@@liamguitars only one or two, but Caution! make sure that pop can shield doesn't short anything out. Most likely you don't even need the shield unless the tube is close to a transformer or other noisy component.

The Russian equipment Г807 (G807) is also great

@@ahmadathari3503 no the 6CG7 is a completely different tube (medium gain) compared to the high gain 12ax7. The only acceptable tubes to sub for the 12ax7 are the slightly lower gain 12at7 or the higher spec'd 7025.

@@tubelab194 thank for your answer, what ablout 12sl/sn7 instead of 12ax7 with converter socket?

@@ahmadathari3503 again it's a very different tube. And adapting from a larger octal tube down to a miniature 9pin is not practical. Going the other way, mini 9 pin to octal is fine structurally. The 12ax7 is a unique tube and should be replaced with 12ax7's. We should still have stock of some excellent vintage 12ax7's. Note if you sub a different tube in a phono preamp the EQ will be changed.

@@daviddabbs1234 completely different tubes, the 6n1p is a twin triode with medium mu (gain) and the 6n2p is a high gain twin triode that's so similar to a 12ax7, I call it a 6ax7. EV is the higher spec version, similar to the Western "mil spec" variants.

@@tubelab194 thank you for the information

@@cobar5342 Thanks, we don't have a tube collection, only the store inventory. We once were roasted by someone online for hording precious tubes. But nothing could be further from the truth, we sell everything we have available. However as inventories of quality vintage tubes head to zero, Charles has suggested we start reserving examples of some of the rarer types, the Sylvania 12SN7 "Bad Boys" for one - probably the best sounding preamp tube ever made - unfortunately not as robust as the later higher spec'd 6SN7GTA.

Good choice !...............this tube does even not have a barrier cathode issue ...performance will stay for decades wheb used correctly ........sound may even get better over time . With the stock version sounds marvelous , that's the right starting point to upgrade components, wiring, connectors and volume pot ...etc . Only a very good design will benefit from this , not a design with flaws to try to hide the flaws ... I even do not use RCA connectors .....straight out and in with Neotech 1220 OCC AG wiring , no selector switch or whatever , only a Duelund tinned copperfoil on the output , Preheating and post heating of the filaments ........RGN1064 mesh rectifiers . Shinkoh 2 watt resistors and A/B......Black Gate capacitors....and Lunfdagl chokes. Sockets mounted on rubber suspension and point to point wiring. Rhodium IEC inlet and switchable bypass for the fuse ( at your own risk ) Do not forget to bias the heater voltage above the ground potential; No plastic isolation on te caps , .........copper foil to replace the plastic foil. BG needs long hours before revealing their magic , unequaled by any other brand , voices come out totaly free out of space of the recording .......layers of instrumentsfloat in gthe air beside, higher or lower, closer or further away..all will have body and air arround them and be separated one from another.....microdynamics will appear and shine without false upfront presentation........you can not buy a preamp with the same musicality in commercial totaly overpriced preamps ! Good luck and happy building . PS : Quality silver RCA plugs /Quality solder (AN or WBT )....lining the inside of the chassis with CU foil/quality noval socket ( military nos - AG)......shield cable for heater wiring. ../ better volume pot than the usual Alps ...Etc ... You will be rewarde with a totaly and silent black background.for the music .......no noise even better than SS ...........and a dramaticaly expansion of the dynamics from micro to macro level.

@@frankgeeraerts6243 Yes , this one rewards a bit of attention to detail. I was almost startled about the dynamics in this one, I perceived some extra punch via this one for sure. I did not go with raised voltage on heaters, but I went with filtered and regulated DC for the heaters. I use that voltage also for nice quality Japanese relays for input switching. I need 4 inputs you see. I went with RCA sockets, of the KLE type, which is basically same style as WBT. I also have full shielding of the circuit beneath my 2mm copper base-plate and I have both steel and copper in the transformer and choke housing. Also mounted a stepped attenuator built on Seiden swith and Takman carbon film resistors. All inn all very happy with it, thus I ordered a set of spare tube, they also sounds wonderful in my Crack HPA.

@@RaviNewfarm Nice .........thank you for reply . I also heard some good things about the Crack ! KLE is great ! ( use them also ) Tackman carbon sounds very good without ruiniing the budget .....

@@dakata2416 almost anyway you can think of (that's safe), the only delicate part is the glass, the electronics are in a vacuum so the internal components basically stay in the same condition they were manufactured. We regularly run Sylvania tubes made in the 1930's and 40's and other than the pins needing a clean up they're basically brand new (if NOS - new old stock). Sometime soon we'll do an episode on this, but in general anywhere safe from breakage inside your house is good. If you have boxes great, make use of them and then store your boxes in a shallow cardboard tray. If you don't have a box, wrapped in a layer of mini bubble wrap with an elastic around it is good, and again in a shallow tray. The most important thing is to make sure that wherever your tray of tubes is stored they can't accidentally get broken.

@@tubelab194 what about environmental conditions?

@@dakata2416 normal household conditions are ideal. What would cause problems is if you live near salt water - in which case sealing the tubes in a ziplock would significantly reduce pin corrosion. We store our store inventory in an unheated garage in clear 16L bins and ziplocks and they're perfectly fine. Now don't take a tube at freezing and plug it directly into an amp, that would be asking for trouble, first bring it inside and give it time to reach room temp.

@@kwacz keep looking, it may just take some time to find someone who has a bunch of them AND will test them. Note all quality vintage tube sellers test and match. Or rewire a new octal socket for the 6K6 which is electrically equivalent with a different base.

@@tubelab194 all the major tube websites give you what they give you. No matched sets for nos. Only current production tubes have option for matched sets

Anyhow i put them in anyway and they sound fine. Just as good as the ones currently in there. No different. The radio is from 1942 so dont know if that matters. I dont know if they even did matched tubes back then.

Not practical, my recommendation would be to drive them with a tube output stage coupled with a multi tap output transformer. We actually have a complete headphone amp prototype that would be perfect, as the lowest tap is 8ohms. If you want to experience an OTL amp, I'd recommend thinking about higher impedance headphones. Large selection starting at 150 and 300 ohm. But first find the amp you want, then the headphones, that way you'll know for sure they're compatible. We're currently developing another Kit Headphone Amp and it should be a good match for 150/300 ohm cans.

@@tubelab194 thank you

Yes this is a nice linear tube, however lots of triodes have similar plate curves. And it doesn't matter what kind of circuit you run it in, you will always have distortion, maybe lower distortion, but it'll be there. We currently have a preamp in development and are running each section at 242vdc 8.5mA and it's working perfectly and sounds amazing (Voskhod 6N1P-EV).

I have three…

We haven't fully bench tested and spec'd the new pre yet, but almost certainly it would be a good match. Input impedance will be 100k ohm and every modern dac I've ever looked at will have very low output impedance (I've seen as low as 32ohm!), so the input side should be no (zero) problem. And your AVR has a reasonable input impedance of 42K ohm and the new pre will have an output impedance of less than 1k so again a good match. The output impedance is the one spec that needs proper bench testing. One of our goals for our new affordable Kit Preamp, was to give people a good pre to use as a buffer and given the sonics, I think this will make an amazing main system Preamp or Buffer.

​@@tubelab194 How does this sonically sound vs your current Universal 6or12SN7 Dual Mono PreAmp? Any comparison you can offer - even subjectively between the 3 pre-amps putting cost aside?

With all due respect, listening, I mean really listening is a far more valuable tool than any sweep. Now that said, we do sweep our Kit designs during development and it can provide valuable information. But ultimately critical listening is far more useful in tube rolling and amp design, in our experience. I was an audiophile in the 70's when all we wanted was the specifications and the sweeps, and our equipment had the life sucked out of it by designers relying on what their screens were saying, instead of what their ears were hearing - never again.

Because they're much simpler, development time is greatly reduced and the circuit is already finalized (2 weeks start to finish). PCB's are currently being designed and will be ordered next week and take about 10 days to get here, by then the parts we're missing should also be in. So maybe ready for test builders in 6-8 weeks.

No and yes, the 6N6P is a unique Soviet tube, with only a couple of factories making them. However the tube is one of the best twin triodes ever made, so you really would never have a reason to roll it out. Which means tube rolling is concentrated on just one voltage gain tube. You could own 4 or more affordable tubes and dial in your sound depending on what you're looking for.

Modern gear generally doesn't include tone controls, the thinking being they will degrade the signal path and they're mostly not needed anymore. If you have quality source material and a good well balanced system you shouldn't really need to adjust the EQ. Back in the day, when I was a wanna be audiophile (1970's), many people ran graphic equalizers, our equipment just wasn't that great sounding - in particular our speakers sucked. But today if you play digital files, you can easily bring up a graphic equalizer in your software. If you play vinyl, then you are limited to adding a physical unit in the signal path. Simply upgrading your existing system may completely eliminate your need to apply EQ.

@@tubelab194 Thanks much for that clear and informative explanation .

Ah interesting, now is that 4vrms or 4vpp? Many dac chips I've looked at use a vpp measurement. The only time we work with balanced circuits is with our Otari r2r decks and even then we drop one phase and wire custom unbalanced interconnects.

@@tubelab194 I don't know how those priced above $1K do it, but it's Vrms for all those I bought in the past 5 years, in the mainstream category.