The sounds are different, but I would never put a modern flathead ring on a prewar archtop. If I want a flathead sound, I’d buy a new one

I don't cut rims if it can be helped! It's only original once!
The no cut rings are what I'm asking about.

The sound will be slightly different but it won't be radical. The conversion ring is not as deep or as heavy as the full weight tone ring. If you want a full flat head sound, you might want to get a new rim and tone ring. If you think a conversion ring would fit the bill, contact Eric Sullivan.

Play around with your set-up, bridge, head tension, etc.....on the arch top, before shelling out any $$ on a conversion ring.

I have found archtops to be much more versatile than flatheads, when it comes to getting different tone, sounds out of them.

Sullivan makes a really nice conversion ring . I’m an arch top fan at heart but the Sullivan ring was neat in the fact it let me tinker around and also gave a nice but different sound than an arch top . You should definitely try one . That’s my 2 cents. Good luck .

I have tried a variety of “no-cut” rings in my ‘36 TB-3 conversion and I always go back to the original raised head ring. It has a “clank” to it that the other rings don’t have

I think I'm convinced to leave "original" original! If the archtop twang was good enough for Dr. Ralph, it's good enough for me!

I put a Huber no-cut conversion ring in a 1929 TB 4, replacing the standard 40 hole. Because I have several pre-war Mastertones with 40 hole rings.

Steve H does a very careful job "fitting" his conversion tone rings to the original rim. He asked me to send the rim to him which I did. The fit at the bottom of the skirt and the inside top of the rim was truly perfect and "seamless" if that is a word that would apply (gap-less?).

Volume came up nicely. Tone-wise, the best way I can describe it is like a 1960s-70s Fender Artist like Bill Emerson and others used to play. A bit on the "silver bells" side. Obviously not the same as a even a Greg Rich flat head. Not as "dry". But definitely louder than the arch top ring, and a very nice sounding banjo. I have left the conversion ring in the banjo, with the original 40 hole in safe storage to stay with its banjo.

I have a Sullivan conversion tone ring on an old post-war archtop and the sound was significantly different than the archtop sound.

I agree with not cutting the rim and I think a conversion tone ring will give you a good option.

RioStat

I'm curious about your comment "Play around with your set-up, bridge, head tension, etc.....on the arch top, before shelling out any $$ on a conversion ring. I have found archtops to be much more versatile than flatheads, when it comes to getting different tone, sounds out of them."

I'd really like to learn more about archtop setup experiments to try. Can you elaborate?

An old friend of mine from decades ago had a 2 pc flange Granada with a Sullivan conversion ring in it and it sounded WONDERFUL.

In fact, tomorrow I am mailing a check and a 2 pc flange rim to Steve Huber to install another arch to flat head no-cut conversion ring for me, which will make 2. The "tone" doesn't have the depth of a full Gibson flat head, but it certainly IS louder than the arch top ring in my experience.

I wouldn't cut a pre-war rim, no sir. And I do have Greg Rich Granadas and an RB 3 and other Gibson reissues that are the all flat head I can ever afford. I can live with not owning a "real thing" pre-war flat head

And I do know the difference. I played Jim Mills' four original 5 string flat head one piece flange Mastertones in his showroom. I'm sure I'll not own anything like that. But I'll be happy.

See if you can find a Mitch tone ring mate. I found one on eBay.
It fits over the arch top ring, converting it tom a flathead. I put one on my 27 TB 3 and am very happy with the results. No rim cutting, and can convert back to original arch top easily. It seems as though I paid around 75 for mine, but that was a few years ago.