Strange. But I'm glad you were able to solve that problem.

  I'm using that kind of stuff while I work on equipment at work (voltages up to 1000V), but I don't see a reason why you need that for the T1. Normally you wouldn't need that unless there is something very wrong with your inhouse wiring. 

  Looks really nice. Unfortunately the price is a little too steep for me right now. But I have oscilloscopes at work that can do stuff like that and more, so maybe I will do some measurements at work.

@sandab   Thanks for the post! I always wanted to do such a measurement but my oscilloscope unfortunately doesn't have a FFT function. I would love to do this on my amp I've built.

  Theoretically it should be possible if the pinout is the same. Of course you have to check the datasheets. Soldering a socket is quite tricky because you don't have any holes for them. I personally don't think it will be worth it.   BTW, i bought two RTC E188CC. Can't wait.  

  I also think that they look like russian tubes. And the Sovtek is really looking similar.   http://www.ebay.com/itm/Pair-SOVTEK-6922-Pre-Ampr-Tube-E88CC-ECC88-CCa-6DJ8-/321141640917

  Thanks. No, it is based on this design here: http://diyaudioprojects.com/Tubes/6DJ8-Tube-Headphone-Amp/   I just made some slight modifications to the power supply. For example the heater voltage on my unit is variable (I set it to 6,3V) instead of a fixed 6V. Technically I could change it...

I finally got my amp together and working. I've been waiting for the parts for about 2 months now. The little T1 is only used as a DAC now. I'm using two Siemens E88CC tubes in my amp for now until I can verify that the amp is working properly. But everything seems to be fine for now after 1...

  He's talking about the capacitors. I agree, the upgrade is worth it. 

  You mean these one?       They are quite nice. I was able to get them for a lot less money than they are normally being selled on eBay.   The sound of these are great. If you can get them for a reasonable price I would recommend it. I'm saving these two tubes for my future amp that I'm...

  Current draw from the heaters is not that relevant. Sure, it shouldn't draw a massive amount of current, but the problem with other tube types is that they have other characteristics. Different capacitances, different curves.   I tried some ECC85 from Siemens with no luck. 3 of them were...

You need to open the cable and then cut the wire.     Or you can drill through the USB A header until the pin for the 5V supply is gone.

  One tube has two triodes inside. One triode per channel. This is enough for a tube buffer. For a full fledged amplifier you need more because you have a more complicated circuit like cathode followers or paraphase amplifiers.

CoiL did help me with identifying the caps. Changing the caps wasn't that difficult because I know how to solder. If you don't have any expirience soldering then take an old piece of hardware and try. If you want to go through with it shoot me a PN and I can give you more information.

Just changed the last caps in my T1. I replaced the really bad Lelon main power caps with Panasonic FR 3300µF 25V caps. They also were bigger than the old ones. I didn't think that I could fit them all inside the case but I managed to do it. Everything is in place and the T1 still works.  ...