Model-T Best tube for Bass??

[MarkG]

Just picked up an early 70s Model T non mid select switch version ,I guess we are calling 1st Generation. Its in pretty good shape and sounds pretty strong as is. But was contemplating replacing the 6550s with a set of matched fresh ones. It currently has a set of SLM "HotRods". Looking for opinions on if there would be a brand that would be optimum for bass work,and a recommendation on websites that I could get info and order tubes direct.I had a few sites bookmarked on my old PC but have since lost them. I also want to replace the supply caps ,can someone recommend a good source to obtain these?   Thanks.  

[Geoff]

I am using Svetlanas currently in my 1st gen. Model T.  I like them pretty well for bass but YMMV.  I think Michael Anthony uses them currently in his SVTs if that makes a difference  Had Rubies in there before and the Svets have much better low end (IMHO) and I think they sound cleaner...

As far as tube & electronics resources, there are a bunch of good ones out there.  thetubestore.com, triodeelectronics.com, Angela Electronics are just a few off the top of my head.  And of course there's Lord Valve (can't think of his URI off the top of my head) -- he tests and hand-matches all of the tubes he sells.  I have links to these and a few other places on my homepage if you're interested in looking (http://www.geoffbullard.com).

Good luck!

[Tom Loizeaux]

I've had a few of these "1st generation" Sunn Model T amps (still have 2 left) and I love their deep, warm sound. They get a little distorted when cranked, but some people really like that...and you don't have to peg it! If you run the MASTER VOL at 10 and the first and second LEVEL controls at maybe 4, with the bass plugged in to the middle (BOTH) input, you can get a very nice bass sound with plenty of power. I  re-tube with "the best"... nos Tung-Sol 6550s, because I have a large supply. I hear the Ei KT 90s are great tubes of these Sunns!

Tom

[MarkG]

Tom,would the bias setting be any different for the KT90s than for the 6550s? I believe the 6550s in the T are normally -55v . ?

[Tom Loizeaux]

I've never used the Ei KT90s myself, so I can't confirm the correct bias for those tubes. I suspect the plate disapation for those is similar to the Tung-Sol 6550s, requiring a -55 volt bias. Some people bias by ear by finding how much voltage the plates can handle and then raising the bias voltage slightly to bring down the plate voltage enough for a margin of safety.

Tom

[JoeArthur]

Well, me neither... but if you look at this...

http://www.vacuumtube.com/FAQ.htm

it will appear that the KT90 and on up really denotes a manufacturer or country of orgin, of a KT88.  I don't bias differently between KT88 and 6550, so I would say "No difference in bias should be required".