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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.  
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Showing 7 responses by lowrider57

lowrider57's avatar
lowrider57
5,397 posts
 
Are there any decent Russian small signal tubes that have the characteristics of NOS? Many 6SN7 type NOS become microphonic and are very noticable in preamps.
lowrider57's avatar
lowrider57
5,397 posts
 
Yes deepee, I'm getting turned off by what could be an interesting thread. Imagine the poor OP.
lowrider57's avatar
lowrider57
5,397 posts
 
@tubegroover ,
So far as new tubes, I really like the Sophia Electric 6SN7 tubes which I'm sure are Chinese sourced. Only problem is longevity but they are both linear and extended
It seems like new production 6SN7's, e.g.; Tung Sol, EH, all have extended highs and no warmth.
Regarding the sonics of the Sophia Electric 6SN7, is there an NOS that you could compare it to?

Have you ever tried the Psvane CV181-TII (6SN7)?
lowrider57's avatar
lowrider57
5,397 posts
 
Thanks, @tubegroover . I looked up the Sophia Electric 6SN7's and they are compared to a VT-231, so that would make them closer in sonics to NOS. The fact that you are using them in your Modwright/Oppo tells me they must sound more enjoyable than the other new production tubes.

Although they are not inexpensive...hope they last longer than NOS 6SN7's.
lowrider57's avatar
lowrider57
5,397 posts
 
@almarg , I remember your issue with the Sophia's and maybe they can't tolerate voltage levels in some amps. Tubegroover is having good results in a low current device; a CDP.
Which makes me wonder if the Sophia's would hold up in a single gain stage preamp. 
Al, although the high sensitivity of your speakers reveal the issue with hum, the specs of these tubes don't lie.

lowrider57's avatar
lowrider57
5,397 posts
 
@almarg , thanks for the additional info. It’s good to know that heater-to-cathode leakage is not influenced by voltage, since I’m considering trying the Sophia’s in my preamp.

Al, although the high sensitivity of your speakers reveal the issue with hum, the specs of these tubes don’t lie.
Specs is the wrong term; I should have stated "measurements" since you knew about Ralph’s criteria in this area. I did look at the GE datasheet and saw that Sophia was comparing their tube to a well known NOS tube’s specs. To be honest, I never heard of heater-to-cathode leakage until your findings.
lowrider57's avatar
lowrider57
5,397 posts
 
tubegroover, that's a serious problem that Sophia has not addressed.

I started a thread a few weeks ago where I brought up the subject of NOS 6SN7's becoming microphonic. I don't like the sterile sound of the new production tubes I've heard in the preamp stage, so I would like to hear the Sophia's.
I will heed your warning, thanks.
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