If NOS pre or power tubes became unavailable altogether, what new tubes would you buy?


Hey tuberollers, 

I'm curious to see what happens if there's a gun to your head, or more practically all NOS tubes disappear (dread).  What would you do with your line/pre stage and/or power stage?  

I have tried 5 different NOS 12AU7s and only 1 new 12AU7 in my preamp section (Cifte, RCA black plates (late 50s), Sylvanias, Baldwin organ tubes, Amperex 70s orange globes, and new Chinese stock Primaluna tubes).  In my power section, I have not tried any NOS tubes and 3 types of tubes (stock Chinese Primaluna EL34s, reissue Mullard EL34s, and reissue Gold Lion KT88s).  

Side note: I haven't ventured into NOS power tubes because of the cost and availability/scarcity.  I need 8 of them!

Without having tried anything else, I would be lost on new or reissue 12AU7s.  On the power tube side, I'd be just fine with either the reissue Mullard EL34s or the Gold Lion KT88s.  
128x128jbhiller

Hi tubed1,

The Chinese CV-181s measure 4" from top to bottom, not counting pins, plus almost 2" diameter at the bulge, vs. 2-1/2" for a typical straight-sided 6SN7. Pin-outs are identical (as they are with mil-spec US and European VT-231s and Russian 6H8Cs. There will be very minor variations in Mu, heater current, etc., amongst different brands, vintages and runs, but all are interchangeable. 

If you're handy with a soldering iron and have a solder pump and small vice, and are on a budget, restoring the Soviet-era 6H8C metal-based MELZ tubes can give you a sound right up there with the best of the Chinese tubes. I emphasise *metal* based because the later Bakelite based 6H8Cs aren't up to hi-fi snuff except as for splitters or maybe buffers: I wouldn't use a Bakelite one in a pre-amp or driver board for voltage amplification as they're noisy. Drawback to the metal-based MELZ tubes is the crappy solder they used to affix the pins to the wires coming out of the bottle. Heat up each pin, suck the old junk solder out, and flow in some good stuff. The base-to-glass glue was, fortunately, crappy, too. So if you want to go out you can de-solder all 8 pins, remove the base, and re-tin the leads coming from the bottle with some good stuff. It's time-consuming but after some practice you can do two tubes an hour's time.

Dear @cleeds :  """  everyone here should be entitled to their preference without you telling them that what they think does not matter.... """

that's exactly the whole " thing ". Preferences does not matters what it really mathers in a home audio system quality performance level is at what " distance " is that performance level of the way ALWAYS sounds the live MUSIC at near-field position. How much is far away or nearest to.

Of course that almost all are enttled to preferences even if those preferences are way different on what is in the recording or how the live MUSIC sounds ( full of colorations that were not in the recording but generated by the home audio system that through tube technology are even higher than with good today SS designs. This fact can't be changed for any one, like it or not. ).

You read in the other post here where I name it distortion sources that normally no one really talks about when we are talking of differences or evaluations  and the why's of those differences with different audio items that are critical especially when we are " testing " tube vs SS. We can add others as: low and high frequency oscillations levels, RFI and EMI interferences even if in an audio item both channels measures exactly the same in the normal specs and in all the ones I posted  in this thread.

There are something for sure: WHEN AN AUDIO SYSTEM PERFORMS WAY NEAR AS A LIVE MUSIC/RECORDING THERE IS NO WAY THAT ANY NORMAL AUDIOPHILE DISLIKE THAT QUALITY PERFORMANCE LEVELS IN FAVOR OF HIS PREFERENCES. 


"""  the way you insist things "MUST BE" just isn't. """


Why not?  am I wrong? why and where?  which or where are the mistakes from my part? how " things " should/must be?. I really want to know those answers with out " touching " preferences that as I posted ( again and again. ) it does not matters. MUSIC is the only subject that really matters.

Regards and enjoy the MUSIC not DISTORTIONS,
R.
Dear @rauliruegas
Disregarding our differences on tube v. s/s, and assuming no-one has built the "perfect" anything linking source to ear, I'd ask your opinion on what you regard as the closest to perfect you've heard, irregardless of price, and same question for one on a budget of, say, <$20,000 (give or take). Thanking you in advance,
deepee99
@rauliruegas --I'm not sure it is helpful to offer opinions about solid state v tube here. Many of us use these forums for information gathering.  If someone has a genuine interest in the title and subject of this thread, they will come to the thread and see lengthy discussion on different subjects. 

Also, I don't know why you dropped in just to knock the technology at its core. I'd have these same issues if a tube head dropped in to bag on solid state amps where the underlying discussion was about preferences within that technology. 


For what it's worth, the CV181 is NOT electrically equivalent to a 6SN7.  If you replace a 6SN7 with a CV181, it is bound to sound different, because the CV181 is operating at a different part of its performance envelope.  But people do it.  Have fun.

Raul, I think one reason that SS has taken a back seat to tubes at the higher end of the audiophile spectrum is that most of the SS gear to which we are exposed is built to a (low) price point, and if you look inside, you see crappy capacitors, bad layout, fail-safe circuit designs, for example using over-size electrolytic coupling capacitors, that assure mediocrity.  There are only a few SS products built purely for max performance with cost no object.  Perhaps you should start a thread to discuss this phenomenon and name some of the best SS products currently and previously available.