Re: Tubes for Hammonds & Leslies (and more)

["Steve Leigh" <stleigh@ibm.net>]

On Mon, 30 Sep 1996 22:37:07 -0400 (EDT), Ed Zeranski wrote:

Hi Ed,

>>For what it's worth, I recently bought several sets of matched 6550s and 
>>made by Groove Tubes.  They're available almost everywhere guitars can be 
>>found.  You can specify "hardness" - resistance to distortion.  Lower numbers 
>>distort earlier, etc. 
>>
>>I also bought an old B&K model 747 tube tester.  

>     I have several tube testers that measure transconductance as well as
>inter electrode shorts etc. I've never seen "hardness" listed as a tube
>parameter as mentioned. ???? 

I'm sorry if I was confusing.  The tubes from Groove Tubes are available in 
different "hardness" ratings, 1 thru 10; ie; the lower the hardness number, the 
quicker they will distort, the higher the rating, the "cleaner" or more 
resistant to distortion.  My tube tester does -not- have a "hardness" 
parameter, but measures shorts, grid emission, dynamic conductance, and 
"good/?/bad" - probably like most testers.  Using a digital meter in parallel 
with the analog meter, I can read milliamps down to tenths.  The meter has a 
"min/max" function also, which makes tracking the tube somewhat easier.  This 
gives me a little edge in relating how "matched" the tubes are.  Again, 
apologies if I misled you.  It felt clear as I was typing it!!! 

>As far as tube organs go, I'm restoring a 1935 Hammond Novocord.
>Ever played with one?

Not me.  I'll bet there are a lot of others on the list here who have knowledge 
of this instrument, though.  



Steve Leigh
stleigh@ibm.net
Canine Training - Lutz, Florida