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Any very good sounding tube headphone amp ideas ?

Dear all, I'd like to build my very first tube headphone amp.
Any ideas, a simple schematics maybe ? I'm not an electrician but I can solder and had some little projects already, all with success.

My headphone's parameters:
Max. power rating: 0.05W (50mW)
Max. voltage: 1.2Vrms (3.3Vpp)
Max. current: 43mA
Max. S.P.L.: 113dB
Impedance: 28 Ω
Efficiency: 96 dB/1mW (111dB/1V)

In the future I'd like to be able to drive some more serious headphones with it too, like Sennheiser's HD800S, which seems to be a very different animal (300 Ohms if I'm correct).

I prefer JJ tubes, we have easy access to them in Europe, but actually any brand might be okay as well.

Many many thanks :wave:
 
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Joined 2011
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I use this. It will swing 42mA. 28R is close enough to 32R that this circuit will drive it. Bonus: No OPT!

The tubes aren't JJ, but you can use ECC99 instead of 6N6P... 6N6P is cheaper though :)
 

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I use this. It will swing 42mA. 28R is close enough to 32R that this circuit will drive it. Bonus: No OPT!

The tubes aren't JJ, but you can use ECC99 instead of 6N6P... 6N6P is cheaper though :)

I already have 2x new JJ ECC99 tubes lying around. No OPT is especially interesting in this design. It seems to be very simple which I also like. Thanks :worship: I'll let you know how it sounds when I'm ready with it. This will be the first one.

What's the equivalent of 6N1P ? I read at some forums it CAN be the ECC85 but not 1:1 - or even yes. Depends on drive, heating, etc. I have 2x JJ E88CCs too (new), maybe I could use them with adjusted circuit values instead of 6N1Ps in your schematics.

Opinion 1:
I would not suggest others trying the ECC85 as a drop in replacement for a 6N1 because it is not. The 6N1 (Chinese) / 6N1P (Russian) have a higher heater current draw at about 600mA, the ECC85 has a 435mA heater current draw. The 5670 has similar specs to the 6N1/6N1P but the socket needs to be re-wired. A circuit built for a 6N1P is a circuit designed for a 6N1P, any other drop-ins other then 6N1P is not helping the circuit. Just because it works and doesn't arc doesn't mean it is suited for the amp.


Opinion 2:
There is no direct drop in equivalent for the 6N1/6N1P besides another Chinese or Russian 6N1/6N1P, the best drop in is the EV which is military spec'd, more rugged built and handle more abuse, whether it sounds better or not to the standard ones is another story based on subjectivity.
 
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I built a modified version (attached) of this:

Mine are "Gaming" headphones for the PC, the Cooler Master MH751. Which are the rebranded Takstar Pro 82, without the adjustable bass ports (which I wouldn't use anyway, just heard my friend's Pro82, but the mic is very useful to me since I'm doing lots of VoIP calls with a friend of mine).

Not a big deal either, especially in this price range but these are kind of
highly praised headphones (price vs. performance) and to my ears they just sound quite revealing already, very well balanced, no sharp edges, no boomy bass, wonderful midrange ... just what I like. They're driven by my motherboard's Realtek chipset (with all the bells and whistles like golden contacts, separate audio circuitry, hifi audio grade caps, etc etc which I think is more marketing than real capabilities but it's still amazing compared to my 10 yrs old Gigabyte mobo's Realtek). Of course I still need something more 'punchy' and my headphones can definitely get much more power, I can easily listen Mark Knopfler at 100% volume setting.

My intention is to build a small external DAC for it (with an ES9038-based ready-made board from Aliexpress) and drive a Class A/AB tube headphone circuitry from that DAC.

Transformer: I might order one from Plitron or similar good quality manufacturer.

We'll see. DIY is fun :)
 
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Member
Joined 2011
Paid Member
What's the equivalent of 6N1P ? I read at some forums it CAN be the ECC85 but not 1:1 - or even yes. Depends on drive, heating, etc. I have 2x JJ E88CCs too (new), maybe I could use them with adjusted circuit values instead of 6N1Ps in your schematics.

Opinion 1:
I would not suggest others trying the ECC85 as a drop in replacement for a 6N1 because it is not. The 6N1 (Chinese) / 6N1P (Russian) have a higher heater current draw at about 600mA, the ECC85 has a 435mA heater current draw. The 5670 has similar specs to the 6N1/6N1P but the socket needs to be re-wired. A circuit built for a 6N1P is a circuit designed for a 6N1P, any other drop-ins other then 6N1P is not helping the circuit. Just because it works and doesn't arc doesn't mean it is suited for the amp.


Opinion 2:
There is no direct drop in equivalent for the 6N1/6N1P besides another Chinese or Russian 6N1/6N1P, the best drop in is the EV which is military spec'd, more rugged built and handle more abuse, whether it sounds better or not to the standard ones is another story based on subjectivity.

There is no true equivalent, but almost any 9 pin dual triode will work there... 12AU7, 5670. 6N3P, 6N23P, 6N24P, 6N14P, ECC84, ECC85 will all work without circuit modifications. Mind the pinouts though. If you need more gain 12AT7 will sub in, too. 6CG7 (or 6SN7/6N8S) will work if you change 240R to 470R (both cathode resistors of the first tube although it will work with 240R, it'll just run hot), and 12AX7/6N2P will sub in using 1k resistors.

Very versatile and forgiving circuit really.
 
Thank you all, I'm really glad I had so many comments here for a simple topic. That's why I love to come and 'chill' here.. great community, great people. :)

I'm going to make the simple design mentioned earlier and then maybe a next one, just for fun and seeing (hearing) the differences. :scratch2:

If interested, I'll post some pics here.

:cheers:
 
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Joined 2016
Paid Member
Very good 6N1P or 6N1P-EV are still available from Russian or Ukrainian sellers on the big auction site for little money. Have bought all my Russian tubes this way.

The more I use this tube, the more I like it :)

Regards, Claas


P.S.: My very first tube amp design was a headphone amp kit I bought from the small German firm Ampdesign, the KHV-88. The owner has since sold on the business because he finally retired from his retirement-hobby, and the new owners only offer the "kit" with fully stuffed PCBs ... but the schematic is still available on the website ... just search for "Ampdesign KHV-88".

The circuit is similar to kodabmx' design.

Hmm ... if you ask them, they might still sell you a pair of bare PCBs ... :)