I have 4 of them,can they be used for sommething?
Maybe substitute for 6CG7??
They have a mu of 60.
Maybe substitute for 6CG7??
They have a mu of 60.
The more detailed data sheets show a mu that varies from around 20 to 70 depending on current and voltage - in other words, very nonlinear. 6CG7 is quite good, mu varying from 19 to 21 over a wide range of currents.
The tube was designed as a relay driver (switch) so it does not require linearity.
Look at the variation of Mu with grid bias in the last plot on this datasheet.
http://www.r-type.org/pdfs/6ev7.pdf
Look at the variation of Mu with grid bias in the last plot on this datasheet.
http://www.r-type.org/pdfs/6ev7.pdf
I played with a similar relay driver tube, the 12FV7 many years ago. A good data sheet is nowhere to be found, but like the 6EV7, they were not intended for linear operation.
They make fair cathode followers if the current is kept high enough. Stuffing them into a 12BH7 socket in an audio driver application raises the measured THD, but it is mostly 2H and doesn't sound bad.
They make fair cathode followers if the current is kept high enough. Stuffing them into a 12BH7 socket in an audio driver application raises the measured THD, but it is mostly 2H and doesn't sound bad.
12FV7 datasheet
I recall seeing a 12FV7 datasheet (plate curves etc) on the CD enclosed with Lud Sibleys' "TubeLore II", which I think is still available.
Like a 6CG7 with more grunt though a bit less linear - mu around 20, gm around 10mS, a lot like the 7044 but lower max plate dissipation and a 12V 450mA or 6V 900mA heater. Useful device, and have used it in common cathode, cathodyne and cathode follower configurations.
I recall seeing a 12FV7 datasheet (plate curves etc) on the CD enclosed with Lud Sibleys' "TubeLore II", which I think is still available.
Like a 6CG7 with more grunt though a bit less linear - mu around 20, gm around 10mS, a lot like the 7044 but lower max plate dissipation and a 12V 450mA or 6V 900mA heater. Useful device, and have used it in common cathode, cathodyne and cathode follower configurations.
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They're actually quite effective in adding "tube EFX" to conventional guitar amplifiers! All that nonlinearity colors amplification a whole bunch, and ends up adding quite a bit to the signal. Not for stage one, of course, but middle amplification stages. Just saying … some people say pig's ear and other claim steak
⋅-⋅-⋅ Just saying, ⋅-⋅-⋅
⋅-=≡ GoatGuy ✓ ≡=-⋅
⋅-⋅-⋅ Just saying, ⋅-⋅-⋅
⋅-=≡ GoatGuy ✓ ≡=-⋅
6EV7 and 12FV7 - and 12FV7 compared to ECC99
OK - Tube Lore says that both tubes were available for relay work. However, only the 6EV7 had variable mu - the 12FV7 is quite linear.
The pin-out, plate curves, inter-electrode capacitances and other electronic characteristics for the 12FV7 and ECC99 look identical (and very close to the 7044 and 7119 too).
However, the ECC99 is a tougher tube than the 12FV7 - key differences include max plate voltage (300V for 12FV7, 400V for the ECC99), max plate current (30mA vs 60mA), max plate dissipation (2.5W vs 5.0W), and max heater cathode voltage (200V vs 100V, if the ECC99 figure is a DC voltage).
As for distortion, the 12FV7s I have used have all performed well and just as expected going by the data sheet. However, I used them at lower plate voltages and anode currents than are allowed for the ECC99 - I don't know how well 12FV7s would behave under those conditions.
Thanks for prompting me to dig out Tube Lore - I am reminded what a valuable resource it is and have now loaded it on to my new laptop.
OK - Tube Lore says that both tubes were available for relay work. However, only the 6EV7 had variable mu - the 12FV7 is quite linear.
The pin-out, plate curves, inter-electrode capacitances and other electronic characteristics for the 12FV7 and ECC99 look identical (and very close to the 7044 and 7119 too).
However, the ECC99 is a tougher tube than the 12FV7 - key differences include max plate voltage (300V for 12FV7, 400V for the ECC99), max plate current (30mA vs 60mA), max plate dissipation (2.5W vs 5.0W), and max heater cathode voltage (200V vs 100V, if the ECC99 figure is a DC voltage).
As for distortion, the 12FV7s I have used have all performed well and just as expected going by the data sheet. However, I used them at lower plate voltages and anode currents than are allowed for the ECC99 - I don't know how well 12FV7s would behave under those conditions.
Thanks for prompting me to dig out Tube Lore - I am reminded what a valuable resource it is and have now loaded it on to my new laptop.
That.
I use ECC189 for the same reason, lotsa flavour.
Think using sauerkraut instead of fresh cabbage in your Shchi, salty anchovies instead of tuna over your Pizza or eating sourdough bread, same thing.
I found a thread where I had found a basic data sheet for the 12FV7 back in 2005. It's from a paper tube manual that I should still have....somewhere. I also have about 15 NOS RCA 12FV7's, so I must have though that they were good for something, don't remember what though.
help 12FV7 datasheet
help 12FV7 datasheet
No youre right about that... 🙂
I wonder why I bought them..
You learn sommething new every day..
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As with the 6386 tubes used in these compressors the distortion produced is mostly even order, so reasonable results can be achieved in balanced (push-pull) circuits.
The 6386 was originally designed for AGC controlled RF amplifiers in radio equipment. NOS tubes go for stupid money today. It is a tiny wimpy tube. Fairchild had to use 4 of them in parallel. The 6EV7 is like 4 or more 6386's in parallel already.
I set out to build a reasonably HiFi version of the variable gain cell seen in the Fairchild 670 compressor for use in a vacuum tube music synthesizer. For a benchmark I built a simplified and cost reduced clone of the 670 circuit, then went from there. I wound up with a pair of cheap TV pentodes and near HiFi performance with cheap transformers.
The experiment is scattered throughout this short thread, but post #39 highlights the results.
Modular Synth build
The 6386 was originally designed for AGC controlled RF amplifiers in radio equipment. NOS tubes go for stupid money today. It is a tiny wimpy tube. Fairchild had to use 4 of them in parallel. The 6EV7 is like 4 or more 6386's in parallel already.
I set out to build a reasonably HiFi version of the variable gain cell seen in the Fairchild 670 compressor for use in a vacuum tube music synthesizer. For a benchmark I built a simplified and cost reduced clone of the 670 circuit, then went from there. I wound up with a pair of cheap TV pentodes and near HiFi performance with cheap transformers.
The experiment is scattered throughout this short thread, but post #39 highlights the results.
Modular Synth build