Sugden IA-4

Thanks for sharing my enthusiasm about all this John; listening to anything from Bennie Green to Rosalia to Dj Python to Szymanowski, it just keeps getting better. You were so right about Sugden's quality.
I'll likely start a new thread once my push-pull 300B comes in to share listener impressions.

As a former 0/93 owner ( I moved up to the Super Nines), I would not consider the Pass XA25 due to its high damping factor. The 0/93 bass response in my opinion sounds "unnatural" with amps that have high damping factors. I auditioned am amp that had a damping factor around 250 and it seemed to choke the life out of the bass. I also heard the XA 25 power some Zu Audio speakers ( can't recall which model) and the bass response also sounded way to tight for my tastes. The Sugden amps have low damping factors ( < 25), which is probably why John uses them for solid state amps at shows.

Thanks!! This is a fascinating perspective and I can see the logic in it quite clearly - also a key factor in my usual preference for tube amps. The IA-4 has a damping factor of 45 and its bass is natural and believable with the O93s with good continuity between bass and mid bass. The LTA Ultralinear perhaps had “faster” bass response but I am very satisfied with the organic quality of the Sugden (which has meaningful advantages over that LTA power amp) and am of course curious to see what the Modwright 300B push-pull brings to the table. Nice to rule out the Int-25 as a contender using your sound deduction and experience. I hope you are loving the Super Nines by the way!

@transience Coming up on two years, are you still using the Sugden IA-4? Asking because I’m considering an LTA Z10 or MZ3 preamp, but your comments give me pause as a friend has very high regard for Sugden.

Despite the long time, would you be able to more insights into the differences between the LTA and Sugden? Maybe if there is any comparison around the tube sound character (or not)? The LTA units are not marketed as "tube sound," but your direct comparison with the IA-4 is more relevant and I'm curious to learn more, please.