12ax7 matched sections

[kneadmomunny]

At the tube store there is an option for matched sections tubes. For my 5 preamp tubes the cost is 25 dollars for them to match my tubes.

I just wanted to know who gets this option, and if there is a big enough difference to justify 5 dollars per tube (on a 9 dollar tube, that is over a 50% increase!).

 

[Christobevii3]

Re: 12ax7 matched sections

Nope! Just buy the tubes. I've actually found that mixing and matching different pre amp tubes to sound better than all the same brand too.

 

[jeremy]

Re: 12ax7 matched sections

i like a matched phase inverter tube but other than that i dont see the need

 

[STRATDELUXER97]

Re: 12ax7 matched sections

i like a matched phase inverter tube but other than that i dont see the need

Agreed!

 

[Bezmotivnik]

Re: 12ax7 matched sections

i like a matched phase inverter tube but other than that i dont see the need

I've read elaborate technical arguments (that actually made sense!) against even that much matching in guitar amps.

People are always trying to sell musicians something they don't need.

 

[marvar]

Re: 12ax7 matched sections

The PI doesn't HAVE to be matched, but I think you owe it to yourself to try one at least once. Then you have real data in which to judge. Otherwise, you are just listening to other peoples opinions.
I happen to prefer a matched PI, I CAN hear a difference in the tone.
The other preamp tubes do not need to be matched, as the dual triodes usually go in different directions (circuits). THe PI is probably the hardest working tube in your amp.
Here is an argument FOR matched phase inverters-
http://www.guitaramplifierblueprinting.com/pastinfo.html
and:
http://www.guitaramplifierblueprinting.com/files/Phaseinverter.pdf

 

[jeremy]

Re: 12ax7 matched sections

myles rose always has good insight

 

[Rich_S]

Re: 12ax7 matched sections

What I don't get is, why spend extra for a matched PI tube? Matching the PI reduces second-order harmonics in the output stage. Then, we pay pedal modders more money for their OD pedals with dissimilar LED mods, so that we can increase the amount of second-order harmonics.

We guitarists are a weird, though gullible, bunch. :jester:

 

[devastone]

Re: 12ax7 matched sections

What I don't get is, why spend extra for a matched PI tube? Matching the PI reduces second-order harmonics in the output stage. Then, we pay pedal modders more money for their OD pedals with dissimilar LED mods, so that we can increase the amount of second-order harmonics.

We guitarists are a weird, though gullible, bunch. :jester:

Agreed, I've heard the same argument for matched output tubes.

That said, I do match output tubes, I don't worry about any of the preamp tubes though.

 

[Bezmotivnik]

Re: 12ax7 matched sections

The PI doesn't HAVE to be matched, but I think you owe it to yourself to try one at least once. Then you have real data in which to judge.

Well, that's not "real data," but subjective impression. I rarely trust my own subjective impressions and especially never, ever those of others.

The in-a-nutshell case against balanced PI tubes in guitar amps boils down to this, as I understand it:

1: The other imbalances in the circuit are typically greater than those within the PI tube itself, which is only one component so --

1a: The balanced-section tube obviously can't in itself balance the circuit...

1b: An unbalanced PI tube can either compensate for the existing imbalance in the circuit or make it greater, which is to say the cumulative error of ALL the components may add up to a more balanced or less balanced output...so a balanced-section PI tube can make the overall circuit imbalance worse...or better, but with less overall effect in either direction than an unbalanced-section tube.

1c: Fastidious audiophile techs use selected, measured unbalanced PI tubes for that exact compensatory "fine-tuning" function based on instrumentally measured results.

2: Guitar amps -- which for their "character" depend on various forms of distortion anyway -- sound "better" with unbalanced PIs.

So the r.a.t experts claim. As far as I understand it, this makes sense -- which does not mean that it's necessarily true or complete -- but seems the most logically persuasive case I've read so far. [shrug]

 

[d1dsj]

Re: 12ax7 matched sections

I now have an opinion as in the last few days I have changed valves in one of my amps. I felt my amp (a Cornford Hellcat) was not sounding as sweet as it used to so I went and spent £100 on a full set of valves, all Groove Tube... 5 x pre amp and 4 x EL84's. Anyway, I put all the valves in thinking I was going to be blown away and was very disappointed with the sound?? Then I put the original Pre amp valves back (Sovteks, nothing special) and left the G.T EL84's in, and now much better... sweeter sounding and not harsh. The main difference is a fuller/ rounder sound. More bass and more clarity. I'm going to try to take the G.T Pre valves back. From now on I will not be too concerned with matched Pre amp valves, only power valves. I have to say that I HAVE heard that EL84's don't tend to last as long as EL34's, 6L6's or 5881's due to the higher running temps. I tend to believe this and will monitor how playing hours I get before I think they are sounding bad.

 

[marvar]

Re: 12ax7 matched sections

This debate has gone on since tube amps were invented. It is not my purpose to keep it going-
All I said was, you should try one before you decide if it is worth it or not- Its not my intent to convince anyone what to put in their amp. After all, tone is a very personal preference. It has taken me years ( and an untold amount of cash!) to find the right combination of tubes, speakers, and pickups to reach the tone I had in my head. I don't play heavy metal, grunge, or high-gain histronics, so my tone is built around my own needs. A balanced PI works for me- may not work for you. And I don't mind paying an extra $10 bucks for a balanced PI, Heck I spend that much on picks and strings in a month or so. People are willing to spend hundreds of dollars on stuff that will change their tone, but ask them to spend an extra $10. on a balanced PI and they start raising all sorts of hell about the extra money. Most pre-amp tubes will last years and years anyway.
I just don't think you should sumarily dismiss any idea that can help you on your own personal tonequest. But I'm pretty sure if you asked your own personal guitar hero what he has in his amps, which most artists don't actually work on themselves, you might be surprised to find alot of them have a balanced PI in there- whether they requested it, or their amp tech installed it.

 

[Jeff Seal]

Re: 12ax7 matched sections

I have no problem going into the specs, but I would suggest not buying into the "hype" and simply play yer guitar!

...I remain consistently amazed at how many "new" terms are created for things..


just sayin'

JS

 

[STRATDELUXER97]

Re: 12ax7 matched sections

This debate has gone on since tube amps were invented. It is not my purpose to keep it going-
All I said was, you should try one before you decide if it is worth it or not- Its not my intent to convince anyone what to put in their amp. After all, tone is a very personal preference. It has taken me years ( and an untold amount of cash!) to find the right combination of tubes, speakers, and pickups to reach the tone I had in my head. I don't play heavy metal, grunge, or high-gain histronics, so my tone is built around my own needs. A balanced PI works for me- may not work for you. And I don't mind paying an extra $10 bucks for a balanced PI, Heck I spend that much on picks and strings in a month or so. People are willing to spend hundreds of dollars on stuff that will change their tone, but ask them to spend an extra $10. on a balanced PI and they start raising all sorts of hell about the extra money. Most pre-amp tubes will last years and years anyway.
I just don't think you should sumarily dismiss any idea that can help you on your own personal tonequest. But I'm pretty sure if you asked your own personal guitar hero what he has in his amps, which most artists don't actually work on themselves, you might be surprised to find alot of them have a balanced PI in there- whether they requested it, or their amp tech installed it.

Correct me if I'm wrong on this topic,but I always thought the PI circuit wasn't perfectly balanced anyway...We like the way tube amps sound with the PI not perfectly balanced...When these great sounding amps came around,do you think they balanced or used matched 12AX7 or even output tubes that were perfectly matched? Probably not...I'd bet reliability was the number 1 concern,plus they had better tubes to work with...All that matching of tubes and all from my memory brings me to Groove Tubes,but that was alot of years later...

I guess what I'M asking is....Does the PI tube need to be balanced if the actual PI circuit isn't? Or are we just trying to use 2 sides of a 12AX7 there that work as an equal strong team together for the PI? I always buy and use the best tubes I can afford to buy though..

 

[Gearjoneser]

Re: 12ax7 matched sections

I have no problem going into the specs, but I would suggest not buying into the "hype" and simply play yer guitar!

...I remain consistently amazed at how many "new" terms are created for things..


just sayin'

JS

I'd imagine that 50% of the world's most notable players don't even know what brand of pre tubes are in all of their amps........and if you asked them if their pre tubes were matched, they'd just laugh.

I'm not making light of your thread, because it's a good question....but there's a point at which gear tech stuff gets downright silly.