Which 12AX7 for my 18 watt plexi build ?

[big_teee]

The whole point was suggesting a tube, any tube is not going to be any closer then he is now. No one on the forum except the OP knows what sounds good in his mix of variables. Pick one out of a hat. If the tube is functioning, the amp will sound fine.

Besides, if the amp sounds bad now, there is a technical reason and that needs to be repaired before dealing with the very subtle differences that working, non-defective tubes make. If he had a basket full of tubes he might find something that appeals to him more than others but the chances of it being one that another person 1000 miles away likes in his own amplifier and with his own playing are long odds.
If there is a problem, fix it. If a tube is bad, replace it, and play. If it sounds good or bad to the audience, the tube will not be the reason. Good and bad are not sound characteristics that are tied closely to a tube difference.

I disagree, but we are both entitled to our Opinions!
On a particular amp build, you can save a lot of ground with what others like.
You can get 75% to 85% closer than just ordering tubes and trying different ones.
I have no experience with the EL84 Amps.
Chuck did and made his recommendations with what he liked.
If dealing with high gain EL34 Marshall type amps, I could get you close, at least save you time with mods, and tubes.
That would be closer than starting At Dirt Level.
Then when you get close Tweak to suit yourself.
That's my story, and I'm sticking to it.
Your Opinion varies from mine, and that's fine!
Peace, Tone, & Volume!
T

[Steve Conner]

I wonder what would happen if Stan met Eric Johnson. They'd probably annihilate each other like matter and antimatter.

As I said in another thread: Tubes don't have filters inside, and so can't shape the frequency content of a signal in the way that tone controls do. But when overdriven, different tubes make different distortion harmonics, and they can shape the frequency content that way. A tube that clips hard, generating a lot of high order harmonics, will sound brighter than one that clips softly.

Stan is probably not too far off in his assessment of how much tubes really matter. But some of us like to tweak! Right now I'm rocking some Mazda 6L13s salvaged from a tube regulated power supply.

[km6xz]

We are talking about preamp tubes, hard clipping varies little and seldom is the goal. What is missed in these replies is the state of tubes as available today. A brand xx 12ax7 will have more variation from the next one off the same assembly line than when tubes were seriously being built for consistency in a competitive market with real design and QC engineers maintaining the brand's product performance.
So player "a" advises builder "b" to use brand "xxx" tubes because it sounds good in his own amp there are significant variables unknown to well meaning player "a", like what the characteristics of the tube that "b" buys, sound preferences, playing style, strings, acoustic environment and a few hundred other variables that have even greater variation than player "a's"results with his copy of each of those variables. So it still comes down to "try a tube, any tube and see if you like it" but realize that testing is very unreliable in isolating a single factor(the tube) when all variables change with the feedback loop containing the player. Playing slightly more aggressively(which happens naturally when the sound pressure level increases) has more impact on harmonic content than a preamp tube. Almost all the uncontrolled variables have more impact in fact. Try one or a few. If you like it, stop and just play, searching for the perfect tube is fruitless and a waste of good time and money that could be used in other ways.
I am coming from this as someone who made his living for decades getting songs to sound good to audiences and players alike and maintaining the characteristic style that audiences recognized and set them apart from the competition. One of the least important component involved in that was which amp was used and certainly which preamp tube was used. So I am not making the same assumptions that is common lore on the internet. If someone wants to waste their time and money chasing every recommendation by strangers who have never heard the player or his preferences that is their business. But I never had the time or patience to be so distracted from the goal of making songs better or optimally appealing. There are higher priorities when trying to create performances which will be listened to for decades and judged through varying culturally based preferences between generations. I know from experience how minor but unglamorous changes can impact the perception...such as a slight tweak in speaker orientation will swamp any differences between any two functioning 12AX7s available. The color and texture of the walls impact the players style in a given performance more than different $4 versus $50 12AX7's. A 1/2 glass of wine has more impact than any choice of 12AX7's. Dimming the lights has more impact in tone and particularly with singers and pitch. Wearing one's "good luck" clothing or trinkets has impact which is why riders sometimes contain bizarre demands for a particular color candy or color dressing room, because players seize on any factors they think were present when they played at the top of their game. The same socks etc, and guess what, they all have more impact on the results than changing between two functioning 12AX7s. Taking an hour Master Class from the player's admired teacher will have more impact than choice of 12AX7s.
This tendency for hobbyists to focus on small factors easily identified and ignore the more important but less glamorous ones is common to most hobbies. I am into photography and the exact same thing happens there but to an even greater degree and at higher cost. A major proportion of hobbyists are not photo hobbyists but camera and equipment hobbyists. Talk and tinkering with side issues dominate and not many actually shoot picture much, or study art or composition which determines the quality of an image far greater than equipment. Music is a pretty cheap hobby compared to most but when the hobby become focused on equipment rather than doing the hobby, myth, lore and user reviews or recommendations sidetrack the whole topic and gets away from the original goal of creating something of interest and pleasing on various levels. I see that most music equipment hobbyists are half hearted in their pursuit, not many are studying the fundamentals, just tinkering around the edges.

[Steve Conner]

Well you're absolutely right of course. Nobody can tell what brand of tubes Eric Johnson (or whoever) was using on his album.

I remember an "experiment" where a film school student shot the same movie twice. Once with the latest HD equipment, and again with a 99 dollar Flip camcorder and a Zoom handy recorder for the audio. The verdict was that a good story would transcend cheap and nasty production, but not vice versa. This is more relevant than ever now that the vast majority of people consume their media heavily compressed as MP3 and YouTube video, making the production cheap and nasty by default. The playing field is now level, all that matters is the story.

However, I think pixel peeping (and its audio equivalent- wave weenie-ing?) is still a perfectly valid hobby. There are plenty of rich enthusiasts who couldn't care less about creating culture, their goal is just to play with gadgets. If they thought like Stan, Nikon, Mcintosh, Linn, Audio Research and the like would go out of business. Would that be a bad thing? Discuss.

[Jazz P Bass]

Just a thought.
As Stan has stated, tube quality from one to the next is poor.
I have seen 12AT7 tubes that had a higher gm than a 'standard' 12AX7.

[Chuck H]

There will always be "cranks" that insist on high end audio gear. Not even going so far as the "single ended 300B ilk. Just people that want better quality audio than they can get from their phone. I would say "kids these days" but it's always been like this. Every generation has had some cheap crappy way of recording and distributing audio when they're young. Then they grow up and refine at least a little. Buying better sound systems for their homes and such.

I don't think Stan is implying that top end audio gear isn't important. More like it isn't critical to every facet of the musical experience. But the phenomenon Steve mentions is a concearn of mine, as many here already know. I HATE that China is making EVERYTHING. Not because they don't make things well. They certainly can. But US corporate greed holds so tight to the bottom line that much of what is produced is garbage waiting to happen (meaning, in a shorter than acceptible time span). Top that the superficial US culture. We love Jerry Springer, we love NASCAR, and we love cheap shit that looks slick. I don't blame the Chinese for the cheap crap they make. I blame Americans.

I don't think high end audio (quality or gear) will dissapear. In fact, I think it will ultimately be better than ever. When CD's were first introduced they sounded like crap becuse of the lousy DA conversion. Combine that with production starting to move away from the RIAA standards and you had some really fatiguing recordings. At that time I was also concearned that the buying public had turned a tin ear to audio quality. But it got better... Much better. Alot of the compressed media is basic greasy kids stuff, not the only available media. It'll get better.

[Alex R]

These days I just use the Chinese 12AX7s, they are pretty consistent and reliable. Some wholesalers supply a low microphonics version, probably just selected for that, they are useful for v1 in HRDLs etc. JJs I found one in twenty let me down.

Dunno about differences in sound, I let my customers think about that, the Chinese ones sound pretty good to me! I think the experience of plugging a couple in and playing the amp to check it, repeated hundreds of times, tells you that you get a good guitar sound from a good amp with properly functioning tubes, end of story, really. Not cut out to be a tube dealer, me!

[km6xz]

Chuck, some of the first CDs did sound bad but not because of A/D D/A conversion but due to remastering old recordings intended for different formats that compensated for weaknesses or character of cassette, vinyl, R-R, 8 track, FM etc.
Quite frankly we did not know how to work with the characteristics of digital so all the old techniques and tricks that had developed over 60 years to make pleasing, musical sounding recordings had to be tossed out. 3M created the first real digital production multitrack machines which were installed in my studio to do the first digital album in the over 30 years ago, a Santana album in 1978. When doing playbacks of initial tracks a lot of adjustments were needed in our listening priories and processes, particularly with dynamics. When comparing the mixes with those coming from the mult'ed Studer 24 track 2" machines the decision to scrap the high cost (mostly subsidized by 3M who sent a team of techs and engineers from the factory to keep those very temperamental prototype decks working) and release the album based on the analog synced Studers.
The digital decks were trucked down to LA where Ry Cooder used them to record his Bop Till You Drop album released, I think a year later, which was really the first general release of a digital album. It sounded stark and hard but a lot of people liked it. We could hear they had similar difficulties with not knowing enough about how to make digital sound musical. By 1984/5, when Sony released the first car CD players, there was a sudden spike in CD sales which had been pretty weak. That CD car unit would enough to kickstart CD acceptance and there was a rush by labels to backfill their catalog of vinyl and cassette tape into CD for release. There were only 2 CD mastering/plate molding houses in the world so there was a backlog and about $50,000 in conversion costs per album.
That was when recording engineers started developing new techniques and methods of recording that made digital sound more pleasing, so by 1988-9 some albums stood out as being optimum on CD. The problem with early digital was simply 60 years of accumulated knowledge of how to create pleasing records using analog really did not transfer directly to the new technology. Everyone had to relearn or invent arrangements, tonality, dynamics, etc to convey the meaning of songs.
Kids have grown up with MP3 and expect different tonal and composition traits(it is cultural and generational for preferences in music sound, just as it is for art of the standards of beauty). Songs are different due to digital, particularly with the addition of another 1-2 octaves lower in response that is added to the options. I still prefer analog mainly because that is what I grew up with and learned a different definition of sound than kids now learn. But mostly I do not care that much about any recordings, preferring hear and dance to a live band even of mediocre quality over the best recorded productions. Here, I get to hear good music played well live, any night of the week from jazz, blues, rock, dance, classical, opera etc so recorded music holds little interest for me.

[Steve Conner]

Stan, can you explain more about having to change arrangements to sound good with digital? I don't get it. If the chorus lacks punch then adding another 16 bars to it isn't going to help. Or do you mean arrangement in the vertical sense, like adding more horns to the horn section to compensate for the "thinner sound" of digital?

The reason I ask is, I'm writing songs for the band that I recently started. I came to the conclusion that most people will hear them either live, or half listened to while doing something else on computer speakers or crap earbuds, so I decided to take that into account right from the start. I think that means the tunes have to be simple and catchy, there is no point writing a prog rock opera in 5.1 surround.

[Chuck H]

Stan has the experience. Having been in the game when and where it was happening. I think by "arrangements" he means simply 'how circumstances for recording are arranged". Be they track EQ's or track balancing.

It was my understanding that digital sounded "thinner" for two reasons. One is that the digital image is a pixelated and imperfect version of the analog information. Since early converters had limited capacity you might have analog info that equated to "4.3" but when processed must either be ommited or allocated to "4", for example. Not that these numbers actually mean anything. Just an analogy. The other reason is as stan said. And goes back to what I posted referencing RIAA standards. RIAA standards were originally in place to minimise rumble and hiss. But the point was that recording standards have developed to compensate for the media. Most analog recordings had a certain criteria for tonal balance as it worked with available media like disks and tapes. Digital has no physical limitations. I also remember some talk about people trying to intentionally enhance the greater capability of the digital media. Thereby making the recordings shrill. Add the limited information transfer and you had shrill and thin. That's how it was explained to me. And that's how it sounded so I accepted that.

[Steve Conner]

Well, as I understand it, analog tape added a few percent of distortion to everything. It sounds kind of funky if you distort an entire mix, but on individual tracks of a multitrack, it's the classic sound of rock music.

I believe this was particularly important for drum tracks. The tape could be overdriven and used to limit the drum transients, making a bigger, fatter sound that worked better in the context of a mix.

I can imagine the heads getting scratched in the control room the first time they tried to record a rock drum kit on the new digital decks. It probably sounded like pure crap.

Nowadays it's easy to patch in a tape saturation plugin in your DAW software, but it probably took this long to understand the problem. The studio engineers might have understood it straight away, but the message had to get through to the people who design the recording equipment.

[km6xz]

Arrangements could be more spare, less layering to get a fuller sound than digital because of the same reasons tube amps overdriven create a fullness that simple playing fills the sonic space with mid and upper harmonics that are avoided at all costs in digital b. Layering complex tracks to get the fullness and richness of analog might nowadays see 20-30 overlayed instruments where a drum and guitar accomplished the same with analog. A similar sort of compression was natural obtained with the non-linearity of tape near saturation that is gotten from an overdriven tube amp. Back in the day, little bass, deep bass was recorded, it played havoc disc-cutting and cut down on track length. Besides it was just noise since playback systems, radio and listener preference limited deep bass. But listen to the old R&B tracks that every 56 Chevy's 2.5 watt 6x9" oval speaker was intended to reproduce. No listener missed the missing fundamentals because the natural distortion boosted second and higher order harmonics which told the brain that the harmonic sequence was the result of a particular fundamental note....we perceived it was there and had no problem with appreciating the great rhythm sections of the day. We did not even know the 32 hz fundamental was totally missing, we knew the note from the harmonic series. If the harmonics were strong, our brains told us the fundamental that created them must be huge.
With digital we had to create more complex layered arrangements, with horns and keyboards when just a B3 was enough before. It also gave some advantages, vocals could have more "air", or silence that was true silence as the song writer intended. In the studio, the vocal and instrument arrangements were often altered as a way to mask problems that nowadays could be edited at the sample level. It was a task to create a recording that sounded good, fit the song, and masked the noise, "problem" voice traits or a million other factors that separated the polished projects from the demo level projects.
RIAA curves were the most effective of dozens of recording pre/de-emphasis schemes that audiences had to deal with. Old hi-fi's often had 10 or more phono EQ curves to select from based on what the record was recorded with. RIAA was an attempt to make sense of the crazy quilt of pre emphasis curves that were popping up. It was a good compromise that was not horrible on anything nor optimized for anything. Disc cutting was an art and was very different than tape mastering, because of the physical nature of a groove, and a massive needle trying to track it without over modulation or too much surface noise. Track pitch was manually, or later automatically adjusted on the cutting lathe based on the bass amplitude and frequency, spacing between tracks widened a lot on heavy bass passages, and passages with no bass would be crammed up close to each other so as to reclaim some of the lost playback duration of the disc due to bass passages. Needles had a hard time tracking bass while keeping velocity and skate error low for high frequencies in the same track. Bass was mixed center not only for greater power available for both stereo speakers being driven in phase but also because intermodulation distortion and cross-talk ruined mid and high frequency fidelity. It was an art for a mastering engineer to create a mixture of all the negative indicators. Each recording was mastered separately for each media format. Disc was the most "artistic", tape for cassette was very different in compression, eq etc than reel to reel distribution, or 8/4 track carts.
I loved working with analog tape, it was very organic and how you treated it, aligned your decks, pushed it etc made all the difference. Some of the best sounding kick drum and snare sounds ever came from simple kits crushing tape 10 db over saturation onset. Every engineer developed their own trademark tape set up. Every time a piece of tape was mounted on a deck the deck was calibrated and aligned and that was an important part of the sound. As higher and higher flux-density tape was introduced, it was like an artist having a whole range of colors to play with.

[sprocket]

As per some wrote before , is that that Analog Mixes ( tape) added some mids to the mix in order to have the sound fuller ! I m asking that question myself for a while , maybe some guys can have some thoughts on this .

[sprocket]

Arrangements could be more spare, less layering to get a fuller sound than digital because of the same reasons tube amps overdriven create a fullness that simple playing fills the sonic space with mid and upper harmonics that are avoided at all costs in digital b. Layering complex tracks to get the fullness and richness of analog might nowadays see 20-30 overlayed instruments where a drum and guitar accomplished the same with analog. A similar sort of compression was natural obtained with the non-linearity of tape near saturation that is gotten from an overdriven tube amp. Back in the day, little bass, deep bass was recorded, it played havoc disc-cutting and cut down on track length. Besides it was just noise since playback systems, radio and listener preference limited deep bass. But listen to the old R&B tracks that every 56 Chevy's 2.5 watt 6x9" oval speaker was intended to reproduce. No listener missed the missing fundamentals because the natural distortion boosted second and higher order harmonics which told the brain that the harmonic sequence was the result of a particular fundamental note....we perceived it was there and had no problem with appreciating the great rhythm sections of the day. We did not even know the 32 hz fundamental was totally missing, we knew the note from the harmonic series. If the harmonics were strong, our brains told us the fundamental that created them must be huge.
With digital we had to create more complex layered arrangements, with horns and keyboards when just a B3 was enough before. It also gave some advantages, vocals could have more "air", or silence that was true silence as the song writer intended. In the studio, the vocal and instrument arrangements were often altered as a way to mask problems that nowadays could be edited at the sample level. It was a task to create a recording that sounded good, fit the song, and masked the noise, "problem" voice traits or a million other factors that separated the polished projects from the demo level projects.
RIAA curves were the most effective of dozens of recording pre/de-emphasis schemes that audiences had to deal with. Old hi-fi's often had 10 or more phono EQ curves to select from based on what the record was recorded with. RIAA was an attempt to make sense of the crazy quilt of pre emphasis curves that were popping up. It was a good compromise that was not horrible on anything nor optimized for anything. Disc cutting was an art and was very different than tape mastering, because of the physical nature of a groove, and a massive needle trying to track it without over modulation or too much surface noise. Track pitch was manually, or later automatically adjusted on the cutting lathe based on the bass amplitude and frequency, spacing between tracks widened a lot on heavy bass passages, and passages with no bass would be crammed up close to each other so as to reclaim some of the lost playback duration of the disc due to bass passages. Needles had a hard time tracking bass while keeping velocity and skate error low for high frequencies in the same track. Bass was mixed center not only for greater power available for both stereo speakers being driven in phase but also because intermodulation distortion and cross-talk ruined mid and high frequency fidelity. It was an art for a mastering engineer to create a mixture of all the negative indicators. Each recording was mastered separately for each media format. Disc was the most "artistic", tape for cassette was very different in compression, eq etc than reel to reel distribution, or 8/4 track carts.
I loved working with analog tape, it was very organic and how you treated it, aligned your decks, pushed it etc made all the difference. Some of the best sounding kick drum and snare sounds ever came from simple kits crushing tape 10 db over saturation onset. Every engineer developed their own trademark tape set up. Every time a piece of tape was mounted on a deck the deck was calibrated and aligned and that was an important part of the sound. As higher and higher flux-density tape was introduced, it was like an artist having a whole range of colors to play with.

So ,it must be some answers to my post before too .

[kg]

so yeah, i gotta say i agree with the "if the tube functions it's a fine place to start."

look, if you've just got the tubes as the singular variable, like 99% of the musicians out there, then you can start to make some generalizations. (that is, of course, given tight enough QC on the tubes to begin with--and that is by no means guaranteed. )

BUT if you're making your own amp, building your own circuits, then all that goes out the window. ime, replacing ONE pio coupling cap with a like-value ceramic version is gonna swamp the difference between swapping that same stage's 12a_7s!