... And yet my experiences differ.
The 6922EH is a 6922. The Sovtek 6922 is a 6H23П-EB. The entire idea of the Electroharmonix is reverse engineered North American tubes to be exactly that. The comments I have just read do pertain to the Sovtek tubes that I used right after New Sensor started with them. Changing to the Electroharmonix branded tubes instantly eliminated comments about the Sovtek being "bright".
I favor Electroharmonix tubes in my own equipment, they are every bit as good as NOS tubes, but with a much tighter control over characteristics. The 6922EH are very quiet as well. In the 12AX7EH, the low noise took me by surprise (maybe we are hitting the crap of NOS with the 12AX7?). I will gladly take a new Electroharmonix tube for any of my NOS tubes (except the ones marked "McIntosh"
).
Anyway, you can't go wrong with an Electroharmonix branded tube. Oh, the 6L6EH plates look like a 7581A plate. They will take a Fender Twin Reverb all day. Not many 6L6GC tubes will.
-Chris
The 6922EH is a 6922. The Sovtek 6922 is a 6H23П-EB. The entire idea of the Electroharmonix is reverse engineered North American tubes to be exactly that. The comments I have just read do pertain to the Sovtek tubes that I used right after New Sensor started with them. Changing to the Electroharmonix branded tubes instantly eliminated comments about the Sovtek being "bright".
I favor Electroharmonix tubes in my own equipment, they are every bit as good as NOS tubes, but with a much tighter control over characteristics. The 6922EH are very quiet as well. In the 12AX7EH, the low noise took me by surprise (maybe we are hitting the crap of NOS with the 12AX7?). I will gladly take a new Electroharmonix tube for any of my NOS tubes (except the ones marked "McIntosh"
).Anyway, you can't go wrong with an Electroharmonix branded tube. Oh, the 6L6EH plates look like a 7581A plate. They will take a Fender Twin Reverb all day. Not many 6L6GC tubes will.
-Chris
I have examples of both and their internal construction is quite different.
Cheers
Ian
Scheme makes for the sound, Not the tube--Unless the scheme design is poor to start with!
--Tubes have very little difference in perceived sound, unless in marginal equipment.
True--most Audiofools will think a $200.00 pre-amp tube will sound better than a $2.00 one--Placebo effect in action!
--Tubes have very little difference in perceived sound, unless in marginal equipment.
True--most Audiofools will think a $200.00 pre-amp tube will sound better than a $2.00 one--Placebo effect in action!
The sound of the circuit-tube combination will change if the characteristics of the tube are far off from the "normal" tube the circuit was designed for. So while a tube doesn't have a sound, its interaction with the circuit will be changed for different characteristics. Put that tube into a corrected circuit and it should then sound similar.
The only sounds that tubes do have are due to defects, like leakage, movement of elements or contamination. Circuits that run tubes "wide open" will be sensitive to tube types more than the standard type of design where the goal was top have consistent performance over the normal range of variable tube characteristics (the ones in the tube manual).
What makes a "best brand" for tubes? One where defects are minimal and characteristics from tube to tube are close (ie production processes are under control). By that definition, Sovtek tubes are very good, as are Electroharmonix tubes. But, they are different tubes and often the Sovtek tubes are not suited to American designs. Just like an Electroharmonix is not suited to Russian designs via cross referenced substitution. The Sovtek tubes have already been cross-referenced and labeled as the closest tube types.
Some day I'm going to have to design something with the Russian tubes. The Reflektor (sp?) factory seems to make really excellent tubes.
-Chris
The only sounds that tubes do have are due to defects, like leakage, movement of elements or contamination. Circuits that run tubes "wide open" will be sensitive to tube types more than the standard type of design where the goal was top have consistent performance over the normal range of variable tube characteristics (the ones in the tube manual).
What makes a "best brand" for tubes? One where defects are minimal and characteristics from tube to tube are close (ie production processes are under control). By that definition, Sovtek tubes are very good, as are Electroharmonix tubes. But, they are different tubes and often the Sovtek tubes are not suited to American designs. Just like an Electroharmonix is not suited to Russian designs via cross referenced substitution. The Sovtek tubes have already been cross-referenced and labeled as the closest tube types.
Some day I'm going to have to design something with the Russian tubes. The Reflektor (sp?) factory seems to make really excellent tubes.
-Chris
Years of tube rolling and a pair of good ears tell me that what you said is not true. There are sound differences between tube brands used in the same circuit.
Umm... Electro-harmonix tubes are made by the Reflektor plant in Russia... why aren't they suited to Russian designs?
Hi Vincent77,
Sovtek tubes (Reflektor) are made to Russian tube specs. They are Russian tubes with the nearest North American number marked on the glass and box.
Electroharmonix tubes (Reflektor) are made to conform to North American tube specs. These were come by through reverse engineering some NOS tubes considered to be the best for that type. The 12AX7EH was an RCA 12AX7A. Guess what? The Reflektor factory did their job extremely well and produce a superior product than what I used to buy here in Canada in the 60's and 70's. The variation from tube to tube is far less than was the accepted norm back in those good (?) old days. Their glass is heavier too, and that probably helps with gassing and vibration.
The characteristics of a tube work with the circuit to make up a transfer characteristic. This is what you hear. You put a tube in there with totally different characteristics and you get a different transfer characteristic and ... it doesn't sound exactly the same. Worse - better? Depends on how well the circuit design works with the boogey tube type characteristics. If the designer messed up, a Russian tube may well match the circuit better than what he intended. Get a design from a real designer and you will see that the tubes closest the standard for the type sound the best. North American types over here, Russian types over there and European types in Europe. No surprises.
When you do "tube roll" (I hate that term), pay attention to the heater current!! Also look at the plate voltages and currents expected. For example, there is a popular substitute for a 6L6 tube with a 25 watt plate. The 6L6 has a 25 watt plate, but a 6L6GC has a 30 watt plate and higher voltage ratings. That oft misused replacement doesn't last long in circuits that push the 6L6GC a little. Yet, people still use that tube to replace the 6L6GC. Fat, dumb and happy in their ignorance. You really ought to know what you are doing while trying different tube types. Just because others do it and report on this doesn't excuse you from at least looking up the specs to see if the substitution is reasonable. There are times the substitution is not a reasonable thing to do, and it is amazing how well parts can stand up to being abused without failing dramatically.
Put this another way. Just because a screw factory makes North American sized screws (not mating with metric threads) doesn't mean it can't produce fine metric screws as well. This is in effect what I am saying to you.
-Chris
Why? You do understand that those varying tube types you are playing with will measure differently - big time. If you can hear a difference, big changes are the cause.
Read my explanation again carefully please.
Sovtek tubes (Reflektor) are made to Russian tube specs. They are Russian tubes with the nearest North American number marked on the glass and box.
Electroharmonix tubes (Reflektor) are made to conform to North American tube specs. These were come by through reverse engineering some NOS tubes considered to be the best for that type. The 12AX7EH was an RCA 12AX7A. Guess what? The Reflektor factory did their job extremely well and produce a superior product than what I used to buy here in Canada in the 60's and 70's. The variation from tube to tube is far less than was the accepted norm back in those good (?) old days. Their glass is heavier too, and that probably helps with gassing and vibration.
The characteristics of a tube work with the circuit to make up a transfer characteristic. This is what you hear. You put a tube in there with totally different characteristics and you get a different transfer characteristic and ... it doesn't sound exactly the same. Worse - better? Depends on how well the circuit design works with the boogey tube type characteristics. If the designer messed up, a Russian tube may well match the circuit better than what he intended. Get a design from a real designer and you will see that the tubes closest the standard for the type sound the best. North American types over here, Russian types over there and European types in Europe. No surprises.
When you do "tube roll" (I hate that term), pay attention to the heater current!! Also look at the plate voltages and currents expected. For example, there is a popular substitute for a 6L6 tube with a 25 watt plate. The 6L6 has a 25 watt plate, but a 6L6GC has a 30 watt plate and higher voltage ratings. That oft misused replacement doesn't last long in circuits that push the 6L6GC a little. Yet, people still use that tube to replace the 6L6GC. Fat, dumb and happy in their ignorance. You really ought to know what you are doing while trying different tube types. Just because others do it and report on this doesn't excuse you from at least looking up the specs to see if the substitution is reasonable. There are times the substitution is not a reasonable thing to do, and it is amazing how well parts can stand up to being abused without failing dramatically.
Put this another way. Just because a screw factory makes North American sized screws (not mating with metric threads) doesn't mean it can't produce fine metric screws as well. This is in effect what I am saying to you.
-Chris
Chris, that is not exactly true. I can hear the characteristic "sound" of different tube brands of the same reference, and it's not only because they measure differently. They have different internal structures, different geometry, different manufacturing tolerances, different cathode coating, different anode material, different insulators, and so on.
And yes, I try my tubes in carefully controlled circuits, with regulated heater PSUs, at multiple cathode currents and anode voltages... and yet I can pick up brand sound characteristics.
I hate to argue about this, so that's all I had to say. People with good headphones and good ears will understand what I mean.
I'm not sure I understand. A 12AX7/ECC83 should respect the datasheet specs, in the US, Europe or anywhere else... But nevermind.
Hi Craig,
Fantastic! Let me know via PM what you found, or was it just the glue?
Hi Vincent77,
If you can hear a difference, there is a difference that can be measured in the characteristics of the tubes in question. Not on a "tube tester" that most people are familiar with, but by using a setup that has measuring points on all the elements and uses higher frequency tests and a network / spectrum analyzer.
I hate to belabor a point, but all active components have production variances, some more than others. Units made on different machines with different materials can be called the same tube type, but within a broader range of characteristics. If you can hear a real difference, then that difference can be measured and quantified. So, while tubes may have the same type number, some will adhere to the spec a lot closer than others. If they are further out, they may still have the markings for a different tube type, as evidenced by Craig's 12AX7 experience. This is the real world with an imperfect way of defining the expected characteristics of a product, in this case a vacuum tube. For future reference, a dual triode tube does not have sections that perfectly match each other. They are two completely separate tubes that do differ, and they just happen to share a vacuum. So don't expect the two sections will match.
-Chris
Fantastic! Let me know via PM what you found, or was it just the glue?
Hi Vincent77,
If you can hear a difference, there is a difference that can be measured in the characteristics of the tubes in question. Not on a "tube tester" that most people are familiar with, but by using a setup that has measuring points on all the elements and uses higher frequency tests and a network / spectrum analyzer.
I hate to belabor a point, but all active components have production variances, some more than others. Units made on different machines with different materials can be called the same tube type, but within a broader range of characteristics. If you can hear a real difference, then that difference can be measured and quantified. So, while tubes may have the same type number, some will adhere to the spec a lot closer than others. If they are further out, they may still have the markings for a different tube type, as evidenced by Craig's 12AX7 experience. This is the real world with an imperfect way of defining the expected characteristics of a product, in this case a vacuum tube. For future reference, a dual triode tube does not have sections that perfectly match each other. They are two completely separate tubes that do differ, and they just happen to share a vacuum. So don't expect the two sections will match.
-Chris
Hi,
To paraphrase Hercule Poirot: " Exactement, mon ami".
And so it goes for a lot of materials active or passive...Most of them do have a sonic signature and become audible when used in abundance....
Cheers,
To paraphrase Hercule Poirot: " Exactement, mon ami".
And so it goes for a lot of materials active or passive...Most of them do have a sonic signature and become audible when used in abundance....
Cheers,
Indeed - Sovtek abusively rebranded 6N2P tubes into 12AX7. Close, but not the same tube. They are not "russian 12AX7" - they are 6N2P with a different heater connexion.
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