Little Dot Tube Amps: Vacuum Tube Rolling Guide
Jun 28, 2013 at 6:06 PM Post #1,711 of 13,435
Hi Hypnos 1,
 
Don't know about other people and their ears and hearing, but my personal experience is that it takes some time to come to a true conclusion of what sounds really good. First impressions are not always reliable.
 
In the world of racing cars there is a saying that if an engine loses five horsepower you notice it right away, but a gain of five horsepower may be much harder to notice. So translated into tubes, some glaring deficiency stands out right away, but small improvements may escape you for a while until it becomes settled in your mind. You may love listening to a set of tubes, but over time some grating quality emerges, and it could take time to identify it.
 
Then we have the ice cream syndrome: Strawberry, chocolate or vanilla? Everybody have their preferences, but if we can reach a consensus on which ice cream is best (6AH6, 6AU6, Heptodes etc) you can then safely pick your own flavor. And just as with ice cream the only real way of experiencing it is to taste it, so we have to try and see what suits us best.
 
Happy tube rolling!
 
Jun 28, 2013 at 6:07 PM Post #1,712 of 13,435
My new arrivals today:
 
Siemens EH90 (6CS6), O-getter, mat grey plate, labelled 678 (June 1978?), on the backside it says EH90 in light grey and smaller white print FOREIGN, suppose this is original Siemens
Russian 6A2P (10 / 1967), shiny dark grey plate, backside in white OTK 20, saucer getter
 
I am not posting first impressions :wink: but the Siemens 6CS6 react differently on 1/7-strapping as compared to the saucer 6BE6, more towards AFBs 5915 strap, I am guessing. This is what I use to burn them in at the moment. Further impressions later.
 
Hypnos-1, do you also have the saucer getter type Siemens EK90 (6BE6)? If I remember correctly, you also bought from tubeshop-24. Please, check out my former post on this tube 1/7-strapped vs. non-strapped. Maybe you find similarities.
 
Mordy, 1. chocolate, 2 vanilla, 3. strawberry! =D
 
Jun 28, 2013 at 6:34 PM Post #1,713 of 13,435
Given the bewildering number of tube rolling options available to LD owners, it might be useful to render these choices into a logic/decision tree chart for each model (and version?) that included comments from the many alpha testers on Head-Fi. I know it would make my decisions easier as to which topology and tubes I wish to audition.
 
Anyone else interested in this?
 
 
Jun 28, 2013 at 6:44 PM Post #1,714 of 13,435
Good idea, but at the moment, this is a quite complex tree and besides it is far from being finished. I would rather recommend to get yourself a small number of tubes that are highlighted in this thread and then follow it being able to compare your observations with others. That way, you would also contribute to the development of our tube rolling progress, which at the moment is quite wide but should be narrowed down over time. 
 
The ultimate goal of course is to find a small number of high end tubes - finals, so to speak - with different signatures so that there is something for everyone.
 
Jun 28, 2013 at 6:45 PM Post #1,715 of 13,435
Quote:
Hi everyone,
 
Am still loving the Siemens EK90s to death - looking forward to seeing how the TFK EK90s compare. Mab : I am so sorry you have had trouble finding some Siemens - I do hope you manage to get some soon...
Re burn-in time - mine certainly benefited from 40+hours, which I would assume goes for other 6BE6s also...
Re 1-7 strapping  -  loud, yes; full, yes; exciting, yes; extended/enhanced treble, yes. BUT...on first listening, some of Genesis's 'Duke' tracks (the massively 'full' numbers) - the WOW almost turned to OW! There seemed to me, anyhow, a somewhat definite loss of overall control/integration. I wonder if anyone else has noticed this to any degree with similarly full/complex(especially electronic) music. Perhaps 'reviving' #3 needs some burn-in time also?...Or do I just need to 'recalibrate' my hearing?!!!Shall have to try further similar tracks...

As i commented earlier to mordy regarding 6BE6 TUNG-SOL tubes i tried ,out of the 4 settings that is possible for those tubes i found that for me the best sounding setting was the  EF 95 SETTING.
 
Jun 28, 2013 at 8:28 PM Post #1,716 of 13,435
Quote:
Given the bewildering number of tube rolling options available to LD owners, it might be useful to render these choices into a logic/decision tree chart for each model (and version?) that included comments from the many alpha testers on Head-Fi. I know it would make my decisions easier as to which topology and tubes I wish to audition.
 
Anyone else interested in this?
 

By "model (and version)", do you mean the different LD models, such as 1+, II, III and IV? If so, I doubt that this will be possible. Other than the 1+, the other models are really very, very similar. And further, I have the 1+ and so far, the tubes that are performing well on the all-tube models are also performing well on my tube-SS hybrid.
 
My best advice is to start with a Tung Sol 6485 or Tung Sol 6AH6W. These two appear to be virtually the same tube, and both have proven to be a top performer on all LD models. As to the current heptodes, you might want to wait on the sidelines until the dust settles. We are still in the early stages of checking these out.
 
On the other hand, if you would decide to order some of these heptodes and add your impressions, that would be great!
 
Jun 29, 2013 at 11:57 AM Post #1,717 of 13,435
Quote:
 
Do I understand correctly, that you love them in the EF 95 configuration with no 1-7 strapping? But strapped, you find them lacking? I am beginning to to think that due to the 6BE6 grid 3's remote cutoff nature, maybe the 1-7 strapping is not optimal.... I have been listening to mine strapped, but am thinking maybe I should go back to unstrapped

 
Hi gibosi,
 
Curiouser and curiouser, as Alice (in Wonderland) would say...after the initial trial with 1-7 strapping (yes, still love plain EF95 config) and my somewhat disturbing experience with those Genesis tracks, have returned to them after 15 more hours burn-in on 1-7 and...Mordy certainly is right - first impressions can be tricky. I didn't really expect to notice much difference after such a short time, but there WAS. Either my head was in a bad way the first time (which is possible given my upcoming 63rd birthday!), or that grid DID need some more time...
Whatever, the mass of notes (too many Mr Mozart?!!) and voices seemed to have pulled together quite nicely.STRANGE...
And I think this could be my new love (for now!) as I am getting what ACAPPELLA11 describes in his assessment of EK90s in 1-7 mode (please read his post - it is so comprehensive).
 
So...to strap or not to strap, that is the question...mikelap prefers not? AFB prefers yes? The rest of us on the fence? A bit of a conundrum methinks...Personal preference rules, OK??...
 
BTW A11, yes - my Siemens are the same as yours... saucer getter; sharp pins; no Siemens logo?,( and look quite different to those that do have it)...
 
This tube rolling is a game with many twists and turns, to be sure...GRRREEAAT!
 
BFN.
 
Jun 29, 2013 at 1:09 PM Post #1,718 of 13,435
Quote:
 
Hi gibosi,
 
Curiouser and curiouser, as Alice (in Wonderland) would say...after the initial trial with 1-7 strapping (yes, still love plain EF95 config) and my somewhat disturbing experience with those Genesis tracks, have returned to them after 15 more hours burn-in on 1-7 and...Mordy certainly is right - first impressions can be tricky. I didn't really expect to notice much difference after such a short time, but there WAS. Either my head was in a bad way the first time (which is possible given my upcoming 63rd birthday!), or that grid DID need some more time...
Whatever, the mass of notes (too many Mr Mozart?!!) and voices seemed to have pulled together quite nicely.STRANGE...
And I think this could be my new love (for now!) as I am getting what ACAPPELLA11 describes in his assessment of EK90s in 1-7 mode (please read his post - it is so comprehensive).
 
So...to strap or not to strap, that is the question...mikelap prefers not? AFB prefers yes? The rest of us on the fence? A bit of a conundrum methinks...Personal preference rules, OK??...
 
BTW A11, yes - my Siemens are the same as yours... saucer getter; sharp pins; no Siemens logo?,( and look quite different to those that do have it)...
 
This tube rolling is a game with many twists and turns, to be sure...GRRREEAAT!
 
BFN.

 
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! :)
 
Jun 29, 2013 at 1:22 PM Post #1,719 of 13,435
I got my Lorenz EK90 today and I can say from first impression without 1-7 strap they are very similar to the Telefunken I very much like them as it without any mods.
 
Once I get my Haltron branded Siemens I'll compare all 3 with and without the 1-7 strap.
 
Jun 30, 2013 at 12:22 AM Post #1,720 of 13,435
After having determined that my version of the Siemens EK90 sound best unstrapped, I decided to listen to the Amperex E91H again, strapped 1-7. With my recalibrated ears, I think they sound great, and I am retracting my earlier conclusion that the Amperex sound best unstrapped.
 
To date, I have three samples of 6BE6 (GE, Siemens and Telefunken), and none of them are acceptable strapped 1-7. I have two samples of 6BY6 (RCA and Amperex), and both are excellent strapped 1-7. And I have one sample of 6CS6 (Sylvania), and it too is excellent strapped 1-7. I have a couple more 6BY6 and 6CS6 coming and will update this tally as I get to them.
 
Jun 30, 2013 at 12:59 AM Post #1,721 of 13,435
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.
 
Jun 30, 2013 at 12:03 PM Post #1,722 of 13,435
After reading through the previous pages Siemens & TFK's EK90's are really good? I'm planning to get some of them if anyone knows where to get some at a good price currently asking NOSTUBESTORE if they have stock.
 
Jun 30, 2013 at 12:52 PM Post #1,723 of 13,435
Quote:
After reading through the previous pages Siemens & TFK's EK90's are really good? I'm planning to get some of them if anyone knows where to get some at a good price currently asking NOSTUBESTORE if they have stock.

 
The NOS Tube Store may still have the Telefunkens, but the Siemens are proving much harder to find. And to complicate matters, there are several versions of the Siemens out there. I have one version (with O-getters), whereas Acapella11 and hypnos1 have another version (with saucer getters). And I think there is at least one other version, which appears to be a relabeled Philips/Mullard EK90 (large squarish holes in the plates) out there as well.
 
In case you didn't see the earlier post, when searching on eBay, notice that on the left you can choose location. Select "worldwide" as both Siemens and Telefunkens will most likely be found from European vendors.
 
Good luck!
 
Jun 30, 2013 at 1:06 PM Post #1,724 of 13,435
Quote:
After reading through the previous pages Siemens & TFK's EK90's are really good? I'm planning to get some of them if anyone knows where to get some at a good price currently asking NOSTUBESTORE if they have stock.


As I am just listening to them, I can also recommend to buy the Siemens EH90 (6CS6), which are better available compared to the EK90 (6BE6) or EH900 / EH900S (6BY6). They slightly brighter, more forward with a bit less ambience compared to the saucer getter type EK90 (1/7-strap).
 
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.
 
Quote:
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

 
Great find Mordy and have a look at this thread: http://www.head-fi.org/t/479031/6sn7-tube-addicts =)
I haven't been reading much but there is loads of info for them being great Hi-Fi tubes. One just need to overcome the threshold of $55 for the socket adapter pair incl. shipping plus $x for tubes...
However, there is a "problem" rolling the power tubes: In a way you need to be able to compare them to other power tubes and that would be a costly maneuver with pre-1985 6H30P-DRs or 6N6P-IRs, which are less than the price of the sockets, or some 6H30P-EV in the arsenal. Everyone would of course consider, are they better than DRs? Naturally, it would be fun to test some cool power tube options. :)
 
Jun 30, 2013 at 1:45 PM Post #1,725 of 13,435
just posted a very efficient way to clean tube pins in another thread, but maybe some of the tube rolling thread members are interested in my solution, so just crossposting the link here:

http://www.head-fi.org/t/632518/analog-paper-2-discussion-and-appreciation-thread/630#post_9573905
 

Users who are viewing this thread

Back
Top