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plig88 26th February 2013 07:55 AM

high gain vacuum tubes
 
hello again.....my amplifier have (total) 6 vacuum tubes. 1 rectifier( ez81)....2 power (el 84) and 3 preamp ( 12ax7) just like vox30.....but my amp is DIY....and those tubes are cheap , because i don't have much money to buy good tubes....so from my tube the rectifier is JJ( only this tube is good ) the other tubes are 2x EL84 ( it's used before i buy and it's from russia) and 3x 12AX7 (those are new but the one is "china" and the other 2 are "sovtek" 12ax7wa...........in preamp tubes have first gain stage ( high gain), second gain stage( tremolo channel) and phase inverter......the problem is , in first gain stage there should be very Distortion ( When I terminus in the intensity).......now with these bulbs do not have much distortion.....I want to buy but what lamps;;; JJ 12AX7 S or GT 12AX7 R?????????????? PLEASE HELP ME

vitahamin 26th February 2013 09:30 AM

schematic?
If its like an AC30 you will never have a lot of distortion from the amp alone.

JRGuitarGuy 26th February 2013 10:05 AM

the china 12ax7 is ok for current production nothing special, now you do need to get rid of the sovtek though I can't stand them, you need some good old Nos the mullards, amperex bugle boys/Phillips, Tungsram, Ei, one of those in V1 would really wake it up lol

Tesla88 26th February 2013 12:14 PM

No matters on tube brands , if they are 12ax7 and quite new (not with years of use) the gain is quite the same , brand differs in "tone" so some tubes are more darker or brighter than others , or more or less microphonic .
What make difference in gain is the circuit itself , so post it ...

12ax7wa are good tubes ...

45 26th February 2013 12:16 PM

Quote:

Originally Posted by JRGuitarGuy (Post 3386574)
the china 12ax7 is ok for current production nothing special, now you do need to get rid of the sovtek though I can't stand them, you need some good old Nos the mullards, amperex bugle boys/Phillips, Tungsram, Ei, one of those in V1 would really wake it up lol

I do not agree. 12AX7LPS or JJ ECC803S, depending mainly on the actual amplifier/guitar combination, can be just as good as NOS. You just need to tweak values of resistors and caps around them a little bit to make them work at their best. The JJ ECC803S in particular is very nice! The sound is rich, warm and high definition at same time.

Also, the Reflector 6P14P-EV or Sovtek EL84M (they are the same thing) are just better than NOS EL84's. Techincally they are superior design with minimum 5000 hours of guaranteed full service and are specified for higher plate dissipation at 14W rather than 12W. Also they have better heater-to-cathode insulation and can take up to 500V with no current on both grid and plate rather than 300V only. The Russian equivalent for the normal EL84 is the 6P14P. Then there is the 6P14P-ER that is guaranteed for 10000 hours just like old European SQ tubes.
I get 20W out of a pair of 6P14P-EV in class AB push-pull and a lovely sound. They sound better, especially when over-driven, than NOS EL84's which are not an improvement from any point of view. I have a nice pair of quite expensive NOS/New Mullards from 1960's. NOS EL84's are just more expensive....
JJ EL84 is also a very good choice.

45 26th February 2013 01:06 PM

Quote:

Originally Posted by Tesla88 (Post 3386687)
N
What make difference in gain is the circuit itself , so post it ...

Still there is little point. The sound will be strongly dependent on the input signal (i.e. the actual guitar) and the speaker. Swapping tubes of the same type but different brands is really a minor thing in comparison. Modifying the circuit on paper gives no guarantee and often the right mod is exactly the contrary of what you would guess! You can only adjust the sound by listening. There is no other systematic way.

JRGuitarGuy 26th February 2013 01:23 PM

Wow so you are trying to tell me a LPS or ecc803s is going to sound as good as blackburn mullards I61s I63s, the bugle boys, tunsgram, Ei. Not sure what you are smoking must be some some good ****, I had an LPS it was that same bright/fizzy Sovtek sound maybe bit more ramped up compared to the WBs but in truth to me it sounded like total ***, popped in good old Nos Sylvania BIG difference where did this come from then? lol then i popped in an old Tunsgram EVEN BIGGER difference lol. Not sure about your ears but Nos everything sounds about 10x better and lasts longer as well lol

JRGuitarGuy 26th February 2013 01:28 PM

Sovtek is just bright/fizzy as hell an no life, JJ the ecc83s is dull and just lifeless and hollow low end, All the Nos stuff to me just has a more 3D presentation to the sound as well as like having a more noticeable presence it just jumps out at you more. Maybe its just me but I hear a HUGE difference between preamps.

Tesla88 26th February 2013 03:54 PM

Ok guys but , stop talking about sound inteded as tone where tubes , pick up , speaker and "player hands" play huge role ...

Plig88 want more gain from that amp design , changing tube brand can't lead to a solution.If the preamp section is not designed to get much gain , there's no tube to change , but only component values and arrangement . He's using 12ax7 , a high gain tube , so mounting what ever you want , don't make difference in terms of gain factor (or just a bit).
i also love NOS tubes , i've got severals GE , Mullard , Telefunken and of course they sound different from current production , but if a stage is done to gain 10 you can try a NOS vs Sovtek with no difference in gain at all....

plig88 26th February 2013 04:50 PM

thanx for all this :)....but i don't know about NOS TUBES....what is it? it's differents from simple tubes?


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