Home SET Asylum

Single Ended Triodes (SETs), the ultimate tube lovers dream.

RE: Fi 2A3 with 45s or 2A3-40s or Fi 45s.............

Paul, hi. I have a home built 2A3 amplifier with Electra-Print 3K outputs and another homey with 45 into MQ FS-050 - 5K. Some years ago I put in a switch to allow 2A3 to be run in the 45 amp. I should mention the 2A3 amp is fixed bias and the 45 amp is cathode bias. The filament transformers in the 45 amp can easily do the extra current necessary for 2A3. I did this purely out of curiosity. Over time I came to the conclusion that the 2A3 comes into its own with a load of 3K much better than a 5K load. In theory the 2A3 running into 5K will suffer only a power loss. What I heard suggested something else. I must say I think the sheer beauty of sound via Mr Eliano's 3K outputs figures into the equation as well. I have tried One Electron 5K and now the FS-050 in the Type 45 amp. I would like to try Electra-Print 5K. My thinking on this subject now is that the 2A3 in particular wants to see something between 2.5 and 3K and will yield optimal performance in all ways when this is done. In similar fashion I have a pair of home brew mono amps built with old Tango iron 5K and Type 50 triode. Via a switch I can drop the filament V to 5 from 7.5 to allow 300B use. Similarly but not as dramatically these amps sound better with Type 50 - at least that is my thought at this point in time. I am still listening and evaluating. I have a pair of JJ 2A3 on order from AES. These appear to be JJ 300B innerds (anode, envelope shape, dissipation etc) with 2.5V filament. My usual 2A3 are RCA CRC-2A3 circa 1943 or some similar mono plates. I have used Sovtek 2A3 with excellent results as well. Bottom line: I took the cathode R switching out of my Type 45 amp to make it exclusively a 45 amp. The 2A3 seems to be much happier with a 3K load than 5K. I have recently augmented the power supply in this amp from 100% polypropylene and paper and oil to include some Black Gate. This has been a plus in every sense of the word. These are just a few thoughts that hopefully may help your decision making process. All the best.


This post is made possible by the generous support of people like you and our sponsors:
  Crux Audio  


Follow Ups Full Thread
Follow Ups
  • RE: Fi 2A3 with 45s or 2A3-40s or Fi 45s............. - elektron 06/8/0710:23:32 06/8/07 (0)

FAQ

Post a Message!

Forgot Password?
Moniker (Username):
Password (Optional):
  Remember my Moniker & Password  (What's this?)    Eat Me
E-Mail (Optional):
Subject:
Message:   (Posts are subject to Content Rules)
Optional Link URL:
Optional Link Title:
Optional Image URL:
Upload Image:
E-mail Replies:  Automagically notify you when someone responds.