Different manufacturers characteristics
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tony_carey
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Different manufacturers characteristics
Charlie, can you explain in laymans simplified terms, why different manufacturers tube amps sound so different to each other. I use Marshall for my own needs, but have an AC30 for the studio & can't help but amaze at the difference in sound. Also, why does some manufacturers overdrive sound better & others have better clean sounds?
'Rickenbacker'...what a name! After all these years, it still thrills me.
Also, why do different manufactures' tubes of the same type (12AX7 for example) sound different? Is there some component within the tube that causes one brand to sound muddier or more musical than another? In other words, if I have a tube preamp, can I add sparkle or grind to it by changing the tubes? Thanks, and welcome.
These are all great questions.
1. There are only a few companies making tubes: Sovtek (under Electro-Harmonix, Sovtek, they also now own the Mullard and Tung-Sol trademarks), Ei in Serbia, JJ in Slovakia, Shuguang in China and a few others. Plus there are numerous new old stock companies like GE and RCA for example
Tubes sound different for three main reasons
A. Materials used. Cathodes, plates, grid wires, etc in some tubes just are more musical, warmer or colder sounding, harsher or sweet sounding. It is like alchemy. Some of the very best sounding 12AX7s are 1950s Tung Sol, RCA and GE. Some of the best sounding 1960s tubes are Mullards and Telefunkens. Newer tubes have lesser quality reagent chemicals and less purity in the metalurgy which makes them sound ****** and wear out faster.
B. Tube design. Some tubes have large plates, some have smaller plates, large plates means larger sound. Also, some have large diameter grid wire, some have smaller diameter grid wire. The smaller wire sounds smaller. Lastly some tubes have more gain due to more grid wire winding and wire set at a different pitch or angle. These physical factors make a difference in sound.
C. Quality control is also a huge issue. Newer tubes are made by slave labor who work for pennies an hour. The classic NOS tubes from the 1950s and 60s were made by skilled laborers in USA and Europe where quality standards were higher than in the 3rd World countries where tubes are made now.
For example, I can get a box of JJ 12AX7s and in some batches of 100 pieces, 30-40% will be noisy or microphonic. In other batches, there will be less than 10% that will be microphonic.
So it is materials used, tube design and quality control that are the main factors in tube sound. You should use different tubes like spices, some times you like it hot, other times cool, sometimes warm, sometimes sweet. The differences are not subtle if you have a good ear and a good amp.
My personal favorite new 12AX7s are the JJ ECC803S because it sounds nice, clean and warm, just like a 1950s large plate GE 12AX7. Also the new Tung Sol 12AX7 reissue because it has 10% higher gain and is very quiet and reliable.
1. There are only a few companies making tubes: Sovtek (under Electro-Harmonix, Sovtek, they also now own the Mullard and Tung-Sol trademarks), Ei in Serbia, JJ in Slovakia, Shuguang in China and a few others. Plus there are numerous new old stock companies like GE and RCA for example
Tubes sound different for three main reasons
A. Materials used. Cathodes, plates, grid wires, etc in some tubes just are more musical, warmer or colder sounding, harsher or sweet sounding. It is like alchemy. Some of the very best sounding 12AX7s are 1950s Tung Sol, RCA and GE. Some of the best sounding 1960s tubes are Mullards and Telefunkens. Newer tubes have lesser quality reagent chemicals and less purity in the metalurgy which makes them sound ****** and wear out faster.
B. Tube design. Some tubes have large plates, some have smaller plates, large plates means larger sound. Also, some have large diameter grid wire, some have smaller diameter grid wire. The smaller wire sounds smaller. Lastly some tubes have more gain due to more grid wire winding and wire set at a different pitch or angle. These physical factors make a difference in sound.
C. Quality control is also a huge issue. Newer tubes are made by slave labor who work for pennies an hour. The classic NOS tubes from the 1950s and 60s were made by skilled laborers in USA and Europe where quality standards were higher than in the 3rd World countries where tubes are made now.
For example, I can get a box of JJ 12AX7s and in some batches of 100 pieces, 30-40% will be noisy or microphonic. In other batches, there will be less than 10% that will be microphonic.
So it is materials used, tube design and quality control that are the main factors in tube sound. You should use different tubes like spices, some times you like it hot, other times cool, sometimes warm, sometimes sweet. The differences are not subtle if you have a good ear and a good amp.
My personal favorite new 12AX7s are the JJ ECC803S because it sounds nice, clean and warm, just like a 1950s large plate GE 12AX7. Also the new Tung Sol 12AX7 reissue because it has 10% higher gain and is very quiet and reliable.
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soundmasterg
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Charles, I was wondering about the new Tung Sol stuff. I'm always distrustful of New Sensor's stuff until I hear something good about it from someone I trust. I like the JJ 803S too, especially for the input stage into the amps. I wish EI would get their act together and make a quality product as they sound good when you have a good one.
Anthony, there are many reasons, but the easiest way to say it is they sound different because they are different. Different power tubes make a huge difference, and an AC30 uses EL84's, while most Marshalls use EL34's. The voltages are different, as are resistor and cap sizes used.
As a general rule, higher voltages in the preamp mean more gain, and a cleaner sound overall, because the tube has more headroom and doesn't distort as easily. Lower voltages in the preamp make the tubes distort sooner, and they can't take as big of a signal coming in to them since they have lower headroom. So a second stage will get overdriven easier by a first stage. Higher voltages on the power tubes affect how much headroom and power the amp has overall, and also how soon the tubes distort. You also need to be sure to design an amp for the correct voltages for whatever power tubes are being used. An EL84 has a much lower maximum voltage than an EL34, so an amp using one or the other has to be designed accordingly, and that affects the sound.
Different cap sizes affect what frequencies are passed from stage to stage in the amp. Stuff may sound good on clean and not so good on overdrive, or vice versa, because an amp is voiced for a particular operating condition, and when you get it outside of that, it doesn't work as well. Most blackface/silverface Fenders are voiced for a good clean sound, but when you overdrive them, they often sound too fat and farty...meaning the bass is flubby and indistinct. If they change it to make it work better when the amp is dimed, then the clean tone will suffer because the nice lows won't be there any more. The trick is to make an amp work well with clean and overdrive. AC30's do both well, although the overdrive from an AC30 is much less distorted than from a Mesa Dual Rectifier! Thats why there are so many amps out there. Different tools for different tones.
Anthony, there are many reasons, but the easiest way to say it is they sound different because they are different. Different power tubes make a huge difference, and an AC30 uses EL84's, while most Marshalls use EL34's. The voltages are different, as are resistor and cap sizes used.
As a general rule, higher voltages in the preamp mean more gain, and a cleaner sound overall, because the tube has more headroom and doesn't distort as easily. Lower voltages in the preamp make the tubes distort sooner, and they can't take as big of a signal coming in to them since they have lower headroom. So a second stage will get overdriven easier by a first stage. Higher voltages on the power tubes affect how much headroom and power the amp has overall, and also how soon the tubes distort. You also need to be sure to design an amp for the correct voltages for whatever power tubes are being used. An EL84 has a much lower maximum voltage than an EL34, so an amp using one or the other has to be designed accordingly, and that affects the sound.
Different cap sizes affect what frequencies are passed from stage to stage in the amp. Stuff may sound good on clean and not so good on overdrive, or vice versa, because an amp is voiced for a particular operating condition, and when you get it outside of that, it doesn't work as well. Most blackface/silverface Fenders are voiced for a good clean sound, but when you overdrive them, they often sound too fat and farty...meaning the bass is flubby and indistinct. If they change it to make it work better when the amp is dimed, then the clean tone will suffer because the nice lows won't be there any more. The trick is to make an amp work well with clean and overdrive. AC30's do both well, although the overdrive from an AC30 is much less distorted than from a Mesa Dual Rectifier! Thats why there are so many amps out there. Different tools for different tones.
I got the skinny on the new Tung Sol stuff from the source, JC Morrision, the Sovtek "tube designer", actually he was a house painter and artist before this gig and also did some writing for the now defunct Sound Practices magazine. He was on the New York Triode Mafia scene and it knowledgeable about tubes to some extent.
According to JC, New Sensor took samples of Tung Sol tubes and characterized them electrically with a curve tracer, distortion analyzer, etc. They also took them apart and measured the number of grid wire turns, grid wire pitch, distances from grid wires to cathode, dimensions of plate, etc.
They did not however do reverse chemical engineering on the plate or cathode material. They continue to use the same stuff they use in all the Sovtek tubes. Plate and cathode material make huge differences in the sound of a tube. They did, however, gold plate the control grids, which is a good thing.
Granted, this would be an expensive undertaking of costly chemical analysis and the sourcing of hard to find reagent grade chemicals, but to call them exact copies would be incorrect. They are "replicas" at best. To make an exact copy would have tripled the cost to consumers and it would not have sold due to the higher costs.
They sound a bit better than the standard Sovtek tubes and will last a little longer, but they do not sound like the original Tung Sol or Mullard tubes. This is just advertising hype. The NOS original Tung Sols such as the 12AX7 and 6550 are some of the best of their type and they do have the sonics and long-lasting ability.
I do give Sovtek credit for coming out with these reissues, as they are making better tubes these days. They are paying attention to quality control and doing better testing.
BTW, they also bought the Genelax copyright and own the US rights to the name. So expect to see KT66, KT77 and KT88 Sovtek "Genelax" tubes sometime soon.
According to JC, New Sensor took samples of Tung Sol tubes and characterized them electrically with a curve tracer, distortion analyzer, etc. They also took them apart and measured the number of grid wire turns, grid wire pitch, distances from grid wires to cathode, dimensions of plate, etc.
They did not however do reverse chemical engineering on the plate or cathode material. They continue to use the same stuff they use in all the Sovtek tubes. Plate and cathode material make huge differences in the sound of a tube. They did, however, gold plate the control grids, which is a good thing.
Granted, this would be an expensive undertaking of costly chemical analysis and the sourcing of hard to find reagent grade chemicals, but to call them exact copies would be incorrect. They are "replicas" at best. To make an exact copy would have tripled the cost to consumers and it would not have sold due to the higher costs.
They sound a bit better than the standard Sovtek tubes and will last a little longer, but they do not sound like the original Tung Sol or Mullard tubes. This is just advertising hype. The NOS original Tung Sols such as the 12AX7 and 6550 are some of the best of their type and they do have the sonics and long-lasting ability.
I do give Sovtek credit for coming out with these reissues, as they are making better tubes these days. They are paying attention to quality control and doing better testing.
BTW, they also bought the Genelax copyright and own the US rights to the name. So expect to see KT66, KT77 and KT88 Sovtek "Genelax" tubes sometime soon.
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soundmasterg
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Wow, thats really interesting! I hope they make the same effort on the Genelex stuff when they come out with them. It would be great to see a KT77 again! How do the new Tung Sol 12AX7's sound as compared to a 12AX7LPS or the JJ ECC803S? I've used those so am familiar with them.
I have a nice pair of slightly used Tung Sol 6550's still around for a project and a couple good used 12AX7's too. And I have some used 12AX7 Telefunkens, Amperex, Raytheon, Mullard, GE, etc. I use them mainly as reference tubes and for dialing in amps, and for recording sessions. I have 5 brand new Mullards in the box too that I got for $5 in the early 90's. They're IEC Mullards, so I have no idea what era they're from, but they sound good. My uncle also gave me a box of tubes in an Army repair kit that he had since he was in the army in the late 50's. A bunch of NICE RCA 12AU7's and 12AX7's, mostly new, and some used. I keep hoping I'll find a barn somewhere full of really great old tubes.
I have a nice pair of slightly used Tung Sol 6550's still around for a project and a couple good used 12AX7's too. And I have some used 12AX7 Telefunkens, Amperex, Raytheon, Mullard, GE, etc. I use them mainly as reference tubes and for dialing in amps, and for recording sessions. I have 5 brand new Mullards in the box too that I got for $5 in the early 90's. They're IEC Mullards, so I have no idea what era they're from, but they sound good. My uncle also gave me a box of tubes in an Army repair kit that he had since he was in the army in the late 50's. A bunch of NICE RCA 12AU7's and 12AX7's, mostly new, and some used. I keep hoping I'll find a barn somewhere full of really great old tubes.
Yes, it will be interesting to see what they come up with. I have also heard through the rumor mill that JJ will be introducing a KT77 very soon!!!
The new Tung Sol 12AX7 is excellent. It has 10-15% more gain than the 12AX7EH or LPS. It is a brighter sound than the JJ ECC803S, which I also like.
For V1 or V2 I would use the Tung Sol in high gain applications for rock and crunch and the ECC803S in applications where you want smooth, clean sound for jazz, some blues, etc.
The IEC Mullards are still Mullards from the Blackburn UK factory which eventually closed in 1977. They are excellent tubes worth a lot more than $5 now. Have you checked eBay lately?
I have found barns full of old tubes, unfortunately, someone who knew audio tubes got there before me and stripped the place of anything good except for radio and tv tubes.
Keep looking for those old ham radio towers!
The new Tung Sol 12AX7 is excellent. It has 10-15% more gain than the 12AX7EH or LPS. It is a brighter sound than the JJ ECC803S, which I also like.
For V1 or V2 I would use the Tung Sol in high gain applications for rock and crunch and the ECC803S in applications where you want smooth, clean sound for jazz, some blues, etc.
The IEC Mullards are still Mullards from the Blackburn UK factory which eventually closed in 1977. They are excellent tubes worth a lot more than $5 now. Have you checked eBay lately?
I have found barns full of old tubes, unfortunately, someone who knew audio tubes got there before me and stripped the place of anything good except for radio and tv tubes.
Keep looking for those old ham radio towers!
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soundmasterg
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Ooooh, JJ is doing a KT77 too? Are we living in nirvana or what?! 
So the new Tung Sol has more gain than the JJ ECC83? Those always had lots of gain from what I've seen, though I thought other tubes sounded better. JJ's new 803S is really nice.
Can you tell from looking at a pic of the IEC Mullards what era they might have been made in? I know there worth bunches.....I just keep holding on to them and watching the value grow. It would be cool to know when they were made though.
There are some cool tubes around that weren't audio tubes that work fine in builds, like the 6CM6, and 5965, or 12AV7, and they are cheap too for good NOS. Thanks to you guys at VTV for bringing a lot of them to everyone's attention!
So the new Tung Sol has more gain than the JJ ECC83? Those always had lots of gain from what I've seen, though I thought other tubes sounded better. JJ's new 803S is really nice.
Can you tell from looking at a pic of the IEC Mullards what era they might have been made in? I know there worth bunches.....I just keep holding on to them and watching the value grow. It would be cool to know when they were made though.
There are some cool tubes around that weren't audio tubes that work fine in builds, like the 6CM6, and 5965, or 12AV7, and they are cheap too for good NOS. Thanks to you guys at VTV for bringing a lot of them to everyone's attention!
I too like the JJ ECC803S, one of my favorite new tubes. Yes I can identify just about any audio tube. I have seen most of them including the fakes out there.
VTV issue #16 has a fairly complete listing of Mullard and Philips date and production code charts if you are interested. It is not totally complete, even though we got most of the information from Alan Blake, an engineer who worked for Mullard from the 1950s to the 1970s. There are still some missing Philips factories, etc.
It is difficult to dig out complete information on tube history and manufacturing. That is why it takes so long for us to produce an issue sometimes.
Issue #21 is almost finished, I have an article from Scott Frankland, a serious tech in Silicon Valley, who wrote an article about the early beginnings of Western Electric and RCA tubes. It has about 80 footnotes and charts.
Yes there are a lot of great tubes that are thought of as junk. We wrote a Tube Dumpster article on the little subminiatures, now several companies are using them for effects pedals and small amps. There are still Billions of tubes going unused out there. The most popular tubes are still the 12AX7, 6L6, EL34 and EL84.
VTV issue #16 has a fairly complete listing of Mullard and Philips date and production code charts if you are interested. It is not totally complete, even though we got most of the information from Alan Blake, an engineer who worked for Mullard from the 1950s to the 1970s. There are still some missing Philips factories, etc.
It is difficult to dig out complete information on tube history and manufacturing. That is why it takes so long for us to produce an issue sometimes.
Issue #21 is almost finished, I have an article from Scott Frankland, a serious tech in Silicon Valley, who wrote an article about the early beginnings of Western Electric and RCA tubes. It has about 80 footnotes and charts.
Yes there are a lot of great tubes that are thought of as junk. We wrote a Tube Dumpster article on the little subminiatures, now several companies are using them for effects pedals and small amps. There are still Billions of tubes going unused out there. The most popular tubes are still the 12AX7, 6L6, EL34 and EL84.
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soundmasterg
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I have all the previous issues of VTV, so I'll have to see if I can figure out what I have by looking in issue 16...thanks for pointing that out...I forgot it was in there! Can't wait for issue 21 to come along.
I had stumbled on the 6CM6 by looking in the RCA tube manual and comparing specs a couple years before you guys wrote your dumpster article, but it was great to get more detail on it!
Also, you may be interested if you don't know already, that Jim McShane, an internet tube reseller, has some kind of tester where he can operate the tubes in circuit, and hit them with lots of voltage to see how well they hold up. He nailed the 6CM6 with up to 450v plate and screen awhile back after I asked him if they hold up as well as NOS 6V6's to Fender Deluxe Reverb voltages. He said they seemed to be just as robust as NOS 6V6's, with no red plating even at that voltage, which is very cool!
I had stumbled on the 6CM6 by looking in the RCA tube manual and comparing specs a couple years before you guys wrote your dumpster article, but it was great to get more detail on it!
Also, you may be interested if you don't know already, that Jim McShane, an internet tube reseller, has some kind of tester where he can operate the tubes in circuit, and hit them with lots of voltage to see how well they hold up. He nailed the 6CM6 with up to 450v plate and screen awhile back after I asked him if they hold up as well as NOS 6V6's to Fender Deluxe Reverb voltages. He said they seemed to be just as robust as NOS 6V6's, with no red plating even at that voltage, which is very cool!
Just another thought. Amps sound different because of different circuit designs, including tone stacks, phase inverters, power supplies, drivers, voltages used in the driver and power sections, etc. There are several types of known and well-utilized designs for all of the above areas of amplifiers. Most boutique amps these days copy Fender, Marshall, Vox, etc. These original designs were taken from classic text books on tubes including the Radiotron Designers Handbooks 4th Edition and the Mullard Tube Amplifier Handbook.
Many of the circuit designs were initiated in the 1930s including the Ultra-Linear output stages. Tube design was an art form in the 1930s. In the 1940-50s, tube hi-fi was being perfected as where guitar amplifiers from our well-known manufacturers.
Designing an amp is like cooking, a little of this, a little of that, add this spice and heat to this temp with this voltage, and on and on. Design is an infinite set of possibilities.
Many of the circuit designs were initiated in the 1930s including the Ultra-Linear output stages. Tube design was an art form in the 1930s. In the 1940-50s, tube hi-fi was being perfected as where guitar amplifiers from our well-known manufacturers.
Designing an amp is like cooking, a little of this, a little of that, add this spice and heat to this temp with this voltage, and on and on. Design is an infinite set of possibilities.