[Heathkit] Re-tubing an SB220

[Ernie Piche N1SW]

Well I have now finished my 220 upgrade.  I installed the external 
transformer and all the internal parasitic stuff along with other 
modifications.  It is working fine but still not getting full output so 
I guess it is time to replace the 3-500 tubes.  I am looking for 
recommendations on who's tubes to buy and what experience does anyone 
have with mail order tubes.

Thanks
Ernie
N1SW