If Steve says the amp checks out, then we need to look elsewhere.

What has changed in the system around the time of the problem?

Did you move your speakers or seating position by chance?

Any changes to the room? Bass is very room dependent and something as innocuous as opening and closing doors can change the sound.

Do you have a different source you can run directly to the amp? That would help eliminate the speakers, speaker cables, amp, and main interconnects as problems.

Divide and  Conquer till you narrow down to the piece that's causing the problems.

Thanks for the prompt replies, questions and comments. As for the room, nothing at all changed. The bassiness wasn't sudden, but seemed to just keep getting worse. I have isolated each source and the results are the same. I've also made an all Decware TT system with just A ZP3 and the MK III, same story. I have swapped the MK III with a Musical Fidelity A-5 and also a Taboo MK III and the results are quite acceptable, but the Taboo is working pretty hard to do so. I have adjusted the treble and bass controls on the Torii per Steve, and also the 35 Hz on the speakers with no appreciable change.  It just seems like the Torii and the Martin Logan's have become incompatible. Very frustrating, especially since things were going so well up until several months ago.  Again, thanks very much for your input.

Thanks, Lon. I told Steve if the HR-1's I have ordered don't solve the problem I'm going to deep six every piece of gear and take up knitting.
The problem is equally bad on both channels, but I'm not smart enough to know what circuits in the Torii might be common to both left and right. I've swapped all the tubes except the rectifiers with no change.
I'm very happy with my ZP3, Taboo MK III TT headphone only rig, but this speaker system is really driving me nuts.

My Torii, in this room, has been too strong in the bass for my tastes from the start, and using MG944s and HR-1s. It was a very minor issue with the SE34 I had before the Torii MkIII. I believe I sent it back to see if something was wrong too, and Steve suggested starting to treat the room with some ideas for bass traps and plugging up some of the speaker plinth space. With bass traps, EQ, speaker tuning, and some tube adjustments, I have balanced it and my sound is off the charts good. It appears that the Torii can just be this way in particular rooms, and according to Steve, with particular speakers, and/or with speakers too close to walls and corners.

The thing I don't get about yours is how it was fine and got worse to the point of being unlistenable. Do you use the amp infrequently? Is it possible that it is the V-caps burning in? I have no idea how they burn in, but they are notoriously long. Seems unlikely, but man, what a weird situation.

Have you tried changing the power VRs in a biggish way? Going from OA3 to OB3, OC3, and OD3 will progressively chill the bass and open the sound. In this case, I might go extreme and try some nice OD3 VRs. They are generally pretty cheap and make a big difference by calming down the power tubes I believe. I have used 40s and 50s Hytrons and found them very nice, but others from that period are probably good too.

For inputs, probably the best bet is a phillips/amperex family 7DJ8. For rectifier, perhaps a brightish 5AR4 will tighten things up...like a JJ, but if you go there, I would ask Ron at cryoset wat he recommends. He now has many cryo'd GZ34/5AR4s including Mullard and Genelex. The most open and least bassy and good sounding power tubes I have tried are probably EL34BSTR Ruby Cryo Matched Quad from cryoset.

But if more tube exploration is interesting, and you have not tried OD3s, they may be worth a try first. They might do a lot.

If it is room, which I expect Steve decided it was at least in part, you will likely need to do some low bass traps. To find out, or if your problems are not extreme after review...it can be a little tedious, but if your music player software has built in EQ, you can set up a narrow Q and raise it heavily, then work through the low frequency ranges with bassy music playing to find the culprits. They will be really obnoxious with a good bump. This is an easy way to identify and then finally Q out the offensive room modes...sort of like mastering your whole collection to fit better in your room. I have found this to be a very transparent solution using EQ in my Pure Music player in my Mac Mini.

I hope you can figure it out. As transporting as this amp can be, it makes me sad to hear your story!

I have not done this, but if you would like to make it more science, some pretty smart folks swear by this for identifying room issues. The learning curve and time constraints have kept me in the tune by listening mode.

http://www.hometheatershack.com/roomeq/

I've used REW in the past, and plan on using it again in the near future once I can afford a better microphone.

It's tough to get into - make sure you read up on the guide threads at Home Theater Shack, AVSForum, and GearSlutz to get an idea of how to set it up and use it.

It's very rewarding to actually *see* documentation of what you're hearing.

so 2 different sources and the same bass problem, I had a similar problem and found that increasing the crossover capacitors micro farad value up a few notches, by .5 micro farads, tremendously cut out the bass boominess , I guess most speakers systems are not in the same ball park as the Torii, push pull vs. transistors amps, 2 different types of amps needing specific consideration with the speaker system they use.. basically the Torrii can produce a much more sustained accurate bass output than most transistor type amps.....

That's interesting, polarity inversion. That would change things somewhat!

Right, I wouldn't expect it to clear up that massive imbalance, but it should have improved the sounds somewhat if the polarity had been inverted.

I hope you can get to the bottom of this, or rather get to less bottom on this.