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Little Dot Tube Amps: Vacuum Tube Rolling Guide - Page 122

post #1816 of 7533

I had a few packages arrive in the mail today:

 

1680, a special IBM version of the 6BE6, manufactured between 1949 and 1956. The third grid was changed from remote cut-off, normal for the 6BE6, to sharp cut-off. In a sense, one could see these as the prototype for the later 6BY6. As this was made by RCA (274), I will be directly comparing it to a pair of RCA 5915/6BY6. AFB first found these tubes, and as they were very cheap, decided to get a pair and see how they sound. Burning in as I type this...

 

 

Telefunken EH900S = 5915/6BY6

 

 

And as a number of posters have been very positive about their EK90s with saucer getters and shiny, sharp pointed pins, decided to try a pair. These were relabeled by Ultron and cheap. Those of you who have these tubes, do these look like the ones you have?

 

post #1817 of 7533

Whats the maximum duration do you guys leave your LD MKIII up for burning in each session?

post #1818 of 7533

I have an older LDII++ and at one point I forgot to turn it off while listening at night and found it dead the next day after work, David repaired it free of charge but I paid for shipping both ways.

 

I learned my lesson, no more then five or six hours.

 

Also with my WA2 the folks at WOO recommend no more then 8 hours and then let the amp cool, I believe he knows more then me about this. LOL!

post #1819 of 7533
Quote:
Originally Posted by siles1991 View Post

Whats the maximum duration do you guys leave your LD MKIII up for burning in each session?

Littledot recommends no more than 8 hours personally if im not there i dont take a chance you never now but i wrote this in another thread but it was all in good fun of course wink_face.gif

Originally Posted by phototristan View Post

So I have a Conductor on the way. Do most just leave it on all the time? Or, do you turn it off when you are not using it? 

I turn it off. but i put a 100% wool blanket on hit taken from himalayan sheep from a pasture between 10 and 15000 feet of course but thats me . Or Burson says to warm it up 30 minutes before hand


Edited by MIKELAP - 7/1/13 at 12:03pm


Edited by MIKELAP - 7/6/13 at 4:48pm
post #1820 of 7533

All depends on the tubes, the 6EW6 get pretty hot compared to the 6BY6 so I don't do more than 6 hours or so on those, with the 6BY6 and 6BE6 I've done multiple 24 hour burn-in sessions.

post #1821 of 7533
Quote:
Originally Posted by Audiofanboy View Post

 

+1 for that! I actually preferred both -very different- pairs of Voskhod tubes I had before burn-in. They were spiky all right, and quite unbearable on poorly recorded albums, but they had a presence that they lost after the looong burn-in. I remember being quite disappointed about that... Like "what the **** happened to my tubes!!!"

 

At one point, and since those tubes were so cheap, I almost thought about just buying a huge stash of them and only using them between 20 and 120h of use! Yeah... I was young and naive back then; now we're all rolling tubes that sound great after 20h and last up to 10k hours, that's progress for you!

beerchug.gif

 

Quote:

Originally Posted by gibosi View Post
 

I had a few packages arrive in the mail today:

 

1680, a special IBM version of the 6BE6, manufactured between 1949 and 1956. The third grid was changed from remote cut-off, normal for the 6BE6, to sharp cut-off. In a sense, one could see these as the prototype for the later 6BY6. As this was made by RCA (274), I will be directly comparing it to a pair of RCA 5915/6BY6. AFB first found these tubes, and as they were very cheap, decided to get a pair and see how they sound. Burning in as I type this...

 

Very interesting. I am very curious about those.

 

Quote:
And as a number of posters have been very positive about their EK90s with saucer getters and shiny, sharp pointed pins, decided to try a pair. These were relabeled by Ultron and cheap. Those of you who have these tubes, do these look like the ones you have?

 

No, mine have a light grey plate and a black bottom without alphanumeric number. The rectangular and longer holes seem to be the same though. I've also got some Telefunken EH900S incoming. It looks like you got a great tube pair trio there!

 

Quote:
Originally Posted by MIKELAP View PostLittledot recommends no more than 8 hours personally if im not there i dont take a chance you never now but i wrote this in another thread but it was all in good fun of course wink_face.gif
Quote:
Originally Posted by mab1376 View PostAll depends on the tubes, the 6EW6 get pretty hot compared to the 6BY6 so I don't do more than 6 hours or so on those, with the 6BY6 and 6BE6 I've done multiple 24 hour burn-in sessions.

 

I have also done 24 h sessions in a 20C room and with loads of space around the amp. If your place is warmer, I would probably stick to 8 h.

 


Edited by Acapella11 - 7/6/13 at 6:34pm
post #1822 of 7533

I have done many 24 hr plus burning in sessions, but, as stated, it depends on the type of tube. I once burned in a EF91-92 tube and the amp got so hot that I could not touch it - scary.

Other types run much cooler. The heptodes I am trying now run very cool.

 

For long runs I rigged up an old 12V fan from a broken computer connected to a 12V wall wart [from an on old portable phone or router ] based on the advice of members of the blog. Rather than blowing air on the tubes directly, I position the fan to suck up air from the amp and dissipate in the room. My amp is also on stilts (aluminum cones) to allow for good air circulation around the amp and heat dissipation via convection.

At first I tried a 120 mm fan, but it lowered the temperature too much and I think it temporarily affected the performance of the driver tubes. Now I am trying a smaller 80 mm fan [from a broken power supply]. IMHO heat is a big enemy of electronics, so if you can keep the amp cool it should not break it, even if it is on much longer than 8 hours. One member of the blog lives at the edge of the Australian desert, so he may have to resort to bigger fans...

 

Tubes change characteristics after burn in. In my experience 20-30 hours should be fine, but my RCA 6BY6 changed drastically after some 50 hours with much better bass. The Voskhods take much longer than anything else, and I burnt in two pairs for 120 hours! Grueling....

 

PS - You can buy computer fans for just a few bucks on sale from places like Newegg and Tiger Direct in the US. (Personally, I enjoy the no cost option of looking through my parts bins...)
 

post #1823 of 7533

Even though I'm still just catching up on my heptodes (I'm amazed how fast some of you get your tubes in the mail, everything I order takes over a week to get to me... I ordered the same IBM 1680 as gibosi a whole week before him and still don't have them lol...), I finally got a few of the "6BE6 essentials".

 

So, I have a pair of Haltron Should-be-Siemens 6BE6 from the NOSTubeStore, actually labeled CV453 everywhere, and also two genuine Telefunken EK90 in Tele boxes. The "Haltmens" actually do look like most of your -assumingly genuine- Siemens EK90 with O-getters and an alphanumeric code on the base, or at least like one version of these I saw here. They look perfectly identical to the genuine Siemens EH90 I've seen here, on the other hand (the holes in the plate are close to the fold in the plate, whereas a few of your O-getter EK90 have the holes further away from the fold; my tubes have two-digit numbers inscribed in the glass at the base, and small ribs in the plate too, though the ribs don't seem as emphasized as in your pictures).

 

Anyway, regardless of what they are (I'm still not sure what we've been calling genuine Siemens were actually made by Siemens, but who cares as long as they sound good), they sound... great, awesome, and even better than my best 6BY6 and premium variants. A natural, detailed, realistic and, above all, thoroughly engaging sound with close to perfect focus and "ambiance", as A11 puts it; these also have a more "normal" soundstage than my favorite Tele/vanias 5915/EH900S -at least compared to those 1-7 strapped- but still plenty large and expansive, just more natural; they are also less forward and have more presence than my second fav' E91H -whether or not strapped. I'm burning these in unstrapped for the time being, as everyone seemed to agree that yielded the best results -and I have to agree up to here!

 

Last detail, I find these tubes -unstrapped- to not sound as "wet" or "tubey" as my other unstrapped heptodes, these are noticeably drier, in a good way; not that I mind a bit of tubeyness or tube echo-like wetness as it adds -often fake- ambiance, but as I mentioned recently, I do find myself straying away from a warm, cozy, or just easy sound signature, and having drier, and perhaps more challenging tubes actually works very well as far as I'm concerned -and on my gear obviously ;) .

 

Mab1376, I believe you had also bought some "Haltmens" from the same source I did. Any chance you could throw in a picture of both tubes and their boxes for reference? I'll do the same as soon as I can pull them out of the amp! I'm curious as to what they exactly look like, since we've been seeing quite a lot of variety in Siemens -labeled- tubes.

post #1824 of 7533
Quote:
Originally Posted by Acapella11 View Post

beerchug.gif

 

 

Very interesting. I am very curious about those.

 

 

No, mine have a light grey plate and a black bottom without alphanumeric number. The rectangular and longer holes seem to be the same though. I've also got some Telefunken EH900S incoming. It looks like you got a great tube pair trio there!

 

 

I have also done 24 h sessions in a 20C room and with loads of space around the amp. If your place is warmer, I would probably stick to 8 h.

 

To be honest i really dont leave anything on except heating in winter once you  come close to setting the place a blaze once, not amp related mind you but still your very careful after that. 

post #1825 of 7533

Received news that my EF95 to EF91-92 socket adaptors are ready to ship so no more jumpers to change or pins to strap of course will see if they work first of course will let you guys know like last time they are $38.00 U.S. a pair + $5.00 shipping i checked there site they dont advertise them yet so we will see but these guys dont screw around if they dont work they just figure it out and send you another pair thats it so anyways will keep you posted.

post #1826 of 7533
Quote:
Originally Posted by Audiofanboy View Post

Anyway, regardless of what they are (I'm still not sure what we've been calling genuine Siemens were actually made by Siemens, but who cares as long as they sound good), they sound... great, awesome, and even better than my best 6BY6 and premium variants. A natural, detailed, realistic and, above all, thoroughly engaging sound with close to perfect focus and "ambiance", as A11 puts it; these also have a more "normal" soundstage than my favorite Tele/vanias 5915/EH900S -at least compared to those 1-7 strapped- but still plenty large and expansive, just more natural; they are also less forward and have more presence than my second fav' E91H -whether or not strapped. I'm burning these in unstrapped for the time being, as everyone seemed to agree that yielded the best results -and I have to agree up to here!

 

Why do you favour unstrapped to burn in?

 

Quote:

Anyway, regardless of what they are (I'm still not sure what we've been calling genuine Siemens were actually made by Siemens, but who cares as long as they sound good), they sound... great, awesome, and even better than my best 6BY6 and premium variants. A natural, detailed, realistic and, above all, thoroughly engaging sound with close to perfect focus and "ambiance", as A11 puts it; these also have a more "normal" soundstage than my favorite Tele/vanias 5915/EH900S -at least compared to those 1-7 strapped- but still plenty large and expansive, just more natural; they are also less forward and have more presence than my second fav' E91H -whether or not strapped.

 

I actually haven't bought a "proper " halo getter Siemens EK90 yet. It seems that is one to have. Cheers, AFB.


Edited by Acapella11 - 7/7/13 at 4:12pm
post #1827 of 7533

Looking forward to these.  Thanks Mikelap!

 

 

Quote:
Originally Posted by MIKELAP View Post

Received news that my EF95 to EF91-92 socket adaptors are ready to ship so no more jumpers to change or pins to strap of course will see if they work first of course will let you guys know like last time they are $38.00 U.S. a pair + $5.00 shipping i checked there site they dont advertise them yet so we will see but these guys dont screw around if they dont work they just figure it out and send you another pair thats it so anyways will keep you posted.

post #1828 of 7533

Off topic  but interesting, how many guitarist can you name !                                                                                           *

post #1829 of 7533

Maybe my imagination or hearing is limited, but until the dust settles on the heptode adventures, I think I will stick with the mil-spec Soviet bottles I'm using. Imaging and other characteristics are very good, at least for my listening library.

 

There's also something emotionally satisfying about running the same Soviet tubes that I faced off against in other equipment in the 1970's.In general, Soviet military tube equipment was over-built, well designed, and stable.

 

I have a Carver AM/FM tuner, an optical cable with a Turtle Beach Dolby surround decoder on order, and am looking forward to my Turbulent X driver-based Martin headphones later this summer. Think I'll just settle down for some listening sessions and not change anything in my audio chain for a good while.

 

Unless someone comes up with an 01A configuration for the Little Dot Series.

post #1830 of 7533
Quote:
Originally Posted by Audiofanboy View Post

Mab1376, I believe you had also bought some "Haltmens" from the same source I did. Any chance you could throw in a picture of both tubes and their boxes for reference? I'll do the same as soon as I can pull them out of the amp! I'm curious as to what they exactly look like, since we've been seeing quite a lot of variety in Siemens -labeled- tubes.

 

Still waiting on them, they're probably at my post office waiting for a signature.

 

I'll throw a pic up once i get them.

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