I'd like to try building a simple tube preamp, and was looking at the 6112 tube. Musical Fidelity seems to have had good luck with them in their products, and the datasheet shows it as pretty linear. I'm new to tubes (and electrical engineering in general), and was wondering if anyone could suggest a preamp design I could use.
Use the values from the tube manual under "typical operation".
NJ7P Tube Database Search
Class A Amplifier
Plate Voltage ................................. 100 V
Grid No. 1 Voltage Derived from
Cathode Bias Resistor ....................... 1500 Ω
Amplification Factor .......................... 70
Plate Resistance (approx) ..................... 39K Ω
Transconductance .............................. 1800 µ
Plate Current ................................. 0.8 mA
NJ7P Tube Database Search
Class A Amplifier
Plate Voltage ................................. 100 V
Grid No. 1 Voltage Derived from
Cathode Bias Resistor ....................... 1500 Ω
Amplification Factor .......................... 70
Plate Resistance (approx) ..................... 39K Ω
Transconductance .............................. 1800 µ
Plate Current ................................. 0.8 mA
subminiature tubes
Yup... I've played with 6112, 6111, and 5744 extensively.
Very interesting tubes, and unique sound compared to their 9pin counterparts ie 12AX7, 12AU7 etc. I wouldn't call them 'terrible' Shoog, unless your standard for terrible is the 12AU7 😉
Yup... I've played with 6112, 6111, and 5744 extensively.
Very interesting tubes, and unique sound compared to their 9pin counterparts ie 12AX7, 12AU7 etc. I wouldn't call them 'terrible' Shoog, unless your standard for terrible is the 12AU7 😉
With a mu of 70 they are not a preamp tube. I've used a few 6112 for phono preamps or amp drivers. If you are looking for a subminature tube for a preamp look for tubes with a mu 16 or under. For example, Russian 6N28B-V, 6N32B and 6N18B are nice.
Matt
Matt
Greenvalve,
I've got many mounted on octal bases but the bases you picture look like nine-pin. Are they and if so where did you get them? For nine-pin bases I use socket savers but your's look like a much better nine-pin solution.
Matt
I've got many mounted on octal bases but the bases you picture look like nine-pin. Are they and if so where did you get them? For nine-pin bases I use socket savers but your's look like a much better nine-pin solution.
Matt
Ha Matt,
Those 9-pin adapters are unobtainium. I've been looking for more for over a decade. Cool huh?
I agree that the 6112 is good for #1 tube in a phono pre. The thing is dead silent in that position, and absolutely no microphonics. In the end, it was 'too good' for me 😉
Ive used the 6111 in a few preamps that called for 12AU7 (like the Trancendent GG). It was very nice, but again I missed the wet 2nd harmonics.
Those 9-pin adapters are unobtainium. I've been looking for more for over a decade. Cool huh?
I agree that the 6112 is good for #1 tube in a phono pre. The thing is dead silent in that position, and absolutely no microphonics. In the end, it was 'too good' for me 😉
Ive used the 6111 in a few preamps that called for 12AU7 (like the Trancendent GG). It was very nice, but again I missed the wet 2nd harmonics.
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Greenvalve,
Those nine-pin bases are cool, they almost look designed for sub-mini tubes. The guitar guys have sucked up many of the 6112s. The hi-mu Russian’s like 6N17B-V, 6N21B and 6N33B are nice, and still available cheaply. I’ve never cared for the 6111 either and I wanted to. Give the Russian 6N28B-V a listen where you need a low mu tube, it’s a nice one as well. I’ve used 6N28B-V with plate voltages from 28V to 160V with no ill effects. There are a host of Russian directly heated sub mini pentodes that are great preamp tubes as triodes, 1J17B, 1J18B, 1P24B-V, 1J29B. Figuring out pin-out is a nice puzzle.
Matt
Those nine-pin bases are cool, they almost look designed for sub-mini tubes. The guitar guys have sucked up many of the 6112s. The hi-mu Russian’s like 6N17B-V, 6N21B and 6N33B are nice, and still available cheaply. I’ve never cared for the 6111 either and I wanted to. Give the Russian 6N28B-V a listen where you need a low mu tube, it’s a nice one as well. I’ve used 6N28B-V with plate voltages from 28V to 160V with no ill effects. There are a host of Russian directly heated sub mini pentodes that are great preamp tubes as triodes, 1J17B, 1J18B, 1P24B-V, 1J29B. Figuring out pin-out is a nice puzzle.
Matt
There's a fellow on the forum selling these quite cheaply - hence my asking. 🙂
Musical Fidelity is quite fond of these tubes, and uses 'em all over the place. However, it seems that the far cheaper 6021s tubes are a better choice, and rated for a lot more output. Thoughts?
Musical Fidelity is quite fond of these tubes, and uses 'em all over the place. However, it seems that the far cheaper 6021s tubes are a better choice, and rated for a lot more output. Thoughts?
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