Home Tubes Asylum

Questions about tubes and gear that glows. FAQ

Re: 6550: Best Current Production Manufacturer?

207.89.249.119

The Shuguang manufactured KT88 that is marketed by Valve Art is a good tube. I understand Shunguang manufactured some tubes for GEC years ago & uses the same tooling, good quality control plus a high vacuum.

One important parameter is to produce a tube with high vacuum of 10-6 Torr or better. Some manufactures do not take the extra time & care to achieve that specification (Eric Barber had talked about that parameter in the past).

The problem of some later manufactured tubes was the Dow Chemical synthetic oil was discontinued in the early 1970s. Using the very common oil dispersion vacuum pump with poorer quality oil did not allow that spec without an additional refridgerated cooler in-between the pump and tube. (That 10-6 Torr spec includes the extra vacuum using the getter flash during manufacture).

I have not any idea of vacuum oil quality overseas or if high vacuum turbines are used for vacuum. Some vacuum turbines are able to achieve 10 to -11 Torr with magnetic bearings.



This post is made possible by the generous support of people like you and our sponsors:
  The Cable Cooker  


Follow Ups Full Thread
Follow Ups


You can not post to an archived thread.