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Little Dot Tube Amps: Vacuum Tube Rolling Guide - Page 415

post #6211 of 10501
Quote:
Originally Posted by bbmiller View Post
 

Please bear with me I am trying to understand this tube rolling stuff are you saying you own at least three pairs 6AS7G tubes or their equivalent and are rolling them for some purpose? I mean per headphones or per type of music or per vintage of recording or per something else?

No special purpose simply because i like to try different tubes to see how they sound,  thats what called tube rolling and as time passes they will get more expensive and rare so you can say i am also stocking up, and collecting those beautiful glass works of art . :bigsmile_face:

post #6212 of 10501
Quote:
Originally Posted by bbmiller View Post
 

Please bear with me I am trying to understand this tube rolling stuff are you saying you own at least three pairs 6AS7G tubes or their equivalent and are rolling them for some purpose? I mean per headphones or per type of music or per vintage of recording or per something else?

 

To sum up what others have said. Tubes manufactured in different factories and at different times sound different. Moreover, everyone has different ears and different gear. And so if follows that some tubes will sound better than others given a particular set of ears and gear. Thus people roll different tubes to try to find the best sound, given their ears and gear.

 

Quote:
Originally Posted by bbmiller View Post
 

I do not know if there is some sort of view thread biased you bring to viewing a thread as lodges this one. But on this thread I have not run across people saying they are rolling tubes per vintage of recording. Do you do things like rolled tubes to listen to your favorite 60s or 70s recordings and have other tubes you use for modern recordings.

 

Also do you have a system of marking your tubes for left and right channels before you remove them. Is there a marker that will withstand the heat tubes make?

 

Is there a premium contact cleaner recommended by the people on this thread? I mean something like the old spray tuna cleaner you used when televisions had those click to change channels tuners?

 

Yes, some people roll different tubes depending on the music. I don't. Too complicated.

 

And no, I can see no reason to ensure that the same tubes are always inserted in the same channel. Again, too complicated and not worth the trouble.

 

I clean pins mechanically by gently scraping them with a dull knife. I have no experience using premium contact cleaners. Some recommend DeoxIT if you are so inclined.

post #6213 of 10501
Quote:
Originally Posted by mordy View Post
 

Hi i luvmusic2,

 

The measurements depend on the reference point of the equipment used to test the tubes. Here is an example from a current Ebay listing:

If the tube was true NOS it should read 100% or even higher, for example 110%. The two readings correspond to the two triodes in a dual triode tube (in our case right and left channel if used as a driver). In this case the tube measures below acceptable in one channel.

If the tube has a life span of 3000 to 10000 hours I would not worry if the value is above good. You may have to turn up the volume slightly compared to a 100% tube.

In summary, you must ask what a "good" value is since each manufacturer is different.

 

General Mutual Transconductance (Gm) Test Results:

44/56 Where the Minimum is: 50/50 and the NOS value is: 82/82
or
54/69% of what a NOS tube should test where the Minimum "good" value is 65%

 

 

 

 

 

 

 

 

 

Thank You for the info Mordy!

post #6214 of 10501

The parts for a more powerful heater power supply arrived today, and I am pleased and relieved that the Tung-Sol/Chatham 5998 lights up and plays. As Mordy and others have noted, these power tubes sound surprisingly good as drivers. However, I notice that the LD 1+ runs pretty hot after a hour or more, so will likely put it away for now until I get an OTL amp. After all, with the Sylvania 7963 and the Siemen's C3g's on hand, it's not as if I don't have any new and interesting tubes to listen to. :)

 

Which reminds me...

 

As the Sylvania sub-miniature 7963 is considered by some to be the best double triode Sylvania ever made, I decided to compare it to a 1945 Sylvania 6SN7W. In many rankings, the 6SN7W is considered to be one of the top 4 or 5 6SN7's ever made, and it is my reference 6SN7.
 
I A/B'ed a couple tracks, Diana Krall, 'Devil May Care' on the 'Live in Paris' album, and Alex McMurray, 'One Step Away from the Hole' on the 'I Will Never Be Alone in This Land' album. And I was pleasantly surprised. My impression is that the 7963 sounds very similar to the 6SN7W, and maybe not all that surprising, it seems to be a tad bit quieter. The bass is detailed and propulsive, the highs are very extended and airy, and vocals have what I consider to be the Sylvania "house sound," slightly warm, liquid, smooth and sweet. Moreover, I believe the added quietness enhances transparency, imaging and sense of stage. Of course, I might change my mind over time, but for now, I consider the 7963 to be as good as any tube I have (600 and counting lol).

 

post #6215 of 10501

600 tubes holy heck. I'll be returning back home in just over a week where I have had all my newly purchased tubes posted to. Cant wait to try out the c3g's and the 4 pairs of 6SN7's I have purchased. Should be good :). Btw do you have any other 6SN7's for reference which you would recommend? I'm sure I will be purchasing more in the future haha

post #6216 of 10501

I have been rolling >25 yrs now and have accumulated over 7000 audio tubes! It gets worse not better.....:)

post #6217 of 10501
Quote:
Originally Posted by sgbwill2 View Post
 

600 tubes holy heck. I'll be returning back home in just over a week where I have had all my newly purchased tubes posted to. Cant wait to try out the c3g's and the 4 pairs of 6SN7's I have purchased. Should be good :). Btw do you have any other 6SN7's for reference which you would recommend? I'm sure I will be purchasing more in the future haha

 

For someone just getting started with 6SN7's, I think the Tung-Sol "Mouse Ears" is a very good tube, especially for the money, and a good reference.

 

post #6218 of 10501
Quote:
Originally Posted by Nic Rhodes View Post
 

I have been rolling >25 yrs now and have accumulated over 7000 audio tubes! It gets worse not better.....:)

 

Let's see now....  7000 tubes divided by 25 years is 280 tubes a year. I have been rolling for almost two years and have 600 tubes, so it appears that I am right on track! lol :)

post #6219 of 10501
Quote:
Originally Posted by Nic Rhodes View Post
 

I have been rolling >25 yrs now and have accumulated over 7000 audio tubes! It gets worse not better.....:)

 

Phew!... Think I'd better pack it in right NOW - can't take much more of this mind- scrambling stuff, lol! :eek:.

post #6220 of 10501

Received 6H30Pi by Electro Harmonix today, and paired them with Mullard CV4010 on my LD mk3 - listening with DT880 600ohm..

 

I am somewhat disappointed because I think the stock power tubes (6H6PI) sounded better in both lows and highs, especially the bass impacts..

 

Would the 6H30Pi improve with burn in? :-/ 

 

I also noted that one of my 6H30Pi has a brighter glow on one of the electrode than the other, is that normal?

 

Additionally, the external ambient buzz sound are more apparent with the 6H30Pi tubes.. is this normal?

The machine isn't overheating or anything and I cant hear pops/hiss/hum from my headphones.

 

EDIT: Thanks @mordy 


Edited by philiptw - 5/23/14 at 11:49am
post #6221 of 10501

Hi philiptw,

 

Like all tubes, the EH tubes will improve with burn-in. However, the 6N6P-IR will sound better. Even better (much better) results will be obtained with 6SN7 tubes.

 

It is not uncommon for one tube to glow brighter than the other - it means nothing unless you hear a distinct difference, such as much less volume. It is simply a matter of how the heaters are mounted inside the tube, and some parts may obscure the view a little. Even if one is brighter, it could also be that one of the pins is not making good contact inside the tube socket. A gentle scraping of the pin with a knife will take care of it.

 

Buzzing sounds and hum are sometimes hard to trace. Make sure that electrical appliances and portable telephones aren't too close to the amp - these things could create electrical interference.

post #6222 of 10501

Hi sgbwill2,

 

I have found certain RCA 6SN7GTB tubes sounding very nice. These are not expensive but require a little work to find. These tubes were made in 60's and have a heater wire running horizontally on top of the topmost mica plate. Since many pictures do not show the top heater wire clearly, you have to ask the seller.

 

Here are a couple of pictures that show the heater wire in action, A RCA tube with the top heater (labeled Hoffman), and a Times Square neon night view.

 

post #6223 of 10501

Hi,

  Anyone familiar with this site Westubes.com?Thanks!

post #6224 of 10501

Hi Guys,

   I just received my Raytheon JAN-6832 Please show me the PIN Layout for this tube.THANK YOU!

post #6225 of 10501
Quote:
Originally Posted by i luvmusic 2 View Post
 

Hi Guys,

   I just received my Raytheon JAN-6832 Please show me the PIN Layout for this tube.THANK YOU!

This tube is same as Mordy's tubeThanks!

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