For Sale: SOLD: Van Waarde single-ended OTL custom headphone amplifier .

A[B]SOLD[/B] For sale is my Van Waarde single-ended OTL custom headphone amplifier.

I bought it two years ago from Headfi-er GuyDebord.


It is powered by an external PSU, which is a rectangular black box a bit bigger than the amp. The amp is based on a circuit typology designed by Aren van Waarde.

It was built by a german specialist with high quality components (alps poti, mkp capacitors).


The chinese Darkvoice 336 is a half clone of van Waarde's circuit, it shares its basic typology but adjusts the power supply by minimizing it, among other sacrifices.


The big tube is a OTK 2, 6H5C.

The small one a almost new National 6922/E88CC, made in the USSR.

I’ll add three Philips JAN 6922 tubes, made in de USA.


More pictures can be seen here: http://www.head-fi.org/gallery/album/view/id/7365/user_id/71967

The black knob on some pictures is replaced by a new grey one.


Warning: IMO this amp doens’t behave good with high sensitive headphones.

The volume goes with small steps, and high sensitive headphones will sound too loud.

Impedance isn’t a problem.


This are the specs from van Waarde himself:

• Extreme simplicity (only 2 double triodes required for stereo).

• Capable of driving low impedance headphones

• Amplifier stages directly coupled

• No global negative feedback

• Single-ended topology


The first stage uses one-half of a E88CC (6922/6DJ8/ECC88) in a common cathode configuration. This is directly coupled to a cathode follower which employs one-half of a 6AS7G.


With good recordings there is a life-like quality to the sound. Voices and instruments are pinpointed on the stage, with lots of musical detail and "air".


Frequency response (-1 dB):
100 kHz (0.775 V out in both 60 and 600 Ohm)


Output voltage:

ca. 28 Vtt in 600 Ohms (onset of clipping) = 10 Veff

ca. 3.7 Vtt in 60 Ohms (onset of clipping) = 1.3 Veff


Max. power output:

170 mW in 600 Ohm

40 mW in 32 Ohm


Voltage gain:

8 x (i.e. 100 mV at the input produces 800 mV output at a 600 Ohm load, volume potentiometer at maximum).


I’ll ask 180 Euro, plus shipping.


The total weight is about 3 kilo.

Shippingcosts, see http://www.tntpost.nl/voorthuis/pakketten/aangetekend-pakket-buitenland/ , and then go to the section "wat kost het?"


Paypal please as a gift, or add 4%.