I like and use the 6P14P-EV in some of my own projects, it is pretty close in performance to the 7189, and even sounds nice.
Indeed.
I will take the EL84 every time although some 6V6's I have look really cool, like the older G type with coated glass or the smaller US Navy RCA GTY with coated glass and micanol base.
forgive us for offtopic moderator ....
7189 - a rigid tube than 6P14P.
Soviet is another interesting tube 6P43P.
When the coincidence of the pin can not be used in place of 6BQ5 and the like.
This tube is designed for TV receiver assembly of vertical deflection.
In PP AB fixity offset, two tubes, you can get a fairly 20-22W RMS output at low distortion.
Raa 8-8,5kOhm, Ea -400V, Ec2-150V, Ec1- -20-25V, Ia-20-25mA.
I thought these tubes put in place 7591, these tubes have difficult to buy.
7189 - a rigid tube than 6P14P.
Soviet is another interesting tube 6P43P.
When the coincidence of the pin can not be used in place of 6BQ5 and the like.
This tube is designed for TV receiver assembly of vertical deflection.
In PP AB fixity offset, two tubes, you can get a fairly 20-22W RMS output at low distortion.
Raa 8-8,5kOhm, Ea -400V, Ec2-150V, Ec1- -20-25V, Ia-20-25mA.
I thought these tubes put in place 7591, these tubes have difficult to buy.
If you want to design the bulb, but need close characteristics EL84 note EL12 tube.Indeed.
I will take the EL84 every time although some 6V6's I have look really cool, like the older G type with coated glass or the smaller US Navy RCA GTY with coated glass and micanol base.
It is a wonderful tube sound!
Excellent if you purchase from Telefunken.
I'll check out the 6P43P, sounds very interesting.. Edit: Seems to be equivalent to EL86/6CW4. (Familiar type and sold by Sovtek and others for many years - first example Svetlana SV86)
The 6P14P is a little different than the 6P14P-EV (I have both), the -EV seems to be of much heavier construction and altogether a better tube. I have also gotten my hands on some -ER as well, but rarely. (One would expect the construction to be the same, but apparently not)
The 6P14P is a little different than the 6P14P-EV (I have both), the -EV seems to be of much heavier construction and altogether a better tube. I have also gotten my hands on some -ER as well, but rarely. (One would expect the construction to be the same, but apparently not)
I've read that in the case of front end tubes, the 7 and 9 pin "miniatures" were considered more durable and reliable than the octal tubes of the day (12AX7 instead of 6SL7 for example). Plus they take up less space. I've also been told by a local tube guru that many of the earlier 8 pin octal tubes are actually more linear than their miniature replacements (6SN7 vs 12AU7 for ex.). In the case of these two tubes (EL84 vs 6V6) I don't know if there's a significant reliability issue. Since power tubes need more space around them for thermals, I don't know if the EL84 really saves space over the 6V6. I know one guy (a professional bluegrass musician) who likes the sound of the EL84 for Hi-Fi so much that his email address is 6BQ5@...
In the case of 6SN7 vs 12AU7, those are actually two different types. 6SN7 looks to be far more linear.
However, 6SN7 and 6CG7/6FQ7 are direct equivalents, except for octal vs 9pin mini bases. What I don't know is if the 6SN7 is more linear overall than 6CG7/6FQ7. If it is, then that would suggest that there is a linearity advantage for the same tube in a larger octal base.
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I prefer the EL84 because it's more "flexible". Can do pentode, UL 20% or UL 43% and thanks to its high sensitivity with high gm it's perfect for cathode feedback with dedicated winding. I particularly like UL 20% with cathode fb. The 6V6 gives no real advantages in UL in comparison to tetrode and is not the ideal candidate for cathode fb because of its moderate gm and lowish sensitivity. It's better if one wants to get some power in triode SE class A2 or PP AB2 (over 3W and over 10W, respectively).
I actually thought that 6V6GT was going out of production because many miniature tubes can now fulfil the same task.
As I see it the main advantage of the EL84 over the 6V6 is its lower signal drive requirement. E.g. EL84 can mostly work very well with a cathodyne phase inverter, whereas a 6V6 type may require an unpractical signal drive voltage, also to be delivered by the input stage.
As I see it the main advantage of the EL84 over the 6V6 is its lower signal drive requirement. E.g. EL84 can mostly work very well with a cathodyne phase inverter, whereas a 6V6 type may require an unpractical signal drive voltage, also to be delivered by the input stage.
I have used 5V6 and EL84 in both Se and PP. I have always been partial to the EL84 as I am to the Fostex FE103.
IMO 5V6 sounds a bit "coarse" or "unrefined" in comparison, iow, it sounds similar to the 6L6. Nothing wrong with it, just i prefer the EL84. I find the EL84 has an authoritative sound with excellent clarity and tone although physically it does not look impressive as a power tube. Perhaps there is something to the "made for audio" tube types.
Its easy to implement, and if you blow on the grid it will amplify
I presently use them in a Diytube "kind of clone" of the Dynaco ST-35 with differences being 12AX7 / 12AUL combo instead of 12DW7 and individually adjustable cathode bias. I made a change where I removed the cathode bias and installed the Enhanced fixed bias circuitry as championed by David Gillespie with individual bias pots.
It sounds absolutely wonderful to me, excellent bass and a nice even tone throughout. It actually got me off SE amps.
IMO 5V6 sounds a bit "coarse" or "unrefined" in comparison, iow, it sounds similar to the 6L6. Nothing wrong with it, just i prefer the EL84. I find the EL84 has an authoritative sound with excellent clarity and tone although physically it does not look impressive as a power tube. Perhaps there is something to the "made for audio" tube types.
Its easy to implement, and if you blow on the grid it will amplify
I presently use them in a Diytube "kind of clone" of the Dynaco ST-35 with differences being 12AX7 / 12AUL combo instead of 12DW7 and individually adjustable cathode bias. I made a change where I removed the cathode bias and installed the Enhanced fixed bias circuitry as championed by David Gillespie with individual bias pots.
It sounds absolutely wonderful to me, excellent bass and a nice even tone throughout. It actually got me off SE amps.
Well Johan it really depends on what you are looking for. Cathodyne is certainly possible and easy with 6V6 for both the typical 14W class AB1 and the 11W class A PP (both in tetrode mode). The class A amplifier being just a small tweak of the AB1 with about 40 mA anode current per tube. The class A amplifier looks like a waste because it runs hotter at 11.4 W plate dissipation and has got less power but distortion is lower nearly up max power, in particular it is substantially lower at low level. The AB1 requires 38V grid-to-grid and the class A about 34V grid-to-grid. It's about half of the drive you need for a typical EL34 PP in AB1, in both pentode and UL, and even there cathodyne is perfectly possible.
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Indeed, mainstream manufacturers not using the 6V6 (a 1936 release) and using the EL84/6BQ5 (a 1954 release) does NOT any any way means the 6BQ5 is a lower distortion or better sounding tube. Sound quality had nothing to do with it.
Not only were the noval 7-pin and 9-pin tubes much cheaper to make, (and the sockets cheaper too) the 6V6 needs a lot more chassis room - more cost.
Also, post-war, the Philips pentode patents had expired - that was a factor in American production changing to pentodes, the American industry dragging the rest of the World along with it. Except for Europe of course - they had been using pentode power amps all along.
But, more importantly, by the time the 6BQ5 came out, the 6V6 had long been listed by its manufacturers as "Available for maintenance replacement only, not for new equipment". This is tube manufacturer-speak meaning "We have stopped quantity production - you can still buy it while stocks last". Once a tube is listed in this way, all professional equipment manufacturers will imediately stop using it.
Once the triode-pentodes intended for TV (eg 6BM8) came out, they reduced the cost of making an audio amp still more, and TV tubes were built to higher reliability standards, as a TV typically had about 20 or so tubes instead of typically 5 in a radio or stereo. To get TV's to have an acceptable fault rate, the tubes had to be much better. Hence single pentodes like the 6BQ5, 6M5, etc had a short run.
There's no doubt that the ultra-linear pentode amps that came out from the mid 1950's on had less distortion than the earlier amps, pentode or tetrode. But you can use ultralinear with tetrodes such as the 6V6. The performance if competently engineered will be just as good, and can be better.
Not only were the noval 7-pin and 9-pin tubes much cheaper to make, (and the sockets cheaper too) the 6V6 needs a lot more chassis room - more cost.
Also, post-war, the Philips pentode patents had expired - that was a factor in American production changing to pentodes, the American industry dragging the rest of the World along with it. Except for Europe of course - they had been using pentode power amps all along.
But, more importantly, by the time the 6BQ5 came out, the 6V6 had long been listed by its manufacturers as "Available for maintenance replacement only, not for new equipment". This is tube manufacturer-speak meaning "We have stopped quantity production - you can still buy it while stocks last". Once a tube is listed in this way, all professional equipment manufacturers will imediately stop using it.
Once the triode-pentodes intended for TV (eg 6BM8) came out, they reduced the cost of making an audio amp still more, and TV tubes were built to higher reliability standards, as a TV typically had about 20 or so tubes instead of typically 5 in a radio or stereo. To get TV's to have an acceptable fault rate, the tubes had to be much better. Hence single pentodes like the 6BQ5, 6M5, etc had a short run.
There's no doubt that the ultra-linear pentode amps that came out from the mid 1950's on had less distortion than the earlier amps, pentode or tetrode. But you can use ultralinear with tetrodes such as the 6V6. The performance if competently engineered will be just as good, and can be better.
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45,
Well, yes - your figures are correct. I was perhaps overdoing it with the 6V6 statement. (Long time no use.) I would cop out of thus feeding p.p. EL34 and the like simply because there are better alternatives, but then greater flexibility with driving stages rather than 'not possible'.
So fine there from you.
@ Keit,
My RCA Tube Manual does not list the 6V6 as 'for replacement only' even in the 1955 edition, but your point taken.
But as you say, can make a perfectly acceptable amplifier in UL; not to be avoided because miniature tubes 'took over'. It simply requires almost twice the drive signal than EL84s and is more efficient - heater heat and such. I generally prefer beam tubes, rather more because I occasionally got a few red screen grid windings in EL84s and EL34s where they were not aligned with G1 (and still within dissipation specs). But that may have been because of the brand.
Well, yes - your figures are correct. I was perhaps overdoing it with the 6V6 statement. (Long time no use.) I would cop out of thus feeding p.p. EL34 and the like simply because there are better alternatives, but then greater flexibility with driving stages rather than 'not possible'.
So fine there from you.
@ Keit,
My RCA Tube Manual does not list the 6V6 as 'for replacement only' even in the 1955 edition, but your point taken.
But as you say, can make a perfectly acceptable amplifier in UL; not to be avoided because miniature tubes 'took over'. It simply requires almost twice the drive signal than EL84s and is more efficient - heater heat and such. I generally prefer beam tubes, rather more because I occasionally got a few red screen grid windings in EL84s and EL34s where they were not aligned with G1 (and still within dissipation specs). But that may have been because of the brand.
Hi Johan,
Please don´t call me a nitpicker but I think you are mixing up two things here.
Obviously an aligned or "shadow" type screen winding design requires more manufacturing precision than a non-aligned one, but that doesn´t automatically imply "lesser precision as required" for a non-aligned design.
Kind regards, Tom
Please don´t call me a nitpicker but I think you are mixing up two things here.
- There are beam power tubes and there are pentodes.
- There are multigrid tubes with aligned screen windings and there are multigrid tubes with unaligned screen wire windings.
Obviously an aligned or "shadow" type screen winding design requires more manufacturing precision than a non-aligned one, but that doesn´t automatically imply "lesser precision as required" for a non-aligned design.
Kind regards, Tom
Sometimes I torture power tubes just to see what they can do....
Among EL84's and 6V6's I have done it with the Russian versions because they are usually well made. The 6P14P-EV works fine both in triode and UL up to 350V. This was just plug in and see.....
The 6P6S will do that as well and in tetrode mode I have gone up to 450V plate voltage without issues. This time I did it having read the EH datasheet....
Among EL84's and 6V6's I have done it with the Russian versions because they are usually well made. The 6P14P-EV works fine both in triode and UL up to 350V. This was just plug in and see.....
The 6P6S will do that as well and in tetrode mode I have gone up to 450V plate voltage without issues. This time I did it having read the EH datasheet....
From my reading of O H Schade, three things are necessary to create a potential well between the the screen and anode and thus make a beam power tetrode:-
a) correct radial spacing of grids and anode - vital;
b) insertion of the two plates connected to cathode - plays a less important role
-and-
c) alignment of screen and control grid - vital.
It is the potential well beween the screen and anode that gets rid of the anode kink and also lowers anode dynamic impedance - not bad thing in a power tube.
So, while you can have aligned grids in an pentode, which only lowers screen current, I think you MUST have aligned grids in an audio power tetrode.
There were tetrodes made without aligned grids, but they were not intended for audio, and so are not relevant to Johan's comments.
Using a tetrode without aligned grids as an audio power amp will give very low power output, distortion, and most likely oscillation, due to the anode voltage/current kink.
What is more interesting is that some audio power tubes were orginally designed as beam tetrodes but some manufacturers made them as pentodes, and vice versa. The example most famous to those in the industry during the pre-transistor era was the 3V4 7-pin miniature power tube. RCA engineers designed it as a pentode. But it was made in vast numbers by all American, British, Australian, etc manufacturers as a beam tetrode. Only a few data sheets described it as a tetrode, but you can see the innards thru the glass, and it is invariably a beam tetrode.
Can you give an example of an audio power tetrode without aligned grids, Tom?
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Hi Keit,
Oh well, what is an "audio" tube anyway? If you think "audio mainstream", I don´t know offhand.
The last time I smashed an EL509 / 6KG6 / PL509 / 40KG6 it certainly didn´t sport aligned screen windings, but these types and their x519 variants have been used succesfully in amps considered excellent (though not mainstream, of course) like Tim de Paravinci/EAR, Seyer/Synola and IIRC Jean Hiraga and probably some famous other Futterman based designs, too.
There are examples of beam power tubes without aligned screen grids which feature absolutely stunning linearity, too. For example the beam power variant of EL83 / PL83 / 6CK6 / 15A6 which is a wide band video driver commonly used in gazillions of European TV sets. While EL83 / PL83 was designed as a true pentode in the first place, I have only a single true pentode one in the drawers (Marconi type N309) but about some 150 ones which were built as beam power types. I suspect these beam power xL83 types even _had_ to be manufactured w/o aligned screen grids to "simulate" the less efficent Ia/Ig2 ratio of the original xL83 true pentode type to qualify as xL83 replacement drop-ins, or just to qualify as xL83 as what they measure and what they are stamped.
Anyway, I still don´t see a valid "point against any pentode", as Johan put it.
Glowing screen grids, regardless of being found within beam power tubes or pentode tubes, in most cases are just a sure sign of running a tube outside of its specs. Unfortunately many people tend to ignore screen grid ratings or allowed areas of operation for screen grids as can be found in tube spec sheets. Most times - if any - there is just a check made at iddle conditions, which often enough is not sufficient.
Kind regards, Tom
Oh well, what is an "audio" tube anyway? If you think "audio mainstream", I don´t know offhand.
The last time I smashed an EL509 / 6KG6 / PL509 / 40KG6 it certainly didn´t sport aligned screen windings, but these types and their x519 variants have been used succesfully in amps considered excellent (though not mainstream, of course) like Tim de Paravinci/EAR, Seyer/Synola and IIRC Jean Hiraga and probably some famous other Futterman based designs, too.
There are examples of beam power tubes without aligned screen grids which feature absolutely stunning linearity, too. For example the beam power variant of EL83 / PL83 / 6CK6 / 15A6 which is a wide band video driver commonly used in gazillions of European TV sets. While EL83 / PL83 was designed as a true pentode in the first place, I have only a single true pentode one in the drawers (Marconi type N309) but about some 150 ones which were built as beam power types. I suspect these beam power xL83 types even _had_ to be manufactured w/o aligned screen grids to "simulate" the less efficent Ia/Ig2 ratio of the original xL83 true pentode type to qualify as xL83 replacement drop-ins, or just to qualify as xL83 as what they measure and what they are stamped.
Anyway, I still don´t see a valid "point against any pentode", as Johan put it.
Glowing screen grids, regardless of being found within beam power tubes or pentode tubes, in most cases are just a sure sign of running a tube outside of its specs. Unfortunately many people tend to ignore screen grid ratings or allowed areas of operation for screen grids as can be found in tube spec sheets. Most times - if any - there is just a check made at iddle conditions, which often enough is not sufficient.
Kind regards, Tom
According to Amperex data, the 6KG6 was designed as a "beam power pentode" intended for horizontal output service in TV sets. Such tubes usually do make good audio power amps, though the requirement for a low impedance low voltage screen supply is inconvenient. However unless there is beam forming, a tube (tetrode or pentode) cannot be a beam power tube. So it must have aligned grids.
The 6CK6 was designed as a pentode for video output service in TV sets with 2nd generation b/w CRT's. In such video output service, the ability to pull the anode far below the screen voltage is unimportant, so if any manufacturer chose a tetrode structure without aligned grids, it wouldn't matter. But it would in audio service - I would expect power output before gross distortion well below what the anode dissipation should achieve.
I've never seen these particular tubes though. Australian TV started relatively late and Australian sets invariably used the later higher rated tube types.
I do agree that if a receiving tube screen is glowing, you are doing something wrong. Horizontal output tubes aren't designed to have their screens at anode potential as is normally done with audio tubes.
The 6CK6 was designed as a pentode for video output service in TV sets with 2nd generation b/w CRT's. In such video output service, the ability to pull the anode far below the screen voltage is unimportant, so if any manufacturer chose a tetrode structure without aligned grids, it wouldn't matter. But it would in audio service - I would expect power output before gross distortion well below what the anode dissipation should achieve.
I've never seen these particular tubes though. Australian TV started relatively late and Australian sets invariably used the later higher rated tube types.
I do agree that if a receiving tube screen is glowing, you are doing something wrong. Horizontal output tubes aren't designed to have their screens at anode potential as is normally done with audio tubes.
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