[jaywillin]

Quote:

 
Haven't really looked for any books, so if you find something, please let us know.
 
In the meantime, these might be helpful:
 
How Vacuum Tubes Work
by Eric Barbour
 
http://www.vacuumtubes.net/How_Vacuum_Tubes_Work.htm
 
Pentodes connected as Triodes
by Tom Schlangen
 
http://www.kaponk.com/~yanyong/ETF06TS.pdf
 
 

 
Quote:

For accuracy and presenting the true engineering also  specs. of tubes try to obtain  RCA tube manuals-Mullard  tube manuals-Osram-  Phillips-Mazda Also The Radio Tube-Vade-Mecum-1950s onward  especially- Radio Valve[tube] Data-- [ Wireless World-AKA-Electronics World.] Characteristics of 7000 tubes/6/7/8editions. While specs of tubes can be downloaded from the Web. It is much better to buy an old engineering manual as it  contains things like -inter-electrode capacitance-output at a set plate current/grid bias. etc and equivalents which is a lot easier to look through than keeping it on your PC. 

thanks guys, plenty of stuff to get me started, plus the stuff here on head fi
, i'll keep looking and reading !

 

[gibosi]

Quote:

Using the cutter posted some days ago by Gibosi, is safe to put the cutting wheel against the glass ?
 
Or is better stay a little bit far ( for example 1 millimeter ) from it ? It's first time that i will do...

 
Quote:

Personnally  i was tempted to use a cutting wheel also but like gibosi said there easy to cut with cutters and what remains about 2 millimeters  i file down with a small file being careful not to touch the other pins close by and after put electrical tape over the 2 pins you just filed down .

 
I posted a picture of some flush cutters, so I am assuming that this is what Iron58p is using, and not a Dremel-type tool. And as English is not his first language, my guess is that "cutting wheel" means the cutting blades of the flush cutters.....
 
And as Audiofanboy suggests, covering the pin stubs with some electrical tape is a very cheap and easy way to protect against inadvertantly shorting something out.

 

[Iron58p]

Quote:

 
 
I posted a picture of some flush cutters, so I am assuming that this is what Iron58p is using, and not a Dremel-type tool. And as English is not his first language, my guess is that "cutting wheel" means the cutting blades of the flush cutters.....
 
And as Audiofanboy suggests, covering the pin stubs with some electrical tape is a very cheap and easy way to protect against inadvertantly shorting something out.

 
I confirm that i have ordered Pro'Skit[size=x-small] 8PK-30D, but until not is not dispached, so i can't tell anything, i think will be perfect for the use !![/size]
 
[size=x-small]And today i have made another order, i'm reading review on this post and i want to test some tubes ( if and when will arrive

 ).[/size]
 
[size=x-small][size=x-small]2 Sylvania 6dt6
2 RCA 6dt6a
2 Sylvania 6hz6 [/size][/size]
 
[size=x-small][size=x-small]Gibosi, my italian/english is perfect !!

[/size][/size]

 

[Oskari]

Quote:

The text indicates that this tube is manufactured by 日本ビクター株式会社 which translates to the Victor Company of Japan. ... Anyway, these don't look anything like any RCA I have ever seen, and they don't look like the few pictures of Matsushta 6AV6 I have seen. So until I learn different, these are JVC 6AV6.

 
That's a Matsush¡ta tube. "Mark of the dog only with Matsush¡ta made ​​JVC." (Dog = Nipper.)
 
Finding good enough photos that show the tube from all relevant angles is difficult but I must put my money on Toshiba.
 

1. http://vintageaudiotube.blogspot.fi/2011/10/toshiba-6av6.html

 
Note the octagon as well as the construction.

 

[gibosi]

Quote:

 
That's a Matsush¡ta tube. "Mark of the dog only with Matsush¡ta made ​​JVC." (Dog = Nipper.)
 
Finding good enough photos that show the tube from all relevant angles is difficult but I must put my money on Toshiba.
 

1. http://vintageaudiotube.blogspot.fi/2011/10/toshiba-6av6.html

 
Note the octagon as well as the construction.

 
First I want to say that your internet sleuthing ability is second to none!
 
And I have to agree with you.... Even though the JVC tube looks to be the same, the Toshiba is a dead ringer. Further, we have quite a bit of evidence to suggest that Toshiba was a major player in the production of tubes for the international export market.
 
The text states that Matushta manufactured the JVC tube, but the picture of the Matushta was so poor that I could not determine if the two tubes were the same. And I have to admit that I was a bit stumped by "mark of the dog" (犬のマーク) as it also means "not very good". I didn't catch the Nipper connection.... lol

 

[Oskari]

Quote:

First I want to say that your internet sleuthing ability is second to none!

 
Thanks (but I must admit that's the first hit I get with toshiba 6av6)! 

 

[Advil]

anyone using an MKIII with q701s?
 
i have a little dot II++ and kind of want to upgrade but idk if it's worth the money. if i upgrade i can use my old tubes (mullard 161's) with it but i'm kind of doubting that it's worth 350 bucks

 

[gibosi]

Quote:

anyone using an MKIII with q701s?
 
i have a little dot II++ and kind of want to upgrade but idk if it's worth the money. if i upgrade i can use my old tubes (mullard 161's) with it but i'm kind of doubting that it's worth 350 bucks

 
I have no experience with the q701 or the Little Dot II++, so I don't have any opinion.... But I am curious. What would you hope to gain by getting the LD III?

 

[Advil]

Quote:

 
I have no experience with the q701 or the Little Dot II++, so I don't have any opinion.... But I am curious. What would you hope to gain by getting the LD III?

I was hoping to warm up the cans a little bit and maybe bring out more of the low end. They're very, very analytical and I like that but sometimes it's a bit overwhelming.

 

[gibosi]

Quote:

I was hoping to warm up the cans a little bit and maybe bring out more of the low end. They're very, very analytical and I like that but sometimes it's a bit overwhelming.

 
Is it possible to run the same driver tubes in the LD II++ as in the LDIII? That is, can you currently run EF91, EF92 and EF95? If so, it seems to me that you should be able to add more warmth and bass emphasis simply by rolling some different driver tubes....

 

[kvtaco17]

The q701 is a 62 Ohm can... the MKIII puts out 300 mW @ 120 ohm  and 100 mW @ 32 ohm... the 1+ puts 300mW @ 120 ohm and  800mW @ 32 ohms... the 1+ will probably put more current into the q701 then the MKIII will... not sure though I sold my q701 long before I got the little dot 1+

 

[Advil]

Quote:

 
Is it possible to run the same driver tubes in the LD II++ as in the LDIII? That is, can you currently run EF91, EF92 and EF95? If so, it seems to me that you should be able to add more warmth and bass emphasis simply by rolling some different driver tubes....

 
yeah the II++ uses EF92 and the III can accept those if i understand correctly.
Quote:

The q701 is a 62 Ohm can... the MKIII puts out 300 mW @ 120 ohm  and 100 mW @ 32 ohm... the 1+ puts 300mW @ 120 ohm and  800mW @ 32 ohms... the 1+ will probably put more current into the q701 then the MKIII will... not sure thoughh I sold my q701 long before I got the little dot 1+

 
That would be interesting and convenient since it's so cheap. I can google around and see peoples impressions of this.

 

[gibosi]

Quote:

 
yeah the II++ uses EF92 and the III can accept those if i understand correctly.

 
So the II++ cannot use EF95? If so, I think it may well be worth while to get a newer LD, one that can use both EF95 and EF92 tubes.
 
And I have LD1+, and I am very pleased with it, especially for the price. The 1+ also allows you to roll op amps as well as tubes, so a lot of flexibility for the money. And I believe that kvtaco17 also has the 1+.

 

[kvtaco17]

Quote:

 
So the II++ cannot use EF95? If so, I think it may well be worth while to get a newer LD, one that can use both EF95 and EF92 tubes.
 
And I have LD1+, and I am very pleased with it, especially for the price. The 1+ also allows you to roll op amps as well as tubes, so a lot of flexibility for the money. And I believe that kvtaco17 also has the 1+.

I do have a 1+ in my collection, I use it a ton!

 

[mordy]

Hi Acapella 11,
 
Some time back you asked me if I had evaluated different power tubes that I had planned to do. I finally gathered up the mental energy to check out four different types that I have, all from the Novosibirsk factory. Driver tubes were the RCA DTox tubes in 1/7 strapping.
 
This task is akin to evaluating Coca Cola cans for taste from different bottling companies. Basically it is all very similar, but each bottling plant has a different water supply and ingredients from different places, and the soda tastes slightly different. In listening to these double triode tubes, I felt that it helped to have honed my ears on listening to heptodes, becoming aware of subtle differences.
 
 
The first power tube is a 6N6P from October 1975. The overall sound is pleasant, but the bass is soft and lacking in punch, slam and attack. The mid range tends towards the cool side. The highs are OK but too sharp. Details are good, but this tube is lacking in excitement and listening satisfaction, mainly because the macro dynamics are somewhat anemic.

 
 
The next power tube is the 6N6P with gold grid from October 1978. In comparison to the 6N6P above, it has much stronger and better defined bass with very good slam and attack. The mid range is sweet, and the upper range is very good.  There is a coherent musical presentation and very good instrument separation. (BTW, GE invented the gold grid. It is found in their long life 5 star tubes. The amount of gold is minuscule, and I don't think that the price of the tube is effected by the changing  price of gold - lol).

 
 
The next tube is the OEM 6N6Pi from June 1984 that came with the amp. Overall sweet and fairly detailed. Bass is good but lacking real heft and punch. The tube is lacking in treble detail and the treble is on the shrill side. Better than the 6N6P, but not the ultimate.
It has been said that the 6N6Pi is rated for 500 hours of service, and the other variants for 3000 hours. So far, none of these tubes have given up, and my guess is that those service hours are rated for a harsh environment in a MIG jet or military vehicle. Looking at the saucer getter, it is obvious that the tube was put together by a left handed person in their forties, and that you need to tilt your head towards the right to get the full listening experience.

 
 
Lastly, the mighty 6N6P-IR tube from May 1983 with smoked glass. These tubes are the best in this group, with real effortless punch, slam and attack in the bass, and top notch mid and upper ranges. These tubes bring additional clarity to the sound presentation with instruments standing out better in the sound stage.

 
In summary, the least desirable of the four types is the 6N6P and 6N6Pi. Then follows the 6N6P gold grid and the winner 6N6P-IR. The main easily noticeable difference between the tubes is how the bass is presented; the other differences described are there but more subtle.
 
The combination RCA 6DT6 (DTox) and 6N6P-IR is just plain intoxicating.....