Tenor 75 Wi OTL


Just bought this OTL by Tenor.

Living in Destin FL and owning the Atmasphere S30 amp I could remove some power tubes to reduce the heat in the summer. Can this be done with the Tenor?

Kelly High End in Ca. who I bought from said the amps puts off very little heat after being on for a hour or two. BS from the seller?
glory
No you can not use the 5751 tube.

Anyone try different 12ax7a tubes rather than the JJ tubes Tenor specs out?
Atmasphere, so now we know the true cause of the global warming problem...:0)
06-10-11: Atmasphere
He can run them all day in his room and not be any hotter, even though his home is not air conditioned and he lives in Guatemala!
Sorry, I should have been more specific...I was referring to running 6 to 12 6C33C-B's per amp. That tube seems to run much hotter than anything I've ever been near. Maybe that is more of a perception than reality, though.
A customer of mine has this amp:

http://www.atma-sphere.com/products/ma3.html

He can run them all day in his room and not be any hotter, even though his home is not air conditioned and he lives in Guatemala!

He accomplished this by putting the amps in a specific location in the room, above which are hidden ducts that have a moderately-powered fan at the other end. The heat goes up through the ceiling and out of the house. It is an elegant and simple approach. You can sit in the room all day and be perfectly comfortable.
I had a stereo 6C33C-B SET integrated, Almarro A318B, and that thing was hot. 6-12 tubes must be like a furnace running.

But, I bet the sound is glorious. Oh, the things we endure for this hobby....
Yes my wife wants them in the fireplace but it to small for both amps.

A couple of days ago I was running the fan to draw the heat up the fireplace and I began to sweat from the heat of the amps in the room. The fan had fallen off the prop I rigged up for it and it was blowing in the wrong direction. Setting it back up restored order to the listening room so I do believe it works as I thought.

Hurry up Fall.
A bit off topic, but can anyone imagine the heat put off by the Joule VZN-300 Destiny monoblocks w/ sixteen 6C33C-B's a channel?

Either your room would have to be cavernous, nonstop AC running, or you place the monos in your fireplace with a fan in the chimney to draw the heat out.
I suspect that it is biased a littler harder than the Joule if that's the case. We've yet to work on a Joule although we have serviced Tenors in the past.
Ralph out of curiosity, why is this amp putting out so much heat, 720 watts per monoblock? This seems quite high based on the number of output tubes at least compared to the Joule which uses this tube as well.
Glory,
You`re quite happy with the wonderful performance of your system, can you leave well enough alone and resist the urge to monkey around with it anymore? LOL.
The Trancendent is Class AB vs. Class A operation of the Tenor

Just FWIW, the math does not support the idea that the Tenor was class A, not if it is also 75 watts output. IME, the tube is difficult to operate in the A2 region due to the prodigious grid currents involved. The amp is class AB1, similar to the Transcendent in this regard.

The big difference is the fact that one is pentode and the other is triode. In OTLs that makes more difference than the class of operation, since you are not dealing with zero crossing issues or commutation (switching) of output devices (OTLs tend to be immune to these difficulties).
Glory, I am glad this seems to be working out for you. On a further note it seems like these amplifiers throw off new levels of heat considering the power rating, 720 watts per amp!!! I'm not sure this is at full power or just when you turn them on, it wasn't clear but the venting through the fireplace chimney seems like a great solution. The outputs on these babies must be biased REALLY high which might be a big contributor to what you are hearing. I can't imagine what your energy cost might be adding a/c costs to compensate for the heat generated. I know the VZN80 was in the 700 watt range but it is stereo. I was listening in February when the weather is cooler and it REALLY warmed up the room in short time. Ventilation seems the only real practical option, enjoy!
Glad you've made everything work to keep the sound you love!!! I get some heat also but love the OTL sound so I too find ways to survive. As for the bill it's cheaper than gas or dock fees, at least that's what I tell my wife!!! FWIW she loves the OTL sound and would be sad to see them go!!! Enjoy!!!!
Glory, congratulations on your system. Sounds like you are having a ball. Have you considered installing central air? A window AC unit?
So the Tenor OTL is a very quiet amp. Sticking my ear next to PDIFthe Zu Audio Presence speakers & 101 Db I hear no noise/ sound. The Atmasphere S 30 was all about hum/noise in my system.

Running my Lampazator Dac straight into the amps was better than having my Dude preamp in the chain. The Dude is sold and gone.

These amps have placed me in the Zone, a place I have never been in audio in ten years.

Have a fan blowing upward in my fireplace to draw the heat out of the house. Seems to be working. Can not wait for the fall to run fbm all night.

How do I explain to the the wife why our electric bill is so high?

The Lampazator dac is in the same league as the Tenor amp. 7 days to hear it and buy it. When you hear it you will not send it back!
The 1.5 watt SET OTL is $1500 assembled including tubes. If he wants 4 watts instead of 1.5 he needs two of them to run as monoblocks. The T-16 is $1599 as a kit with tubes. 15 watts per channel so the stereo version is plenty. There are expert assemblers out there who build these for people who do not have the experience to assemble the kit. I know Ed Schilling at the Horn Shoppe has built a few. He raves how these amps sound with his ~100db horns. For the kind of money we're talking there is not much risk and they do play well above their price point,
Hi Darkmoebius,
I hear you loud and clesr LOL. Sometimes when reading another person`s reply the intended humor is`nt apparent. Based on your system, you certainly appreciate low power /high quality amps also.
One point about the Trancendent that does bear consideration is that it is a quite inexpensive for its performance. I am not sure what the current pricing is but you DO get a lot for your money. In retrospect, it is unfair comparing a higher priced component that performs at the highest level to one that is really an overachiever at its price point. The T8, a 25 watt stereo amp, idles at 300 watts, not sure how hot it gets when playing but is more than enough juice for those Zu speakers. The Berning idles at 100 watts and maxes out at 300 watts full power, cooler than virtually all tube amps let alone the Class A OTL variety.
My recommendation was based on the requirements for low watts and less heat. It just may be Glory has to give up something to get something. Not my decision. For Summer months in Las Vegas I have a nice selection of amps to choose from that don't put out a lot of heat. In the other seasons I can use OTL's.
05-27-11: Charles1dad
Darkmoebius,
If there`s one thing thats been demostrated often in high end audio, higher cost does`nt mean better sound.
Of course, I was being slightly sarcastic with my remark.
With the very efficient Zu speakers the additional power is`nt an advantage, it`s sound quality. Often times a lower power amp will have superior sound to a larger and more complex design.
Get it, got it, preaching to the choir here. I have similar high(er) efficiency widerange driver speakers and have/had several SET amps(300B, PX-25, 6C33CB, 2A3).
Clio09 I don't mean to rain on the parade concerning Trancendent amps, I owned the T-8 prior to the Berning, great amp btw, but to paraphrase Senator Lloyd Benson to Dan Quale during their debate for VP in '88, "Mr. Trancendent you're no Mr. Tenor. In any case Glory, the Trancendent is a great product but I doubt it comes anything close to what you have been listening to the past few days. The Berning is a step above the Transcendent in all parameters or I wouldn't have switched. The issue with the Tenor is dealing with the heat only. I doubt there are any other issues in question based on your observations. The Trancendent is Class AB vs. Class A operation of the Tenor therefore less heat and of course the sonic compromises but it still runs warm, more than the Berning.
I see a pair of Transcendent Sound SET OTL monoblocks in your future (perhaps even the stereo version given your speakers). Maybe even a stereo T-16. My T-16 does run hot, but not nearly as hot as my S-30.

As previously stated price doesn't always equate to quality, but I get the gist of Darkmoebius's message. In which case you'd find Transcendent Sound amps can play right up there with amps that cost significantly more.
Darkmoebius,
If there`s one thing thats been demostrated often in high end audio, higher cost does`nt mean better sound.

With the very efficient Zu speakers the additional power is`nt an advantage, it`s sound quality. Often times a lower power amp will have superior sound to a larger and more complex design.

I would think most audiophiles at one time or another have heard quite expensive systems/components that sound like crap.

When I got my 300b SET amp it was less expensive than the 100 watt/60watt triode push-pull I was using, yet the "8 watt" amp sounds better.
Best Regards,
05-26-11: Glory
The Tenor is mind boggling. Far above my AS S30 in every area. Bass has texture and vocals are 3D and real sounding. Duke Ellington's band sounds so natural and organic in the brass section. That is an area I never heard sound so right in my system.
I would hope so when comparing a $20,000 amp to a $5,000 amp with half the power.
Glory,
It`s funny you cite the duke. I use the CD Duke Ellington "Dance Concerts California 1958" for system/component evaluations. This sound is so natural, dynamic and just a wonderful live recording. It`s as though I`m right there with them in the dance hall.
It seems you`ve found a fabulous amplifier. Continue to enjoy it for a long time.
Have a chance to get the Tenor HP 150 from Tenor.

The Tenor is mind boggling. Far above my AS S30 in every area. Bass has texture and vocals are 3D and real sounding. Duke Ellington's band sounds so natural and organic in the brass section. That is an area I never heard sound so right in my system.
Glory: If I remember correctly, the Tenor 15 watt monos run virtually as hot as they are class a full time.
Hi Glory,
How does the tone and timbre of the Tenor OTL differ(if at all) from your Atma-sphere S30 with vocals and acoustic instruments? Is one more life like or organic? I`m curious, as they`re both well proven designs.
Ok so these suckers run hot. A northern amp for sure. My 22' ceilings are allowing me some time in May but JJA I will have wait and see. The 15w would be a better fit for me.

The Tenor OTL is a world class amp and every positive word spoken about It is true.
I've always been impressed with Tenor amps in friends systems back in the day---if my speaker would work well with them (Zu Def2), they would definitely be a consideration.

Look forward to hearing more thoughts on the sound with the Presences Glory.
"Looking a little deeper at Tenor back then this goes to show you the company they kept at consumer shows and dealer show rooms with the likes of Pipedreams and Karma. Marketing know how of high dollar crap aimed at the gullible with deep pockets, and it works well."

Your comments are interesting Blackburn. At that same show I heard the Lamms matched with the Kharma 2-way, 3.2 I believe? In any case I found that set-up among the best at the show. I was quite taken by the Lamm amps and now completely understand the buzz on that amp. The Pipedream/Tenor set-up was in a large room and in my experience under show conditions it is much more difficult to make a large speaker come together in such a short period of time. While the sound certainly wasn't bad it wasn't magical either. In any case it was quite easy to recognize the transparency and musicality of the Tenor amps, the speakers seemed to be the issue.
Glory,
Congratulations! I know some folks who say the Tenor is the best OTL they`ve ever heard. I hope things workout for you.
"I would rather listen to this amp one hour and turn it off for the sake of heat in the summer than listen all night to a lesser sounding amp."

Enjoy your amp Glory. I hope you find a solution to the heat from those big 6C33C outputs, keep us posted, love to hear your system!
Glory- Agree totally w Tubegroover about the diff btwn Berning ZH-270 and Joule VZN-80. In my system, to my ears, a no brainer. Also a no brainer that those Russian MIG output tubes will dissipate WAY, WAY, WAY more heat than an S-30. In my house, 8 of them (same as the Tenor monos, I believe) gave off WAY more than a pair of the M-60 monos. Even in New England in the winter, they very quickly heated up my 15 x 23 x 8' LR and the adjacent hallway and staircase area. Very interested to hear what you think of the Tenors compared to the Atma amps; the Tenors are beautiful and I've always wanted to try them on my Merlins.
OK so we have 2 hour + on the Tenor amps. My thoughts are a lot of heat and the best amps/sound I have ever heard out of my system.

Jonathan helped set the amps up by phone after the seller caused me to wonder if he knew anything about the amp. You may not always agree with Jonathan but he does have a passion for this hobby called audio. Treated me as if he just sold me the amps yesterday. Thank you so very much J.

I would rather listen to this amp one hour and turn it off for the sake of heat in the summer than listen all night to a lesser sounding amp.

More thought later as I break these suckers in.

Oh buy the way I have the 7th pair made so who are you that first bought these?
Glory, Since you have ZU speakers you will not have much advantage in seeking an OTL with more power.
I am certainly surprised by the comments of Blackburn. He insults countless people and companies in one statement. Who knows what his motivation is.

Anyone I know that has ever listened to the Tenor OTL has loved the sound. It is certainly, when paired with the proper speaker (impedance), one of the finest, if not the finest, sounding tube amplifiers I have ever heard.

If you have any questions, please feel free to call me and I will be happy to help.

Jonathan Tinn
Glory, I have heard the Tenor's on several occasions and IMHO, they are an excellent amp. They will give off a lot of heat into the room, but that is to be expected with most tube amps. I saw these on 'Gon before you bought them and was tempted to buy them myself. BTW, the same seller has a JR model 8 for sale; this is one of the amps that I currently use and it is also an excellent piece. Perhaps if you don't like the Tenor's, then maybe the seller would allow you to trade them back for the model 8. The 8 has more power than the Tenor's and can control the bottom end better, it's not quite as holographic, however. But if heat is the issue, then the 8 would be a great swap.
I live in Destin which is in the panhandle of FL. As my wife says lower AL.

With my open floor plan of my house and the fan thought I might be able to pull it of.

Tube,

thanks for the offer to hear your amP. When in the area I will look you up.
So far as the zh270 going up in price 10 fold, i'm not too sure about that Lewm. I wasn't aware that they were ever 2500.00 when they were first introduced but if that was the case I can't imagine Berning doing anything but breaking even if one is to consider that the amps took him 30 hours to assemble. The wiring for the impedance converter alone must be done manually and I can only imagine how tedious that task alone is. Yes indeed, at 2.5K it must be one of the greatest values ever in audio. at its final price with all the modifications I believe it listed at 5.5K

There were some substantial improvements, at least in my experience with several of the mods that improved the amp's performance no less than a wiring change and a few input caps along with some other lesser changes including cryoed outputs. The total net gain was significant. While I have done a direct AB to a Joule VZN80 in my system many years back the Joule clearly was harmonically richer with greater density where as the Berning was somewhat leaner. This was before I performed any of the mods and tweeks including much experimentation with vibration isolation. Sure would love to do an AB with the Atma-sphere in my set-up, I have always been curious all these years. I can imagine your system, great choices!
I have heard the ZH270s on many occasions over a period of more than a decade, in my friend's system. He has a pair strapped for mono, driving a pair of large Acoustats. They are wonderful, bullet-proof amplifiers. However, to my ears they do not give that last 5% of clarity that one can get from a true OTL. I am specifically referring to my own Atma-sphere amps driving a pair of Sound Lab M1 speakers. I and my friend give the edge to the Atma's. I have a longstanding curiosity regarding the Tenors, and I look forward to hearing what you think of them compared to your S30s. Too bad heat is such a big issue for you.

By the way, the ZH270 was once one of the screaming bargains in audio, when it sold for $2500. Evidently David Berning (one of the geniuses in audio, IMO) met up with a marketer who raised his prices about 10-fold. I think the ZH270 was discontinued just to facilitate the price rise. Of course, there is no crime in that.
One other thing Glory fyi. If you can't make the Tenors work for any reason there is another OTL amp option. I recently read on a thread a response from a dealer of these speakers, Audiofeil that the Berning zh270 was one of the best he heard with these speakers brought into is store by an owner auditioning. Unfortunately this amp is no longer made and they are becoming more difficult to come by on the used market as most who own don't want to give them up, yours truly included. However they do have a 30 watt zh230 that is supposedly more refined at less power. Unfortunately the jump in price was quite a bit over the zh270, in the 8k range I believe. Advantages wide bandwidth performance, low heat, extremely low noise, it uses an advanced switching power supply, long tube life, self biasing, OTL clarity and transparency as it uses an impedance converter but no output transformer the best bass control I have heard on any tube amplifier in my experience. I am not in any way affiliated but since you live in Florida you are most certainly invited to my place (Rockledge near Cocoa Beach) for a listen to decide for yourself if it might be an option IF you can't make the Tenors work for any reason. Good luck!

PS The Berning is a no nonsense design if you consider aesthetics important. It will not compete with the beautiful Tenors as it is very simple and unassuming on the outside no exposed tubes which can be an advantage in a smaller space. The advantages are all in the brilliant design by one of the most brilliant amplifier designers in the industry.
I`ve been told by some who are familiar with the Tenor that they sound excellent. For 6 grand you may have hit the sonic jackpot.Your plan for a simple fan installation may solve your conern about heat.
Best of Luck,
A miscarriage. Wanted to sell a SS amp to me after the miscarriage but with my 16 ohm speakers not any SS amp will work. Talking to Zu I was told NOT to buy it as it did nor meet their specs.

OTL amps are the best sounding amps on these speakers.

So I will buy a fan and install it in the small door opening that goes to the attic to drive the trapped heat in the loft area that will be generated by the Tenor space heaters.