I got an interesting headphone amplifier board today. There's a 6N11 tube on it, other silicons are 2xIRF630, 2xLM317 and 2 TO-92 transistor. The sound is fairly good with my HD600. Most interesting of all it is powered by single DC 24V! How can 6N11 work at such low voltage?
Google a bit, found that most 6N11 circuit need much higher voltage such as 150V or higher.
This is the headphone amp board
Google a bit, found that most 6N11 circuit need much higher voltage such as 150V or higher.
This is the headphone amp board
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There's no voltage multipler on board. The circuit should be like the one VictoriaGuy posted but there's one more transistor to drive the gate.
See the following photo, the TO-220 on the left is IRF630, right is LM317. There's a small TO-92 transistor near the IRF630.
See the following photo, the TO-220 on the left is IRF630, right is LM317. There's a small TO-92 transistor near the IRF630.
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Most all tubes will sort of work at low B+ voltage.
The distortion will be very high, but most of the distortion will be even-order distortion that most people perceive as sounding nice. And there is nothing wrong with that.
The (c) Rogers Gomez schematic looks like yet another variation on an amp designed a few years ago by a korean who went by the handle "sijosae" on the forums. He called this basic sort of design the Multi-Hybrid Headphone Amp or MHHA. He designed 6dj8 and 12au7 versions, with irf610 for output i think.
They were very popular back around 2004-2005. Many lookalikes have turned up on ebay.
Since the 6n11 is similar to a 6n1p which is similar to a 6dj8, i would assume that it's just another version.
There is nothing new under the sun, so i would not be surprised if it's been done before sijosae did it.
The distortion will be very high, but most of the distortion will be even-order distortion that most people perceive as sounding nice. And there is nothing wrong with that.
The (c) Rogers Gomez schematic looks like yet another variation on an amp designed a few years ago by a korean who went by the handle "sijosae" on the forums. He called this basic sort of design the Multi-Hybrid Headphone Amp or MHHA. He designed 6dj8 and 12au7 versions, with irf610 for output i think.
They were very popular back around 2004-2005. Many lookalikes have turned up on ebay.
Since the 6n11 is similar to a 6n1p which is similar to a 6dj8, i would assume that it's just another version.
There is nothing new under the sun, so i would not be surprised if it's been done before sijosae did it.
Those little 'Bravo/G2-style' amps are fun (I've got one), but it's not a direction that holds much interest for me. I think the tube is a bit of a gimmick- same as in the 'tube preamp' guitar effects running tubes at low voltage.
I've assembled both SS (Panda) and tube (Crack) HP amps and they are both miles ahead of the little hybrid I have. (More $$ by factor of 4?, also.)
But give it a shot and let us know how it turns out!
EDIT: ericJ has given you the pointers you need.
Eh, whether or not a boatload of 2nd order harmonic distortion is a gimmick is a question of taste.
If you're going to run at low B+ there are space charge tubes, but 12au7 is cheaper than 12ae6a these days.
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The 6N1p is often touted as similar to the 6dj8, especially by ebay sellers. But it's not equivalent.
The 6dj8 is known to work well at low B+, but I doubt that the 6n1p works anywhere near as well.
A better choice, and a real equivalent to the 6dj8 is the 6n23p. Not sure if it's pin compatible with the 6n1p though.
Well I did say 'similar'.
I agree that the 6n1p likes a lot more voltage than the 6dj8 or 6n23p, and that the 6n23p is the true russian 6dj8.
AFAIK the 6n1p and 6n23p are pin compatible, meaning that they both have the same slightly different heater configuration vs. 6dj8 types. Always check datasheets and wiring diagrams when swapping tubes.
I have yet to see curves for the 6n11, but the implication I've seen is that it's supposedly a chinese 6n1p.
I have yet to see curves for the 6n11, but the implication I've seen is that it's supposedly a chinese 6n1p.
A 6N1 is, predictably, a 6N1P.
A 6N11 is equivalent to a 6N23P (is a 6DJ8 is an ECC88).
The Soviet 6N11(P? S?) is some third thing that you never see. Ask Wavebourn maybe.
So much for the otherwise OK nomenclature. This may have occurred in a period where the USSR and PRC stopped talking so much, I don't know. At least it's not the monoclonal antibody naming system.
A 6N1 is, predictably, a 6N1P.
A 6N11 is equivalent to a 6N23P (is a 6DJ8 is an ECC88).
The Soviet 6N11(P? S?) is some third thing that you never see. Ask Wavebourn maybe.
So much for the otherwise OK nomenclature. This may have occurred in a period where the USSR and PRC stopped talking so much, I don't know. At least it's not the monoclonal antibody naming system.
Interesting. is a 6gm8 a space charge tube? I have a few schematics of a home made low voltage power amp. Not sure if I could use it for a standard Push Pull config, it appeared to be for guitar use. May want to play with one of these designs as the power transformer I need for my 6bm8 push pull amp from Edcor is a bit more than I can afford right now.
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