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6sn7 brand

Hello everybody,
I need help:
I'm looking for 6sn7 tubes for Aikido. I usually listen Pink Floyd, Dire Straits, Miles Davis.
I want: very good bandwidth, bass, detail and soundstage.

Which is the best brand for this characteristics?

SOVTEK
GOLDEN DRAGON
ELETTRO HARMONIX
TUNG SOL
SOVTEK
SHUGUANG

Thank you
Paolo
 
I don't think that you can just say buy the XXX brand and you will be happy. There are going to be differences in sonics as a result of the brand and type of caps, and resistors. Another factor could very well be the amplifier of choice as well as speakers.

Without starting WWIII here I would suggest trying different tubes in your input stage. My personal belief it that the input usually is the factor in sonic differences.

I like 5692 for jazz, GE 6SN7GTB's or Sylvania chrome top 6SN7GTA's for rock.

I am also very fond of a Russian Military nickle base 6SN7 version 1578 ebay reference # 250193341846

The 1578 is my very favorite tube for any listening. It is superior in my opinion to my 5692's.

The Russian tubes that I have listened to have zero noise in ANY line stage I've used them in. I cannot say this for some of the NOS american tubes I have.
 

kevinkr

Administrator
Paid Member
You'll just have to try a bunch, without knowing the specifics of your system and your own preferences it is hard to give advice.

In my system, almost without exception I prefer the Sylvania 6SN7GTA/GTB depending on location.

I've yet to get my hands on a pair of 1578, but I have heard very good things about them from a variety of sources.
 
I have a big box of 6SN7s... I buy them untested and sort them out later. I don't have golden ears, so I'll stick to the noise issues mainly, and let the others comment on the sound. I can give burnedfingers a +1 on the US tubes... I think that the good ones are getting scarce, and many of the older bottles (used or NOS) I own have a bit of ring, and a few have some issues with hum from the heaters, depending on how sensitive the circuit is to that sort of thing... I seem to remember the Tung-Sols working out best as far as noise, but I tend to like the Sylvania in terms of sound, but it varies so much from one to the sent. I have not tried the Soviet versions in a while, but I remember them being fairly neutral and even... not super exciting, but not in any way detrimental that I can recall. So like kevinkr said, get a bunch and try them out.
 
I don't have golden ears, so I'll stick to the noise issues mainly, and let the others comment on the sound. I can give burnedfingers a +1 on the US tubes... I think that the good ones are getting scarce, and many of the older bottles (used or NOS) I own have a bit of ring,

I have boxes of 6SN7's that I managed to buy over the last few years. Some are new never used NOS tubes and some have a service history. I don't have golden ears either but have formed the opinion that the better circuits show less effects of tube rolling than some of the others. Microphonics is an important factor in 6SN7 choices also. I have noticed even the cheap Soviet
tubes are NOT microphonic at all. Like I mentioned earlier the military 1578 nickle based tube with the 1578 marked on the glass is the one to buy. This tube will clearly tromp my best 5692
red base RCA's.

Yes, some of the hum issues of the US tubes will drive you nuts but on the other hand you will only hear the slight hum when you have your head right next to the speaker.

I would however steer clear of the coin based 6SN7 tubes as all I have tried are total junk for audio but suitable for a TV set.
 

kevinkr

Administrator
Paid Member
I heat with dc in almost all of my designs and in those where I don't I generally elevate the filament supply well above the voltage on the cathode. I've never had a hum problem with these tubes even with speaker systems in the >100dB efficiency range.

I haven't found any 6SN7GT/GTA/GTB to be particularly microphonic compared to any other tube I have evaluated, and I used a lot of them commercially and my current SE and PP 300B amplifiers use them as well. My previous SRPP, differential SRPP and cross-coupled inverter based line stages used them as well, and again no particular problem with microphonics, so I am not sure why my experience differs all that much from other posters here.

It isn't that they aren't microphonic at all, just that they don't seem worse than any other particular type. (I'm used to dealing with DHTs and they are far more microphonic in general. Yeah 5842 and D3A are less microphonic - a good thing since they have much more gain..)

I have GE, RCA, Sylvania, Tungsol, Brimar, and Russian ones of various vintages, but I really do prefer the Sylvania 6SN7 and Brimars over the others I have mentioned. I also have red and black base 5692 which are over-rated imo.

6SN7 are very easy to find on eBay and the Sylvanias are very reasonably priced compared to say the Tungsol which have a mystique that pushes their prices way uppppp.

My only advice in terms of the issues raised would be to heat with dc and elevate the filament supplies, and choose the least microphonic devices on hand if you have a problem. I haven't tried any of the current crop.

IMHO Still one of the very best sounding medium mu triodes in existence for voltage amplifier applications.

YMMV...
 
DC heater life

DC on the heaters does have a theoretical impact on life, but in receiving tubes, the effect is negligible. What happens with DC flowing through tungsten wire is that the metal shifts at the crystal boundaries which can cause the wire to eventually get thinner, leading to a hot spot, where it evaporates faster than normal. However, this is only a measurable effect where tungsten filaments are used until they burn-out, such as in light bulbs or in huge transmitting tubes.

In receiving tubes built since the mid-1950s, the oxide cathode will wear-out sooner than the filament will burn-out (except for defectively-made tubes or ones subjected to extreme surge currents). In all my tube research, I've never come across reports of DC causing life failures, except for the very large pure-tungsten transmitting tubes.

- John Atwood
 

7N7

Member
2003-01-18 10:43 pm
England
For DC heaters, it is wise to use a current-regulated supply since this removes the thermal shock on start-up.

As for microphony on 6SN7s, I recall having one or two that seemed that way; then I learned that the amplifier was oscillating at over 2MHz. Fitting larger grid stoppers solved both the problems. It's also a good idea to by-pass the heater supplies - at the valve base with a couple of cheap ceramic capacitors, direct to chassis, as recommended by RCA in the 955 data sheet.

Sorry a bit off-topic, but the only valve I ever had that had a "sound" was the E182CC, and the sound was rather nasty.

7N7
 
For choice of 6SN7, you certainly have read about trying a bunch of them. I'll vouch for that method. You could buy older, used tubes at flea markets or hamfests, or even Ebay. Find those that you like best, then go for NOS tubes of those types.

In my own system which gets used for classical, rock, folk, new age, etc. I have found that I prefer TungSol 6SN7GTB on the input and Sylvania 6SN7GTA on the output. Once, I found this combo through trial and error, I ensured that I purchased a second set for the time when my current ones give-up the ghost. By the way, none of these tubes were NOS, all were purchased from Ebay as "used, test good" or something similar.

Charlie