2. amps-preamps
  3. 183518-179778

Tubes for a pre stage... matched NEW or unmatched identical NOS?

I have this question for so long:

On a integrated amplifier that uses a pair of 12au7 tubes (or alternatives) on the preamp section (Rogue Sphinx, for example) what is best option:
a) to have an unmached unbalanced pair of identical NOS tubes
b) to have of matched balanced pair of modern tubes
c) to have balanced 12au7 tubes no matter if they are matching

Once asked JJ why they didn’t offer matched 12au7 type of tubes and the answer was the it is irrelevant for the kind of use they are intended in audio circuitry. Is this right?

My question only makes sense when forced to keep tube-rolling costs down (or tube substitution when the stock ones fail) because the obvious and better choice is matched NOS, like those from Amperex or Mullard.

audiofilo123
thecarpathian
4,185 posts
 

You guys like the cleartops??

Couldn't get them out of my pre fast enough. Way too bright in my system.

 

jjss49's avatar
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jjss49
6,612 posts
 

i agree that clear tops can be a little tizzy... regular top getter rca’s seem a touch smoother

as usual, tubes, like anything else in a good system, is subject to synergies (or lack thereof) and the taste of the listener

ieales's avatar
ieales
1,201 posts
 

I'm curious if the clear tops were a cost saving measure? Definitely simpler construction.

Perhaps a thinner glass.

Anyone run them for 24 hours on heater only before listening?

vthokie83
675 posts
 

Certainly all tubes are subject to system matching. My amp tends to run a little laid back, so the extra detail from the clear tops was welcome. Yes my Amperex and Philips tubes best the clear tops…..but now we’re into $200 to $600 for a pair of tubes, and not $40

Another surprise, early to mid 80s 6N23P Russian tubes (Rocket logo)

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