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Little Dot Tube Amps: Vacuum Tube Rolling Guide - Page 116

post #1726 of 6932

I would like to share some initial impressions of a few heptodes.

 

There is something about the Amperex E91H, a special quality that I really like. Although the treble is very slightly rolled off (more "tuby"), it has a great musicality and balance and even between heptodes it sounds that bit cleaner and has a better focus ("spooky"). 1/7 sounds fine,  At the moment, I haven't decided which strapping is the best. Mainly I am still making up my mind between 1/7 and 2/7. 1/7 and 2/7 sound louder than unstrapped, which is a small problem. Besides, 2/7 sounds opener than unstrapped, a bit more forward and brighter. 1/7 is in between.

After some more listening, my tendency goes to 2/7 (again ;) ) as this removes (most of) the treble roll off and makes the tube more engaging.

 

The Siemens EH90 would be brighter, sounding a bit more engaging if you wish, with a focus quite close but not exactly there. The EK90 (saucer getter) would be following them in terms of focus, not exactly as open sounding but with a very similar signature to the EK90. To me, so far the EH90 sounds better than the EK90, almost a brighter version of the Amperex but not quite.

 

First impressions of the Russian 6A2P are that their focus compares with the Siemens EK90, their treble is quite nice because it is extended but round as well.

 

The comparison was done with the 1/7-strap for all and all tubes perform on a really good level. I am going to look at them some time later again after more burn in. The Amperex was burned in most (~ 18 h), others were about 10 - 12 h.

 

 

Edited twice: Corrected Siemens type in the 6A2P impression and Amperex differences between 1/7, 2/7 and unstrapped.


Edited by Acapella11 - 6/30/13 at 4:45pm
post #1727 of 6932
Quote:
Originally Posted by mordy View Post

In my search for replacements for the 6N6P power tubes I came across this converter that if I understand correctly converts the 6SN7 Octal tube for use in 6N6P applications. Would this be an alternative to the Little Do MKIII/IV power tubes?

http://www.ebay.com/itm/two-Adapters-for-ECC32-6SN7-plug-adapters-to-instead-6N6P-tubes-/261051244115?pt=Vintage_Electronics_R2&hash=item3cc7ddde53

Now, I do not understand the advantage of the 6SN7 tubes; apparently they are a dual 6J5 triode. The original Tung Sol versions sell for $100 each and (much) higher. There is even a current re-creation of the Tung Sol tube which I think is made by Sensor Corporation and selling for under $20. Other NOS brands can be had for a few dollars and up.

Would appreciate the opinion of the knowledgeable members of this forum if this is something to explore.

Could the little dot support the 6sn7 electrically?
post #1728 of 6932
Quote:
Originally Posted by Acapella11 View Post

Here is a picture of my tubes, which I got from ebay.de (http://www.ebay.de/itm/1-Stueck-EH90-Roehre-von-Siemens-nos-neu-/251035838020?ssPageName=ADME:L:OC:GB:3160)

 

 

Different versions exist also here: with or without logo, colour of the mica and the arrangement of holes in the plate vary. All seem to have a halo getter in common.

 

 

And it is getting curiouser and curouser! I have a pair on their way to me from the same vendor. And from the picture on eBay, with the large squarish holes, I just assumed that I would getting Philips/Mullard tubes relabeled as a Siemens. Not real Siemens, but even so, I figured they would probably still be good. But the plates on yours are different. Moreover, the placement and size of  the holes resembles the plates on my Siemens EK90, which I believe were actually made by Siemens. So now I am wondering.... What I will get? lol :)

post #1729 of 6932

NOSTUBESTORE is out of Siemens and TFK EK90's T.T I shall settle for Tung Sol 6AH6WA for now...


Edited by siles1991 - 6/30/13 at 8:22pm
post #1730 of 6932
post #1731 of 6932

More money = less fun. I keep telling myself that . . .

 

Anyway, the only things drawn to the abyss are lemmings.
 

post #1732 of 6932

Look, Steve Guttenberg is a down to earth reviewer that I trust, and I have confidence in his opinions. The Abyss headphones are out of reach price wise, but it is always interesting to read about the state of the art, and many times certain features trickle down to less expensive items.

 

Funny, but I had in mind to write about a cheap hi-fi trick that I learned from Steve Guttenberg some 30 years ago. This isolation platform trick is so inexpensive that it just cannot be marketed (or maybe it could..).

 

I have a sturdy hi-fi rack made out of metal with spikes. The shelves are MDF particle board and rest on four little rubber covered metal tabs. His idea was to reduce the vibration that comes from all transformers and power supplies and could muddle the sound, by placing  the shelves (or equipment) on little glass marbles to reduce the vibration.

 

I placed four little glass marbles on the four rubber covered tabs that hold the shelf, and they allow a little bit of movement within the frame around the shelf. In addition, I used blue tack to stick three aluminum cones to the underside of the LD. The LD MKIII sits on top of the shelf, and with this set up there is ample airflow around the amp, and I have never had an issue with micro phonics or acoustic feedback with any tubes.

 

Just make sure that the amp stays in place and doesn't roll away if you just use the marbles. I snuck out a bag of marbles from my kids, and I don't think they miss them any more since they are all grown up by now....BTW, green works best - JUST KIDDING!
 

post #1733 of 6932

Not criticising you or Guttenberg or the Abyss. Just having fun.
 

post #1734 of 6932
Quote:
Originally Posted by siles1991 View Post

NOSTUBESTORE is out of Siemens and TFK EK90's T.T I shall settle for Tung Sol 6AH6WA for now...

 

The Telefunken EK90/6BE6 is also a great alternative if they still have any.

post #1735 of 6932
Quote:
Originally Posted by mordy View Post

Look, Steve Guttenberg is a down to earth reviewer that I trust, and I have confidence in his opinions. The Abyss headphones are out of reach price wise, but it is always interesting to read about the state of the art, and many times certain features trickle down to less expensive items.

 

Funny, but I had in mind to write about a cheap hi-fi trick that I learned from Steve Guttenberg some 30 years ago. This isolation platform trick is so inexpensive that it just cannot be marketed (or maybe it could..).

 

I have a sturdy hi-fi rack made out of metal with spikes. The shelves are MDF particle board and rest on four little rubber covered metal tabs. His idea was to reduce the vibration that comes from all transformers and power supplies and could muddle the sound, by placing  the shelves (or equipment) on little glass marbles to reduce the vibration.

 

I placed four little glass marbles on the four rubber covered tabs that hold the shelf, and they allow a little bit of movement within the frame around the shelf. In addition, I used blue tack to stick three aluminum cones to the underside of the LD. The LD MKIII sits on top of the shelf, and with this set up there is ample airflow around the amp, and I have never had an issue with micro phonics or acoustic feedback with any tubes.

 

Just make sure that the amp stays in place and doesn't roll away if you just use the marbles. I snuck out a bag of marbles from my kids, and I don't think they miss them any more since they are all grown up by now....BTW, green works best - JUST KIDDING!
 

Ya mordy its always like that regarding the marbles tisk tisk lol . Which reminds me of a story my 29 year old finally admitted to me a couple years ago some 20 years after the fact he's a wise kid and i guess the survival instinct kick in to ,that it was him that poked in my tweeter on my PRECIOUS JBL L100 what else am i going to find out about in another 20 years who knows kids.

post #1736 of 6932
Quote:
Originally Posted by gibosi View Post

 

Yes, indeed, curiouser and curiouser..lol...  And now that I know that you and A11 have the same tubes, I have to admit, I would like to be able to get a pair like yours to hear the difference. As to my Siemens EK 90, for the first hour or so in the 1-7 strap, they were indeed very different than no strapping, and I wasn't at all sure I liked them. But after a while, I ultimately "surrendered" to them, and began to think they were the best tubes I had ever heard. But now that I have been listening to them for some time, I think they are better unstrapped. For one thing, I noticed that I was shying away from complex music, in favor of simpler vocals. And then I noticed that vocals were sounding too thin, and sometimes, with certain artists, a bit "reedy." Anyway, I have put them aside for now as I am getting acquainted with the Sylvania 6CS6....

 

Oh, and happy birthday! I also have a birthday coming up soon, in July. And of course, I am trying to decide what present(s) I should buy myself! :)

 

Hi gibosi.

 

Perhaps you might treat yourself to something REALLY useful for your birthday, as I hope to - a head DESCRAMBLER/REBOOTER...to help with this rolling pastime!!! Good luck with the search. Please let me know if you succeed!

 

Audiofanboy : A heartfelt plea to you on this topic of "to 1-7 strap EK90s, or not"...I know you did warn us re possible 'shock' on first encounter, but perhaps you should have issued a Gov't (mental) health warning!! I refer to the perceived 'wayward' control element in complex tracks, and a thinness in vocals (especially voiced by gibosi). It would appear most regulars on this forum are now shying away from said strap. The point is, after my initial doubt re overall control -  then less doubt -  my head is spinning somewhat! I am wondering if you have explored further in this particular direction yourself, and whether you can shed some of your invaluable insight on the subject...Look forward to your views AFB...

 

Acapella 11 : The same plea to you - have you encountered these aspects in your extensive trials? Part of me wants to stay with the strap, the other wants to go - could love/hate relationships also exist in the rolling world? Certainly seems to be creeping into mine!!! Would love to hear your views also - perhaps others might too?...

 

Got some Siemens EH90s on the way, so perhaps my mental state will improve with these on 1-7...I certainly hope so!...lol...

 

Awaiting some Confucian wisdom with anticipation,

 

A crazy junior headfi roller...

post #1737 of 6932
Quote:
Originally Posted by hypnos1 View Post

Perhaps you might treat yourself to something REALLY useful for your birthday, as I hope to - a head DESCRAMBLER/REBOOTER...to help with this rolling pastime!!! Good luck with the search. Please let me know if you succeed!

 

 

For sure, I will search Google for said device and, of course, I will let you if I am successful! lol

 


 

Well, I got a package from Germany today, two pairs of EH90, Telefunken and Siemens.

 

The Telefunkens, "Made in Germany" printed on the glass and the diamond between the pins. I plugged them in to make sure they are not dead and they are now burning in.

 

 

And the Siemens...  I got one of each!!!! (>_<) At first, I thought the one on the right was actually made by Philips, but there is a circle with a number between the pins, so it appears that both of these are genuine Siemens. But still, these are not an acceptable pair. However, I don't feel that I can fault the vendor as he did send me two Siemens EH90, so I have contacted him to ask if I can purchase one more of each, to make two pair....

 

post #1738 of 6932

Hi A11,

 

Why did you have to mention the Russian 6A2P tube? Just when I thought that we had things under control with US, British and German tubes who all have their specific sound (THIS IS A JOKE - NOT TRUE, but...) and on the edge of picking a winner or winners among the heptodes, the Russians are coming!

 

The (alphabet) soup thickens:

 

Russian flavor - 6A2P

 

Italian flavor: Fivre 6BE6

 

Hungarian flavor: Tungsram 6BE6

 

Chechoslovakian flavor: Tesla 6H31

 

The shakeout continues - always wanted to sample Tesla tubes, so I ordered a pair that barely squeezed under my $8 rule. However, the Tungsram and Elektronorgtecnik 6A2P should not be expensive. Could not find ANY information on this Russian factory, but so far it seems that only one factory made these heptodes.

 

Yes, I have all my marbles, but if I am perfectly happy with the RCA 6BY6 tubes, why do I have to order more tubes? When does it end? I guess that it is human nature never to be satisfied....

 

PS: Here is a new designation for a 6BE6 tube: Sylvania GB (Gold Brand) 1217

post #1739 of 6932
Quote:
Originally Posted by mordy View Post

Hi A11,

 

Why did you have to mention the Russian 6A2P tube? Just when I thought that we had things under control with US, British and German tubes who all have their specific sound (THIS IS A JOKE - NOT TRUE, but...) and on the edge of picking a winner or winners among the heptodes, the Russians are coming!

 

The (alphabet) soup thickens:

 

Russian flavor - 6A2P

 

Italian flavor: Fivre 6BE6

 

Hungarian flavor: Tungsram 6BE6

 

Chechoslovakian flavor: Tesla 6H31

 

The shakeout continues - always wanted to sample Tesla tubes, so I ordered a pair that barely squeezed under my $8 rule. However, the Tungsram and Elektronorgtecnik 6A2P should not be expensive. Could not find ANY information on this Russian factory, but so far it seems that only one factory made these heptodes.

 

Yes, I have all my marbles, but if I am perfectly happy with the RCA 6BY6 tubes, why do I have to order more tubes? When does it end? I guess that it is human nature never to be satisfied....

 

PS: Here is a new designation for a 6BE6 tube: Sylvania GB (Gold Brand) 1217

I ordered a couple pairs of Tesla  and looking into some russians Electronorgtecnik 6a2p also there a couple a buck each thats good. And yes you have all your marbles ya but its your kidssss marbles tisk tisk atsmile.gif

post #1740 of 6932

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Quote:
Originally Posted by MIKELAP View Post

 

 

Processed By eBay with ImageMagick, R1.1.1.M2b

 


Edited by MIKELAP - 7/1/13 at 11:45am
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