Tag: 2P29L DHT

6e6p-dr Headphone Amp – part 3

6e6p-dr HP amp in action – cap coupled output

I’ve been running with this HP amplifier for a few weeks now and I have to say I’m delighted with it. I matched a pair of 6e6p-dr on my eTracer and after fiddling with the operating point a bit, I settled for Ia=25mA and Va=180V. Anode voltage will depend on the valve as said before, the Russian valve parameters tend to be all over the place. Anyhow, expect anode voltage to be around 170 to 185V. The beauty of the gyrator PCB is that you can adjust the anode voltage with the trimpot.

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2P29L DHT Preamp – final build

Finally I managed to build a stable version of the 2P29L preamp. The wooden modular version inspired on DHTRob designs paid off. Here it is:

The result is fantastic. The 2P29L is a superb DHT, quiet and it sounds amazing. The circuit is similar to the original one but with a slightly different operating point due to the valves themselves:

I’m still running them at 20mA. This time the anode voltage has to be increased to 150V to achieve this. Consistent across the 2 valves used.

C2 was modified to fit a gift I received from my friend Vyacheslav. Instead of the usual 220nF, I fit a bigger 470nF FT-3 version which improves the LF response.

The frequency response is very good, as I published before.  For the curious ones, here are some further pictures of the build:

 

 


I can’t say more than what I said before. This is a fantastic DHT, it provides a great detailed sound and is quiet. No microphonic noise and the dynamics are great. One of my favourite clearly.