[Johnnysound]

  Is there any difference between 6J1P-EV, 6Ж1n-EB and 6ZH1P? From my eBay search, 6ZH1P is much more expensive. Also the price of 6J1P-EV varies a lot. Any recommendations?

I am not a tube "expert", but  those are the same basic tube,  the various  denominations come from different  translations of of the original cyrillic (russian) name.  Read Post # 8555 by mordy for a complete explanation.    My recommendation ?  the 6J1P  tubes are real cheap (lots of stocks) so  do not pay more than 5 dollars per tube,  try to get the oldest ones possible with "gold grids"... and buy at least 4, to have spares in case some are microphonic. 

 

[MIKELAP]

 

  You can try the Voshkods 6J1P-EV (6ZH1P) which are 5654 compatible.  In my opinion, very good sounding tubes.  See post 8569 

Is there any difference between 6J1P-EV, 6Ж1n-EB and 6ZH1P? From my eBay search, 6ZH1P is much more expensive. Also the price of 6J1P-EV varies a lot. Any recommendations?

 

[ToTje]

  Is there any difference between 6J1P-EV, 6Ж1n-EB and 6ZH1P? From my eBay search, 6ZH1P is much more expensive. Also the price of 6J1P-EV varies a lot. Any recommendations?

Hehehe I just asked the same thing a bit earlier: the only difference between them apparently is the price, nothing else.
Soms tubes actually come with all those names. I bought the tubes that are $3 a pair on eBay, and apparently they are exactly the same as the $36 a pair tubes.
 
If you look a bit further, you'll see that some tubes even have all those codes you mentioned.
 
However, try (if possible) to get tubes from before '83. Read the previous page in this topic if you want to know more. 

 

[ToTje]

 

Oh? So there actually is a difference? RF pentode vs rectifier?
 
Edit: I think these tubes must always have a combination of these codes, since very early in this topic others also say they're really the same thing.

 

[Artsi]

I haven't been active at all here. 

 
At last i got my own simple emission tube tester. Superior Instrument Co. TV-11. It needed just a little service and now it works like new and can test all my tubes. Since it is just emission tester, it's not very scientific or absolutely accurate. However there seems to be many suspicious tubes in my collection and one previously used 6DJ8 showed some flashing welding inside one triode. Even new tubes are not safe, one JJ ECC83 tube was very weak and triodes were far from matching ones. Won tube tester from USA ebay, and it uses 110v, so i needed step down transformer too. Better testers are just far too expensive. 

 

 

[Artsi]

Haven't been resting much with my diy amps. Here is phono preamp for MM cartridges. Followed this schematic http://www.hagtech.com/pdf/cornetoctal.pdf. Rectifier is 6X5 in my amp. Somehow this was rather tricky to make quiet. There is 2 6SL7s triodes doing their best to amplify signal in series. It is like little dot at max volume and more. Input in front and output from back to keep signal path as short as possible. Those GE 6SL7GT coinbases look fun.
 
Next week i should get 2 old Hammond Organ amplifiers. Around 35KG of some serious stuff. Main transformers from those push about 6A 5v, 10A 6.3v and to anode 415v-0-415v. Got those hammonds rather cheap from GB and there is 6 output transformers too. I need to buy more tubes like EL34, KT88, 5U4G and 5Z3 to make amplifiers with those transformers. So they are not primarily for headphones.

 

[Johnnysound]

   
I haven't been active at all here. 

 
At last i got my own simple emission tube tester. Superior Instrument Co. TV-11. It needed just a little service and now it works like new and can test all my tubes. Since it is just emission tester, it's not very scientific or absolutely accurate. However there seems to be many suspicious tubes in my collection and one previously used 6DJ8 showed some flashing welding inside one triode. Even new tubes are not safe, one JJ ECC83 tube was very weak and triodes were far from matching ones. Won tube tester from USA ebay, and it uses 110v, so i needed step down transformer too. Better testers are just far too expensive. 

 

Wow, very nice tester, congratulations.    In my "Tube 101"  self imposed course,  I always wondered why in the tube era there was no "standard"  technology  for testing tubes.  As a result, it is amazing to read that  vintage tube testers are quite  different from each other,  because  almost every single  brand employed its own design.   
 
 I understand that  "emission"   tests  the basic function  of the tube,   in other words its ability to convert volts to amperes with a fixed signal.  The number  will give an indication of  its life span, and  so you can detect  "bad"  tubes that are below the standard.  I also read  that this test  should be complemented with a "transconductance" test to give a more accurate idea, because "low emission" tubes should  be perfectly operational  if they have good transconductance values...and still have a long life span ahead.    What ?   Maybe there are many "endgame" 1945 Tung-Sol round plates for $ 5, because they tests "low"... low in emissions only  ? 
 
 In any case,   transconductance  (Gm) looks very relevant  in terms of SQ, because it measures the "ratio"  of  V to Ampere emission with a  variable input,  or the "efficiency" of the tube in real world conditions.  The higher, the better, and  this value  is obviously  important for  audio,  because high GM  translates into better S/N,  more gain,   and a linear current output.   A higher GM means less distortion between input and output ,  and this is what we want  in  an input tube, which deals with small voltages.     It is not by chance that the  Siemens C3g  have super high GM values, (4 times that of other tubes)  because the engineers decided that this parameter was necessary for low-noise, critical audio applications.      Continuing with my "course",  I discovered   that high GM was also introduced into tubes designed for radio or early computer applications,   to increase their performance and durability. .  The 6AU6 (GM¨= 4500)  was replaced in RF amplifiers by the 6AH6 (GM= 9000) with excellent results.  (The 6485 is  just a "computer grade" 6AH6 tube).   I have heard both,   and while the Mullard 6AU6 sounds quite good, have deep bass and a mellow, relaxed sound, the Tung-Sol 6485s are clearly above,in all terms...   

 

[Nic Rhodes]

I got interested in transconductance  (Gm) some 20+ years ago whilst experrimenting and came across some fun tubes. Some were well known with high price tags but others were not. Long known about were the 417a and 437 triodes and 7788 pentode (look that one up, Gm 50,000). However even when I looked at these there were good value variants like 5842 for the 417 (Gm 24,000), 3a/167m for the 437 and E810F / CV5809 for the 7788.
 
This started to lead me to other tubes like the 6688 / E180F (Gm 16,000) which appeared to me to be like the 404a / 5847 but just on a different base wiring and much cheaper then. On route I did lots of work with 5687, 7044, 7119,  E182CCs. My paths crossed with 12SX7GTs, 6BL7GT, 6BX7GTs, EC8010, 8556, EC8020, D3a, C3G, C3M etc and nowdays we also have access to Russian 6C45Pis. It was a great journey but I did learn theat my desire for high GM is not the magic path to audio bliss I thought it was but it thinking this way was the foundation of 20+ years of adiction Often some tubes came with some excellent spec (but not the best) that were being forgotton and went for cents / pennies like the excellent 6688 / E180F.....whilst the world used second rate Russian 6922 / E88CC into designs which were vastly inferior to the tubes the hobbiest had access to.

 

[rosgr63]

Hi Nic,
 
I too have discovered that the highest possible test scores don't mean audio bliss.
 
Some tubes of the same type but of different maker that don't test as strong may sound much better.
 
This is the tube magic.......
 
I am still learning been into headphone more than 40 years.

 

[Nic Rhodes]

It has got me thinking again, given the love for 6080 / 6AS7G as an output tube with a new PSU, has anyone tried the 6C33B Ulyanov made 'trawler valve'? [You recognise it with it the tripple nipples]. I know it is getting rarer now but technically it has always been a valve that look excellent for OTL / SE outputs.

 

[bbmiller]

  Hi Nic,
 
I too have discovered that the highest possible test scores don't mean audio bliss.
 
Some tubes of the same type but of different maker that don't test as strong may sound much better.
 
This is the tube magic.......
 
I am still learning been into headphone more than 40 years.

So were you looking at tubes in the 6SN7 family would you only look at what people have to say about type and brand and not look at this transconductance? And if you did look at transconductance is it always posted as GM and the datasheets order of their other ways to post transconductance other than GM figures?

 

[gibosi]

  It has got me thinking again, given the love for 6080 / 6AS7G as an output tube with a new PSU, has anyone tried the 6C33B Ulyanov made 'trawler valve'? [You recognise it with it the tripple nipples]. I know it is getting rarer now but technically it has always been a valve that look excellent for OTL / SE outputs.

 
The Eddie Current Zana Deux SE uses a pair of 6C33C-B....
 
http://www.eddiecurrent.com/Zanadeux.html

 

[i luvmusic 2]

 
Haven't been resting much with my diy amps. Here is phono preamp for MM cartridges. Followed this schematic http://www.hagtech.com/pdf/cornetoctal.pdf. Rectifier is 6X5 in my amp. Somehow this was rather tricky to make quiet. There is 2 6SL7s triodes doing their best to amplify signal in series. It is like little dot at max volume and more. Input in front and output from back to keep signal path as short as possible. Those GE 6SL7GT coinbases look fun.
 
Next week i should get 2 old Hammond Organ amplifiers. Around 35KG of some serious stuff. Main transformers from those push about 6A 5v, 10A 6.3v and to anode 415v-0-415v. Got those hammonds rather cheap from GB and there is 6 output transformers too. I need to buy more tubes like EL34, KT88, 5U4G and 5Z3 to make amplifiers with those transformers. So they are not primarily for headphones.

Very nice!Where did you get the power switch?
 
Thanks! 

 

[TrollDragon]

  Very nice!Where did you get the power switch?
 
Thanks! 

I found this really neat thing here...

 

[i luvmusic 2]

 

  Very nice!Where did you get the power switch?
 
Thanks! 

I found this really neat thing here...

I will check it out .THANK TD!