My new tube headphone amp

[MCLL]

Using this circuit


Other Photo

[Pentium100]

Similar to mine. My is with NFB (100K resistor from output to V1 grid to increase power to 32R headphones) and is using 6N2P (low current, high mu, like 12AX7, but 100% pinout compatible to ECC88) tube for V1, 110K for R2.Also I use 680uF 200V capacitors for output. What can I say, sounds very good (way better than chip amp I used before) and has not very low power to 32R phones and was made with tubes that are available to me

[jaudio]

Would this part of the schematic posted make a good buffer?

[Pentium100]

No. the grid of that tube must be at about +110V for the tube to operate normally. Otherwise the power will be very low.

[Tubes4e4]

Hi Pentium100,

Originally posted by Pentium100
Similar to mine. My is with NFB (100K resistor from output to V1 grid to increase power to 32R headphones)

No free lunch here. Realistically, you cannot expect such a design to really drive 32R phones - even a paralleled sections 6AS7 CF would have problems doing so, not speaking about the problems implied by the driver requirements.

For such severe loads (including my own Sennheiser HD595 at 50 ohms) I would prefer and suggest to build a "real" amp instead, as small as it might be output-wise.

Here is my own approach to drive to such severe loads (even small 8 ohms bookshelf speakers are no problem):

Toms headphone amp

Tom

[Pentium100]

Originally posted by Tubes4e4
Hi Pentium100,



No free lunch here. Realistically, you cannot expect such a design to really drive 32R phones - even a paralleled sections 6AS7 CF would have problems doing so, not speaking about the problems implied by the driver requirements.

Power is enogh for me for now (I use Philips SBC-HP200 headhones). 6AS7 would be better, I think, but I have one minor problem - I can't find 6AS7 anywhere (the same applies to all octal socket tubes, and most of power tubes, well, except EL84). If I had 6AS7 I would build amp for speakers instead.

I used this schematic http://headwize.com/images4/cmoy5_1c.gif but changed R2 to 120K after V1 (which was originally ECC88) died. I hadn't another ECC88, so I put 6N2P and changed R2.

[MCLL]

Originally posted by Pentium100
Similar to mine. My is with NFB (100K resistor from output to V1 grid to increase power to 32R headphones) and is using 6N2P (low current, high mu, like 12AX7, but 100% pinout compatible to ECC88) tube for V1, 110K for R2.Also I use 680uF 200V capacitors for output. What can I say, sounds very good (way better than chip amp I used before) and has not very low power to 32R phones and was made with tubes that are available to me

Hi Pentium100
I want to using 6N2P in V1 and I don't want to change R2 to 110K. Is that possible?

[Pentium100]

Yes, but you will have very low power because of incorrect bias of V2. it should be possible to *** a capacitor to V2 grid and add +110V to it, it should work.