[gibosi]

  Hi 

I Need some help for buy the Voshkod 6ZH1P-EV for my LD MKII.
Could you tell me if these tubes or these are the same as the 6ZH1P-EV seen in this guide ?
Thanks,
 
Aurélien

 
Yes, they are the same.
 
I have purchased from this vendor:
 
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=130436695928&ssPageName=ADME:L:OC:US:3160
 
$3 US Dollars for a pair plus shipping.

 

[gibosi]

Received two adapters today: Loctal to 6CG7/6DJ8 and Octal to 6CG7/6DJ8. For me, these adapters offer two significant advantages over my 6SN7 to 12AU7 adapter.
 
First, I don't have to reconfigure my socket to run octals and loctals and this allows me to much more easily swap out a 6CG7 or an E88CC for a 6SN7, for example.
 
And second, I can use 12 volt Octals and Loctals simply by adjusting my external PS to 12.6 volts. This enables me to take advantage of the fact that the 12 volt versions are often significantly cheaper, for example, 12SN7 versus 6SN7. And similarly, if I want to run any 12A-7, again, all I have to do is increase the heater voltage.
 
With the arrival of the Loctal to 6CG7 adapter today, I was finally able to test out the 7AF7 and 7N7, and they both sound great!
 

 

[nsixtyfour]

Thank you gibosi,
I was not sure because I wondered why yenaudio sell them 36 $ 
Also, Can you tell me if there is a difference between the Mullard M8100 and the CV4010 ?

 

[mordy]

Hi G,
 
Sounds great - could you post link where to buy the adapters?

 

[gibosi]

I bought them from Ayumi Studio:

http://www.ebay.com/itm/261365150027?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1497.l2649

 

[gibosi]

1951 National Union 6SN7GT...
 
A quick comparison with the mouse ears Tung-Sol. The NU has more bass presence and punch, a very smooth, liquid midrange, but less air. As one reviewer wrote:  "A bit dark, beautiful sound". I still prefer the Tung Sol, but this is a very good tube that just might shine in an otherwise bright system.
 

 

[Nic Rhodes]

  I was not sure because I wondered why yenaudio sell them 36 $ 
Also, Can you tell me if there is a difference between the Mullard M8100 and the CV4010 ?

 
Technically there should be minor differences, in reality many are dual badged and the diffierences are not really worth bothering about. They are so close then the differences are mostly ignored anyway in the less pedantic times.

 

[Oskari]

 
Technically there should be minor differences, in reality many are dual badged and the diffierences are not really worth bothering about. They are so close then the differences are mostly ignored anyway in the less pedantic times.

 
Why should there be minor differences and what would those minor differences be?

 

[Nic Rhodes]

just the differences in the two spec sheets, the CV4010 earlier largely from 1957  (on my sheets but believe is the valves was 1948 originally) and the M8100 from 1960 revised 1963 on my copies. As I said earlier I don't see a difference personally between the two valves and neither did the makers with many cross marking of these valves but the spec sheets do show differences in the originals though very minor and not worh bothering about as I said earlier. It is not worth worrying about. The two are interchangeable for the coarse operation we have here as opposed to the high vibration / shock / noise environment they were often aimed at back in 1960.

 

[Oskari]

I think it is a single type (with the internal type code 59). The CV sheet tells what the government required and the other sheet what Mullard felt comfortable promising other customers.

 

[Nic Rhodes]

Either way it is largely irrelevant for use in LD. They both will work and appear to be the same in the LD.

 

[gibosi]

7N7 Loctal (Electrically equivalent to 6SN7)
 

 
 
From what I have read and seen, almost all the 7N7 were manufactured by Sylvania. The only other manufacturer I am aware of was National Union, and their tubes, with gray smoked glass are easily identified. So if you see a clear glass tube with a chrome top, it is almost certainly a Sylvania, regardless of how it is labeled. I have seen two variations, a tall bottle and a short bottle. However, I do not know how they differ.
 
While I don't have a 1950s short-bottle chrome-top Sylvania 6SN7GT, the reviews I have read suggest to me that the 7N7 is very similar, if not identical. This tube has a very good high end and a strong tight bass. Mids are more forward and aggressive than the mouse ears Tung-Sol, but in exchange, this tube has very good detail and imaging. These are often very cheap and an excellent buy.

 

[TrollDragon]

Well I found the schematic for the old console carcass I acquired a while back.
 
Going to repurpose some of this into a little 2W amp for headphone and speaker use. I am going to use one of my 5751's to replace the bad 12AX7 that was in it. It has two 6GW8 / ECL86 power tubes the 12AX7 was the driver and a 6CA4 / EZ81 rectifier.
 

Going to relocate the transformers and the AF board to a smaller chassis. Something nice to tinker with over the cold months.

 

[mordy]

Hi TD,
 
Any update on the power protection circuit so that you can use the LD amp with DC coupled amps?

 

[gibosi]

1945 RCA VT-231/6SN7GT with grey glass
 

 
This is one of my favorite tubes. It is simply grand and smooth, with good bass, an incredible midrange, and pretty good detail and highs. The tonality of this tube is just right. Vocals, piano, horns sound spot on, very musical. And then there is this huge spacious 3-D sound stage.
 
I have come to believe that the 6SN7 family is just as good as the 6DJ8 family of tubes, but different. The 6DJ8 is cooler with great detail. The 6SN7 is warmer with more musicality and a palpable 3-D soundstage. Both are excellent but again, they are different.
 
It appears to me that great detail and coolness go together. As the sound becomes warmer, the reverberation masks some of the lowest level details. But in exchange for the loss of some detail, the extra warmth adds more musicality and a spacious 3-D soundstage. So for the most part, the 6SN7 is not for detail freaks. But speaking for myself, musicality and a spacious soundstage are more desirable than ultimate detail.
 
Coming back to the RCA, I believe it strikes an exquisite balance between warmth and detail. And in my opinion, this belongs in the collection of everyone who wishes to explore the 6SN7 tubes. RCA manufactured this tube from 1942 through the mid 1950s, and the general consensus is that the 1940's production are the ones to get.
 
In conclusion, of the four 6SN7 -- CBS/Hytron, National Union, Tung-Sol "mouse ears" and the RCA -- I recommend the Tung Sol and the RCA as worthy additions to your collection. I have two more coming, another Tung Sol with round plates and black glass, and a Sylvania "Bad Boy". These have received very good reviews and I am looking forward to their arrival.