high gain vacuum tubes

plig88

Member
2013-01-04 11:40 am
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
 

Tesla88

Member
2011-12-21 8:37 am
Italy
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

Member
2008-12-18 2:29 am
UK
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

Member
2008-12-18 2:29 am
UK
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

Banned
2012-10-09 11:25 am
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

Banned
2012-10-09 11:25 am
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

Member
2011-12-21 8:37 am
Italy
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....
 

JRGuitarGuy

Banned
2012-10-09 11:25 am
Its not about gain, yes some current production can be gainy as hell, so can Nos but Nos actually has a lively character though lol., you been smoking crack though lol, lots sovteks are medium gain for most part, lots of Nos really test out high and sound like it too, RFT and Ei ecc83s come to mind instantly. but key difference they have character with that gain and not some fizzy harsh top end, Telefunken is just really Hi-fi and I know old pre yugo Ei were made on that tooling and they sounded really gainy and hairy lol, they were prone to noise/microphonics though, I dont care what anybody says, swapping/rolling different 12AX7s sound HUGE to me keep doing it till you find what you like xD
 
what is nos???????????????????

Shorthand for New Old Stock. Tubes that were made by the original big vacuum tube manufacturers back in the golden days of tube amplification, as opposed to tubes manufactured now. They were made to much higher quality standards than currently manufactured tubes, on fresh, well maintained equipment and from much higher quality materials than are used today. As a result, they are said to sound better and last longer than tubes available today. In those days, tubes were used in all sorts of consumer electronics, so reliability and quality were major selling points.
 

Tesla88

Member
2011-12-21 8:37 am
Italy
Ok , can you post a schematic of the amp , or just want to go ahead discussing of nothing like tube brands? Dunno about JrGuitarGuy test method , i test tubes in real circuits with real instruments , not only by ears ...
Want to get more gain ? post circuit and i could help you .
 
Not forgetting that even in the best case, gain variations will be modest.
Something in the order of, say, 20% to 30% at most, and that testing a lot of tubes to find the best.
An extra 1dB or two of gain won't impact much on the distortion you are seeking.
To have a really noticeable improvement you will need 10dB to 20dB extra gain at least, and that will come from either an added extra tube gain stage (what Mesa/Marshall/Soldano/etc. did) *or* add a clean boost stage between your guitar and the amp input.
It's not bad to search for a better tube, but don't think you'll have dramatic changes.