rackmonkey said:The Crimson is the clear winner in this circuit IMO. It sounds as close as I could expect to any A-10 I've ever heard. I'll save the laundry list of subjective descriptors and just say it sounds fantastic.
I concur with you, Dan, that there is something slightly metallic in the mids of the Cinemag. I'm a Cinemag fan, but in this scenario it's not as nice as I'd expect.
And Justin Heron, I realized I never directly answered the implied question in your comment above: "The turns ratio of the Crimson and the Sowter I have are totally different, yet they still both work."
So while "any old transformer" won't work (or work well) as you can see from the simplified description of selection factors above, many will work acceptably well, even if not ideal for the front end.
Just realized that I never followed up. I wanted to say thanks for getting back to me. The transformer knowledge you and the others shared really set me on a path to learn even more about transformers. While I am still not sure how all the technical details would translate into fel and sound, it was a fun rabbit hole looking into the papers on Sowter's website.
Still debating on whether or not to swap out the Sowter for the Crimson input transformer. I have my (D)LA2A open here, trying to solve a meter problem - I can't get the meter to zero anymore.
When I swapped out the stock MIC transformer in my Chameleon Labs 581 for the Carnhill, it was a pretty clear and obvious difference, but that was going from a very inexpensive transformer to a really really nice transformer. The sound was much more free flowing and impactful after the swap.
To be honest I have never swapped a good transformer out with another good transformer, so I don't know that I would feel the same way - but the turns ratio alone would impact the tone, as would the make/model.
One this is for sure, my LA2A does not sound as rich, weighty, and syrupy as the first vintage LA2A I had heard, but it DOES sound very nice. Kenetek T4B, NOS RCA 12BH7, and Amperex Bugleboy 12AX7, Carnhill output transformer. I am debating if the Crimson is the last ingredient in the secret sauce, or if I can live without it.