[vlach]

I've just started reading this thread (because I just bought a LD Mk VIIISE ;~) and have been interested in some of the tube rolling comments.

Conspicuous by their absence, is the (12AT7) GEC A2900 (or CV6091 - military version, but the same tube).  I've been collecting them (on eBay) since they were $60 - $85 a pair;  but now up to $250/pair,  which should say something about their desirability.  In fact, they'll knock all other 12AT7's out of the park (I promise!)  I use them in all my 12AT7 apps:

Atma-Sphere MP-3 balanced phonostage (3 pairs)
McIntosh MC275 amplifier (2 pair)
Little Dot MK VIII SE (very soon ;~)

These tubes (when in good shape) have the highest transconductance (gain) of any 12AT7 you will run across.  This is an especially important quality when they are used as drivers for (whatever) power tube(s) because they can provide unflinching control over the power tubes' grids.  Their sonics are also excellent, as in my phonostage -- but of course once again, their incredible gain makes the biggest difference in the phonostage too. (in S/N ratio)

If you're eBay-shy, you can buy brand new ones (matched and guaranteed) from Jim Rhodes at Langrex in the UK, or from his eBay ad:  http://www.ebay.com/itm/260877535635?ssPageName=STRK:MEWAX:IT

I'm really anxious to hear the LD Mk III SE.  So far, I don't have 'balanced' and 'tube' in the same headphone amp ;~)  My current 'stuff' is:

• Melos SHA-1 tube headphone amp (single-ended)
• HeadRoom Balanced Home Amp;  the 'Beast', with outputs for two pairs of BAL headphones
• HeadRoom 'Cosmic' headphone amp
• 2 pr. Sony MDR-V6
• 2 pr. Senn 650 (one w/ AudioArt Equinox SE cable)
• 1 pr. Senn 600
• 1 pr. Denon AH-D7000 (w/ AudioArt Equinox BAL cable)
• 1 pr. Grado SR60
• 1 pr. Grado SR125
• 1 pr. Yamaha YH-1 (w/ Cardas FatPipe BAL cable)
• 2 pr. Yamaha YH-2's  

I know, it's nuts;  but it was all an accident . . . honest!  The truth is, a year ago, all I had was the two pairs of Sony's, and NO amps, except a little ASL HD-1 headphone tube buffer that was plugged into the tape loop of my preamp;  oh, and the headphone jack on my Nak CR-7A cassette deck ;~)
You can see my main system here:  http://forum.audiogon.com/cgi-bin/fr.pl?vevol&1109799786
 
I just turned 71 today (thanks! ;~) and my hearing, while not exactly "shot", is of course, old ;~)  And I find I'm getting a lot of enjoyment listening to headphones.  Often more than my beautiful main system and speakers (sniff, sniff ;~)  One thing that contributed to that turn of events, is the "Crossfeed" feature on HeadRoom's line of headphone amps.  Before that, I just couldn't bear the "ping pong, hole-in-the-middle" effect of headphone listening (except of course when I could listen to an occasional rare binaural recording.)  I only wish HeadRoom (or somebody) would make a balanced tube unit with that feature (or am I uninformed?)
 
Anyway, I've enjoyed reading all your posts, and expect to be much better informed for doing so!  I need to do some 'weeding-out' (obviously ;~) but please feel free to criticize (or advise;~) on my current collection of stuff;  keeping in mind my deteriorating hearing, and the fact that I probably don't have a lot of time to amortize any (expensive) changes ;~)  Thanks.
 
Neil

My advice: sell the X qty of headphones that will allow you to purchase the HD800 and never look back

 

[nsgarch]

Quote:

[size=medium]I'll see if I can clear up a few things here. For orthodynamic headphones the Mk6 is the clear choice since it has the greatest power for the low-efficiency lo-Z headphones which normally is harder on tubes.[/size]
 
[size=medium]Hi John  --  I haven't checked the specs on the current orthos, but here are the Yamaha specs:[/size]
[size=medium]Impedance: 150 ohms[/size]
[size=medium]Frequency Response: 20-20,000Hz[/size]
[size=medium]Diaphragm: 12 micron polyester[/size]
[size=medium]Magnet: Sintered Ferrite, 55mm Diameter[/size]
[size=medium]Sensitivity: 96dB/mW[/size]
[size=medium]Rated input: 3w[/size]
[size=medium]Max input: 10w[/size]
[size=medium]Harmonic distortion: < 0.3% at 90dB SPL[/size]
 
[size=medium]What would you consider them: hi-Z, high efficiency, but power hungry?[/size]
 
[size=medium]Both can drive hi-Z  high efficiency and to a point Hi-Z low efficiency headphones. The Mk8 however may have better “refinement” in sound with higher grade caps and “voiced” better for the Hi-Z headphones.  The Mk6 is better for the wider range of headphones that are in used today.[/size]
 
[size=medium] It is not common to find a tube pre-amp with a fully balanced phonostage [size=11pt]section[/size] using XLR inputs for turntable. For me I am not using my turntable but I am using my CD,s ,audio DVD,s and Blu-Ray,s. My computer software player J.river gives me quite a few setting for crossfeed when I needed it.  I noticed that your Atma-Sphere has 11 tubes inside.[/size]
 
[size=medium]"Not common" is an understatement.  Try "impossible"!  There are a few ss phonoamps with true balanced circuits, and with XLR ins and outs.  But the only other BAL tube units I know, are BAT and Aesthetix;  and they both use some kind of help before the first (tube) gain stage.  Either a step-up transformer, or a FET stage.  The Atma-S[/size][size=medium]phere is all tubes  - 3 pairs (you can pull one pair out and replace them with dummy/jumpers for MM cartridges.)  Yes, there are 11 tubes.  6x 12AT7 in the phonostage + 1x 12AT7 constant current tube for the phonostage.  Then there is a pair each of 12AU7's and 6SN7's for the line stage.[/size]
 
[size=medium](The two coils of) moving coil phono cartridges are inherently balanced output devices.  When you connect them to a phono amp with single-ended (RCA) interconnects, one end of each coil is tied to one end of the other, and to ground  --  it's just like driving headphone coils single ended, but in reverse!  By making the two coils share a common ground, crosstalk is unavoidable, and the output (current) of the coils is essentially cut in half!  Again, this is exactly  analogous to driving headphone coils BAL vs. UNBAL, only in reverse!  So, amplfying the two coils of a MC cartridge while keeping them electrically separate results in 1.) better soundstage/imaging and channel separation, and 2.) twice the gain  --  which translates into a twofold improvement in signal to noise ratio;  and BTW, eliminates the need for step-up devices ahead of the phonostage ;~)  I already know the results are nothing short of spectacular though loudspeakers;  so I can hardly wait to hear my vinyl through tube-balanced-driven headphones![/size]
 
[size=medium]I'm just waiting for both the LD MkVIII and my preamp to be delivered (I had Ralph add two more BAL main outputs to the preamp  --  one more for the subwoofer, and the other for the BAL headphone amp.)  I'll report back then . . . .  if I can get to my computer![/size]

 

[baronbeehive]

Quote:

My advice: sell the X qty of headphones that will allow you to purchase the HD800 and never look back

Agreed!! Problem is we all have our favourites. I can't understand Sennheiser owners but I can quite understand if they don't like HiFiMan owners. There are quite clear leaders in the field - HD800's, HE6's, Beyerdynamic T1's and LCD's. However people still like their Sen 595's and such like. They all have their own characteristics which people love them for. I think with headphones you need something else not just an accurate presentation. Personally I go for the forward mid range because I love the enhanced emotion that this gives to vocals for example, whereas others, quite understandably go for massive. "out there", soundstage of top end grados. Whenever I've read reviews I've tried to go for a good all rounder and that's why I'm now down to one set of cans!

 

[john57]

[size=medium][size=medium]Neil,[/size][/size]
[size=medium] [/size]
[size=medium][size=medium]Now I see that you have three pairs of Yamaha Orthodynamic headphones that were made in the late 1970's? Providing that they have the same sensitivity of 96dB at 150 ohms today as when they are new you should not have any issues in driving them with the LD Mk 8. Today’s Orths are about 50 ohms or less with sensitivity as low of 83dB which I would use the LD Mk 6 for those especially with the HiMan HE6.[/size][/size]

 

[Neogeo333]

Just a little report on new driver tube for the MK6.  OMG, these BL63 are everything they say they are.  Been using my new favorite 6sn7, Sylvania 6sn7w metal base and in my opinion the Sylvania bested the Tung Sol VT-231 oval mica.  But boy these BL63 are a step higher than even the Sylvanias.  First thing that I notice is how the soundstage just expanded.  Better instrument separation and a much cleaner background than the other two.  One thing this tube lacks to my hears is bass.  Its there, its clean and tight but not much like the TS or Syl.  Mids and highs are clean and clear.  Definitely more transparent than the other two.  This is just after 1 hour of warm up, who knows what it can do with a couple of hours more. 
 
A big thanks for Glenn from Glenn Studio for the adapters. 

 

[rosgr63]

The BL63 is a wonderful tube, enjoy it.
Make sure the transformer can cope with the 1.3A heater current to be on the safe side.

 

[john57]

Neogeo333
 
About a month ago you said that you were going to sell your LD Mk 6. What changed your mind?

 

[DefQon]

Quote:

I've just started reading this thread (because I just bought a LD Mk VIIISE ;~) and have been interested in some of the tube rolling comments.
 
Conspicuous by their absence, is the (12AT7) GEC A2900 (or CV6091 - military version, but the same tube).  I've been collecting them (on eBay) since they were $60 - $85 a pair;  but now up to $250/pair,  which should say something about their desirability.  In fact, they'll knock all other 12AT7's out of the park (I promise!)  I use them in all my 12AT7 apps:
 
 

I'm using some Psvane 12AT7-T Grade A tube's in one of my hybrid tube amp for my bookshelf monitors, bests any other 12AT7 tube's I've tried up to the $350 margin. Some of those old expensive tube's are only expensive due to it's rarity, age or some military spec'd tube's manufactured within-tight specs.
 
Give the Psvane's a try, you will be surprised.

 

[Neogeo333]

Quote:

Neogeo333
 
About a month ago you said that you were going to sell your LD Mk 6. What changed your mind?

It still for sale, just havent found a new owner.  I'm getting a Cavalli Liquid Glass and thus the MK6 need to go. 
Been buying new tubes to get really too tube roll when the LG arrives.  I even listed all my 6080 and its variants for sale too.

 

[pkjames]

The idea of liquid glass is really really good. Tks a billion different types of tubes and the SS power section just there to faithfully reflects the characteristic of the input tubes. Wonder how it compares with the LD 6/8.

 

[nsgarch]

Quote:

I'm using some Psvane 12AT7-T Grade A tube's in one of my hybrid tube amp for my bookshelf monitors, bests any other 12AT7 tube's I've tried up to the $350 margin. Some of those old expensive tube's are only expensive due to it's rarity, age or some military spec'd tube's manufactured within-tight specs.
 
Give the Psvane's a try, you will be surprised.

Hi DefQuon:  I have already made that comparison, trying the Psvane 12AT7's in both the phonoamp section Of my Atma-Sphere MP-3 preamp, and as drivers for my KT88 power tubes in my McIntosh MC275 MkIV.  The Psvanes are very nice tubes, quiet, with nice flat response top-to-bottom;  but the GEC A2900/CV6091 were still much better in all parameters, including their (important to me) ability to drive the KT88 power tubes with authority.  I can not only hear the difference, but I also know this because with the A2900's driving the power tubes, the amp draws 270 watts (of wall power) and with most other 12AT7's, the amp only draws between 225 and 240 watts.  What this tells me is that the GEC tubes are enabling the power tubes to 'work harder'  --  putting out more power and therefore providing more headroom.
 
Right now as a matter of fact, I'm burning in a quad of Psvane KT88-T black-coated power tubes in my amp, to compare them with my Shuguang Black Treasures, and my (reference ;~) NOS Gold Lions.  The P's have almost 300 hours on them, the Shuggies about 4500.  There are some things the Shuggies actually do better than the GL's.  I'm waiting to make the same comparison when the P's burn in a little more.  I will say that physically, the P's are better made than the Shuggies.  Heavier bottle, ceramic base, and a thicker more evenly applied carbon coating.
 
BTW, if anyone is thinking about buying either of those brands, the best price (and service) you'll find is from Clark at www.goodcomponent.com  He'll even select and match tubes with highest plate current for you which he pulls right from the assembly line.  You can email me for more info if you like.

 

[atistatic]

Quote:

It still for sale, just havent found a new owner.  I'm getting a Cavalli Liquid Glass and thus the MK6 need to go. 
Been buying new tubes to get really too tube roll when the LG arrives.  I even listed all my 6080 and its variants for sale too.

Hi Neogeo333, i want ask how many should spend for get a better quality amp than MK VIII?

 

[DefQon]

Quote:

Hi DefQuon:  I have already made that comparison, trying the Psvane 12AT7's in both the phonoamp section Of my Atma-Sphere MP-3 preamp, and as drivers for my KT88 power tubes in my McIntosh MC275 MkIV.  The Psvanes are very nice tubes, quiet, with nice flat response top-to-bottom;  but the GEC A2900/CV6091 were still much better in all parameters, including their (important to me) ability to drive the KT88 power tubes with authority.  I can not only hear the difference, but I also know this because with the A2900's driving the power tubes, the amp draws 270 watts (of wall power) and with most other 12AT7's, the amp only draws between 225 and 240 watts.  What this tells me is that the GEC tubes are enabling the power tubes to 'work harder'  --  putting out more power and therefore providing more headroom.
 
Right now as a matter of fact, I'm burning in a quad of Psvane KT88-T black-coated power tubes in my amp, to compare them with my Shuguang Black Treasures, and my (reference ;~) NOS Gold Lions.  The P's have almost 300 hours on them, the Shuggies about 4500.  There are some things the Shuggies actually do better than the GL's.  I'm waiting to make the same comparison when the P's burn in a little more.  I will say that physically, the P's are better made than the Shuggies.  Heavier bottle, ceramic base, and a thicker more evenly applied carbon coating.
 

 
Why do some people say my name with 'uon' lol, anywho coming from the top of my head, the MP-3 is that long tube amp with one side being the transformers  and the otherside is a whole bunch of tubes on one side. I'm a little not surprised those GEC A2900 are much better than Psvanes, as I've heard some and seen people say that it is indeed a superbly sounding tube, having not tried the GEC's, how much better would you rate over the Psvanes?
 
I'll admit I haven't played with a lot of 12AT7 tubes but I've got a good little expensive collection on the 12AU7 and the only time I see the Psvanes lose is as someone quoted on another forum with their comparison, comparing it to a rare NOS level 1950's Telefunken diamond based tube. What would be your second best 12AT7 valve besides the GEC's? (They don't come cheap).

 

[Neogeo333]

Quote:

Hi Neogeo333, i want ask how many should spend for get a better quality amp than MK VIII?

The money is yours, I'd say whatever your budget allow.  I have never listened to the Cavalli, just going by other people impressions.  But the thought of been able to use lots kind of tubes got me.
But most importantly people that I known and have good rep. in here all mention its one of the best amp around.  Now Im geting of topic.  
To sum the LD MK6, I put it at the most bang per buck in the tube amp market.  Similar to what the Schiit Mjolnir is to SS amp.  For the money you cant beat those two.   

 

[john57]

For the MKIII the one thing that comes in my mind that might be better is the  Emmeline II, "B-52" by Ray Samuels Audio. I have listen to their Dark Star amp two years ago. You will have that the Little Dots are very good and to get the very "best" which can be very subjective at that level,  is a huge price increase. I decided to keep my LD MK6 and more so today since I found my "Holly Grail" of driver tubes.