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Little Dot Tube Amps: Vacuum Tube Rolling Guide - Page 132

post #1966 of 7674

This tube looks almost identical, except that the plate is not ribbed.

 

 

 

post #1967 of 7674
Quote:
Originally Posted by mordy View Post

This tube looks almost identical, except that the plate is not ribbed.

... and the nip and the pins are all wrong...
post #1968 of 7674

 

                                                                                     

                                                                                                               

 

Got those today Siemens EH 90 from Germany  same tubes as mordy post #1937 page 130


Edited by MIKELAP - 7/15/13 at 6:01pm
post #1969 of 7674

The quote was just a joke - whatever you write is very clear and appreciated. - I don't have the dots on my keyboard and never bothered to install the Swedish characters on my computer.

 

Anyhow, so far I am voting for RFT as the manufacturer of the Siemens tubes.

 

http://www.ebay.com/itm/EH90-6C6S-RFT-HEPTODE-TUBE-NOS-in-BOX-/250640179082?pt=Vintage_Electronics_R2&hash=item3a5b519f8a

 


 

post #1970 of 7674
Quote:
Originally Posted by mordy View Post

Good try, but the getter mounting on top of the mica on my Siemens tubes does not have a bar across (look at left tube).

I think you see the octagon, not a bar. Otherwise, I don't know what bar you're talking about.
post #1971 of 7674
Quote:
Originally Posted by gibosi View Post

 

"I would suggest in this particular case it is well worthwhile to pay the extra for the genuine article"

 

Ah, but this is crux of the problem, How to recognize the genuine article. We are still not sure which ones are genuine and which are not..... Which were manufactured in the Halske factory and which were manufactured elsewhere. And where is "elsewhere"... And to the heart of the matter.. Which tubes sound the best?

 

By the way, have you posted a picture of yours?

 

Hi gibosi.

 

Yes indeed : wherefore art thou genuine tube?!  The various permutations of manufacturer (and even within the same one!) is mind-boggling, to say the least.

 

With regard to Siemens, I am wondering if we are on fairly safe ground if the Siemens logo (as well as name) is on the tube, plus the yellow & blue with orange end cap box?

Especially if, like mine (see photo), Siemens& Halske is written on the bottom of the box....

 

Whatever, all I can say about mine is that with 40hrs burn-in now, everything I have mentioned in previous posts is holding firm - if not even firmer. Sensational - for me anyway.

 

I can only hope others have the same experience - with similar tubes, or from 'elsewhere'!

 

GOOD LUCK everyone...

post #1972 of 7674
Quote:
Originally Posted by hypnos1 View Post

With regard to Siemens, I am wondering if we are on fairly safe ground if the Siemens logo (as well as name) is on the tube, plus the yellow & blue with orange end cap box?
Especially if, like mine (see photo), Siemens& Halske is written on the bottom of the box....

That's what their brand looked like at the time. A positive sign, but hardly a guarantee of origin. They did away with the SH logo when Siemens & Halske was merged with Siemens-Schuckertwerke and Siemens-Reiniger-Werke to form Siemens AG in 1966.
post #1973 of 7674

Just a quick info with respect to Svetlana 6A2P and Siemens EK90 (black bottom, saucer getter): They do not sound the same. Hence, one would not be a substitute for the other.

 

Otherwise, I changed something on my system and have to now go through tubes again. Also, I am suffering from heptoditis (= the choice of many good sounds), so I decided to not rush it but rather get used to them and come a bit delayed with a "more definitive" opinion.

 

I agree that focussing on one mode of operation (unstrapped that is probably) will make reviewing tubes easier. Every reviewer has anyways the option to try different modes "in secret" if he/she wishes and include information about them, if useful.

 

Good luck rolling everyone!


Edited by Acapella11 - 7/16/13 at 2:06pm
post #1974 of 7674

My Tesla 6H31 heptodes arrived after 2 weeks shipping time from Lithuania. They came exceptionally well packaged in a big box with layers and layers of rainbow colored foam strips.They are on slow simmer for 40-50 hours to burn in.

 

Because I had the 1-7 straps in place, they are burning in this way. Would it be any advantage burning them in unstrapped? Maybe more of the internals will be activated when you burn in a tube unstrapped?

As I understand it the burning in process burns up unwanted gasses and impurities. However, there must be more to it, since some tubes require over 100 hours to burn in. Perhaps different materials in the tube need various times to stabilize for optimum performance.
 

post #1975 of 7674

Here is an early update on my Tesla 6H31 (6BE6) from December 1958 after 9 hours of burn in on EF95 1-7 strap:

 

Very strong and detailed mid bass. The sound stage is wide but the instruments are not portrayed as totally separate but more like an organic whole. At the same time these tubes astound me with their portrayal of micro details - I suddenly hear new nuances in familiar recordings that I did not hear before.  The treble is also very detailed. The mid range is starting to sound very sweet.

 

They sound a little bright but that could be a function of the 1-7 strap - will try later with no strap. Overall very pleasing and engaging tubes. Who knows, maybe a top tier tube....

 

The date code on the tube is SH (12/58). Reminds me of a new brand of pre-amplifiers whose name also starts on Sh... I take affront that somebody would name it as such and don't think it's funny. (How does your sh.... sound?) A new low in the music world?

 

From their home page:

 

And yes, that is our name. "And yes, it’s pronounced exactly like you think.

I

Or, well, no. Yep, Schiit is our name. As in “Hey man, that’s some really cool Schiit.” Or, “We like music and Schiit.”

 

 

Would not buy something with such a name....

an we show you some Schiit?

post #1976 of 7674
Received my valvo tubes. Codes 3L8 and cutoff 48D3. How should I use them hmmm I have some left over spc 26awg about 7-8 strands would those work for the socket mod?
Edited by siles1991 - 7/17/13 at 12:14am
post #1977 of 7674
just put the valvo's in....I prefer it over the voskhods. Not too bright and and forward/aggresive. It's very smooth but lacks a bit of sparkle.

On another note: Guys I have michael jackson's discography in FLAC and whenever I hear the song Billie Jean the Snare drums are very piercing to my ears. Any reason to this? Only this particular song gives me this problem. It happens even from Youtube videos. It's like the snare drums are right next to my ears and its punching me in the ears.
Edited by siles1991 - 7/17/13 at 1:11am
post #1978 of 7674

Guys, thanks for the recent heptode business. I'm currently listening to the IBM 1680's and really liking them. I'm finding their highs more refined than the 6485's with more bass/sub bass presence. They're currently in straight EF95 mode. I'll try the 1-7 strap after they've cooked a bit.

One thing I'm a bit worried about is that one of the tubes has an almost imperceptible getter flash. The other tube has a more substantial flash but considering these were somewhat "custom" tubes and that they have the old D getters I'm wondering if this is just me being paranoid. Was the vacuum that hard?

I've also noticed that there's a slight, very slight buzz coming from that tube that generally goes away if I tap on the tube.

 

I've got some Telefunken EH900S on the way too. :)


Edited by inphu510n - 7/17/13 at 1:15am
post #1979 of 7674
Quote:
Originally Posted by inphu510n View Post

Guys, thanks for the recent heptode business. I'm currently listening to the IBM 1680's and really liking them. I'm finding their highs more refined than the 6485's with more bass/sub bass presence. They're currently in straight EF95 mode. I'll try the 1-7 strap after they've cooked a bit.

One thing I'm a bit worried about is that one of the tubes has an almost imperceptible getter flash. The other tube has a more substantial flash but considering these were somewhat "custom" tubes and that they have the old D getters I'm wondering if this is just me being paranoid. Was the vacuum that hard?

I've also noticed that there's a slight, very slight buzz coming from that tube that generally goes away if I tap on the tube.

 

I've got some Telefunken EH900S on the way too. :)


Mine have the same very light getter flash on one tube, and still pretty light on the other one anyway, so I wouldn't worry about it (I believe the historic change from D to O-getters was mainly meant to get more uniform and well flashed, well, getter flashes on tubes; all my tubes with D-getters have pretty irregular or "pattern-less" getter flashes, whereas my O-getter tubes usually look alike).

 

About the buzz: clean the pins, thoroughly (sand paper, small knife, ... any kind of good mechanical cleaning). Those tubes are nice, but are 60 years old and came to me quite dirty -both glass and pins- so I cleaned everything before I even dared to put them in the amp, which I hardly ever do.

post #1980 of 7674
Quote:
Originally Posted by Audiofanboy View Post


Mine have the same very light getter flash on one tube, and still pretty light on the other one anyway, so I wouldn't worry about it (I believe the historic change from D to O-getters was mainly meant to get more uniform and well flashed, well, getter flashes on tubes; all my tubes with D-getters have pretty irregular or "pattern-less" getter flashes, whereas my O-getter tubes usually look alike).

About the buzz: clean the pins, thoroughly (sand paper, small knife, ... any kind of good mechanical cleaning). Those tubes are nice, but are 60 years old and came to me quite dirty -both glass and pins- so I cleaned everything before I even dared to put them in the amp, which I hardly ever do.

Hah ok thank you for the info. The top of that one tube is almost totally clear which is odd when compared to the amount of flash in something like a Russian 6N6P.

I'm pretty sure I cleaned the pins well. I used the back of an xacto knife to scrape them clean because WOW they were dirty. Some of the most filthy pins I've seen.

I typically clean the pins in this manner for most of the tube types I try out. It's a PITA to clean them like this because it's 14 pins every time!
I've actually tried soaking the pins in Coca Cola. Hey it dissolves egg shells right??? That worked somewhat but not enough for my taste. Something more corrosive would be needed...

Any how, thanks for the advice. I'll check to make sure they're totally clean.
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