The MK5 uses 3 amp fuses (3.15) not 6 amp.

Welcome Fabio.

I'm a big fan of the Swiss Digital Fuse Boxes--one of the best improvements I've made to the system in the past years--I have three in use with Graphene Sluggos. Though "audiophile fuses" made a difference, these Boxes are a step even further. As I am sure you have discovered they really do assist with resolution and dynamic contrast.

I would strongly recommend using the values of fuse/Swiss Digital Fuse Box that Steve posts for the component and not varying them either higher or lower. So get a Box set up for 3 amp for the Mk III and when the time comes one set for 5 amp for the Mk V.

I had Mk IIIs (three of them at once for a spell--two in my house, one at my Dad's) and before that one of the first Mk II ever made and fuses blew a few times. . . and not at start up. . .rectifier related failures. I think it's best to follow the recommended values. And yes, I don't use the Pigtails either--never tried them, I had on hand and use the same great power cable before and after the Fuse Box--that works well.

Interesting. On another forum two posters said using that adaptor was detrimental to the sound. Good to know it isn't.

Yes, I read that too. I didn’t notice any significant negative effects after sufficient burn-in. For example, if a power cable is terminated with gold-plated plugs and the adapter isn't, there may be a slight difference.

If you have identical cables on each fuse box, that’s the ideal setup. However, if the need for two cables has been holding you back from purchasing additional fuse boxes, give the adapters a try — they’re very inexpensive.

Hi Will,

Thanks so much for the insightful reply. The forum has already proven to be a great source of inspiration and incredibly helpful. Especially when it comes to new gear, it always helps to consult others with more experience. So thanks to all of you!

The missing bass knob doesn’t bother me at all. I have so many ways to adjust the sound by changing signal or power cables, or rolling tubes. Having the treble knob alone is phenomenal. I was very pleasantly surprised by how strong its effect was.

The gain knob would definitely be helpful for gain riding. I can currently adjust gain on my DAC (via the high/low switch) and, of course, on the IcOn autoformer. The MK5 will eventually give me another option.

Interesting how you simplified the “fuse setup.” I think I’ll play it safe and just order two: one each for the MK3 and MK5. Also interesting were your findings about the graphene Sluggos. On the switch, I ended up removing an SDFB and going back to a SR Purple, which is warmer and more musical. Swapping the Sluggo would’ve been another option. I had a similar experience when switching from SR Purples to SR Masters. After the third or fourth Master, the overall presentation became too forced and clinical.

I’ve had fuses blow on me in the past too, and since I’m not able to repair anything myself, I prefer to play it safe.

Speaking of rectifiers. I read on the website that the MK5 uses an 8uF capacitor, which makes it more rectifier-friendly for tube rolling. I assume the MK3 doesn't have that feature. I was wondering whether I could use my Type 80 rectifiers in the MK3. I saw a post where someone used them in some Decware amps (though I’m not sure if that included the Torii MK3). Given the lower output current rating of the Type 80 compared to the 5U4G, I’m worried I might overload or burn them out quickly.

Very good point. I‘ll ask Mark to include a copper and gold sluggo too. Another easy option to tune the system. As you say, he‘s a very nice guy to deal with. Also very open to critical feedback. From what I know he started developing a proprietary adapter to avoid the pigtails which really don’t do his product any justice after having received several feedbacks.

We ended up with the treble knob ~90% open too. With Siemens 6922 we were around 75%. With Tesla Gold Grid which is slightly richer we increased to ~90%. I’m with you in terms of treble quality vs. attenuation. In the end it’s also a question of balance, personal preferences and quality of recordings.

Thanks on the guidance on Type 80. I have globes and coke bottles. I prefer some of them over 5u4, 5y3 and 5ar4 in my DAC. Most measuring strong or being NOS/NIB. But I‘ll probably abstain from  experiments. Even if these are less pushed in MK3, I don’t want to blow these for nothing. There’s plenty of options still.

The globes are usually airier. Especially the very early production RCAs. Some of the STs are meatier with higher tonal density. Also here, all a matter of taste and starting point I guess.

I really look forward to receiving my Torii. Such a wonderful sounding amplifier and such a joy to tune.

Started to look into the ZROCK3. Don’t think I fully understand yet. Will lool for more information today.

I have used several different 5R4GYs without issues. Steve's amps are generally pretty flexible with being able to work well with some variety of tubes in any of the positions. Some exceptions, but generally pretty nice latitude. Sounds like things are getting really good there!

Though I have no GZ37s, having used GZ30, GZ32, GZ33 and GZ34s, your observations make some sense to me. After using mostly 5U4G types for quite a while, I found the speed and dynamics of the GZ family exciting...reminding me, though much less variable, 5R4GYs being one type electronically, I found they can be similar in speeds and opening the soundscape. My setup is warmish as a baseline, and GZ30s went too far here toward lower power, leaving the sound too lean in general. And 33s and 34s tended too far into signal intensity here, with a bit too much density/concentration, darkness and fullness in my setting.

The ways I hear it, this is a lot to do with how powerfully or not the given rectifier pushes the other tubes. All else the same, if every aspect of the signal is stronger, I find that will increase every aspect of the sound, creating more signal density, fullness and extension. But music reproduction limitations, wave length influences, and rooms making it easier to obviously mess up the bass and how it balances... too much signal power and concentration can make the mids and highs harder, but less obviously "off." Whereas, it can make the bass cancel and/or amp up parts of itself, while making it slower and more smeared... sometimes to a point of feeling like less bass, while being too much bass signal for the system/room to "digest" ....slow and thick rather than defined, dynamic, resolved, textured...

All rooms and systems having countless influences on resolution, speeds and space, spectral balances, hard to guess exactly what will be "best" with given tubes, but I am with you, we can compare the characteristics of tubes and try to fit them in by comparison. And all else the same, at some point more tube power, if it goes too far, I find to be an important indicator for tuning, the signal strong and concentrated enough to overwhelm the system and room, while throwing off the potential for the amp's complexity of resolution, speeds and spectral balances.

Clearly countless variables within all setups create variable beginnings. But with the Torii's many tubes and adjustments, as you are experiencing, their relatively transparent and resolving nature shows tubes well, and they can allow a lot of ways to experience the beauty of different tubes and tube synergy... each of the five tube positions powerful sound shapers, and mixing and matching tubes that might be too much in some sets, or not enough in others, can result in musical beauty.

But as I have said, I personally prefer to go for relatively resolving, complex, neutral, and fast balances with all the tube choices, less tube extremes and compensations making playing well across recordings easier for me. And each contributing their own influences, with five tube positions in the Torii (and for me, 6 other tube positions before the Torii), even within relatively narrow sonic perimeters, there are lots of ways to experience the music, awakening my perception and experience in different ways, and in doing so, changing me and my life.

So in this particular setting, the power push from the GZ32s was my favorite of the GZ tube types. The whole faster and less smeared than with their more powerful siblings, they allowed more unaffected complex resolution and immediacy... more space contributing to more defined edges that remained complex... and the whole more live feeling. With all levels of resolution and dynamics rising out of more open space across the spectrum, they tended to be mildly warmish, but not overly full or concentrated, the bass fast and complex with just enough warmth to sweeten mids a bit without slowing or darkening. My system and room does tend to be warmish without compensations though, which helped make especially transparent and resolving Mazdas with double rectangle bottom getters my favorite of the type. On the other end sonically, some late 50s Mullard GZ32s were quite nice with the right company, but all in all needed compensation in this setup, tending a little too dark, full and slow for me overall. And no doubt, some rooms might arrive at similar balances I get using stronger tubes like GZ33s, or 34s, or 37s.

5R4GYs to me can be nice similarly to the GZ32s, tending toward fast and spacious, while pushing the other tubes (and therefore the signal) less forcefully than some rectifiers. When they work, they can give similarly nice balances with good speed and space throughout, allowing complex fine detail, immediacy and dynamics everywhere. But then, like all the tubes, depending on the setting, some of them could be too open and spacious, some fuller/warmer/thicker, less extended, etc.

Of the 5R4GYs I have used, some black base Fivres were the most open and fast... very much about space and clarity (with them you may need to turn the treble down again there), and some NOS Phillips, here, were just too slow, veiled and full for me to enjoy their good qualities. 50s RCAs are always nice at first, but finally a little veiled for me, lacking some top extension, and subtly a little slow. 5R4GWYs can be nice depending what is needed too, with their different shape and added damping, tending pretty open, but also pleasantly smooth and mildly warmish. For me, very fine resolution and speeds, along with subtle musical warmth, a necessity, the GWYs tend toward being a little too smooth and lacking in fine detail complexity, but I recall them as being nice tubes if their characteristic qualities fit with all else.

To remind myself, not having used 5R4Gs in years, now I put in some brown based Sylvanias labelled 5R4GA, with hanging filaments, ribbed black plates, and a centered side horseshoe getter. I think some of these are called 5R4G-Bs with their semi-fat straight bottles, and compared to my more usual rectifiers, RGN-1064 globes and similar variants of B4, 4V euro tubes I have been tuning with for years, the Sylvanias are a little too full, and a little slow and lacking in dynamic contrasts for me. But this is me and my setup, and the Sylvanias, without notable imbalances with the other tubes I have in, I think they could be beautiful with the right company.... just not as natural, alive, and musical with the rest of the tubes as they are.

Importantly, for reference though, my setup is heavily modified across all components, and tuned for very complex speeds and resolution without concentrations or hardness, making it really easy flow. This makes any tube stronger than in most Decware gear.... so most "normal" tubes that fit well for most people, similarly to solid "sluggos" here, tend to be a little strong for me, especially without compensations.

Anyway, relative to VR signal power, I use OB3s, for my setup, pleasantly a little milder than OA3s, and OC3s sometimes a lot of fun for their open spaciousness, but they eventually end up being a little clean for me. I used them more often before modifying my components for less smearing and more enhanced resolution and speeds, and I am guessing that if you try your GZ37s with your coming OC3s, OC3s pushing the other tubes less powerfully, the GZ37s may end up somewhere a little closer to the Marconi 5R4GYs with the OA3s you now have. As things were before the Marconis, a strongish GZ rectifier, and the OA3 the strongest VR for signal power, the OC3s will relax half of that, changing the whole a fair bit. Not that this would be "better or worse," but I bet it will be fun to explore!

Hey Fabio. I am glad my post helps.

As you are finding, every tube, in every position, will have different ways of influencing the sound... and how they are combined, along with amp adjustments, offers literally countless possibilities toward tuning and refining the many balances of balances in a given setting.

Seems likely the foibles of the Marconi 5R4GYs in your setting are at least in part just the tube characters. But also, you will find you can tune within that, about any tube position having possibilities for relaxing the sound, and especially in some positions more than others, coloring it depending on the tubes used. I worry some from your description though that this tube may just be too clear there, sounding like the intensity you are experiencing with the mids being forward is likely inherent. But as you suggest, with some luck, relaxing that may make them work. OB3s will likely be a safer bet for turning down the intensity a bit without getting too clear, and if the intensity is toned down, being most concentrated in the mids, maybe the bass and highs will balance up a bit... But generally, VR tubes that lighten intensity, making things less powerful, tend toward clearer overall. Still, part of why I like OB3s is that they are pretty neutral and warmish, whereas most OC3 in my experience with Toriis tend to be quite clear... also good depending on what is needed, but guessing not ideal for your current need. You never know though just how these pretty organic acting tubes will interact, so worth a try!

And this will all depend on where you are coming from, whether the OA3s are brighter or warmer.

By the way, not sure what he is saying now, but Steve always used to say not to get too concerned about the technical parameters of the switches, better to just go by sound unless obvious problems show up sonically. I have found this to be true... in my amp, sometimes the 4 ohm output setting works better with given tubes, and sometimes the 8 ohm setting... Same with bias controls... Just more tools to keep in mind with tube tuning. In my warmish setting, I tend to leave the bias switch off, and the speaker switches using the less powerful, more open, 8 ohm setting. But these may be good tools for you if you have not already explored them.

Also relative to trying to find a little more from the Marconis, you are using relatively powerful tubes all around, including clear and resolving inputs. In my setting, I like less powerful tubes especially for the inputs, larger VRs, and rectifiers. I also gravitate to more open, resolving, and fast power tubes. And for the small VRs, I would recommend (something I rarely do) trying some 75C1s. To me, compared to RCA or Raytheon made OC2s, they are warmer and more textured without being dark or slow and without masking fine detail...a nice friendly tube to me. You can usually see some labelled Valvos, Mullards, "ENGISH ELECTRIC VALVE CO LTD," RFTs...  All I have sound good to me, and not knowing if mine are representative or not, I would say Mullard, English Electric, and Valvos seem pretty close in design and sound...warmish and textured while being open, fast and expressive. The WA labeled (I think maybe RFT) tubes I have been using for a while, are similar in outside appearances, but having a darker interior flash, I can't see the interior structure once lit up. With this pair, the sound is more on the warm/smooth side, a little more contained, a little softer. Though to me, somewhat less lively and spacious, textures and fine detail are still pretty good... the variation potentially a little better or a little worse depending on needs. Still, all I have are pretty close, and I don't think you could go wrong with any of them for a test.

For inputs, late 50s/early 60s Siemens or Heerlin made ECC88s with hallow getters tend to be quite resolving, textured and spacious without being too dense or pushy here, and they are definitely milder/more relaxed than E88CCs tend to be... good or bad there... not sure, but guessing that if you have some nice ECC88s around, they could be worth playing with and see how the Marconis and all sound with them.

As to the Mazda GZ32s I have, they are the ST shape. May be different there, but to me, the fat bottle Euro GZ32s, like Mazda or Dario are really nice tubes, but are a little too open and clean here except for special needs. Even the ST Mazdas would likely be considered too clean in many rooms that need "warmth." But it was my preferred tube here for quite a few years.

What led me to RGN1064s and AZ11s, UU5, MU14s etc, was a seller I bought some Telefunken GZ32 ST shapes from. They sounded really beautiful, better to me than the Mazdas, having similar open spaciousness, but a little more textured and warm as I recall. Trouble was, one day one would flash and die. I finally figured out that these tubes, and some Adzams, Dario, and maybe some others, were probably earlier GZ32s and the cathodes were just not up to Decware amps. The tell-tale on them is pretty easy to see, quite narrow cathode tubes rising out of the top mica. So if you go for GZ32s, be aware of getting those with the noticeably bigger, cathode tubes.

This guy was a really nice audio head, and he sent me replacements until we figured out the tubes just could not stand up to the rectifier caps in many modern amps. It was then he told me that he was using UU5s and and MU14s finding them to sound similar to GZ32s, and when I asked, he said in his amp he was not having any issue with these tubes being rated for 4V, where ours, and maybe most amps these days seem to use 5V rectifiers. He sent me a pair of each with some sockets to change into my amp. I ended up ordering some nice convertor bases instead that would allow B4 type tubes in a 5U4G socket and have used mostly these variants ever since... not good at tracking time, but quite a few years. Once I got the convertors, that opened the door to other B4 tubes, and I ended up preferring less powerful RGN1064s, which then led to more variations with different bases, like AZ types, AZ11s electronically the same as RGN1064 and other AZ types closer to the UU5 or MU14s, but needing a different convertor.

Anyway, I am glad you mentioned wanting to try GZ32s so I could warn you about this potential cathode issue. And I am glad to reminisce on this, as I have since put 15 uF caps in my rectifier position, and I suspect that the Telefunken GZ32s might work there now... I will have to check it out!

Hi 4krow,

Let me start by saying that the shout is all gone. The GZ37 from Mullard is a bit lean on the lower midrange shifting the focus to the upper mids and treble region. With the Marconis and the Reflectors getting some hours and with a switch of a Ethernet cable I did yesterday, the sound is wonderfully balanced by now.

I have used the Bönicke‘s W8 SE+ for several years. These are very inefficient with 83db and dropping to 2.7 ohm. So I always drove them with solid state amps which are capable of delivering enough current. I had a Beta 24 DIY amp and a Sanders Magtech. At this year’s show I bought the Ella floorstanders from Wiener Lautsprecher Manufaktur. I heard them several times and I was always impressed how good these perform. Whenever I switch a component it takes some time to find the right balance. But I‘m super happy with where I am after such a short time. Nearly there.

With regards to the rest of my system, I‘m using a Lucas Domanski Audio Server, a Lampizator TRP DAC, an Icon 4 Pro silver autoformer into the Zen Torii MK3. Power comes from a Bönicke power gate with directly soldered LessLoss cables on digital components, a Audience front row reserve on the icon and a Douglas Connection on the Torii. For the signal I use my own solid core silver based cables.

Hi Tony,

Thanks for the warm welcome. I have a minimax, which is a sonically maxed out version of the mini with external lpsu and copper base for both server and lpsu. It doesn’t have the upscaling capabilities of the Maximus though, which I personally don’t need.

It’s a wonderful, reliable server without any of the digital glare you often get from peer products. Also, the client support from Lucas is top notch. Lucas is a good friend of mine. He actually offers my cables which I developed for his servers as internal upgrade option. I can put you in contact if desired.

It’s a special project they did a few years ago. The cabinet is made of massive cherry wood. It uses a 7 inch paper driver with bottom ported bass. The driver almost acts like a full range and is only cut a bit on the top, where a paper based cone-tweeter takes over and handles treble. So very simple - no frequency switch or anything. They also do the same driver concept today with two bookshelves, their Ella Ellington and the bigger version the Ellington XL.

Here’s a link to my speaker. Unfortunately, only in Gernam. WLM is a small producer from Austria: https://www.hifitest.de/test/lautsprecher-stereo/wlm-ella-die-moebelmacher-wlm-w...

I agree with you on starting with speakers. I used the Bönicke‘s for around 7 years and built my system around it. Heard these Ellas several times and they are not too far from Sven‘s speakers tonally. Andreas and Martin from WLM and Sven know each other well. Both use the same carpenter for the woodwork. I was super happy with the setup getting tone from the tubes in the dac and then keeping the signal simple with an autoformer into the Magtech. When buying the speakers I knew I’d buy an amp too. No need to change the frontend. When the speakers arrived, I was actually surprised that they sounded very good on the Sanders Magtech. Bass to my surprise was not overdamped. But the aim of buying the speakers was to get tube amplification and the Toriii is doing a wonderful job. The emotional connection is on a higher level than before.

I don’t know the Markaudio Drivers. Also, I wouldn’t be able to do such projects with two left hands  :D

Hi everyone,

It’s been about two months since I’ve had the joy of living with the Zen Torii, and I thought I’d share an update on the various tubes I’ve tried during that time. The amp came equipped with a Mullard GZ37, Telefunken EL34, Sylvania OA3, and Raytheon OC2. One of the input tubes was defective, so I swapped it for a 6N23P Reflektor 1975 SWGB Silver Shield.

I’m amazed by how many different sonic flavors this amp can deliver just by rolling tubes. Initially, the sound was on the lean side. The first change I made was replacing the output tubes with Philips EL34 brown base from the Blackburn factory (xf3 codes). This brought much more body, but something felt off in terms of coherence.

I switched the rectifier to a Marconi 5R4GY. The dynamics and speed were astonishing, almost too much. It became fatiguing, with a lack of bass and a presentation that was too upfront and in-your-face. I then tried a Mullard GZ34, which was better, but still somewhat forced. Then, I tried a Brimar GZ32. This brought a more relaxed feel, fuller body, and a nice warmth without being syrupy. Next I tried the RCA 5U4G, which offered a cleaner, more precise presentation with excellent bass control and linearity, along with extended treble. However, it lacked emotional engagement.

I moved to Tesla Gold Grid input tubes. These gave more body and midrange magic but still sounded a bit too sober. I tried Ei, but they were lean with an odd tonality. The Sovtek tubes were better with good body and bass but lacked precision and lacked depth. Next I tried the Valvo E88CC from the Heerlen factory. These were lovely with voices, rich, euphonic mids but slightly rolled off in the treble and a bit soft overall.

I returned to the Brimar GZ34 and paired it with the 6N23P Reflektor. This was a beautiful match. The Reflektors are direct, raw, and very linear, with great dynamics and attack. They perfectly complement the more relaxed character of the Brimar. I also tried the Teslas and Valvos again, but they now sounded too muddy in comparison.

Though the Brimar GZ32 and Reflektor combo was less forward than others, some tracks still felt a bit too “in-your-face” for the kind of music I enjoy (mostly singer-songwriter and jazz). I swapped the Sylvania OA3 for a Westinghouse OA3, which was softer but more musically involving. But still, the sound felt slightly pushed.

I then tried a Toshiba OC2, which turned out to be too soft, warm, and muddy. Quickly went back to the Raytheon OC2. The difference was substantial: much better clarity, dynamics, and speed.

Next, I replaced the Westinghouse OA3 with a Westinghouse OC3. This combination was excellent if you’re looking for a more relaxed presentation.

I revisited output tubes and tested the Gold Lion KT77, which provided a more modern, linear sound that was less midrange-forward. Pairing them with the Valvo and Tesla input tubes brought a bit more emotional involvement. Still, I quickly returned to the Philips EL34 Brown Base as they simply offer a more engaging and complete presentation

My Favorite Long-Term Combination:
•      Input: 6N23P Reflektor 1975 SWGB Silver Shield
•      Output: Philips EL34 Brown Base (Blackburn xf3)
•      Rectifier: Brimar GZ32
•      Voltage Regulators: Westinghouse OC3 and Raytheon OC2

If I want a more energetic presentation, I swap in the Westinghouse OA3 instead of the OC3.

I plan to explore more output tubes (like 6CA7 and 6L6). Would also be interested in some higher power tubes like Siemens F2A but not sure these can be used safely.

The Zen Torii continues to impress, an absolute gem, and a joy to shape sonically.

I’m currently on the waitlist for the Torii MK5. However, I’m likely to switch to a Sarah 300B to broaden my Decware lineup.

I see where you are coming from, James. Luckily, it’s been a great joy so far and I’m very pleased with the sound. Apart from the voltage regulators, I already had most of the tubes at home, so trying them out hasn’t been much of a hurdle.

Thanks for the advice. I’ll avoid the F2A, then. I’ll also give the OB3s a try. Do you have any recommendations for specific brands? And are there any output tubes you’d suggest besides the EL34?

Thanks for the advice, James. Much appreciated! Indeed I had been looking through some of those tube-rolling threads.

Thanks for the recommendations, Lon! Will be looking out for the Arcturus branded ones. These VR tubes are luckily all relatively inexpensive.

Thinking of OB3s, the ST shapes I have are from two primary construction/vintage variations. Sound is a little variable within each group, but in my experience these two versions are primary for sonic differences between the ST shaped OB3s I have. I had two pair of each handy and tested them a little this morning.

To verify my memories, I found an email conversation from 2013 with Brendan at TubeWorld. He thought all were made by Sylvania and relabelled for various companies like Westinghouse, Dumont, Tung Sol, Marconi, etc. He said one was from 1950 and after, and the other 40's up to 1950.  

The primary differences in construction and labelling define vintage.

Looking inside the tube from below, so that you can see under the getter flash, the later style has three wires evenly spaced as they come out the glass stem (blob), and the middle wire just above the glass stem looks just like the others, no D wire welded to it. These also are labelled with a symmetrical octagon surrounding the OB3 marking. Brendan said then that these are the 1950-on versions. In the bottom of the first two images, I am trying to show the wires rising through and above the glass stem.

Hopefully you can see within the glass the three wires are copper colored, and then black once in the tube space and the black wires are evenly spaced.  Really hard to get readable pictures with so much glass and getter flash, but hopefully these will help.

Roughly, though they can be variable within this design variation, I would say these feel a little more powerful, are a little faster, and are the more transparent/spacious of the two.





The other, earlier versions (40's to 50, though some Dumonts I have, were relabelled '71), have the middle wire above the glass stem offset to one side some, not centered, and on that middle wire, there is a D shaped wire welded just above the glass stem. Those with the welded D wire, are labelled with two octagons that are horizontally widened and on top of each other, like two octagons squeezed together top to bottom. The top one says OB3, and the bottom, VR90. To me, these generally have a little softer, slower, warmer feel, and in ways are a little more textured feeling.

Which is "better," can't say. I have enjoyed both for extended periods, OB3 my primary VR in my MKIII and later MKIV, as well as in all the progressions of my highly modified MKIV. Having been using 50's versions labelled Marconi for a few years, after these minor tests, I am enjoying the earlier version now, labelled Dumont, a tube I used for years before the Marconis. I find it especially nice after shifting from Mesh plate RGN1064 rectifiers to straight bottles with solid plates, both Telefunken, the latter a little more clear and articulate and so far working nicely with this slightly softer/warmer OB3 variant.

Anyway, if you like whatever version you get in your amp Fabio, being pretty particular about tube sound and how tubes work together to shape your sound, I was imagining you may want to try to pick up a pair of each version to check out.

Hey Fabio,

I found the early 70s marked Sylvania OA3s clear, but sort of lacking in character... Whereas some late 40s Hytron OC3s are even more clear, from being OC3s and pushing the signal development less, but also they are more refined tubes... clear, but supporting good complex character. So the Sylvania’s, may be the most clear sounding of the OA3s I have tried, but they felt a little flat and sterile, an odd juxtaposition when lots of times quality clear leaning tubes are some of the more resolving ones.

Related, the most powerful VRs for these amps being the OA3 and OC2, having the least voltage drop, they will help show everything they do more. But as you have heard, within each type, they all bring out different tonal, speed, space and resolution characteristics, some more than others, and this can confuse evaluation... maybe the same voltage drop, but more or less warm, more or less fast, more or less complex… these balances can sometimes make the power effect a little more difficult to differentiate.

And like rectifiers, do VRs have a sound, or do they have different ways of effecting the sound of the tubes that follow? From lots of experiments with tubes, and with caps for power, bypassing, and in the direct signal path, I would say it goes both ways. Everything affects everything in a resolving setting, and the more I explore, the less I think of the power supply as separate from signal. Especially apparent using the same bypass caps with similar values for power supply bypasses, and for coupling, it is clear that power supply bypasses impart individual sonic signatures in very, very similar ways as those same caps in the signal path. Finally, interdependence and influence of one thing on the rest with nice tube gear make it hard to believe from sound tuning that there is a difference between signal and the power that feeds the signal path. So if the signal is what we hear, it is all signal path to me I guess, making rectifiers and VRs signal path sonically.

Related, you have heard that just changing OC2s with the same input tubes following them, that the perceived OC2 sound qualities will vary some depending on the inputs used, and I think part of this is that the OC2's influence what the input can bring out of itself. Like, all else the same, if you try a Raytheon OC2, followed by your ’75 6N23Ps, listen a while, then try your Tesla E88CC... Log that in mind, then replace the Raytheon with a nice 75C1, and do the same, listen for a while with the 6N23P, and then the Tesla. Though it might appear that the changes are from the VRs, I think the VRs have sonic traits they impart, but this also changes how the actual input tube forms and balances it characteristic qualities. So the VR is not independent from the input, instead, feeding it, and working with it... both tubes having notable characters, and both together changing each other's basic qualities.

Add to this the power VRs, power tubes, and rectifiers, all variable sounding within their type, and each effecting the others, not just based on each tube’s sonic traits, but based on what they bring out of each other. So we can define characteristic traits of a given tube for reference, and this is very useful as a start for tuning. But none function independently. To me, this helps describe the beauty of tubes when it works at it's best... a potential for a synergy that is beyond the sum of the parts, illusive and seductive, but also transient since tubes are basically alive, always changing.

So I use memory of the sonic balances a given tube has to fine tune things, but this can take some time to refine in a complex tube arrangement since everything effects everything. And though I over time I feel like I have become pretty good at identifying the complexity of balances within a given tube's tendencies, making the right choices in tuning is always a bit of a crap shoot, the subtler interactions from the combination of all the tube qualities influencing each other and making a much greater complex.



In the case of these OB3s I tested, one step less powerful than OA3s, the ST shaped OB3s may be the most uniform sounding tube type here. Still there are sonic differences between each design group, and variations within each. In the case of the D wire versions, though notably similar, if I tried, I guess I would find a pair that I prefer in a given tubes set, and another might be preferable in another. And more so between versions, though still pretty close, I found yesterday after putting in the slightly milder/warmer OB3, I needed to put in a slightly more defined rectifier.

Relative to bass, comparing those two OB3 variants, I started with some Linlai 5U4G-ST, though pretty linear and neutral here with good complexity, they are a more powerful and dense sounding rectifier than my usual RGN1064s and variants, including more bass in the balance. With them, all other settings and tubes the same, the more transparent and slightly more powerful feeling 50s OB3 pushed the bass a little deeper and harder... This was definitely more obvious with the more powerful rectifier. So to me, "warmth," though associated with more bass in the balance, is variable in the broader spectral balances, more powerful tubes pushing all they are able to show harder, including whatever bass tendencies they have, and milder tubes will push it all less hard, in the case of bass, often less notably full and deep. So the clearer, slightly more articulate and powerful seeming OB3s could potentially articulate your bass more, making it feel stronger, or the slightly softer/warmer versions might depending on all else.



As I listen for bass, with a standard of a natural bass complexity and balances, it has density, depth, fullness, as well as articulation, speed, complexity and textures... and without notable smearing, muddle, bloat. I think this is in large part from having really good timing throughout with good integration of other musical aspects of the spectrum, allowing fine detail and inner space that supports clear leading edges and nuanced harmonics in the bass… textures, decays, wood and interior space of instruments, etc.



Importantly, the rest of what makes the amp aside from the tubes is also complexly influential… all the connectors, all the wires, all the resistors, transformers, fuses or slugs, the solder used, vibration mitigation, etc, etc, all effecting one another. In my experience, changing any of these individually is a real choice, so "voicing" is a big deal.

In this respect, I have found the MKIII and the MKIV, in both my rooms, and with the different speakers I have, tend toward a little too slow and unresolved bass for my needs, preferring a little less bass intensity that can be a little more easily tuned to be fast, dynamic, and complex. As I have said, to me, it is a fine line, and sometimes less can be more with the right speeds and articulations of all that makes convincing bass enlivening the depth and body.

Still, as you are finding, these amps can be really beautiful with tubes and all else tuned toward a lively/real sound. But with pushy tubes especially, for me, especially tubes that are also a little slow and full low down, thickish bass can become exaggerated and harder to identify as the issue, and therefore harder to solve... But whether a little too much or not, without enough resolution and good speeds, not always, but I have found smeared and thick bass can end up feeling like less bass when it is actually more bass….just lacking enough definition and speed to differentiate all the complex information that makes bass sound dynamic and real. This is part of why I am pretty attached to gain tuning. With more than one complimentary gain stage, I can gain tune more or less lucidity, bass weight and speed, dynamics, fine detail, presence, density, etc in fine tuning the system/room, then for fine-tuning individual recordings where needed.



Thinking of GZ32s, I had some Brimars that I never could quite love because especially lower down, in my amps and system/room, they were a little too dark and slow, but you are finding them one of your best rectifiers in ways so far, in part for the same reasons. Then the question becomes, is it the Brimars, or the EL34s, or the two VRs, the inputs, or possibly amp tendencies?

Relative to amp tendencies as I have experienced them, especially if your Valvos are early 60s with hallow getters, the input E88CCs you have mentioned are all nicely resolving tubes, and to me, all on the clear side. That you may not experience them all that way, along with recently preferring GZ32s, OC3s, and clear and resolving Raytheon OC2s…all these compared to stock tending toward spacious resolution and speed... Not having heard them, I am assuming the well loved XF3s are favored for good reasons, guessing, warm with good resolution, complexity, and balances. And from what little I have been able to find on them, Psvane Phillips EL34PH (perhaps replicas of similar NOS EL34s???) are supposed to have a pretty strong and deep bass. So looking at hopes for improvement are interesting, seeming that on one side, you are preferring a little more clarity, speed and resolution, and on the other, missing some body, especially in the mid bass, and deeper bass??? Speculation, but all this makes me wonder if you may be adjusting in part to tendencies of the Torii MKIII as I did.

Especially if not though, I imagine that from what you seek, especially if the 5U4GBs you ordered are complex and balanced tubes, they may well get you onto another level. The best of those tubes to me are spacious and complex, while also having nice, not usually overwhelming warmth, and weighted toward deepish bass that can be relatively tight and fast if in a setting that can take it without over-thickening bass. Trouble is, there are lots of them, and they all sound different, but also pretty low cost, fun to explore if they seem good in a system.

As to JJ 6CA7s, I had not heard them in years, and adjusted to them way back, but never loved them without some work as I recall. Also, back in the day, JJ tubes in general tended a little unresolved and slow to me, but as I recall 6CA7s were pretty nicely dynamic, resolved and spacious, though especially 6CA7s in the past had issues with durability.  

Since I have done a lot of system/room improvements, I went to look around for some JJ 6CA7s and found a cryo’d quad, as well as some button based and normal based 6P3S-Es, a few modern EL34s I have liked, and a few modern 6L6s I have liked. So I was thinking I could listen to these over the next few days and give some impressions if you like.




All this leads me to suggest considering power supply bypassing and coupling cap upgrades if not already done in your amp. That your revelatory introduction to Decware was an amp with what Steve coined Anniversary mods, as well as how deeply you listen, causes me to think you might love good modifications. There are some risks in that they are powerful tuning tools for better or worse, but with known quality caps, and without extreme values, improvements in most every aspect of the sound can be pretty amazing.

So if you have not looked inside, it may be worth checking to see if anything has been done to improve the stock setup. As I have worked on my amp, progressively more resolved, immediate, and refined in complexity, density, and speeds top to bottom, all tubes sound better. So if not done already, doing (or having done) modifications to speed up and better balance the power supply spectrally and musically, as well as upgrading coupling caps could be a major shift.

Since yours has no bass knobs, it may well be like mine, a very early MKIII version. In my case, it came with some little red Wima coupling caps, a good sounding low cost cap, but once the system/room got really good, they had a little hardish leaning synthetic quality in this position. I was reminded of this when working on my "new" DAC over the last months... For me, even with refined voicing like Steve is so good at, a system can only go so far before these Wimas can become an impediment, at least in some positions.

In my DAC, focussing on bypassing base power supply caps, while exploring different combinations of output tube caps at first, I could see some Wimas were in the DAC in several positions. But as I began to refine the DAC, I was sonically reminded of those early MKIII days, I could hear that Wima sound.

So in the DAC, I changed out a Wima I thought would be most influential, right before the DAC's output tubes, and like magic, that odd, slightly synthetic sound disappeared, even with Wimas still in seemingly less critical areas. Not that it was an easy fix, having to try a number of nicer caps I know along with some value experiments and bypasses for them. But once I found it, along with other tuning, with my needs for convincing complexity that is not hard and sounds natural, it really transformed the DAC.

That said, as I mentioned, having found that power supply bypasses in nice gear effect the sound eerily similarly as signal chain changes with the same caps, the idea that power and signal are separate does not work for me. And I bet the DAC will get even better once I get around to exploring just-so upgrade caps for some of the other Wimas.

Just wanting to illustrate how powerful internal tuning can be in transparent designs, and as a 1st step of tuning a stock MKIII so that it is faster, more complex, and more musical, it could be a pretty simple operation.

I agree Lon. Exploring and refining the musical experience is, for me, medicine.... harmonic tuning, not just a harmonically rich system/room, but myself.

Especially, with so many fast-lane habits that are not healthy "cultured" into us as "normal," seeking deeper harmony in self and the world seems impossible.... warring polarization and associated, chronic frustrations, fears, anger and hatred... chronic time stress that has been normalized but is deadly in excess... perpetually speeding up with a vast array of ways to "spend" and "fill" our time as we have integrated concentrated earth energies and technology to do so much of the work toward helping us fulfill our desires more quickly.

I guess time stress, is fundamentally the most damaging current cultural habit... causing us to not look deep enough at the issues we are collectively creating, and making too-fast decisions that often have negative "side-effects." And under these influences, since we can do everything we do faster and faster with ever-expanding technology, the negative sides of the not-so-good decisions often effect more things, more powerfully.

I am not suggesting this is the fault of technology, but that cultural development can't seem to keep up with it in optimally healthy ways, and habitually, we are prone to rationalizing and normalizing what we do, for better or worse. Our desires driving so much of our progression, to feel OK about things that are not really OK, we tend to change the reality enough to feel OK about actions that hurt ourselves and others... the foundation of delusions... "truths" that are close enough to the truth to feel real without relatively clear examination that is less biased by cultural belief patterns.

Many age-old doctrines, still developing by many consciousness explorers, suggest that unhealthy desire leads to delusion, and delusion is the basis of suffering. Basically, by believing a complex of modified reality that is not fully real, our thoughts, desires, hopes and expectations are not fully real, leading to "cutting corners" and doing damage to others without noticing... And not least, shocking and disappointing us as Reality "imposes" itself on our less-than real belief systems...

Compounded by ever-faster, fast-lane habits leaving less and less time for deeper consideration, delusion helps us avoid realizing we are often responsible for imposing toxicity that degrades our physical, intellectual, emotional, and spiritual well-being and health. And by nature, too many toxic stressors make us less healthy, duller, less centered, less attuned, less associated with nature, the nature from which we come and are a part of... making us less able to discern and cultivate solutions.

Finally, I think this complex causes us to too easily forget that if we damage our home environment that creates and sustains us, including others who are a part of it and live in it, we damage ourselves. Whereas, if we work to make our body/mind/hearts more healthy, we tend to realize we need to make that which sustains our body/mind/hearts healthy... our air, water, soil, food, drugs, habits of feeling, thoughts and actions. In some schools of eastern medicine we could call this harmonizing, working to re-associate with and cultivate our Harmonic Nature.

I realize that for me, my life-long interest in learning to feel better in a difficult world, is a lot about solving the damaging delusions I help support. At the same time, and interconnected, I think seeking and cultivating natural harmonic balances can be a means to uncover reality and balance in myself.

In my case, mostly catalyzed by loving playing really nice sounding instruments, and then from finding Decware with its natural revelation and harmonic qualities, I realized that supporting and cultivating a truly harmonic musical experience can be a powerful support in my pursuit of Harmonic Balance.

Associated, the focus of tuning an audio system, and the experience of increasingly harmonic musical experiences, both tend to naturally grab our attention, clearing the mind of habitual fast-lane thoughts and feelings. So both can easily be called natural meditation. And meditation, including deep prayer, have been baselines to help us find balance and equanimity for Millenia, in turn supporting feelings and thoughts less-biased by delusions from culture, and thus allowing for discovery and potential for gradually solving delusions that uphold our self-defeating patterns of suffering.

So harmonic audio is a real medicine for me, seductively beautiful, and by association, helping to harmonize inharmonic patterns I struggle with.

Sounds like you are having fun and good success learning the amp and how tubes interact with it. I used mostly PCC88s in my MKIII, liking their nice combinations of speeds, spaciousness, dynamics and fine detail in that amp. I think that your finding them to have more realistic and complete bass, while also being less forceful than nice E88CCs, supports my sense that you may be having a similar experience as I did with the MKIII.

To me, PCC88s are actually less bassy than E88CCs. But as I have been talking about, with my Toriis, less deeper bass signal in general, if not extreme, can be more, if supported by speed, resolution, and openness top-to-bottom. If we can bring out nice leading edges and dynamics, the bass is more articulate and impactful, hopefully enough to balance the rounder/deeper bass qualities and making it feel and sound like more bass. Being clean sounding across the spectrum, I am guessing your Tungsol 5U4Gs might be coke-bottles? But whatever, clean 5U4Gs would give a little extra push compared to Brimar GZ32s, and I can imagine they could deepen the bass qualities of the PCC88s while not overwhelming low bass and/or being dark or thickening.


I agree, for me it is a lot of fun to discover different qualities of beauty the Torii can make. With tubes and settings, so many ways for discovering the many balances, that when balanced well together, can be pretty mind expanding. Offering potential for sort of endless variations of the musical experience ... pretty sweet!

PS: I am slowly exploring comparing qualities of different modern and lower cost NOS power tubes. And if you get around to trying the Russian 6L6/5881 variants you have, that might help me. I remember those as pretty deep, full and warm leaning with a little slow, but not quite syrupy euphonic qualities... wettish with pretty nice detail, and full bodied. So they may fit in with some tube tuning.