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Anyone Tube Roll with the ZMA yet? (Read 97492 times)
Jeff of Arabica
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Re: Anyone Tube Roll with the ZMA yet?
Reply #500 - 09/22/18 at 16:54:44
 
Stone, that is correct  regarding running the 7581A’s at 70%, which puts the bias at 63/64mA.  However, pushing them a tad bit more and running them at 75% max, put them at the 68mA mark which I think is fine.  In theory it may have a slight impact on overall tube life, but not sure a 5% change will amount to a significant overall lifespan difference.  Personally, I wouldn’t be afraid to push them up to 75% on something that is fairly replaceable and reasonably priced.  A rare and expensive NOS set?  Probably not.  

Stone, have you pushed your set up to the 64+ range yet?  
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stone_of_tone
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Re: Anyone Tube Roll with the ZMA yet?
Reply #501 - 09/22/18 at 17:04:24
 
Nice/J of A, thanks for the clarification on this.

No, I have not put up to 64 to 68 yet. I will though....and post.

42 to 60 only so far....and absolutely love these 7581A's.
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Archie
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Re: Anyone Tube Roll with the ZMA yet?
Reply #502 - 09/22/18 at 18:07:02
 
Quote:
As you stated, one of the big changes, at least for me was the increase in audible detail.  The information was always there but the lowering of the noise floor and increase in the amps response with the faster caps is bringing those micro-details to the forefront where you can hear them.


I'm glad you mentioned this.  I am definitely hearing more detail -- song lyrics that I've heard right after 40 years!  I hesitated to mention this because it's becoming cliche for me with every upgrade.  I don't know what the limit is.  Maybe a truly live sounding performance?  That would take a different listening environment for me.  I have a grand piano in the same room and there has never been an "Is it live or is it Memorex?" moment for me between the two.

The bass is bigger and I've dialed back my ZR2 slightly.  I still like the ZR2 in the chain though.

Despite all of the enthusiastic talk of the Anniversary amps, the stock are still so good that the modifications haven't hit me in the face, so to speak.  Still, I'd never consider going back.
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stone_of_tone
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Re: Anyone Tube Roll with the ZMA yet?
Reply #503 - 09/23/18 at 18:29:24
 
Interesting...with my Ediswans's, I enjoy the 7581A's at 46 to 50 mA. I put my NOS Mullard's in this morning and after an 1.5 hour warm up....absolutely love the A's at 60 to 64mA. The bias window of the A's is quite nice.

Arch, good news on your 25th enhancements. My idea to get a JR 25th might leave me short. I'm going to pine further about doing my ZMA.
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Jeff of Arabica
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Re: Anyone Tube Roll with the ZMA yet?
Reply #504 - 09/23/18 at 19:24:29
 
Nice Stone!  The beautiful thing about this hobby...  endless opportunities to pull the levers and turn the knobs to get things just right for our listening pleasure.  

Glad to hear of this new discovery with you other tubes and higher bias setting.
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Archie
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Re: Anyone Tube Roll with the ZMA yet?
Reply #505 - 09/23/18 at 19:45:21
 
Stone, I think your master plan should be to buy a 2nd ZMA with the mods, see how you like it and if you do, modify your current ZMA and run the two as mono-blocks!   Grin
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stone_of_tone
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Re: Anyone Tube Roll with the ZMA yet?
Reply #506 - 09/24/18 at 11:23:12
 
No doubt J of A! Fun.

Arch, .....yeah, I wish I could do that!  :)
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Re: Anyone Tube Roll with the ZMA yet?
Reply #507 - 09/26/18 at 14:57:38
 
Norm: you're 3 weeks in at Decware for your ZMA 25th'd. Hope to get your initial impressions. Here's hoping you get it back before the Fest and not after.
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Re: Anyone Tube Roll with the ZMA yet?
Reply #508 - 09/26/18 at 17:17:31
 
Steve started it last week and they said they would ship this week. Looking forward to it!
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Re: Anyone Tube Roll with the ZMA yet?
Reply #509 - 09/27/18 at 13:04:34
 
Nice. Knowing you sent yours on 9/6 and DeVon mentioned they shut down the week of the Fest (I spoke with her about sending mine in and decided to wait), and as busy as they are, very nice, Steve can get done and on the road to you this week.
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Archie
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Re: Anyone Tube Roll with the ZMA yet?
Reply #510 - 09/29/18 at 18:09:39
 
I don't know if this is related to the modifications but I am getting a "bloom" in volume and density when I push the volume to the point of getting the metters jumping 4 to 8mA.  If this isn't just imagination, could it be related to the ZMA going from Class A to Class A/B at that point?  I have yet to push things into distortion.  I'm not even sure where that point is -- way beyond the start of meter movement.
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HockessinKid
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Re: Anyone Tube Roll with the ZMA yet?
Reply #511 - 10/10/18 at 22:45:41
 
BTW, I have ordered a quad of TungSol 7581a tubes for my ZMA.  I tried to place an order with Ron Sheldon @ Cryoset, but the website indicated that he is very ill and not filling orders at this time.  I wish Ron a speedy recovery, as he has been one of my main sources of tubes over the years.  

I should have the quad this weekend.  I'll report back on my listening impressions after I get 100 hours or so on the set.

HK
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stone_of_tone
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Re: Anyone Tube Roll with the ZMA yet?
Reply #512 - 10/18/18 at 21:47:17
 
Yes, wishing Ron a speedy recovery. HK, hope you enjoy the 7581A's. I have
been very pleased with them.

Norm, how is your ZMA enhanced 25th going? Plus, want to read about your impressions of the JJ 7027A's you received. No hurry, knowing you only received your ZMA back, a week or 10 days ago.


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NormD
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Re: Anyone Tube Roll with the ZMA yet?
Reply #513 - 10/19/18 at 03:14:10
 
The 25th anniversary mod is awesome! Even when I am working off-axis from the listening chair it is amazing. I’m still running the 7581a’s and the 7027’s are still in the mailing box. I want to listen more to the mod and 7851’s before I make changes.
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stone_of_tone
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Re: Anyone Tube Roll with the ZMA yet?
Reply #514 - 10/19/18 at 11:18:07
 
Cool Norm. Sounds like a good plan.
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HockessinKid
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Re: Anyone Tube Roll with the ZMA yet?
Reply #515 - 10/31/18 at 23:32:15
 
So I have had a quad of Tung-Sol 7581A tubes in my ZMA for about 3 weeks now.  Figure I have about 60-70 hours on them.  To make a long story short, they are now my favorite ZMA power tubes.

Extremely clean sounding with extended treble and bass.  They image extremely well, creating a realistic and wide soundstage. Acoustic and electronic instruments, voices and piano just sound real.

They do everything better, IMHO, than the stock Tung-Sol or Gold Lion reissue KT66 tubes.  The musical presentation is a bit more forward and the soundstage in not quite as deep as the GL KT66's. I have not tried any KT77 or KT88 tubes.

For less than $100 for a quad, these tubes are quite inexpensive.  I am buying two back up sets for future use.

HK
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Archie
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Re: Anyone Tube Roll with the ZMA yet?
Reply #516 - 11/01/18 at 01:31:47
 
The Tung-Sol 7581As are my current favorite too.  What are you biasing?  I've been biasing at 68mA and with the Anniversary mods my trannies are running cooler than when I biased in the mid 50s pre-mod.  Anyone else having similar experience with their modded ZMA?
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HockessinKid
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Re: Anyone Tube Roll with the ZMA yet?
Reply #517 - 11/01/18 at 18:46:40
 
Archie,

I am biasing the 7581A's at ~54mA.  My ZMA is currently stock, but I plan to get the 25th Anniversary mods (Full Monty) once Steve receives the new Nichicon capacitors.  

Looking forward to the mod, as my CSP3-25 mods sound great.

HK
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Archie
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Re: Anyone Tube Roll with the ZMA yet?
Reply #518 - 11/02/18 at 00:28:20
 
Have you tried higher bias?  At 54mA you might not be getting everything out of these tubes.  Even with the std ZMA higher bias won't overheat things from many hours.
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HockessinKid
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Re: Anyone Tube Roll with the ZMA yet?
Reply #519 - 11/02/18 at 00:32:52
 
No, but I'll give them a whirl at a higher bias.

HK
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Archie
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Re: Anyone Tube Roll with the ZMA yet?
Reply #520 - 11/02/18 at 01:32:15
 
I found this site after reading some of J of A's posts.  I think the 7581As dissipate 35W as do the kT88s so I use that tube in the calculation.  Jeff's ZMA was running about 380 volts or a little higher.  I think the Class AB is 70% capacity.  Gets you in the ballpark of what the tube can handle.

http://www.tedweber.com/webervst/tubes1/calcbias.htm
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Jeff of Arabica
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Re: Anyone Tube Roll with the ZMA yet?
Reply #521 - 11/02/18 at 02:51:51
 
Yes, the tool Archie found basically takes the manual math away so you simply plug in the numbers.  I would use "7027" as the tube type for your 7581.  If you run the tube safely at 70%, you can bias it up to 62.8mA.  

I agree with Archie's recommendation.  I would incrementally run it up to 63mA and see what setting you ultimately prefer.  Ive been running my tubes at 70% - 75% on my ZMA and monitoring heat on the transformers.  No issues with overheating and based on the sound I am hearing, I will stay within this range with most of my tube sets.  EL34's are one of the exceptions.  I did not hear a marked difference at a higher bias with the two sets of EL34's I have.
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Archie
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Re: Anyone Tube Roll with the ZMA yet?
Reply #522 - 11/02/18 at 16:18:17
 
Jeff, what voltage are you using in the calculation?  With that link, I get the same bias setting for the KT88 and the 7027.  I think they might be using a slightly different formula?

I'll bet you run cool due to the modifications you did on you ZMA.  I'd like to hear what Steve thinks.  For me it's been a significant "side benefit" of the anniversary mods.
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Jeff of Arabica
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Re: Anyone Tube Roll with the ZMA yet?
Reply #523 - 11/02/18 at 18:16:06
 
Hey Arch,
I was using 390 volts.  I am able to measure my voltage directly at the plate and it hovers between 385-390 volts, generally.  

You are correct in that KT88's, 7027's and 7581's all have a 35W plate dissipation, so for that simple formula, they will all produce the same results.  

I concluded the same about the output transformer heat.  After the mods, my IR thermometer reads a good 5 degree F lower than before the mods.
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Archie
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Re: Anyone Tube Roll with the ZMA yet?
Reply #524 - 11/03/18 at 01:04:24
 
I'm pushing my bias a bit then.  Fortunately the tubes I'm using are cheap and things stay nice and cool.  I don't know exact temps but in the past, with mid 50s bias, I couldn't hold my hand on the transformers after a few hours.  Now at 68 I can still hold them after all day.
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Jeff of Arabica
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Re: Anyone Tube Roll with the ZMA yet?
Reply #525 - 11/03/18 at 01:24:20
 
The touch test is valid.  Many agree that if you can keep touching it for 8 seconds or more, you are good.  My background as a scientist, and my OCD forces me to measure with instruments but it sounds like yours are running within range.  

As far a 68mA, that is 76%.  70-75% is an acceptable range and I have run some of my tubes at 75% which is just shy of where you are at.  I don't think you have anything to be concerned about.  
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Re: Anyone Tube Roll with the ZMA yet?
Reply #526 - 11/03/18 at 01:37:55
 
I just haven't got around to getting an IR thermometer yet.   Wink  But it's good to know I won't be melting my beeswax caps.
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Re: Anyone Tube Roll with the ZMA yet?
Reply #527 - 11/03/18 at 02:13:49
 
I bumped my 7851’s to a smidge above 60ma using the ZMA meters with my 25th anniversary modded amp. I can’t say much about heat, but the music has certainly jumped into my room!  The bass is even more solid and low and the highs are crisp. The mids are is clear and the soundstage is wide. I’m not sure I want to spend time to evaluate the 7027’s I have sitting on the shelf because love this sound.
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Re: Anyone Tube Roll with the ZMA yet?
Reply #528 - 11/03/18 at 22:45:23
 
I did it Norm! My ZMA is on her way to the Mothership!
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Jeff of Arabica
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Re: Anyone Tube Roll with the ZMA yet?
Reply #529 - 11/03/18 at 22:58:55
 
Nice Stone!  I am excited for you.  I know you were wavering since the inception of the ZMA mods but I am confident that when the ZMA returns the only regret will be waiting so long to have gotten it done   Smiley

Exciting stuff!  And honestly, I would recommend just installing the large caps yourself to save shipping both ways as well as some labor cost.  Literally just (4) connection screws and loosening and retightening the clamps.  15 mins, start to finish.  Get the parts from Steve to ensure they are exactly the model he is using.  

Can't wait for you to get it back and hear your impressions!
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Re: Anyone Tube Roll with the ZMA yet?
Reply #530 - 11/04/18 at 02:59:36
 
Thanks Jeff! Excited indeed.

I will do that for the Caps/from Steve.

I assemble and test DC to AC Inverter's. Dimensions/Sensata. Pure sine.
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Re: Anyone Tube Roll with the ZMA yet?
Reply #531 - 11/04/18 at 15:06:29
 
So I've had the ZMA for 4 years now and have been running with the original KT66 tubes. I figured it was time for some new tubes and all this talk of the 7581A's got me to order a matched quad of new production Tung Sols.

It may have been that the KT66's were getting a bit tired, and eventually I will get a fresh set of those as well. But I have to say, the 7581A's have glued me to my listening spot in ways I've never experienced with audio ever before.

When the tubes first arrived I warmed them up with Rubber Soul (mono LP) from the boxed set. I like to listen first in mono to see if everything is balanced and how the soundstage presents itself. Everything sounded fine. So I began the "burn my ears in" (and maybe just maybe the tubes) phase. During the first couple of hours I actually began having regrets and that I had wasted my money on tubes that really weren't doing it for me. The sound was both too close and too far away at the same time - muddled is the best way to describe it.

It was about five songs into The Starseeds Parallel Life (trippy mellow ambient stuff) on Tidal (PCM) through my Schiit Bifrost multibit DAC (speakers are ProAc Anniversarys, with a separate SVS SS subwoofer run off the Van Alstine SS preamp) that something unsettling happened. This is the creepiest audio experience I've had recently. I mean, since we're all tube amp listeners here, I know we've all experienced sounds that seem to come from unexpected places, either because it was mixed that way or due to serendipity. Sometimes I swear I hear my wife calling out to me from the other room but it's just some vocal! Anyhow I'm sitting there passively listening while reading some stuff on my laptop where I get the creepy sensation that the leading edge a bubble of sound has just made its way past my ears...



...there is a sensation of eerie pressure and the very real feeling that a comically large, soft/fluffy pair of headphones is being gently lowered onto my head. Now, while I was chatting with mother nature earlier, we chat all the time and I can say that this wasn't about that... ;) ... so I remained glued in my spot for about 10 minutes while the music continued to play lest I lose this bit of magic... but what I discovered was that indeed this effect was persistent, and that I could modulate it by moving my head forward or backwards. I first moved about six inches forward in order to see if I could "swim in the opaque sphere of sound" and on some music this was a wonderful effect and with others it was just too much. Dead-center-mixed vocals and other midrange-prominent instruments can sometimes feel like they are coming from within my head, which is a nice parlor trick but not the most relaxing experience. On music where this effect was too much, moving backwards ameliorated it nicely, making the prominent midrange sound "out there" more.

Steve - have you done any serious listening to the stock ZMA with 7581A tubes? I'd like to hear your perspective on these since I very much trust your ears.

Tube amps have ruined my scientific certitude when it comes to some things audio (I am a working scientist). Psychoacoustics is a fascinating subject to me. As you can see above I have a dedicated listening room and I have put up room treatments. The room is large and opens to a larger room, effectively opening to an infinitely large space. So the bass is wonderful in this room, no more annoying nodes. But the imaging is insane, partly because tubes/Decware, partly because ProAc, and partly because of symmetry. I do ponder the fact that 99% of studio produced music is a complete utter fabrication of whatever the dude at the mixing desk decided to do when putting things together. Considering that some more maybe a lot of mixing consoles are running noisy and/or out of spec components and for a thousand other reasons, the idea that what we audio nuts hear on our awesome systems when we are in the sweet spot is what is actually intended is ludicrous to me. Once I came to the realization that hi-fi isn't about a straight wire with gain but more about a pleasing aural experience, I freed myself from worrying too much about measurements, or at least taking them with a large grain of salt. I believe what makes Decware amps (and other high quality tube amps) so great is largely due to simple circuits with short signal paths. Something gets bleached away with solid state amps, at least the in my experience, which is admittedly limited. Because I've found audio nirvana with the ZMA I'll likely stay here, maybe indefinitely.

In closing this somewhat rambling post I'll come back to tube rolling. I also have some nice NOS 6CA7 tubes that I will give a more serious listen than the first time when I gave up after a few hours, not liking the less lively sound than I heard through the KT66s. One of the reasons I got the ZMA was because it would run with different tube types. This is my first experience with a 6L6 type tube, it was EL34/6CA7/KT77 on a Dynaco ST70 before I got the ZMA, and KT66 since I got the ZMA. Putting in a different tube type makes it sound like a different amplifier - not necessarily better or worse, but different. I now "get" voicing... having sort of scoffed at it back in my more reflexively objective days.

I've also come to realize that some people just plain have better ears than I do, or at least know how to use them better than I. I do not trust my ears, as they say, in the least... but I do trust the ears of certain other people whose products make great music... all of my gear has been bought sight unseen and so far I have not regretted anything.

In summary, the stock ZMA rules, the 7581A tubes produce liquid honesty with just a small asterisk by honesty that says "beware that the 3D holographic soundstage may not have been what was intended on original recording."

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Re: Anyone Tube Roll with the ZMA yet?
Reply #532 - 11/04/18 at 17:38:37
 
Yup, I have read your kind of post every year for 30 years + now ~ and it never gets old. Tubes, cables, cleaner power, room treatment, I could praddle on with more.....none of it should matter but it does.

I'm not an engineer....but know enough to be dangerous assembling Inverter's and Testing them. My engineering buddy at work, Mel....just realizes like me....the ear brain connection is really something special for all this.

Glad you like the 7581A's.....I like them too. Wink
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Re: Anyone Tube Roll with the ZMA yet?
Reply #533 - 11/04/18 at 18:02:46
 
Quote:
... but I do trust the ears of certain other people whose products make great music... all of my gear has been bought sight unseen and so far I have not regretted anything.


Leigh, exactly what I do and I couldn't be more pleased.  Now try the ZMA mods for a next level experience!   Smiley
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Re: Anyone Tube Roll with the ZMA yet?
Reply #534 - 11/04/18 at 18:44:39
 
Leigh, I'm glad to see your ProAc Tablets. Reminds the high sensitivity crowd the ZMA CAN RUN 89db Monitors, give or take. I have heard those guys at Audio Research when they came out.

I run modded Acoustic Zen Adagio's at 91/92db 1watt/1meter. Your stock ZMA is fine and does rule. I could have stayed put....But, I'm ready to Tweek her up and she is in transit to the Mothership.

Arch, post a signature. I keep my old one below for my ode to my 2001 new purchase enlightenment SE84CS.
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Re: Anyone Tube Roll with the ZMA yet?
Reply #535 - 11/04/18 at 19:12:19
 
Stone, I made a list.   Wink
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Re: Anyone Tube Roll with the ZMA yet?
Reply #536 - 11/04/18 at 23:29:02
 
Awesome!
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Re: Anyone Tube Roll with the ZMA yet?
Reply #537 - 11/04/18 at 23:45:33
 
Quote:
Yup, I have read your kind of post every year for 30 years + now ~ and it never gets old. Tubes, cables, cleaner power, room treatment, I could praddle on with more.....none of it should matter but it does.

I'm not an engineer....but know enough to be dangerous assembling Inverter's and Testing them. My engineering buddy at work, Mel....just realizes like me....the ear brain connection is really something special for all this.

Glad you like the 7581A's.....I like them too.

That tubes, cleaner power and room treatments matter does not surprise me. I am in the "cables don't matter so long as they aren't completely awful" crowd. So some things matter more than others, in my opinion.

I think we just all need to agree that good sound should be the goal, not numbers but also not woo-woo voodoo either. I will probably get the ZMA upgrade eventually but I still have a couple years to get used to the current amp and want to hear more of what others are experiencing with the upgrade first. I enjoy passionate audiophile hypberbole as much as the next guy (and engage in my own for sure) but I could seriously die happy with this being my last amp, sometimes really knowing that is valuable. I have found that delayed gratification is a worthwhile aspiration in this hobby.

Or, I just need to find a big stack of money somewhere and buy all the amps.
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Re: Anyone Tube Roll with the ZMA yet?
Reply #538 - 11/05/18 at 00:32:34
 
Quote:
Leigh, I'm glad to see your ProAc Tablets. Reminds the high sensitivity crowd the ZMA CAN RUN 89db Monitors, give or take. I have heard those guys at Audio Research when they came out.

Way back when I was in grad school in the 90s my PhD advisor loaned me his Tablettes (the first version of that speaker). I had a Harman Kardon integrated amp (still in service today). Those monitors definitely needed help in the bass department, so I added a sub and that's been my basic listening configuration ever since. The imaging of the ProAcs is just stunning and the tonal quality and speed are superb as well. The Anniversary's are like the 6th(?) iteration on the Tablette line and are definitely stronger in the bass department and much more refined in a good way. While I would love to hear something like the Zen + DNA2 speakers (maybe someday I'll make the 3 hr drive to Peoria to listen myself) I am satisfied with the nice solid state bass frequencies below 50 Hz or so (24 dB/octave slope). This is what is recommended and I carefully follow bass lines up and down through the crossover and it sounds pretty good with no huge holes or hills, not perfect, but even floor standers have their issues in this regard.

I have an even larger room with a pool table that could use some amplification, and I've actually been giving thought to very efficient horns plus a low powered tube amp as an option. But this is a long term goal and I may go the smaller solid state route, we'll see.
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Re: Anyone Tube Roll with the ZMA yet?
Reply #539 - 11/05/18 at 01:29:45
 
From Leigh "That tubes, cleaner power and room treatments matter does not surprise me. I am in the "cables don't matter so long as they aren't completely awful" crowd. So some things matter more than others, in my opinion.

I think we just all need to agree that good sound should be the goal, not numbers but also not woo-woo voodoo either."


I enjoyed reading your experience with your new, very revealing tubes Leigh! 6L6 are certainly a nice arena, and the Tungsol 7581A exceptionally revealing, so depending on all else, I can easily imagine how they could enhance your soundstage and immersion!

Speaking of wires and "voicing," I just changed 4 resistors/channel from the power tubes, to coupling caps, to ground in my Torii. Stock metal films, changed to other metal films (so far inexpensive PRPs).... dynamics, body, depth, textures, etc were improved. Revealing and warm, as they burn in, the integrative balancing is nice....

Several weeks ago I changed internal Mogami copper signal cables to Neotech silver/teflon, causing notably more beneficial effects. The general tonal values and range remained similar, but all aspects of the presentation sounded better to me, particularly the amount of information and speed increasing...The revealing aspects from this OCC silver, perhaps somewhat similar to what the 7581As did for your listening experience. This was maybe 3 feet of wire for both channels!

Usually having to dig for the right "voicing," synergy is the real thing, indicating again that different material and design interpretations can produce the same technical values but different sound.

The point of the story though...at this level, everything matters in my experience. I am not sure what your cables are, maybe nice...But judging from what you are hearing, I would be amazed if you did not hear differences in nice cables, some complimenting the system/room perhaps quite a bit more than others. Just thinking...after adapting to the "new" ZMA from this transformative tube change, if you get to where you feel like going to another level, objectively testing some nice ICs and speaker cables could be illuminating.
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Re: Anyone Tube Roll with the ZMA yet?
Reply #540 - 11/05/18 at 17:17:04
 
Quote:
I am not sure what your cables are, maybe nice...But judging from what you are hearing, I would be amazed if you did not hear differences in nice cables, some complimenting the system/room perhaps quite a bit more than others. Just thinking...after adapting to the "new" ZMA from this transformative tube change, if you get to where you feel like going to another level, objectively testing some nice ICs and speaker cables could be illuminating.


I'm (somewhat) active on the Hoffman forums under the same moniker and have my "equipment profile" listed. My interconnects are all Blue Jeans. That is probably overkill for me, but a little overkill is fine in this hobby, I think!

I simply won't consider cable rolling or spending more than what I currently am on my current interconnects and speaker cables, which I see as scientifically defensible decent cables. To me, cable rolling would be as pointless as changing the color of the walls in my listening room as a tweak, or eating nothing but broccoli on my listening days. Yeah, I'll probably "hear a difference" but it would have nothing to do with changes in sound, only my perception of it. I can't get past LRC when it comes to cables. I have a theory where some super high priced audiophile cables really do sound different but it's because of some badness not goodness. But that's just my opinion, my mindset. My mind is open - to a point.

It's nice to just not consider a part of your system as being upgrade-worthy. It just keeps you from worrying about whether it will change the sound. Speakers, amps, sources, room treatments, I can deal with those. But not interconnects. Not for me! And don't get me started on power cables!! Let me close by saying I believe people when they say they hear a difference, I just choose to avoid this particular area of tweaks. Since this is a hobby there are no rules to follow as far as I'm concerned :)
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Re: Anyone Tube Roll with the ZMA yet?
Reply #541 - 11/06/18 at 00:57:34
 
Quote:
Yeah, I'll probably "hear a difference" but it would have nothing to do with changes in sound, only my perception of it.


I'm more in your court than not given that I went for Steve's silver ICs and delaired "good enough."  But I don't see how anyone can deny that cabling changes the sound.  Better or worse may be completely subjective but cabling as a tuning device seems to be well established.
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Re: Anyone Tube Roll with the ZMA yet?
Reply #542 - 11/06/18 at 06:03:34
 
Quote:
I can't get past LRC when it comes to cables. I have a theory where some super high priced audiophile cables really do sound different but it's because of some badness not goodness. But that's just my opinion, my mindset. My mind is open - to a point.


Leigh, you don't have to go any further than Blue Jean Cables to see how that company has subscribed to the theory that cable design DOES matter, even at higher price points, by adopting Galen Gareis's Iconoclast line of cabling, which I would say falls into the price category you are not willing to explore - at least based on your post.  You did mention "science" in your post and while Blue Jean Cables does speak about LCR, the Iconoclast line from Galen that Blue Jean Cables has partnered with and is now the exclusive dealer, is accompanied by volumes more supportive evidence to justify its superior performance in the LCR category over any other cables Blue Jean (and other vendors) supplies - yet they are priced well above any other cables Blue Jean sells.  

At the end of the day, YOU decide what is best for YOUR system and that is the absolute best way to go about it.  You should receive no criticism for that.  It really matters nothing what others say or think.  It is your money and your decision and if you feel cabling is not worth the trouble and/or money required to vet, that is certainly fine.  I just thought it might be of interest to you that BJC (which you mentioned) is adopting the scientific-based design of the Iconoclast line and is admitting it is superior (LCR) to any cables they offer, which by default would include the ones you own.  Based on Bob's commentary on this very subject, I refuse to believe BJC has decided to sell-out or jump on the "snake oil" bandwagon.  I honestly believe that Bob truly believes in  Galen's design and that his Iconoclast cables outperform all of his typical cable inventory in the LCR categories.  And according to Bob and Galen, that can certainly lead to better sound quality.  But, every system has its own DNA which affects how a cable performs in a particular system.  Nobody can predict how it will perform so it must be auditioned in order to truly know.  

Out of curiosity and interest I have read much of Galen's material.  However, I don't own, nor have I heard any of the Iconoclast products so this is no attempt to "sell" you on  any particular cable or cable philosophy.  I am just pointing out that BJC, the manufacturer you trust (I assume),  is taking a much different opinion/position than what you have embraced in your post.  

Happy listening!
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Re: Anyone Tube Roll with the ZMA yet?
Reply #543 - 11/08/18 at 00:15:06
 
My ZMA has returned to the Ship today!

May Steve and the Orbs that visit Steve's incredible work, continue to be moved for sonic greatness.
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Re: Anyone Tube Roll with the ZMA yet?
Reply #544 - 11/08/18 at 17:42:13
 
As usual, I'm revisiting this thread a bit late.  :)

I'm glad it was clarified above that you guys are checking the plate voltage when throwing out what you're biasing your tubes at...I was worried reading the last page of posts and seeing ma thrown about but no reference to plate voltage! I'm glad Jeff is being the proper scientist and doing the maths.  LOL

Anyways, I've not verified this myself, but an inside track I have told me that the Tung Sol 7581A are the same innards as the Tung Sol KT66, just stuffed into the skinny bottle. And, they seem to sell for much less! So it's no wonder we're liking them. If someone has both sets handy, compare the innards and see how they look? I've also been told you need to be looking at Tung Sol made after 2014 as the earlier ones were different and not as good.

Same person also mentioned that TAD (Tube Amp Doctor) tubes are usually the more consistent ones as they demand a higher level of testing and matching, if you like the Chinese tubes.





I'm going to be doing some tube testing soon - I have NOS 7027, 7581, vintage milspec 807, and other NOS 6L6 variants with the Anode on the top like the 807....maybe including some British Made Marconi KT66 variants from the late 50s early 60s I may have scored from a warehouse in Europe.  I'm very excited about my experimentation, and hope to post my thoughts here...assuming I don't get distracted by silly things like work and paying bills and house projects. LOL

I'll probably be dumping all these tubes after I'm done, and just sticking with one or two sets I love and stocking up on them. So if anyone wants to play after me, I'll have some fun stuff up in the next month or so.

Oh crap! I still haven't sent Lon his damn tubes back! FML.


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Re: Anyone Tube Roll with the ZMA yet?
Reply #545 - 11/08/18 at 22:04:09
 
Leigh, remember I said "I've heard them"....I never said the ProAc's were any good. Just kidding. I would not dig that suck out mid bass hump ~ no matter how you want to describe your slope...etc... .

Anyway, I have let Ray Kimber defend his Kables ....I don't need to! I just enjoy what the KS1030 and KS6063 do for my Decware.
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Re: Anyone Tube Roll with the ZMA yet?
Reply #546 - 11/09/18 at 00:07:47
 
Quote:
... but an inside track I have told me that the Tung Sol 7581A are the same innards as the Tung Sol KT66, just stuffed into the skinny bottle. ...


My ears aren't the best but the 7581As don't sound anything like the KT66 in my opinion.  They are much closer to the 6Ps many of us like so much.  As a class, aren't the 7581As a 35W plate dissipation tube and the KT66s 25W or 30W?
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Re: Anyone Tube Roll with the ZMA yet?
Reply #547 - 11/09/18 at 00:14:25
 
Arch, I have to wonder if LR posted as what the heck. Exactly, way different sonic's.

Way closer to 6P's .... Very correct.

But, LR says sh__ about what he does not own and spent 500 + hours with, as us!?
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Re: Anyone Tube Roll with the ZMA yet?
Reply #548 - 11/09/18 at 02:33:15
 
I’ve tried the KT66’s and 7581’s and there is a world of difference. The KT66 have strong, punchy bass but a average midrange and high end. The 7581’s have a deeper and fuller base mid ranges that are clean and clear and crisp highs. I’d be happy to part with my KT66 for a reasonable offer. I’m keeping my 7581’s.
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Re: Anyone Tube Roll with the ZMA yet?
Reply #549 - 11/09/18 at 02:59:49
 
Quote:
But, LR says shit about what he does not own and spent 500 + hours with, as us!?


Hey, all I did was pass on some information from an industry insider who actually toured the Russian and Slovac tube factories. Sorry if I stepped on your dick there and got you all bent out of shape! They could very well be completely different tubes. Or even the same tube with a minor tweak. (more below)

Quote:
As a class, aren't the 7581As a 35W plate dissipation tube and the KT66s 25W or 30W?


Sure, if you were talking about original manufacture spec. But we aren't talking about US made 6L6, or the "super" version called the 7581A made in the 60s, nor the British KT66 which was their version of a 6L6, and their "super" version with the KT names.

But there are only 3 real tube factories left in the world, the Slovakia plant, the Russian plant, and the Chinese plant. I'm sure there are some boutique tube shops around, but a lot of them are often purchasing from the 3 main tube factories with some specification tweaks and are only finishing the tubes in house.

So we're not talking 7581A from GE and KT66 from Osram, we're talking about a Russian plant that has purchased the name Tung-Sol and producing tubes that *look* like Osram KT66. FYI, Tung-Sol was an *American* company, and never even made a KT66 which is a British version of a 6L6. So the modern, Russian made Tung-Sol KT66 is a completely made up tube along the lines of a 6L6 using modern manufacturing techniques and material that *looks* like a British tube with it's fat glass and box cutouts.

Which do you think is more likely, that this Russian factory is painstaking recreating the exact materials and specs of each original manufacturer, even down to limiting their plate dissipation and output....or that they are using retooled 6P3S equipment and modern manufacturing techniques to produce a 6L6 "type" tube that can take 500v on the plate, 500v on the screen with 35 watts dissipation that happens to *look* somewhat like a famous extinct tube, and stuffing them into different glass envelopes and just marketing them differently? As long as the tube guts are 6L6 "type", and can handle the abuse a higher voltage amp would put them through, you could stuff it into anything from a 6V6 to KT66 envelop and send it out the door.

That said, I'm sure there are variants and tweaks to make the tubes sound different. It could be as simple as wider spacing on the grids or different halos, or fatter plate. (shrug) Or Vlad could have been enjoying his weekend and the specs were off...oh shit, these measure a bit on the weaker side because our grids aren't wound as tight, stuff these into the fat glass. These are analog devices that fall into a wide range of specs that could make some of them more suited for one type of 6L6 variant over the other.

Anyways, my point was just to share some neat and likely info. I also suggested that if you have the two tubes handy, look at them yourself and see what you think.

If you guys are hearing big differences, then I'm sure there is something going on there.

Anyways, I got some of my experimental tubes in.  These are definitely not Russian or Chinese.



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