Chosing Tubes ? 12AX7/12AU7/EL34

tapeshc

Just got my Jolida 1000A integrated amplifier rated at 100W/ch.

Can you guys please help choose some good tubes.

12AX7 - 2 Should they be matched pair ?
12AU7 - 2 Should they be matched pair ?
EL34 - 8

Also what these pre-amp tubes 12AX7 and 12AU7 do, I mean whats their purpose in pre-amp stage.

Also if you know any other source for purchasing tubes other than thetubestore.com

Thanks

Tapesh

organ

tapesh,
What kind of sound are you trying to get in your system? Are you trying to get a more neutral or romantic/vintage sound?

If you want neutral, here's what sounds neutral to me...
12AX7: Ei ECC83, Sovtek 12AX7 or 5751.
12AU7: RFT ECC83, Electro Harmonix 12AU7EH
EL-34: Electro Harmonix 6CA7 (Very good sounding), Electro Harmonix EL34 (very smooth but lacking bass and dynamics), JJ E34L (Probably my least favorite).

For a warmer sound:
12AX7: Svetlana 12AX7
12AU7: Mullard ECC82
EL-34: Svetlana EL34 (Awesome tubes)

Since you didn't ask about rectifier tubes, I'm guessing your int is using SS rectification?

The purpose of the tubes? I think your amp is a push-pull design, 2 EL-34 for the +ve wave and another 2 for the -ve. The 12AU7 is most likely controlling the gain that goes to the 12AX7 which splits the +ve and -ve parts of the sine wave and sends them to the appropriate power tubes (EL34).

Anoter great place to buy tubs is www.triodeelectronics.com

So when are we going to see a review and pics of your new toy?

Maurice

organ

Forgot to answer your other question...The 12AX7 and U7 doesn't need to be matched pairs. The EL-34 HAVE to be matched. For more info on this, check out the FAQ section of thetubestore.com What tubes did your int ship with?

Maurice

HBombToo

Originally posted by organ
Forgot to answer your other question...The 12AX7 and U7 doesn't need to be matched pairs.
Maurice

Maurice I mean no disrespect but I do not agree.

Think about it this way:

1.) if the two grid circuits don't match then two power supplies must be used. All tubes should be matched!

I'll edit from here:D

Twin

organ

Hbomb,
Thats what I thought too. But to tell you the truth, I can't hear the difference with unmatched pre amp tubes. The set I'm using right now is unmatched. Small signal tubes demand a lot less power from the trannies.

The tubestore and triodeelectronics both tell you that you don't need to match small signal tubes but will do so at an additional charge. The tubes I got from triodeelectronics.com are matched but all the ones from thetubestore aren't. I had to pay extra for the matched sets. All my power tubes are matched quads.

I think that when using a set of pre amp tubes, all you really have to do is make sure the two, four, etc tubes came from the same factory and made at the same date. This ensures close tollerance levels.

Back in the days when tubes were everywhere, all tube companies didn't bother testing pre amp tubes and allowed power tubes to have a tollerance difference of 20% when you need a pair, quad, etc:eek: . That's much higher compared to the 5% we get today.

I understand why you need a matched set of power tubes though. Matched power tubes give the trannies less stress and you won't get any that hog too much current from the others.

Maurice

organ

****, I just took a look at your question again. Are you talking about matching brands or grid voltage/current? On my answer for the previous post, I was talking about matching brands of 12AU7 and X7 not grid voltage. I think I should've made that clear on my response to Tapesh.

Maurice

madmax

My next el34's will be chinese shuguang brand tubes. Should sound really sweet but should be somewhat loose on the bass. I like it a little loose though. From my understanding the power tubes must be matched in some circuits to prevent premature destruction. If you can adjust the bias on each one it doesn't matter as far as destruction goes. Do you need to match for better sound? I can't tell but certainly it can't hurt. I don't think many match preamp tubes but again, it can't hurt. (except the wallet) Even if you match the main electrical parameters it doesn't mean they will sound the same. Also, they may age differently anyway. The cool thing is you can listen and make a decision. Perfection isn't always the key to the best sound. How different is the frequency response of your left speaker compared to your right one given your room characteristics and their locations anyway?
madmax

organ

madmax,
You really enjoy the loose bass eh? I think you might like the EH EL-34. For me, they're almost too smooth. To my ears, they lack dynamics, slam and bass though. But they do vocals extremely well if you like smoothness. They're so smooth that it's almost fake sounding LOL. Maybe I'll give them another listen tonight:).

Maurice

madmax

I have not tried the EH. The shugang tubes are supposed to be pretty different. I'm not even sure "loose bass" in our definitions are the same. I do know the "so smooth they sound fake" thing you are talking about and that is different. Tubes are so cool for this very reason. There are so many sounds out there. If there were a really true sounding setup out there I think it would take the fun out of the whole thing!
madmax

PS: I have tried Svetlana tubes. In my opinion you might as well have SS at least for the bass. (not that theree is anything wrong with that)...

madmax

organ

I think I'll give those Chinese a try for my next EL-34 purchase.
Oh man, I just listened to the EH last night again but this time I'm really enjoying the sound! A combination of Mullard and Svet on the ASL really brought out the bass and still having the "smoooooth" sound. I didn't really like them before because I had the RFT in the pre which is more neutral and lean sounding compared to the Mullard.

So when will you be getting the Chinese tubes?

That's very interesting about the Svet's. In my system, the Svet is one of the strongest performer in bass.

Maurice

HBombToo

Originally posted by organ
Hbomb,
Thats what I thought too. But to tell you the truth, I can't hear the difference with unmatched pre amp tubes.

That is what gives our Forum a serious cool factor. Sometimes the correct engineering approach does not always afford the desired end product. Live and Learn!

HBomb

tapeshc

Thanks a lot for such a insightful discussion. At least now I know what I am doing and looking for when I choose one over the other.

It seems there is no clear winner in EL34s may have to try both of them Svetlana and EH Although smooth vocal is some thing good because lot of old recordings don’t have very high quality recording.

But it seems, its not going to be a cheap upgrade when I checked the price.:D