The weather is cooling down and I am thinking of firing up the ARC space heater. I got it a year ago now. As it is a bother to move I would like to do any tube swapping before I drag the thing back into the rack, she is rather heavy.
Hence I am looking at buying power tubes again. I decided I would buy from a dealer in Ontario. I have dealt with them before. They are reliable and there are no border duties. It helps they have competitive pricing.
That is as simple as the story gets. I still have 3 alternatives from that dealer, 4 if I rationalize spending more $$$.
I need 8 power tubes. The least expensive is a JJ branded 6550 (option 1).
Good reputation and liked a lot by some hippies in Oregon. There is an upgrade (more$$ Option 4) going to a Russian Electro-Harmonix 6550 which is recommended for ARC amps.
Tribal legend is that ARC designed the amp around this tube.
Then there are KT 88s with two options. Option 2 is the JJ KT88 for 6 bucks more per tube than the less expensive 6550.
KT88 are supposed to be stronger and more reliable. My old Dynaco amps used both 6550s and KT 88s with no issues.
Option 3 is a "preferred" selected Chinese tube that is 3 bucks more than the JJ 6550.
It is Chinese from that huge Shuguang factory, but these go through several layers of QC and inspection and have a 6 month warranty. The Tube Store sells a less fancy version of this tube for $30 bucks less each.
The choice matrix gets messed up a bit because this last tube is pretty. Triple Getters (The shiny bits) and a close up picture shows some nice construction. All the others have only single getters.
The Philips tubes in the amp now have triple getters. Better shielding?
My ARC factory biasing instructions note that Russian, or Philips 6550s or Chinese 6550s and kt88s have been used in this amp. So any of these options will work.
I cringe when I read about tube rolling where people tune their amplifiers by swapping out the tubes. How can you afford to do that? Actually power tubes should be the least variable compared to front end small signal tubes. Still people are crazy.
So my thinking is either the JJ 6550s or the Chinese fancy KT88s. Oh and I have to spend almost 800 bucks all in. It will happen, but I will stew on it a bit longer.
You don't have to do this with solid state.
