6N2, 6N6, 6N11 - Please help a beginner! (long)

[paul_peraic]

So I guess there are no Guru's here that can give me an answer on this

[Globulator]

Originally Posted by fdegrove

I still have to come across a single Russian tube I'd consider exceptional.
Mediocre at best but gladly they made stuff we did not have in Europe.
Which is nice but nothing more.

Then you have been missing out! The GU50 and the 6N2 are exceptional tubes to listen to in my experience. Can't imagine how dull and expensive life would be without them

[piano3]

I have never had a Russian tube that disappointed me and I have used many different types.

[Blaireau]

Right! Russian tubes are excellent for many applications, and their price remains decent, compared with some european or US tubes!...

[Bob Richards]

One of my best friends, Matt Kamna, is a tube Guru (here in Portland Oregon USA). I've learned a lot from him, but also largely from my own research. I don't doubt that certain Russian tubes are technically at least competitive with the best, but I tend to be a pragmatist about it. I like to use tubes that are for all practical purposes just as good, but are much more available. I'm designing and building a Line Level preamp right now using 6922's and a 6SN7. My poweramp has 6SN7's driving EL34's. My guitar amp has an EF86 (JJ version actually) front end, 12AX7 for distortion generation, 6SN7's in the tone control circuit (4 section James (passive)) and EL34's. What matters every bit as much in my opinion, is the rest of the circuit. I've got mu follower plate loads (effectively a constant current source with a low-Z output) on any voltage gain stages so the tube will be most linear and with substantially improved powersupply hum and noise rejection (plus if the tube shorts out the current is limited so minimal smoke). In my self biased (as opposed to direct coupled) follower stages of my hi-fi preamp, I'm using IXYS brand current "sinks", again for maximum linearity, PSRR and safety. I also use 0.1uF polyprop caps for power supply bypass right at each tubes B+ and B- with it's own ground return. Grounding is where most people blow it. I return everything to a common "star ground center" where the circuit ground ties to the chassis ground (must be done in only one place), but I also connect up the primary power supply stuff separately first (PT center tap to primary filter caps, and then run a wire from that junction to the star center, to minimize current surges in the star center stack. Each section of circuitry has it's own ground return wire also. I use a bolt with about 25 lugs on it for the star center. If you do the grounding right, I've found that I don't need to have actively regulated power supplies, to get very acceptable hum levels. I generally do a two section RCRC, and I'm there. The current sources and sinks make this particularly practical. I rectify and filter the 6.3 volt filament supply, but again if you were to use a voltage regulator as many do for this, you burn up roughly half the power in the regulator, so now you need a much more hefty transformer just for the filaments. All AC carrying wires, Including DC filament wires (since they will have some ripple and high current) should be twisted tightly so the electromagnetic field they emit will be largely self cancelling. My friend Matt loves the Russian GM70 output tubes and the 6C45. To see what I've done with non-Russian tubes, see my website for more info. Bob's Website

[Tony]

this is my latest preamp based on the 6H23 tubes....