Little Dot Tube Amps: Vacuum Tube Rolling Guide
May 26, 2013 at 2:08 PM Post #1,382 of 13,432
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Hi redrum42,
 
I have found that many tubes from different brands exhibit too much treble. I have the luxury of having tone controls in my system, so I can turn down the treble and making it much more pleasant.
In the absence of tone controls, I did find that changing the original power tubes which were 6N6P-i to 6N6P tubes (available cheap) or even better to 6N6P  gold grid tubes "tamed" some of the excessive treble.
 

Thanks for your suggestion. I'll get some of them. Any signal tube recommendations that would have softer treble than the rca black plates I am currently using? Thanks.
 
May 26, 2013 at 5:35 PM Post #1,383 of 13,432
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Hi G,
 
In addition to the Raytheon 6AH6V tubes I was able to find 6A6V tubes from Tung Sol, CBC, TUBE and Capeheart through a simple Google search.
 
 
Found this seller who has 6AH6 tubes from $0.60 to $3.50 (shipping not specified). Does anybody have experience with John Kendall's Vintage Electronic Services?
 
http://www.king-cart.com/vintageelectronics/product=tubes/keywords=/exact_match=exact/next=390/return_page=
 

 
It is interesting that the most expensive 6AH6 this vendor carries is the 6AH6V. One could infer that the "V" implies something better than a standard 6AH6, but we have no data to support that inference. And I have no experience with this particular vendor.....
 
This eBay vendor, AudioPathic Distractions, has pictures of the Raytheon 6AH6 and 6AH6V. 
 
http://www.ebay.com/itm/390452122072?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649
 
The one with 6AH6 etched into the glass, second from the left, looks very similar to the TS 6AH6. The right-most tube, which I assume is a 6AH6V, looks somewhat different.....
 
May 26, 2013 at 5:55 PM Post #1,384 of 13,432
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Thanks for your suggestion. I'll get some of them. Any signal tube recommendations that would have softer treble than the rca black plates I am currently using? Thanks.

 
It is very hard to say... Everyone's ears are different....
 
In the end, I think you will just have to try a more few tubes and decide for yourself. At a minimum, I would encourage you to try something other than another 5654. While I do not have personal experience with HD6X0 headphones, I have read that the Mullard M8161 (CV4015), an EF92 tube, sounds very good with them (See page 1 for a little more info.)
 
May 26, 2013 at 9:01 PM Post #1,385 of 13,432
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Thank you for that detailed and informative reply.
I'll have to look at the hardware store for some boxes like you mentioned.
I'm really looking for some kind of "list: software to keep track of my tube collection.  I've bought duplicates of several tubes, just because I forgot I already had them
It would be nice to have something tracking things just so I could at a glance tell what I have, what I might be interested in, etc.
I'm a computer geek, and a list-a-holic,
:)
Again, many thanks for your info-packedreply!
 

Hey BG what i do to remember i take pictures of the tubes i buy i open a folder on the computer stick the pictures in the folder along with all the infos related to the tubes thats it instant archive .
 
May 27, 2013 at 12:37 AM Post #1,387 of 13,432
Great idea! Better than the shoe box, but wait, where do I store the physical tubes in the PC? LOL
 
I thought I only had one 6AG5, but now I found another five RCA 6AG5 tubes in the bottom of a box of spares of TS 6AJ5 that used to be my favorite tube before I got acquainted with the great tubes on this forum.
 
I guess that you could put in the location of the tubes in the computer file. Maybe the file could be organized like this:
 
Picture
Brand Name: Unobtanium
Family: 6XYZ6/1234
Production Date: Can't decipher, but probably 1960's
Best setting: EF92 (or was it EF95 2-7 strap?)
Buy Date: 13/03/2020
Price paid: Embarrassed to tell
Tube location: Bottom of bigger box on top of the Win XP PC next to printer and sub woofer. Tube box not original but in Standard Electronics red/white box with shaky hand writing of seller from AK
Flavor: Subtle hints of tannins, blueberry, vanilla and a peat moss with a lingering burning finish            (tube runs HOT)
 
Where were I - never mind!
 
May 27, 2013 at 2:28 AM Post #1,388 of 13,432
Hahahaha I love it Mordy!
The extra peat I've found really adds a shimmer to the highs that isn't sibilant and yet still manages to add more micro detail to the vocals.
 
I received the 6AU6 to 6AK5 adapters from the eBay seller "happydiy998" this afternoon and immediately switched my jumpers and plugged in some 8425's.
I am NOT happy. All I got through my headphones was a mid level buzzing sound and if I cranked the volume to 90 I could faintly hear the music. I switched through several tubes, made sure things were seated correctly and still had the same effect with all of them.
I then checked the amp with a pair of Sylvania 6AU6WC's where I soldered pins 2+7 together and it works fine.
Now I'm very curious to see what reports come back from the others who have ordered these adapters.
 
I believe my MKII simply doesn't like triode tubes. The light buzzing I was experiencing in the right channel is not present with tubes on the 6AK5 setting and the few other EF91/92 compatible tubes I have were fine with their jumpers set.
This is pretty much fine with me because as has been noted, they had a tendency to compress the instruments together and had a general thinness to them that was unfavorable. Not a bad tube by any means but going back to the 6AU6 series tubes is more fun.
 
May 27, 2013 at 6:32 AM Post #1,389 of 13,432
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I have what I think are the stock tubes that came with the amp (bought this second hand), and a pair of rca black plate 5654s that came with it. I cant hear much difference between these two when it comes to the ultra-highs. Keep changing my mind on which is harsher.


Hi redrum42, I imagine your driver tubes are already on the "tubier" side and agree with Mordy that the 6H30P tubes can be the culprit. They sound hard, "glassy" if you wish. This describes them well also in a different way, as they are also quite revealing, more than the 6N6P tubes to my ears. Generally, the 6H30P-tubes are considered higher spec than the 6N6P-tubes. It really comes down to system matching in the end, even cables play their role. For 6N6P-tubes, older tubes are considered better than newer ones.
The end of the Cold War is often used as guide line to the last years yielding good Russian tubes. It ended 1991. However, the most important marker relevant for Soviet tube production seems to be the point when 1985 Mikhail Gorbachev became General Secretary of the Communist Party of the Soviet Union. He has not only liberalized the Soviet Union - 1985 glasnost ("openness"), 1987 perestroika ("re-organization") but also the tube production. This removed the strict government control of tube production. I would suggest to aim for a 1984 and to be safe maybe a 1983 or older tube.*
My favourite power tube is the 6N6P-IR but I haven't use the 6H30P-DR yet. R indicates a special low noise quality also seen in the pinnacle tube 6H30P-DR (where the cyrilllic H is also often written as the transliterated N). 6N6P-I and 6N6P-IR have only 500 hours guaranteed working hours due to high cathode current used, which could equal to a year of operation. But they may of course also work longer than that. My 6N6P-IR was produced 1974 and does not sound "glassy" as the 6H30P tubes do but a bit warmer, has deeper bass, larger stage and the treble is well extended but not harsh. The stage is the largest between all tubes I tried.
 
Now, the choice is yours. Enjoy the tube rolling.
May 27, 2013 at 9:28 AM Post #1,390 of 13,432
Hey guys i just received the sockets i put in the 6136 tubes i got the ef95 setting right  it doesnt work it is the ef 95 setting got any ideas
 
May 27, 2013 at 9:55 AM Post #1,391 of 13,432
Also received my other tubes 6ah6wa tried those doent work so maybe they got thing backwards the 6ak5 tubes on top and 6au6 on bottom of socket who knows and god knows i was diligent in explaining in detail to them what was needed for those sockets i will send them an email later today but right now im gone fishing .because im kind of p...... right now. but if you have any ideas or i did something wrong setting wise let me know thanks guys.
 
May 27, 2013 at 10:21 AM Post #1,392 of 13,432
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Hey guys i just received the sockets i put in the 6136 tubes i got the ef95 setting right  it doesnt work it is the ef 95 setting got any ideas


Hi Mikelap,
I was at one point not sure whether I set the jumpers correctly to EF95 or not :). So, as a reminder for everyone including myself, I drew up a schematic highlighting the setting. You could keep this as reference, might came handy at times.
 
 

 
May 27, 2013 at 11:52 AM Post #1,393 of 13,432
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Guys, If you have a heptode at hand. Make sure you try the EF95 setting after burn in. I haven't been using this for quite a while.
 
When I set this up today, I was quite surprised, to say the least. I really love it with my TS 6BE6.
 
After a little more listening and also comparing the 6BE6 to the TS 6485, I think it is now quite clear to me that is the setting. It is like a veil was lifted.
On my setup, with my gear, IMHO, this is better than the TS 6485. I can hear details clearer leading to a better holographic experience, there is more air, the bass is slightly lesser punchy but does go deeper, the stage is more organized. Everything just comes together. Simply put, it sounds of better quality. That's it for me :)
 
1.) Tung Sol 6BE6, EF95 jumper
2.) Tung Sol 6485, 2-7 strap
3.) GE 8425 6AU6A, 2-7 strap
 
Now you can shoot me :wink:
 
 
 
PS: I imagine the TS 6BE6 to work best with setups, which tend to a brighter or very neutral signature. These tubes have a natural, darker signature, which is rather, "round", very refined and true, not "hard and exciting".
 
Updated 24/05/2013

Hi A11.
 
Have been burning-in some Sylvania Gold  Brand  5750s on EF95 (minus 2,7) with 9 hour stretches and no problems...they sound amazing. Hope everyone gives this a try...Well discovered!!
 
May 27, 2013 at 3:07 PM Post #1,394 of 13,432
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Hi A11.
 
Have been burning-in some Sylvania Gold  Brand  5750s on EF95 (minus 2,7) with 9 hour stretches and no problems...they sound amazing. Hope everyone gives this a try...Well discovered!!

 
So for the 6BE6/5750, use EF95 setting with no 2-7 strap for optimal performance?
 
May 27, 2013 at 3:46 PM Post #1,395 of 13,432
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So for the 6BE6/5750, use EF95 setting with no 2-7 strap for optimal performance?

Hi mab.
 
Yep! Acapella 11 (see page 90) found there was no need for the strap, and that the sound IMPROVED - two for the price of one,even! And as I mentioned, I've experienced no problems so far - even after long burn-in sessions. What more could you ask for? These guys really are the business...
 

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