| Author |
Topic: Tube Hardness |
Jerry Malvern
From:
Menifee, California, USA
|
Posted 16 Jun 2007 11:52 am |
|
| I am going to replace the power tubes in a Super Twin Reverb. What hardness level should I use? I was told a hardness level of 8 would work for pedal steel, lots of clean headroom with tube warmth, but would like to hear from other forumites before I buy them. |
|
|
 |
Scott Appleton
From:
Ashland, Oregon
|
Posted 16 Jun 2007 12:33 pm tube hardness
|
|
Your talking about Groove Tube testing .. That does
not always indicate the musicality of the tube ..
however 8 is a good number for clean with some body. |
|
|
|
Dan Beller-McKenna
From:
Durham, New Hampshire, USA
|
Posted 16 Jun 2007 5:31 pm
|
|
Sorry to be dense here, but could someone explain tube "hardness" to me??
Thanks,
Dan
_________________
Durham, NH
dbmCk mUSIC |
|
|
|
Robert Harper
From:
Alabama, USA
|
Posted 16 Jun 2007 6:01 pm Tube Hardness
|
|
| Yes please explain, I have been in and around electronics all my life. My father was a TV Repairman, Amatuer operator,back when eveyone used tubes and built there own equipment. Me I have worked on TV Radios Helicopters computer, Two Way FM telephone systems and now cellular never heard of this. |
|
|
|
Scott Appleton
From:
Ashland, Oregon
|
Posted 16 Jun 2007 6:44 pm tube hardness
|
|
Its not actually "tube Hardness" the scale from 1 to 10 from Groove Tubes tells us when a tube is going to distort. At lower numbers 1 to 3 your amp will distort
at say 3 on the input volume. A tube with A GT rating of 8 will distort at say 5 or 6 on the Vol controll.
This rating system was designed fo power tubes especially. Also the ratings indicated higher output
from a matched pair of say GE 6L6's. The preamp tubes
also benefit from this system. GT also tests for microphonics, gasification of internal elements and leakage. All are factors in grading tubes. |
|
|
|
Donny Hinson
From:
Glen Burnie, Md. U.S.A.
|
Posted 17 Jun 2007 4:12 am
|
|
| Forget the Groove Tubes. Get something else, JJ Teslas, or the Winged C SED's. |
|
|
|
Ken Fox
From:
Nashville GA USA
|
Posted 17 Jun 2007 4:53 am
|
|
I agree with Donny. Groove tube 5881 and 6L6GC sound great in Russian jet planes, as that is what they were designed for!!! They sound harsh to me but do last for a long, long time in an amp. I have replaced a lot in Fender amps lately with the TAD (Tube Amp Doctor) tubes. They make a short bottle and tall bottle variety of 6L6.
Try TAD, Svetlana (SED). JJ runs cold as a fritter now and requires re-biasing your amp! If your amp does not have an adjustable bias you will get crossover distortion and low output. I used JJ 6L6GC for years and had to stop! My customers do not need to pay to have their amps modified just to run a cold tube!
My friend in Portland, Oregon put a set in his Musicman and had the same trouble. I sent him a pair of TAD 6L6GC tubes and his problems were cured immediately.
JJ makes a great tube and I will not hesitate to use a 6L6GC in an amp that can be biased. But the customer has to be aware that swapping in a regular 6L6GC could result in thermal runaway of that tube ("red plating" or glowing red plates), unless the bias is lowered back to normal. |
|
|
|
Scott Appleton
From:
Ashland, Oregon
|
Posted 17 Jun 2007 8:00 am the tube thing
|
|
Right you are "O" guru of the electron (ken). The matching system GT uses for pairs or quad sets of tubes
are rated to go into fixed bias amps and run correctly.
You can buy them blue to white. They now own the original manufacturing equipment that GE had to build the 6L6's everyone wants. Is that not a good thing? |
|
|
|
Jim Sliff
From:
Lawndale California, USA
|
Posted 17 Jun 2007 9:48 am
|
|
Tube "hardness" is a made-up term by one company...and personally, I wouldn't use that brand of tubes so the "hardness" is irrelevant.
If you do a search there have been many threads regardiing tube types for similar amps. It's kind of pointlless to keep another one going.
The one issue I disagree with Ken on is that ANY amp should have the bias checked/adjusted when new power tubes are installed. When the amps were built tubes were more consistent and it wasn't an issue, but there are so many inconsistencies nowdays biasing is required. Most techs only charge a few bucks to check it, and not more than $35 or so to rebias in an amp without an adjustment pot (but I'd pay to have one installed). I've also not had the same experience with JJ's and they are the only newly-manufactured tubes I install or recommend.
_________________
No chops, but great tone
1930's/40's Rickenbacher/Rickenbacker 6&8 string lap steels
1921 Weissenborn Style 2; Hilo&Schireson hollownecks
Appalachian, Regal & Dobro squarenecks
1959 Fender 400 9+2 B6;1960's Fender 800 3+3+2; 1948 Fender Dual-8 Professional |
|
|
|
Donny Hinson
From:
Glen Burnie, Md. U.S.A.
|
Posted 17 Jun 2007 10:06 am
|
|
| Quote: |
| They now own the original manufacturing equipment that GE had to build the 6L6's everyone wants. Is that not a good thing? |
Maybe, maybe not. The thing that made American-made tubes great was the crusher. 
Every tube manufacturer would test their tubes, and then send any that didn't meet every spec to their "crusher". The number of rejects which went to the industrial crushing machine was a significant portion of the production from the late '40s to the late '60s. Then, with the advent of solid-state gear, financial concerns made some of the manufacturers sell their "FR's" (functional rejects - tubes that worked, but not really well) to other manufacturers for "re-branding" under some generic label, which were then sold at discount stores.
Quality usually goes down when you try to increase yeild, and cut corners to save money. That's due to the "M.B.A's brand" of thinking, and not the equipment that's used. Tubes require good components and for the manufacturer to take time to pull a good vacuum, and test them stringently.
There's no voodoo or rocket-science necessary. |
|
|
|
Ken Fox
From:
Nashville GA USA
|
Posted 17 Jun 2007 10:51 am
|
|
I agree, Jim. every amp should be checked. That's what happens when they go thru my shop. All Silverface amps I have restored are converted to adjustable bias and set properly before they leave my shop.
The average user does not have the proper test equipment and is likely not going to re-bias their amp.
I would not recommend a cold, JJ tube for those folks at all. |
|
|
|
Jerry Malvern
From:
Menifee, California, USA
|
Posted 17 Jun 2007 1:36 pm
|
|
| Ken, which TAD tube do you recommend TAD 6L6GC-STR or 6L6WGC-STR ? The first one says "like SRV to Nu-Metal"........that NU Metal part concerns me. |
|
|
|
Ken Fox
From:
Nashville GA USA
|
Posted 17 Jun 2007 2:06 pm
|
|
I have only been using the short bottle tubes so far. That is the 6L6WGC. I have tried to find the specs for the tube, no luck yet. The tall bottle may well handle plate voltage better, the 6L6GC. Today tube manufacturers seem to vary a lot in specs.
For plate voltage, there is nothing tougher than a JJ and I like the sound. You just have to be able to re-bias the amp! I run them in my old Peavey Mace, 6 of them for whooping 160 watts of tube power. The old RCA and other tubes I tried ran in the 30ma range or more in that amp. The JJ tubes were idling at a mere 3-7 ma each. As the Mace VT series did not have an adjustable bis (as did the original Mace) I added one.
I am considering the Svetlana (SED) now as standard for my shop. The reviews I have read are better on it than the JJ or the TAD tubes. I want the best tube I can get for my customers!
Do some web research and see what you find out as well! I am always learning, too. Its a new game everyday, it seems. |
|
|
|
Jim Sliff
From:
Lawndale California, USA
|
Posted 17 Jun 2007 5:44 pm
|
|
I guess my feeling on tubes amps is pretty basic - if you can't spend $25-30 on a simple tool and know how to work a multimeter so you can at least check bias, you shouldn't really ber playing one unless you don't mind paying a tech all the time.
NO...repeat NO...power tube is plug and play. It's too risky to the power transformer and other components, and I would never recommend it.
If your amp was biased at 35ma for Svets and you plugged in a set of TAD's, what's your bias now? Your plate voltage?
You have NO way to tell. So my position is pretty simple, and I daresay backed up by 90% of the professional tube amp techs in the country. Maybe more.
| Quote: |
| They now own the original manufacturing equipment that GE had to build the 6L6's everyone wants. Is that not a good thing? |
Except they don't - they own SOME of it. Parts of the tubes are made here, but the final product is made in China. There's some "gray area" marketing about the 6L6GE - the "made in USA" is part of it, because if you mean "built in the USA", they're not.
_________________
No chops, but great tone
1930's/40's Rickenbacher/Rickenbacker 6&8 string lap steels
1921 Weissenborn Style 2; Hilo&Schireson hollownecks
Appalachian, Regal & Dobro squarenecks
1959 Fender 400 9+2 B6;1960's Fender 800 3+3+2; 1948 Fender Dual-8 Professional |
|
|
|
Ken Fox
From:
Nashville GA USA
|
Posted 17 Jun 2007 6:16 pm
|
|
I agree with Jim. Even if it's the same brand of tube the bias is going to likely be different. Without the proper test equipment it is at best a shot in the dark. I use a Bias King Pro. It has never let me down. It show quickly too that most "matched" tubes are not all that close! I have several in depth discussions with Mojtone about their poorly matched tubes, to no avail.
I no longer buy tubes from them. I was just a small dealer making noise they did not want to hear!
Most people that do not set their own bias typically do not know or want to understand anything about electronics. Let's face it, not all of us are techs. We all have our talents! Best to take it to a tech you trust if electronic testing is not your gift.
I hate to see anyone probing around in an amp that is not trained properly. |
|
|
|
Jim Sliff
From:
Lawndale California, USA
|
Posted 17 Jun 2007 9:06 pm
|
|
Hey! Same here!
What Ken says is good stuff, and he knows I'm not really disagreeing - we seem to always add to each other's info. And man, is he right - safety first. If you do not know how to discharge caps (and especially if you have no idea what I just said) do not even OPEN an amp to look at the chassis. An amp stored for months...some designs, years even...can kill you when not plugged in if you touch the wrong thing.
Back to tube amps overall - in the 60's and 70's we could go to the corner drugstore and buy tubes. Most players rarely biased amps, and rarely did they NEED to - because tubes in those days were pretty consistent from brand to brand. I learned (as did many others back then) because I took high-school electronics, found it was applicable to my guitar stuff, and went on from there.
Fast forward to the late 80's/early 90's. US and Western European tube manufacturing is pretty much dead. Everything is coming from Russia, China (later, due to trade embargoes), and Eastern Bloc countries. Tubes like the aforementioned Russian "5881", neither a 5881 nor a 6L^, are adapeted for guitar amp use.
But the bias/plate voltages differ wildly from the "consistent" tubes of a decade or two before. Biasing becomes critical. Tube amps often sound awful, hence the rise of solid state...few know how to make a tube amp "sing".
Fast forward to "the internet" - communication goes worlkdwide, people learn the realities, and tubes are back in the saddle.
But -
Having a tube amp means one of two things: 1) you have an amp tech nearby you get to know real well, or 2) you learn how to work on them yourself.
Lacking either of those options, players give up on tube amps - and probably SHOULD, because they need care, maintenance, and "tweaking".
But -
IF you have the right tech, or IF you learn how to tweak an amp yourself, there is NOTHING that matches a good one tonewise.
The good thing is that basic safety and the major maintenance items are NOT very complicated - on older amps with hand-wired circuits. Printed cicuit board make things pretty tough. However, you can learn how to safely do a visual check and bias an amp (that has an adjustable bias) in a couple hours. You can also learn how to convert a Silverface Fender with a non-adjustable bias to adjustable very quickly - it's not a hard job in most cases.
If you like "plug-'n-play and don't want to fool with stuff, stick with solid state. But if you want "the" tone, take the time and learn how to work with tubes. It's well worth the effort.
_________________
No chops, but great tone
1930's/40's Rickenbacher/Rickenbacker 6&8 string lap steels
1921 Weissenborn Style 2; Hilo&Schireson hollownecks
Appalachian, Regal & Dobro squarenecks
1959 Fender 400 9+2 B6;1960's Fender 800 3+3+2; 1948 Fender Dual-8 Professional |
|
|
|
Dave Boothroyd
From:
Staffordshire Moorlands
|
Posted 17 Jun 2007 10:45 pm
|
|
In the early 1960s, when I used to build my own transmitters and receivers for radio controlled models, there were two fundamental types of valve available. (We call the things that you call "tubes", valves)
They were hard valves and soft valves.
A hard valve was made with a very high degree of vacuum, and a soft valve was gas filled.
Hard valves were the little bottle-shaped things with the octal pins on the bottom.
Soft valves were much smaller, almost rectangular in section, with the connectors inline and just made of wire.
I was puzzled at the title of this thread, because I thought soft valves had vanished forty years ago.
It's another example of someone using an old term for something new (and possibly non-existent!)
Cheers
Dave |
|
|
|
Jim Sliff
From:
Lawndale California, USA
|
Posted 18 Jun 2007 4:31 pm
|
|
Yes, Dave - in this case "hard" and soft" define ranges of tube "breakup",but only as defined by one manufacturer. It's not a commonly-used term unless you have those tubes.
_________________
No chops, but great tone
1930's/40's Rickenbacher/Rickenbacker 6&8 string lap steels
1921 Weissenborn Style 2; Hilo&Schireson hollownecks
Appalachian, Regal & Dobro squarenecks
1959 Fender 400 9+2 B6;1960's Fender 800 3+3+2; 1948 Fender Dual-8 Professional |
|
|
|
David Doggett
From:
Bawl'mer, MD (formerly of MS, Nawluns, Gnashville, Knocksville, Lost Angeles, Bahsten. and Philly)
|
Posted 18 Jun 2007 8:43 pm
|
|
Well, it may be their own private rating system, but it is certainly useful when buying tubes. I doubt that the tubes are being manufactured to fit a certain level on the hardness rating scale. I suspect the qualtity control is all over the map, and they try the tubes they get and give them whatever rating they happen to fall into. It's a useful idea.
I hope you guys aren't scaring people off from tube amps. Usually, even a poorly adjusted and maintained tube amp has better tone then any solid-state, if tube tone is what you want. And with tube amps, you definitely need a backup, so you can have an amp in for service and still have something to play with. But an amp can go for several years between servicing. It is not something that has to be constantly tended to, and you don't have to learn electronics, anymore than you have to become an auto mechanic to drive a car. And this business of trying all sorts of tubes and finding the very best is not a prerequisite for using tube amps. Frankly, the advice seems conflicted. It is just like trying different brands and gauges of strings, or different types of pickups, or different effects units. If you want to spend time and money on that issue, you can. And maybe you'll end up sounding a little better, at least to yourself. But you can also just get a tube amp and play. |
|
|
|
Marlin Smoot
From:
Kansas
|
Posted 18 Jun 2007 10:01 pm
|
|
| My amp tech just put some Ruby Tubes in the power section of my Fender Twin, and 3 new 12ax7's and so far they sound really good. |
|
|
|
Jim Sliff
From:
Lawndale California, USA
|
Posted 19 Jun 2007 5:25 am
|
|
| Quote: |
| t is certainly useful when buying tubes. |
I think it's a terrible idea, and told Aspen Pittman so. It keeps players thinking they do not need to rebias...or even CHECK the bias...on their amps. That's an awful misconception. But it certainly will keep amp techs in business. Mesa does the same thing with their "color" ststems (and Randall Smith's foolhardy insistence that his amps don't NEED to be rebiased). Yech.
_________________
No chops, but great tone
1930's/40's Rickenbacher/Rickenbacker 6&8 string lap steels
1921 Weissenborn Style 2; Hilo&Schireson hollownecks
Appalachian, Regal & Dobro squarenecks
1959 Fender 400 9+2 B6;1960's Fender 800 3+3+2; 1948 Fender Dual-8 Professional |
|
|
|
Scott Appleton
From:
Ashland, Oregon
|
Posted 19 Jun 2007 7:00 am bias
|
|
In the old days before I had a good bias bridge system
I would just tweek the bias level on my TR until the
hum got the least and the redness went away .. very
crude but in the early 70's there were few good techs.
I burned a few sets of tubes with some fixed bias models trying different values of resistors. Finally i learned to install the bias pot .. life got
better .. boy those tubes sure do stink when they burn.
Transformers would often inexplicably fail after running with quad loads unbalanced. ahh the good old days. |
|
|
|
Mitch Adelman
From:
Pennsylvania, USA
|
Posted 19 Jun 2007 8:26 am TAD tubes
|
|
| My take on tube hardness is the headroom the tube offers with increasing volume. The tube with the most headroom won't break up into saturation as quick. I have used both TAD 6l6 tubes in both my Twin and vibrolux. The tall bottles defintely have much more headroom and are cleaner at higher volumes and seem to be louder. Real nice tone and great for effects. They say they are like RCA old tubes.The short bottles have a more tweedy vintage tone and break up sooner and are sweeter. They didnt cut in in a twin but are great in the vibrolux.I love them with break up at about 6 with Weber speakers. I run them both at about 34 with my Bias rite.Of course breakup is really very dependent on the speakers. Either way, the TAD tubes have been very reliable and closely matched from the Tube store.Hope this helps make a decision cause i've been there. Best just to try both!Good luck. |
|
|
|
David Doggett
From:
Bawl'mer, MD (formerly of MS, Nawluns, Gnashville, Knocksville, Lost Angeles, Bahsten. and Philly)
|
Posted 19 Jun 2007 10:02 am
|
|
| Jim, I didn't mean to imply one should put new tubes in without rebiasing. If a player can't adjust the bias themself, they can take the tubes to their tech and tell them to put the tubes in and check the bias. A rating system, if done well, has the potential to take some mystery and trial-and-error out of choosing tubes. |
|
|
|
Jim Sliff
From:
Lawndale California, USA
|
Posted 20 Jun 2007 4:20 pm
|
|
David, I agree with that - the problem is the misconception many players have, though (especially ones inexperienced with tube amps) is that it creates a "plug 'n play" environment, which is wrong.
| Quote: |
I would just tweek the bias level on my TR until the
hum got the least and the redness went away . |
Question - how did you kill the hum AND the plates with a bias control? An actual bias control does little for hum unless you had the bias set at an incredibly high level; a hum balance control, which controls the filaments, is actually a useful device...but it doesn't bias the tubes.
I can't figure out how you accomplished two things with either type of control alone (unless the "glow" was just the filament glow, which would only pertain to hum - not bias)..
_________________
No chops, but great tone
1930's/40's Rickenbacher/Rickenbacker 6&8 string lap steels
1921 Weissenborn Style 2; Hilo&Schireson hollownecks
Appalachian, Regal & Dobro squarenecks
1959 Fender 400 9+2 B6;1960's Fender 800 3+3+2; 1948 Fender Dual-8 Professional |
|
|
|
