I have a Rhea and Calypso. I can attest that tubes that would otherwise be too noisy or microphonic can often be quelled with Herbies dampers (but you do have to experiment sometimes to get the damper positioned correctly). You should always have at least a pair of these around. They have saved me megabucks and hassles.
The Calypso 12ax7's don't have to be as quiet as those in the Rhea. I use my Rhea rejects in the Calypso. I'm not sure which Calypso gain setting I'm using but I do remember having to change it when I first received the Rhea. The two didn't interact well with the high gain I had selected for the Rhea.
If I recall correctly I was told by Glenn at Aesthetix that if you select an input on your Calypso that is not connected, turn the volume from zero to eight and listen at each increment in between, you will hear the maximum amount of tube noise that the Calypso will contribute to your overall sound. You may only have to listen at eight.
I have not tried old stock American tubes but have tried most of the Euro's including the 10M. I prefer Philips - D getters (Heerlen, Blackburn) and the Hamburg long plate slanted O getter - in the critical gain positions in both the Rhea and Calypso. You might prefer the sound of a Telefunken or even a 5751. It really depends on so many things, your amps, speakers, listening room, etc. The only way to know for certain is to try different types.
The Calypso 12ax7's don't have to be as quiet as those in the Rhea. I use my Rhea rejects in the Calypso. I'm not sure which Calypso gain setting I'm using but I do remember having to change it when I first received the Rhea. The two didn't interact well with the high gain I had selected for the Rhea.
If I recall correctly I was told by Glenn at Aesthetix that if you select an input on your Calypso that is not connected, turn the volume from zero to eight and listen at each increment in between, you will hear the maximum amount of tube noise that the Calypso will contribute to your overall sound. You may only have to listen at eight.
I have not tried old stock American tubes but have tried most of the Euro's including the 10M. I prefer Philips - D getters (Heerlen, Blackburn) and the Hamburg long plate slanted O getter - in the critical gain positions in both the Rhea and Calypso. You might prefer the sound of a Telefunken or even a 5751. It really depends on so many things, your amps, speakers, listening room, etc. The only way to know for certain is to try different types.