert the use of inferior materials and poor quality control standards for todays tube manufacturing. Do you know this for a fact, or is it an assumption you are making? Many times people tend to think that because something was made years ago, it was better. That is not always the case.

Hey - if you want to use the new power tubes, go right ahead. But if you do some research, you'll see that it ain't just us talking about this. I absolutely hate having to rely on NOS power tubes. I don't sell 'em, and I have nothing to gain and everything to lose as a result - it just costs me money. Frankly - and back to the context of how this came up - I limit my usage of my old tube amps because they're such a PITA to keep tip-top now because of this.

The JJ 6L6GC can even handle the 700 volts of the Musicman amps with ease.

The old Music Man amps I'm talking about had 6CA7 power tubes. Really - 700 volts? I'd love to see it - I ditched my last Music Man HD-130 because I couldn't find decent 6CA7 tubes for it without taking a mortgage. I could run it at Lo-Power, but it sounded terrible at Hi-Power. I resolved to stick to amps with either 6L6 or 6V6 tubes or EL34/6CA7 amps like the Traynor or Laney, which don't seem to put such high voltages on the plates - at least the ones I have.

For the record - I would love to see really great new manufacture tubes. I was into vintage guitars when a lot of the name-brand new guitars were terrible, but there are great new guitars being made now, so I'm happy to oblige. But for power tubes and most anything but a pretty pricey point-to-point tube amp, I generally still prefer old amps. There are some exceptions, but that's my take.

Pride in product and workmanship has succumbed to the bottom line in most big businesses.

I think the bottom line was always important to businesses, but I think a big issue was that an awful lot of customers just wouldn't tolerate an expensive piece of equipment to be made poorly from poor-quality materials.

But another issue - as has been stated repeatedly here - is that there just isn't a big or critical market for vacuum tubes. Hell, they're hardly making TV picture tubes anymore - Sony just closed their big plant in Westmoreland, PA and Sony-Corning/Asahi just closed their plant here (in State College, PA) to consolidate what's left of their market demand to plants in Mexico. When the demand is very high, there's a lot more incentive to do whatever it takes to go after the market. When that demand wanes, I think it's much more difficult to justify taking it seriously enough to lavish great metallurgy or vacuum technology on it.

My opinions, naturally.

[Jim Peters]

Seems I read that a major problem to manufacturing tubes in the US is environmental concerns. JP

[Lynn Oliver]

Here is a somewhat dated list of tube manufacturers. Interesting that 90% of production goes into guitar amps.

[Jim Sliff]

I'm a great supporter or JJ's jubes. But this statement:

To me it's not worth searching for and paying the premium for NOS when there are alternatives that sound just as good.

...while based on opinion, is not correct (of course, that's MY opinion!).

I use JJ's when I install NEW tubes - but tonally NO new tube can match my Philips STR387's, Mullard EL37's, vintage Tung-Sol 5881's or RCA blackplates for 6L6's, which I save for the studio or critical gigs. There's also NO current equal to Amperex metal-base EL34's - or ANY US-made 6V6! 6V6's are one of the real weak points with new tubes, as are EL84's...EL34's come next. There are certainly good 6L6 variants in new production, but EH really fouled the market (IMO) when they introduced the wafer-base "5881" - which was not even an audio tube (it was a Russian servo tube). While it DID help get tube manufacturing moving agin, it got many players used to simply crappy-sounding tubes.

Preamp tubes are an entirely different subject, and again while I'll use JJ's for "new" replacements, I have a large stash of US and European 12A*7-types that are FAR superior to anything being made today.

That's why I am thankful I collected (and inherited) hundreds of amp tubes.

(edited)

Seems I read that a major problem to manufacturing tubes in the US is environmental concerns. JP

Correct. Lead and other toxic materials are part of the process...it's a nasty manufacturing business and environmental controls are extremely expensive.