2. amps-preamps
  3. 1242175690

12AX7A and AT7 tubes

I recently changed all 8 power tubes (KT88) in my 8 year old Mac 2102 power amp. Used Gold Lion tubes as recommended by the majority of the Audiogon respondents to I thread I ran asking for KT88 advice. As suggested, these tubes really made a difference in the sound produced by the 2102. I am now thinking that maybe I should be replacing the 4-12AX7A and the 4-12AT7 tubes as well. I am pretty sure there is nothing mechanically wrong with the OEM tubes currently in the amp. but I am just interested in what this change would do for the sound, if anything. I have some questions about this move. First, do you think this is a worthwhile investment? Second, if this is a good move, what tubes do you recommend? Lastly, should I also change out these tubes in my C2200 preamp? If cost gets to be a factor, would you do the preamp first, last, or not at all? (As an aside, Upscale Audio recommends the Mullard CV4004 and CV4024. The CV4004 tubes are a whopping $80.00 each. Are they worth it?)
frepec
tpsonic
1,092 posts
 
Try the Shuguang triple mica 12ax7s (G9).These were discontinued,but still available.About $10-11/ea.
thorman
1,262 posts
 
I think it is most important to know which direction in sound you want to go with the new tubes...Many good tubes you could use but,would be nice to know if you want a warmer 12ax7/12at7 or a neutral sounding tube...Whole lot of difference between a Mullard and a Telefunken....Amperex Bugle Boys are somewhere in the middle....
lapierre
547 posts
 
Depends if your direction is wanting to extend highs and smoother midrange with very low noise floor. The 12AX7s will effect your sound the most compared to the KT88s.

I would change the tubes in the preamp after you complete the MC2102. I put more money in my preamp tubes than the my MC275 amps. If I had to do it over I would have increase my money into my MC275 tubes using long plates with big warm sound and lower noise.
mechans
3,048 posts
 
Tpsonic,
After telling you of these remarkablebtubes. Mind you not the absolute unamynous all time weorld best but a decent really cheap tube from the Sino conglomerate Shuguang, I can't souce them. So I ask where did you find them? To the original poster no other shu is worth your time it really must be their 12AX7C or 9th edition only. no more than $10 a tube. Mike Sanders of Quicksilver audio insisted that a new owner of the Triodes stick with the because he thought they great and voiced those amps using them. Our buddy Trelja was as skeptical as i a was which dictated extirpating the offensive terrible excuse for a real tube never mind a good one. It took quite a bit of convincing so just to make him stop harrsing me I said OK and paid 9 bucks for a pair of brand new 9th ed Sino branded Shuguang. And I would not be writing this novel if I wasn't floored by them. Shu has made more with the B or 8th for the biggest group of tube consumers the shreding electric guitar guys . It just didn't distort readily therefore useless for guitar and good for audio. Now they are gone.
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