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6SN7GT Plate type?
11/19/2006 6:28:44 PMDick
Apparently there is something special about the plate of a 6SN7GT plate and I don't know what it is. What do I look fore?
11/19/2006 10:20:58 PMDick
:Apparently there is something special about the plate of a 6SN7GT plate and I don't know what it is. What do I look fore? I understand that certain plate designs are very desirable to some people and I'm wondering what the most desirable ones look like. I know that AES charges more for the brown base, but they don't mention the plates type or shape. I have 22 of these tubes, but I don't know which ones are the most popular. Please help. Dick
11/19/2006 11:52:17 PMThomas Dermody
Ah. Supply and demand.

There are certain characteristics about certain element designs, though. This is true. Whether it be flat or shiny plates, or grid structure, or cathode shape, they all affect tonal response. Personally I don't know how each one affects how the tube operates. I do know, however, that different designs do sound different, even if only slightly.

T.

11/20/2006 10:02:34 AMRMeyer
If the tubes you are selling have any of the " special" qualitys that the audiophiles are looking for the amount you can get is amazing. Red base, brown base, black plate, 4 post, are some of the key words. If you read any of the hardcore audiophile magazines or web sites you will see black plate(s) mentioned time and time again. One expert says you must use CBS/Hytron Red Base 6SN7 in his designs or you will loose the "ethereal properties".
Whether or not you believe this, enough people do, to run the prices into the stratosphere for these tubes.
11/20/2006 12:08:26 PMThomas Dermody
Well, the color of the base certainly makes no difference. Just looks pretty.

Different internal structures do sound different, but this can often be corrected with changes in filter circuits and negative feedback. For instance, my Super Silvertone 6V6G has a much sharper treble than any of my other 6V6s. The rest have a much crisper fresher treble.

For really radical differences, try a 6V6 against a 6F6. The treble and bass will be much more pronounced with the 6V6. This isn't really what everyone is talking about, though.....I know that they're talking about subtle differences in different makes of one specific tube. The way the elements are structured and what they are made of does affect electron flow. If the electrons bump off of things or bend around things, this can set up cancellations and/or accentuations of certain frequencies. Interelectrode capacitance and cathode-plate resistance changes can affect tonal response, too.

T.

11/20/2006 3:37:52 PMT.I.
:Well, the color of the base certainly makes no difference. Just looks pretty.
:
:Different internal structures do sound different, but this can often be corrected with changes in filter circuits and negative feedback. For instance, my Super Silvertone 6V6G has a much sharper treble than any of my other 6V6s. The rest have a much crisper fresher treble.
:

So does this mean as you get older and your hearing starts to go you can buy the "less desirable tubes" cause you won't hear it anyways?

T Inatice
:For really radical differences, try a 6V6 against a 6F6. The treble and bass will be much more pronounced with the 6V6. This isn't really what everyone is talking about, though.....I know that they're talking about subtle differences in different makes of one specific tube. The way the elements are structured and what they are made of does affect electron flow. If the electrons bump off of things or bend around things, this can set up cancellations and/or accentuations of certain frequencies. Interelectrode capacitance and cathode-plate resistance changes can affect tonal response, too.
:
:T.

11/20/2006 3:40:44 PMThomas Dermody
I suppose you could. If you don't like the way an amplifier sounds, you can always correct it anyway. The negative feedback circuit I built allows me to tune in and out all sorts of frequencies.

T.

11/21/2006 9:21:48 AMNorm Leal
Hi Dave

Going back to your original question.. I would look for a 6SN7GT marked that way, made in the USA. To my ears they all sound the same if the tubes meet data book specs. I can't hear the difference in something that can't be measured...

Foreign 6SN7's may be ok too. Just quality control isn't always the best.

Norm

:I suppose you could. If you don't like the way an amplifier sounds, you can always correct it anyway. The negative feedback circuit I built allows me to tune in and out all sorts of frequencies.
:
:T.

11/21/2006 10:35:15 AMDick
Isn't there a lot of differencd in people's ears? Maybe some people can hear a difference and others can't. Perhaps the only way to say if there is a real difference in the sound is to do it with double blind experiments or else do it with a digital breakdown of the sound. My ears are all I have, so I will have to believe what they tell me. Dick


:Hi Dave
:
: Going back to your original question.. I would look for a 6SN7GT marked that way, made in the USA. To my ears they all sound the same if the tubes meet data book specs. I can't hear the difference in something that can't be measured...
:
: Foreign 6SN7's may be ok too. Just quality control isn't always the best.
:
:Norm
:
::I suppose you could. If you don't like the way an amplifier sounds, you can always correct it anyway. The negative feedback circuit I built allows me to tune in and out all sorts of frequencies.
::
::T.

11/21/2006 11:11:52 AMBill G.
:Isn't there a lot of differencd in people's ears? Maybe some people can hear a difference and others can't. Perhaps the only way to say if there is a real difference in the sound is to do it with double blind experiments or else do it with a digital breakdown of the sound. My ears are all I have, so I will have to believe what they tell me. Dick
:
:
::Hi Dave
::
:: Going back to your original question.. I would look for a 6SN7GT marked that way, made in the USA. To my ears they all sound the same if the tubes meet data book specs. I can't hear the difference in something that can't be measured...
::
:: Foreign 6SN7's may be ok too. Just quality control isn't always the best.
::
::Norm
::
:::I suppose you could. If you don't like the way an amplifier sounds, you can always correct it anyway. The negative feedback circuit I built allows me to tune in and out all sorts of frequencies.
:::
:::T.

Hi All,
I remember as a kid that TV repairmen would carry a large number of 6SN7GT. That is probably whay Dick has so many. Often they were asked to repair a TV which had lost vertical sync (picture would roll vertically).
When faced with this problem they would try swapping out 6SN7GTs until one oscillated in a stable manner. Often this was a 6SN7GT pulled from a neighbor's set because it wouldn't synchronize in that set.
They didn't seem to know what was going on and mentioned the plates 'getting soft' as a possibility, whatever that means. I think they were hinting at internal capacitance.
Of course all of them tested good on a tube tester.

Does anyone know what was going on?

All the Best,

Bill

11/21/2006 12:40:48 PMThomas Dermody
Well, regarding tube sound, tubes do sound slightly different, though it's often hard to notice the difference.

Also, people's hearing differs. Simple differences in the shape of an ear lobe can make all the difference. People with ears that are bent out more will catch more of the sharp treble notes, whereas people with ears that are flat against the head will tend to hear the highest register best. All sorts of other things affect what we hear, I'm sure.

At any rate, when one person is used as a constant, he or she will hear subtle differences in each tube, if he or she listens carefully. The way that person's ears are shaped, and the way that person's brain registers will determine which tube that person favors, if that person cares at all.

....And there are slight differences in tubes that can cause them to oscillate irratically, etc. A long time ago someone on here mentioned why it's a good idea to have a transconductance (or whatever it's called) tube tester, because such a tester could find a tube that has a cathode 'hot spot,' or a spot that emits a lot of electrons. Such a cathode stream would be difficult to control, since it'd only flow through a portion of the grid (theoretically.... though if the grid went negative, it might also disburse over the entire grid). Such tubes would be impossible to locate with an ordinary emissions tester, and such tubes might cause oscillation problems. As everyone seems to suggest, however, all sorts of things contribute to how a tube functions, including structure, minor flaws, slight assembly deviation from tube to tube, etc. Until someone takes the time to see just what these differences cause, and then write it down in a book, it will only be possible to see for yourself by trying the tubes for yourself. It would be interesting if, at very least, someone published a book on amplifier tubes, and how different brands and different variatios in each brand sound....and not just verbal explanation, but also graphical reports showing the slight differences. Such a report would also have to be made with the tubes being tried in many different amplifiers with many different circuit layouts and variables. It would be even more interesting if the book also had a section on radios and televisions.

T.

11/21/2006 5:39:23 PML.N.
Spock has 20hz to 20khz +/- 3db ear response.

L. Niemoy

11/21/2006 8:46:01 PMDoug Criner
Better than my hearing, but otherwise not all that impressive. Modern audio amplifiers with good speakers can do better.

When you say +/- 3dB, that's quite a range by audiophile standards. A factor of 4, audio power-wise.

:Spock has 20hz to 20khz +/- 3db ear response.
:
:L. Niemoy

11/21/2006 10:25:24 PMNorm Leal
I remember having some problems using Sylvania 6SN7GTW tubes. They have less capacity between elements and oscillators won't always lock in.

Norm

:Better than my hearing, but otherwise not all that impressive. Modern audio amplifiers with good speakers can do better.
:
:When you say +/- 3dB, that's quite a range by audiophile standards. A factor of 4, audio power-wise.
:
::Spock has 20hz to 20khz +/- 3db ear response.
::
::L. Niemoy



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