Jadis DA60

Jadis DA60 can use any tube among the EL34/6CA7/KT77 and 6550/KT88/KT90 variants. Jadis says it themselves, and I've done so as well in mine with no problems whatsoever. Why do you need anything more than what the people who build the amplifier have to say on the matter?

For the record my preference is EL34 first, KT77 second, then KT88, but that's why they make vanilla and chocolate. Use whatever sounds best to you knowing that the amp will play beautiful music with no issues whatsoever with your choice. It's difficult for me to think of a better, more musical amplifier than the Jadis integrateds.

When I picked the amp after its repair I was told that all the problems were my fault for using the wrong valves (Tung Sol 6550 reissues), and that the new Genalex KT88 reissuess could not run in my amp and would soon destroy it. And there woud be no warranty on the repair.

Without plugging the amp in I took it to David Peach of Peach Audio at Balmain in Sydney. He found that the heater voltage was set to 13.85V instead of the correct 12.6V (two KT88s in series), and there was a dry solder joint on a new cap.

I asked him to make the amp reliable and he designed and made the following changes:

· Removed the cathode fuses and instead fused the anodes as per http://www.audionote.co.uk/articles/tweak_fusing_valves.shtml

· Each pair of valves was previously cathode biased. Now every valve is cathode biased.

· He protected the output transformers from back EMF by installing shunting diodes.

· Changed the transformer taps from 4 Ohms to 8 Ohms to suit my speakers

· Reset the heater voltage

My amp is now back and sounds and works great. Peach Audio is highly recommended.

http://www.audionote.co.uk/articles/tweak_fusing_valves.shtml