845 or 211 based tube amps?

Are there any unique properties of the amps based on these tubes? Are 845 & 211 interchangable? Which are 845 & 211 good tubes that are cost effective & reliable?
Call Steve at Quest for Sound in Bristol PA...he's a tubemaster and can head you in the right direction
They are not interchangeable.. they require some similar voltages, but that is all.. the 211 is higher mu and also higher plate resistance and requires a much more difficult to wind output transformer.. the 845 is more forgiving here and therefore can be built more inexpensively.. but beware, both of these tubes built into a proper amplifier should be expensive... if you find a cheap 845 or 211, you will not really get to know the 845 and, especially, the 211 "sound"..

the tubes themselves are another story.. NOS 211's and VT-4c's are relatively cheap.. $200 to $300 a pair.. NOS 845's are more like $1200.. luckily, the chinese 845 sounds quite good for it's paltry cost, like $100 a pair!

Anyone compared theShuguang 845B & 845M? Read the review on positive feedback & some input from Ed Sawyer. 845M sounds more natural but with slightly forward treble & less dynamic. That does not sound like the one i want. I generally dislike forward treble.
I have owned both types of amps- I found the 845 more powerful and the 211 slightly more refined- if I had to choose, probably the 211 in the long term...
The 845M is smooth! Smoother than the 845B. IMO the treble is not forward, or irritating as you seemed concerned about. But the 845M is no longer in production unless Supertnt.com has started back up with a new version.
Thanks guys.

Budrew, according to TNT website, they are available. Do you lose base control with the 845M comparing to the 845B?
211 can be successfully driven to much higher power in class A2 mode, too

The Kondo Ongaku used the 211 tube with great success.