It's a little off topic about the 660S2, but for me the KOSS PortaPros got a second chance for listening outside the home after discovering and trying the Morphit plug-in in the USB Audio Player Pro. After searching for KPP in the list of headphones and setting the target curve, the Studio...

Congratulations on a beautiful yet brutal amplifier!!! Could I ask about some available parameters (power) and what tubes are used? ;-)

I also wish everyone a happy new yEAR! (this is what Wieslaw wishes...!) ;-) I didn't like the upward headphone output and it seemed prone to damage to the cable at the connector. The idea with the input sensitivity switch occurred to me already with the TA-26. Because I have a DAC with a fixed...

I had the amplifier made by Wieslaw according to my ideas and he made the amplifier perfectly as I wanted. My requirements were: a transformer admitted outside (I'm "old school" and the transformer simply belongs to the tubes + better cooling of the transformer), headphone output connector from...

So the Christmas gift for me manifested itself in the form of a headphone amplifier and I am a new user of Wieslaw's work and that is the H5 KPCU, which was created exactly according to my ideas... I am delighted with the sound and my HD660S2 sounded better than with the TA-26. Just a small...

The HD600s are back from repair and playing great again with no rattles. Changing the springs helped...! ;-)

The headphones are currently in a CZ authorized service center, and upon agreement the contact springs will be replaced, all four as a precaution. The service confirmed that this problem occurs occasionally.

Hello, I discovered a small problem with the right headphone jack on my HD600. I bought the headphones on 11/11/2020 and they always played great without errors. I bought an HD650 last year and an HD660S2 more recently, so the HD600s fell out of my current interest for a while, but yesterday I...

I have already written this question, but after a long time I am asking other discussants. Does anyone have experience and how do the S2 play with the OTL amplifier xDuoo TA-26, Darkvoice 336se, or Eufonika h5 (I'm thinking about it for the next listening station)? All these amps should have...

You are a lucky person to be so happy with the stock xDuoo tubes, I wasn't happy with it one bit, just like the current TAD. Your great reviews from the TAD link are from 2017 and 2019, when TAD probably bought from better manufacturers. According to my experience, it is so, and you enjoy your...

I will share my experience with xDuoo and TAD tubes. I have a TA-10R amplifier which is fitted with one 12AU7 / ECC82 tube. I was not at all satisfied with the stock sound, and it also suffered from high microphonics. I bought a TAD 12AU7A and was extremely satisfied with the sound and no...

Thank you for the positive evaluation of the combination of the OTL amplifier in conjunction with the 660S2 headphones! I'm a few steps closer to deciding to get these headphones again... ;-) Right now I'm listening to the xDuoo TA-26 and after a few songs and sometimes even during the song I...

Thanks for the reply, I've already tried tube swapping with the TA-26 and currently I'm most happy with the Russian NOS 6N8S (Foton) and 6N5S (Svetlana) in conjunction with the HD600. I was wondering if anyone has tested if this amplifier plays "warmer" with warm playing headphones (according to...

I would like to ask if anyone has tried the 660S2 with the xDuoo TA-26 OTL amplifier (or DarkVoice 336SE, similar design...) ?

I also use a tube saver so that they don't heat up the inside unnecessarily and the beauty of the tube glows. This protector pad can be printed on a 3D printer.