KT120 transformer failures

Hey Wolf

I can't help you answer your query but maybe the gents over at Conrad-Johnson can. The CJ Classic Sixty SE Amplifier utilizes KT120 tubes throughout. Maybe they saw the current draw issue you speak of and overcame it. From stuff I've read about them they are really good people over there and who knows they may be willing to chat with you about the KT120 transformer issues.

Info about the Classic Sixty SE.

http://www.conradjohnson.com/It_just_sounds_right/Classicsixtyse.html

Prices being equal. Would it be better to have tubes custom matched by TC Tubes or cryogenically treated by Cryoset? I saw both for about $200/quad. Factory platinum matched was about $25 less. I don't think either process would affect how the tubes work with the transformers of an amp.

Hi Johnsonwu

I shall offer my reasoning for posting multiple questions about TCtubes throughout the forum here. It is not as funny as Wolf's though. When trying to price out places that sold the Tung Sol KT-120 and found that they offered a service called: Precision Power Tube Matching

Direct from the TCTubes website:

"Our power tubes are burned in for 48 hours and tested on a laboratory grade Amplitrex AT1000 tube tester. We match tubes for both current draw (mA) and transconductance (Gm) at typical operating conditions (see #3 below) for no extra charge. We can also custom match power tubes at whatever specifications you provide (see #4 below)."

They then ask for amp maker/model, how to bias the amp and finally the plate and screen voltage for a custome match. I'm new to tubes and had never seen this before. I was trying to get information from members but since I never really know what the moderators will put through I have to post questions in different threads.

I'm new to tubes and don't know if this precision matching will really make a difference. I'm trying to gather info about it. I have no affiliation with TCTubes whatsover.

For me it is now down to a cryo treated platinum factory matched quad of KT-120s or a precion matched quad of KT-120s from TCTubes.

Hey Wolf
I got the KT-120s but my 502p is @ my local Jolida dealer getting upgraded. The guy is a tube expert so I trust him with modding the amp. In another couple of weeks I'll be able to enjoy the music as well as the buring smell you mention from the Jolida & the KT-120s. Thanks for the heads up on the buring smell. I probably would have been worrying about that. Which KT-88s did you try? I have my eye on the Penta KT-88SC tubes just in case if the KT-120s don't work out. Also when I spoke to the dealer/tech he said the Jolida 502p could handle the KT-120s w/ no problem. I can't wait to get up & running w/ everything.