UPDATE:

Here is the updated tube compliment for the SE84UFO25. Since my last rambling about this I have decided to add even more tubes and enlarge the case.  My first effort was pretty good but I knew I could do better, so here it is!






Contents of the case:

2) OA3/VR75
1) OA3/VR75R
1) OC3/VR105
1) OD3/VR150
1) 5U4
4) 6P15P-EV
1) 7DJ8
1) 6N5P
1) TUBE PIN STRAIGHTENER
1) SOCKET SAVER

Also as you can see there are six empty places for additional input tubes. The amp comes with a select grade NOS 7DJ8 and a 6N5P. Additionally it is compatible with 6N1P, 6N11, 6DJ8, 6922, 7308 and CV2492 so it makes sense to put some place to put extra input tubes that you might accumulate.

Also you can see a tube-pin straightener for the audio tubes and an 8-pin socket saver for the rectifier tube to elevate it.

This is the tube compliment I feel the amplifier should have to be fully appreciated and it is what will be sent with the amplifier when "include tubes" is selected in the shopping cart.

-Steve  :)

Amazing, thanks for all the love to the details Steve! Looking forward to holding mine in hands  :)

Quote:


I realize this doesn't have a lot to do with this thread but can someone please explain the physics of this to me?  I've seen this kind of statement many times in the audio world and "draining vibration" isn't something I've ever encountered in Engineering.  Damping (which is mentioned as "...absorb energy and transfer it to heat.") and avoidance through tuning are both real concepts.  All "draining" means to me is that vibrations travel through the audio chain until something damps it.  Far from ideal.

The way I see it is there are 3 sources of vibration:

1) Sound in air
2) Vibration from the ground
3) Vibration from the amplifier itself, specfically the power transformer.

Of the three I think #3 is by far the biggest contributor.

So we have enegy being generated at the power transformer that is coupled to a steel plate that has higher mass than the transformer.  The energy moves into the steel plate which is connected on it's boarder to an even higher mass hardwood base.  The energy moves into the base which is then coupled to a special amplifier base (plinth) which is higher mass still.  The progression of mass keeps the energy moving in one direction.

Now we also have the energy from the floor moving into the audio rack or table your amplifier is on trying to get into the amplifier but the high-mass plinth is constrained-layer dampened so that energy that comes into it is turned into heat.  The design of this layering must also have a nucleus of mass that is higher than all of the above mentioned items to be an effective vibrational sink.

I've been working on these plinth designs since last summer and the resolution of the UFO25 is making it easier to hear the effect.  When they're ready I'll have them on the site for sale.

Steve

The natural damping of materials is called hysteresis. It is when the molicules rub together and create friction.
The natural vibration harmonics of materials are different, then you get into the actual mass of the materials plus the unsupported areas of the materials.
Thicker is normally better, more support is usually better. Varying the density of the material is better.
There is a reason that bells are made of bronze and not of lead or wood.
Vibrations are damped  by varying degrees by the material that it is transferring through. I don’t recall ever being taught anything about draining vibration, just damping it or changing my perimeters to change the harmonics.
I work on eleminating vibrations in my profession every day.
Of course my education is from MIT (Mississippi institute of truckin’) so I might have made it all up.

Donnie and Steve,

That's the way I've always seen it.  I don't doubt that vibration moves through the system but it goes in all directions, not just from low to high mass.  Once the transformers get the plate moving the vibration also goes into anything attached to the plate.  The damping needs to be local.

With all due respect, I would differ in Steve's order of concern with the induced vibrations.  While the transformer is important, it has a limited spectrum.  The vibrations that come from the equipment supports are potentially much worse since the spectrum can be so much wider (potentially 0 to whatever the top end of the speakers).

I've no doubt that this amp is a step in the right direction with respect to vibration control/mitigation but I still maintain that the "gold standard" is magically suspended in a vacuum.  The closer we can get to that, the better.  In the real world, I think this means good design and a better than good isolation platform.

One of my first projects when I was a "rocket scientist" in the 80s was to come up with a launch lock that would keep a delicate piece of equipment from coming loose during a shuttle launch.  Given the ridiculously wide vibration spectrum involved, I gave up on tuning the resonance and went for spring isolation that put things completely outside the vibration window.  That experience prejudiced me towards isolation.  Now I just remodel kitchens and bathrooms so, take the former for whatever it's worth!  

Quote:


My experience with remote power supplies comes from making the same amp with a remote power supply and without and comparing the sound. The difference is the B+ wire length goes from 4 or 5 inches to several feet. In my tests, the long B+ wire ruined the sound. By the time I got a cable that was well shielded from RF and thick enough to carry the current that far, and used the best conductors to try to make it seem like they weren't there... I had created a cable that was more expensive than the power supply itself and it still didn't sound right. Perhaps this isn't noticeable on less transparent amplifiers but it gave me enough to understand it's a bad idea for my own amplifiers.

The best way would be to isolate the power transformer with grommets, sadly it is impossible to ship an amplifier that way.  In fact I have had more amplifiers come in for mods that were poorly packed and poorly handled by the shipper who's power transformers were actually ripped part way off the amp due to high G-forces.  

Back in the 1980's I got an opportunity to see what Polk Audio was doing in the laser refractomotry lab at John Hopkins University with model resonance studies of speaker cone materials and gained some real insights.  When energy is introduced into a material and that material isn't touching anything stiff, the energy becomes trapped and immediately sets up a pattern in the material.  This is called modal resonance.  If you touch the material while energy is introduced into the material, some of the energy goes into your finger.  That amount of energy that's now in your finger/hand is that much less energy trapped in the material reflecting back on itself.  This changes the modal resonance pattern in the material and lowers it's amplitude.

Some might call that damping it, but since the energy does in fact transfer from one material to another, I think of it as draining, or moving from one place to the next.

If you want to find out how effective any type of vibration control is, gain up a tube and listen to it with a solid state headphone amplifier with 90dB of gain!  You can hear the air move across the tube and tiny vibrations among the elements inside the tube sound like giant bridge trusses coming apart in an earthquake.  Whether one frequency or music or both, it does not help the clarity of the sound.

Anyway, this is the reason why I choose the African Padauk hardwood, because I'm trying to get the vibrations minimized.  Peruvian Walnut turned out to be only half as hard (Janka hardness around 1K).  Of course it's not going to make any real difference if you just set the amp on a rack with it's rubber feet.  However, pin it to a plinth with 4 cones and then float the right kind of plinth and set that on properly selected sobothane pucks floating on teflon sheets and it begins to work.

Steve

Steve,

 A smile starts to form as I read your reply. I know exactly what you mean. When I built my headphone amp, I too was concerned with the transformer causing more than it's share of the sound. It was a bitch, but I made an isolation attempt with Sorbothane T washers, and then Sorbothane washers on the other side of them, so that the tranny was truly floated from one side to the other. So may people just use rubber washers to isolate, and no, because of the bolt contacting the chassis when it is tightened it is instant failure right there and then. Point is, if you can get damned thing disconnected mechanically from the chassis, at least to some degree, it is undoubtedly better. I have never been so pleased with the performance of a product.
I suspected, as you mentioned about the umbilical power cord that there is no free lunch. With such voltages and lengths, more has to be considered. I can just see a power cord with armored sheathing .

 Good explanation of the reasoning along about where the experience came from as well. How many of us out there will ever see the inside of such a lab?

Quote:


Thanks, I understand where and how the term "draining" is being used now.  It's the difference of resonance of a component and resonance of a system.  

I have the newest Technics 1200G turntable and the platter is a work of art and will not ring no matter what you hit it with.  It's heavy and made up of a composite of aluminum, rubber and brass.  If the top plate of the amps is the biggest issue (and it makes sense that it could be) how about laminating heavy rubber to the underside?  Another thought is to laser cut the tops.  I use Freud saw blades and they now laser cut squiggles in the blades that make them go "thunk" instead of "ding" when you tap them.  Lot's of ways to skin a cat!  (Please no politically correct outrage at my anti-feline expresion.   )

Yes, it should be very happy there! : )

Thank-you,

Steve

Hi Leon,

Can you post a picture of your Monoblocks and the price for same. Are they six watts each? Do they have the meters? As I would like to order the Monoblocks but the shopping cart does not indicate.

Regards

Quote:


Yes, it is a miniature tesla coil. As you can see it is effected by the presence of my hands, in fact I can overcome it with my own energy field which is why it completely vanishes at the start of the video.  At the point where my energy field resonates with it, that point being the correct distance away, the spark is much larger.  When I come towards it with the bulb in hand, it is once again my enegry field that that begins to resonate with the spark and you can see it grow just before the bulb lights.  Also if you have the sound turned up you can hear the spark.  Nothing is fake in the video.

Steve

Indeed!  And... welcome to the forums!

Steve

Ironically, he will be here in 20 minutes.  I have the combo warming up now.  My first take-away was that the ZOB's have a lot more bass than I remember.  Stunning really, I thought the demo might involve passive subwoofers which is a great way to turn these speakers into monsters, but what I am hearing right now would not indicate any reason to hook up the subs.  Very interesting for sure.

I'll keep you posted.

Steve

Actually the demo is on Thursday and today is only Wednesday, I figured this out shortly after my post.

Steve

Courtesy of our host,  posted on the Facebook page.

https://www.decware.com/newsite/UFO25designlog.pdf

No, that wood is for the UFO 50’s. The tree has a few more years of growing in it.

UPDATE:  UFO25's bridged mono driving the Zen Open Baffles



Now having had 3 days (and a demo) under my belt with the Zen Open Baffle speakers I think I can make some comments.

I placed the speakers in a wide arc about 3 feet from the front wall.  The toe-in was such that the intersecting X lands just in front of the listening chair.   This is pretty much where I placed them at last years DECFEST for my “2-watt demo” that i like to do every year.  

The 2-watt demo uses the Zen Open Baffle speakers in parallel with a 15 inch low-frequency driver passively crossed at 90Hz and at a 12dB per octave slope.  Doing this adds an octave of low frequency information that extends to 22 Hz and a substantial amount of it making the resulting sound seem impossible to be generated by a 2 watt amplifier.

So that’s the back story and for the demo I set things up a bit differently.  I used a pair of UFO25’s bridged mono into the Zen Open Baffles with no bass support.  When I first tested the combo I was shocked at how much bass there was. It was more than I remember the speakers having during the 2 watt demo.  The added power and weight of the bridged amps was definitely ensuring good bass performance which was my concern.  The FRX2 drivers used in these speakers have detail and presence beyond all of our other speakers including the DFR8 drivers, so to balance such amazing hyper detail, good bass performance is needed.

My plan was to demo the speakers like this and see if the subject of bass augmentation comes up at any time during the demo.

So at this point it is still Wednesday night, and I am enjoying a nice test run and getting great sound.  That’s when I remembered the bass on the Zen Open Baffles is determined by how loud they are turned up.  The louder you play the speaker the fuller the bass response becomes.   If you play the speakers quiet at a background level, the bass diminishes.

To drive the amplifiers, I used a ZCD240 hooked directly to the inputs of each amp with a pair of DSRII silver interconnects.  The ZCD240’s output level was adjusted to max (7.75 volts)   During the demo we mostly played CD’s, with a touch of memory stick tracks and some streaming from Linn Radio.

I set the level to comfortable, but full.. I would say around 1 or 2 dB louder than I do with a single 2 watt amp.  The bass was good.

What does the ZOB bass sound like?  It’s strong at 40 - 50 Hz and then rolls off a bit by the time it hits 80 Hz.  This means that the speaker has a dryer sounding mid-bass than most speakers.  If you hate bass bloat or boomy mid-bass, or you have a square room with 60Hz room-boom issues, you might love this speaker because no matter what the bass is ultra clean.  The down side is that it will be more apparent when you come across a thin sounding recording.

What did it sound like?  It sounded more real from 50 Hz on up than the DNA2’s.  The presence is the same as electrostatic speakers but with more subjective velocity.  There were several levels to this presence that we explored during the evening.  There were as follows:

1) FRX2 drivers have a HI and NORM presence control switch on the back of each driver... or you could say they have  NORM and LO switch depending on your perspective. We started with it in the lower setting.

2) The UFO25’s have a bias switch for the input tube that does exactly the same thing to the sound as the switch on the FRX2 drivers. We started in the lower setting.

3) The speaker impedance switch on the amplifiers also creates a very similar sounding effect between the two settings, and either setting runs the speakers without effort.  We started in the lower setting.

You can amuse yourself with different combinations of these three settings, but I have found they are pretty cumulative. Start out with all the settings on the most laid-back mode and then as the night progresses add more presence until you're at maximum potential.

After several hours of listening the topic of subs did come up since the speakers don’t do ultra-low bass it eventually lead to conversations on how to properly augment the low bass and get it right the first time.  Adding a powered subwoofer is not the answer, which is what most if not all people would tend to do.  It was the gentelman's plan so I saved it with some education about integrating correct bass augmentation.

Rather than kill it with a powered solid-state subwoofer, adding a pair of pro-audio 15-inch drivers that have the same 96 dB of efficiency and putting them into a large tuned cabinet, one per side, is the best way to get the bottom octave correctly integrated without phasing issues and lagging issues caused from the low-efficiency high-mass home subwoofers.

To drive the subs nothing is needed, we just parallel them with the Zen Open Baffles and put a simple 12dB passive crossover set at 90 hz between the speaker and sub.  The advantage of this is that the same amplifier is driving both speakers so the harmonics and signature and phase angle are absolutely perfectly integrated.

I ended up demonstrating this using a pair of 15 inch woofers in a pair of Imperial Folded Horn cabinets (SO version) and that set the stage for another several hours of listening.  With this gigantic scale in the bottom end and effortless, deep, and fast not to mention 1000% seamlessly-integrated bass there was many head-shaking moment and from the adjacent spaces around the listening room the music felt and sounded real.  The combo of non-compressed ultra-fast subterranean bass with the hyper detail of the FRX2 drivers in the ZOB is pretty hard to argue with.

The imaging on this setup has always been good, but with the UFO25’s it is so well focused you just couldn’t ask for better.

Since the demo ended on Thursday late night ( or maybe Friday morning I didn’t check) I have been hearing what the amps are truly capable of in the extreme low end, and all the way through the spectrum.  With all the levels of presence I discussed earlier, we quickly migrated to everything all the way up for maximum presence because the amplifiers are so good, you just can’t over do it.  Until hearing these amps on this combo, I have always ran the presence at less than full for what I felt was the best sound… so that is very telling on multiple levels.

When it comes to REAL bass, like this, where you can't see the woofer move, the cabinet is the size of a double door refrigerator and horn-loaded and there are two... my feelings are this:

If the music paints a mountain i would like to feel the mountain.  I do not want to be restricted to music that only paints trees and bushes because that is the only thing I can reproduce.

And this brings me to a flash-back about these very horn-loaded bass cabinets I am using for the demo.  Clearly the bass from these UFO25's bridged IS the best I have every heard from these cabinets. Simply stunningly perfect. Then suddenly I remembered hooking these same exact cabinets up to a 800 or 1200 watt solid state subwoofer amplifier from Parts Express and it was the most complete sonic disaster that you could have scripted. I couldn't get any rich deep bass out of the damn things without the woofers trying to flop out of the cabinets as they try to rip the surrounds of the cones.  It was so obscene it gave me a migraine headache trying to adjust it to at least try to work right! After 2 hours of trying everything I could think of, I had to give up and send the amplifier away.

The following week after that hellish experience I built a 60 watt tube amp to drive both subs in mono and it worked gloriously and still does!  In fact it sounded so good on music also, that I built two more as speaker amps and those are today our Zen TORII Mono's.

The point to all of this is even a single 2 watt Zen Triode Amplifier will absolutely embarrass the 1200 watt solid-state sub amp I tried.  Not only sound quality, but bass output.  They make the speakers just roll out this wonderful deep bass that is full and rich, and the solid state amp couldn't make it happen.   A testament to output transformers on zero-feedback amplifiers vs. some feedback-laden solid-state output stages.  

NOTE:  Horn-loaded woofers are hard for some solid-state amplifiers to drive which is why the results were in this case as indicated.

NOTE:  When you listen to similar speakers like Lowther and all the rest with lessor electronics (which could the norm by comparison) it becomes obvious that this is the sound they were hoping for.  The detail is extreme.  The textures in the low frequencies are just to die for. The liquidity and the overall balance makes for endless fatigue-free listening.

It's going to be hard to un-hook this setup and go back, but happily the DNA2's are as close to having both sounds in a single box as you're going to get, without the extreme presence, just real good presence.

The imperial horn itself has a spell that it casts upon you once you hear what the bass sounds like coming out of one... especially with the UFO25's!  Look what it did to the cat!



-Steve  

Thank you for this detailed and highly interesting review of the ZOB/bridged UFO25 combination, which I have been looking forward to, Steve.

As always, well written.

I somehow suspected that this combo would prove to be quite a memorable experience, and even with " only" a single SE84UFO25 I am certain it will be quite a capable set-up in a smaller to mid-size listening environment.

Currently running a single SE84UFO2 with a pair of Tonian Labs M2 and am quite satisfied with what I am hearing from this combo.  Can't wait though to hear what the SE84UFO25 will bring to the table, and I have always had a weak spot for the ZOB, so who knows what comes next....    

/M.

RLB,

I have no doubt that a pair of open baffle subwoofers that went down to no less than 40Hz and wired the same way could be a viable alternative.

Steve

Oh yeah.....for ZMA enhancement too. When Steve said, he knows how it is going to sound already in his head.....I hope it includes those guys/resistor's (Vishay glass)...or not?

The way I read it, Steve is recommending drivers that will go down at least 40Hz. In other words, they can go lower but if they don’t at least go as low as 40Hz, look elsewhere.

So tonight I am listening to ZMA with some very fast output tubes and 7DJ8's on the input stage paired with the HR-1's since I demo'd that combo today to a gentleman from Canada.

I noticed something when comparing it to the SE84UFO25, and that is that I found myself turning it up louder searching for the same sound.  That lead me to realize that I was right about the speed of the UFO25 being basically equal to power.  As I got the ZMA louder and louder there was more excitement similar to what the UFO25 gives you at 1/3rd the volume.  Very interesting.

I also have great confidence in my ability to push the ZMA to a similar place.  I've thought about how to change the OA3 circuit and a bypass strategy so I'll update you with the results when I've done it and had plenty of time to evaluate the results.

Steve

Yes, I remember well how you could always hear it coming from my SE84CS/lower volume too. Great news Steve about the ZMA. Look forward to the development!

Need to get the 7027A's. I love the 6P's. Jeff, good info of your experience/ZMA. I want Steve's enhancement for mine and down the road get the SE84UFO3/25th Mono-blocks. They have that touch more of power to drive my modified Adagio's over the the single 25th. Though strapping a pair of those puppies would be nice.

"The way I read it, Steve is recommending drivers that will go down at least 40Hz. In other words, they can go lower but if they don’t at least go as low as 40Hz, look elsewhere."

I say, let's let The Man speak for himself here. If Steve meant what you say, Jeff of Arabica, then he clearly misstated it. "Down to no less than 40Hz" is a bit different from saying at least 40 Hz or below.