EL 34

Pairs? Quads?

Push pull or Single ended?

What are you running for gear.

KT77 are an option? 

NOS save your money, there are a lot of great EL34 or KT77.

No need to be a goober when you can spend peanuts and get the same results. :-) GL, Rubys, Tung Sol, EH, Wing C, Russian military (W) and quit a few more are really good new valves..

Expensive NOS.. Unless you already own them, don't spend a bunch of money.. 150-250. for a quad is about right..

I just picked up 2 sets of (6) Golden Lyon KT66s. Wonderful valves..

Regards

When anyone tells me the TOP is a little harsh, I always ask if they can BIAS a little lower. The valve is breaking up to soon.. 50% of the time it increases the mids and highs and usually increases the  peak to peak by a bit. What I do notice is low volume playing (VERY low) is not near a clear or pleasant.

Swapping a signal valve or two always smooths out the rest. Telefunken or Mullard Blackburns will do it..

<<<<<<<<<<<<<<<<<<<<<<<<<<<>>>>>>>>>>>>>>>>>>>>>>>

 Electric EL34 and KT88s, on the Leben 600X. Gives an idea of what room for improvement might exist over the stock EH for your type amp.

<<<<<<<<<<<<<<<<<<<<<<<<<<>>>>>>>>>>>>>>>>>>>>>>>

I'm just assuming you can use a 6550 too. There are GREAT 6550 (W) Russian surplus and new that are wonderful valves.. That W means they are MiG tough.. That's pretty tough.. They are a thick black plated valve.
Super stout banded/base.. Just make sure YOUR vendor checks the factory match.. Their QC for boxing valves sucked.. CHECK for matching.. Mids and highs.. 6550s..:-)

Regards