New Power Tubes in the House!

A while back I was toying with the thought of building a ST-70 amp for a smaller listening room. I instead decided to keep using my ST-120 since it sounds so great. So I invested in a quad of Tung-Sol 6550 tubes from the seventies. I decided to go with the 3 hole gray plate versions, which are said to be better in the midrange that the earlier black plate versions. I am here to tell you that I now see why these are considered to be the holy grail of 6550 tubes. I can't stop listening to my music!

kevinmi wrote:A while back I was toying with the thought of building a ST-70 amp for a smaller listening room. I instead decided to keep using my ST-120 since it sounds so great. So I invested in a quad of Tung-Sol 6550 tubes from the seventies. I decided to go with the 3 hole gray plate versions, which are said to be better in the midrange that the earlier black plate versions. I am here to tell you that I now see why these are considered to be the holy grail of 6550 tubes. I can't stop listening to my music!

Kevinmi, I'm having the same experience as you with a quad of original British GEC KT-88s. Can't get enough of 'em.

deepee99 wrote:
Kevinmi, I'm having the same experience as you with a quad of original British GEC KT-88s. Can't get enough of 'em.

I feel sorry for the people who don't hear any difference in tube rolling!

I used the Tung Sol 6550s from 1974 to 1990 in my Dyna Mark IIIs. Rebuilt them and used the GEC KT88 from then on. Rebuilt again last year and retained the GEC KT88s. They both are great tubes. I was fortunate to obtain a nice quantity of both types at hamfests during the 1975-2005 time period. Now they are hard to find and/or very expensive.

So where might I find this vintage tubes?

The usual place to find these tubes is Ebay. It has it's good and bad points but they sometimes do have them.

Another option that may be available. Do a Google local search for "radio museum". There may be one or more in your area. These are usually run by ham radio enthusiasts. From time to time they take in collections from members that are reducing their electronics. Many times it includes old supplies of tubes.

Contact the Curator and ask if they have any of these tubes and would be interested in selling them. Most Curators know the value of these so the prices will not be low. However they may be available. They sometimes have tube testers so you could match up used ones or test new ones.

I volunteer at a local radio museum and they have many thousands of tubes. They do not actively sell them but other places may be more willing as their monetary needs arise.

I have my own supply so I do not need theirs.

A reliable (though you pay for it) option is Vintage Tube Services. Andy Bowman is quite the character and the website is a wealth of information and informed opinion. With rare exceptions, I'll only to Andy for both signal and power tubes. Here's his website.
http://vintagetubeservices.com/
You can spend half a day on there.
All of which begs the question: is the TS 6550 or the GEC KT88 the better tube for our purposes?