what trafo output single ended A class amp for various headphones ?

Hi,

I'm looking for advises what next amp should I make.

I have a good DAC, new RIAA is ongoing for my turntable, I listen to music through 2A3 PSE amp and AN E like speakers ... when I can. Unfortunately, I rarely can. Family sleeping in the next room, my daughter watch cartoons in the same room etc.

I'm searching my way for a while now. I had an old HD 565 ovation, but in the last two years has bought 2 other sennheiser, and also sold one of them because I still like the 565 more. I made an OTL single ended headphone amp, which sounds very good on the desk, but has two major disadvantage. One is the power consumption, the other is sensitivity on mains voltage changes. Unfortunately at home the mains changes from 215 to 235 quite quickly. I can feel it and see it on a speaker connected to the amp. Also, it still can not drive 32 ohm headphones.

I have also built a CK2III, I'm pretty impressed with the quality from this price, but I want to upgrade now.

I have decided that now I'm looking for trafo output headphone amps, for different reasons :

- no coupling cap needed, no DC problems, less risk of killing the headphone driver with a quick DC change.

- better coupling to the tube impedance, no high cathode current need, smaller tubes, less power, no/less need for large chokes

The problem is, I could not find a design I'm looking for : single ended, class A, no feedback, use a trafo which is available and has several output where I can connect 32 to 600ohm drivers.

I have looked at Andrea Ciuffoli's designs, but with the LL1630 it can not drive under 150ohm drivers.

Any other suggestion ?

Thanks,

JG

LL1689 looks better for sure, but in the Andrea Ciuffoli's designs, it goes down to 150ohm, which is still not enough for me.

There are commercial amps, like woo audio 6, which drives low impedance headphones. No one DIY design ? I'm not good in tube circuit design to do it, I'm looking for a tried way :-)

Series resistor is not good.

Regards,

JG

well, I'm changing the scope now.

I do not want to sacrify the quality on the 180ohm+ impedance headphones just for being able to drive a 32ohm headphone. I drop it out, I do not think I will by a grado, so I start from 180ohm now.

What I see now

-Andrea's project with LL1689 (my preference now).

-MAD Ear+ Purist HD2

-Hagerman Castanet

What else should I consider before start ?

The reason why I prefer Andrea's design now is the Lundahl trafo. In general I like much better the Lundahl trafos in normal speak amp. Maybe that is false also, for sure subjective, and I do not know how much applicable to this smaller trafos.

ANother reason why I'm turned to trafo designs now, my previous diy is VERY sensitive for the hum coming from the PSU. I had to use 2 large choke also to filter. I hope the trafo output amp will scale down the noise also by the trafo, also the trafo better match the headphone to the tube, I do not need as high current as in OTL designs.

Tell me pls if you think my thinking is wrong.

5 years ago I hated tubes. 3 years ago I hated trafos. Still hate them for the weight, power, price etc., but love the music coming out. I'm changing :-)

Thanks,

JG