[Amps] 2 x 4-250A Amp

[Hsu]

Hi, I just rebuilt a junk TL922, I use a pair Chinese FU500F( same as 4x500A) replace the 3-500Z( worked in GG service) , all grids are grounded
  I replace the origional fan with a noisy AADA fan , but the tubes still over heat,I add a odditional heat sink on anode, it seems OK now.But the fan is too noisy. I have a pair Mulard TB3.5/750( 4-250A), maybe I can replace 4X500A use them, Any gus have this experments?
       73!Hsu