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Thread: The difference a tube can make

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    The difference a tube can make

    I am a little green on knowledge about vacuum tubes and the differences that certain tubes might make in an amps sound.

    I have read quite a bit about NOS tubes, different tube brands, etc. It seems some people are big believers in the tone improvement that certain tubes can make in their amps.

    Can someone give me a little background on why one tube may be better than another (assuming both are in good working order). For example what might make one 12ay7 tube yield better tone than another?

    I am not opposed to paying up for tubes if I really thought they would make a huge difference... but from what I have read, it sounds more like buy a bunch of tubes and swap them in and out and try to find a combo that yields an improvement. That sounds a little like a hit or miss approach which could be a bit expensive and not yield much if any improvement.

    Thanks
    I am learning. My posts should not be considered as expert advice or suggestions for you to implement... on the contrary, I am looking for expert advice!

  2. #2
    Senior Member Enzo's Avatar
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    First off, take all such comments with a grain of salt. What does it really mean when Joe Blow Guitar-god comes online and claims Tube-X is "better" than some other? He likes it better, OK fine. DO you have the same taste in tone as he? Is his amp identical to yours? Does he play the same guitar and pickups? Same speaker? AT best it is a suggestion. It is like someone saying lobster is better than steak. Maybe for some guys it is, but for others it ain't.

    What makes tubes sound different? SUbtle differences in the internal element spacing, slight differences in interelement capacitances, maybe some cathodic material differences. whatever.
    Depending upon the circuit and how you play through the amp, you may or may not notice a lot of difference.

    To me, the tube differences are about on the order of the differences betwen brands of guitar strings.

    Remember that NOS doesn;t specify any particular tube, it just means old tubes that have not been used.

    And remember also, that each socket in the amp does a different job. There are inoput stages, tone stack recovery stages, phase inverter stages, and reverbs and trems, and other things. SOme amps have extra tube stages added in for OD channels, while others use separate channel paths.

    Really, ther is no scientific procedure for netting your tone from tube specs. You get yourself a selection of tubes, and pick a socket. Try the various tubes in that socket. You may or may not notice a lot of difference. If you do, great, use the tube you lihe. Then move to the next socket. DO it all again.

    Hit or miss? Maybe. Or maybe it is like going to the same restaurant and trying a diferent entree each time. The tubes you don;t use will be fine as spares. Can you tie up $100 in tubes? Sure, but that is the price of glory.


    This is of course just my opinion, others may disagree.
    Education is what you're left with after you have forgotten what you have learned.

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    Thanks for the comment.

    It sounds like your experience has been that certain tubes might make a marginal difference, but not transform the sound and tone to a completely different level.

    I have read many comments from people (their opinions). I must admit, I am a bit skeptical about claims of transforming of the amp (unless the tubes were bad)... I do believe there might be marginal improvement.

    Here is an example I was reading... it is a review: Torres Tweed Deluxe 5E3

    The author describes swapping out the tubes with NOS tubes and describe a complete transformation.

    He also claimed orange drop caps are harsh in fender amps??


    I was wondering... are different tube manufacturers' designs for a given tube type (e.g., 12ax7 or 6V6) different... or are they typically very similar (in design and spec)?
    Last edited by BluesDude; 01-26-2010 at 10:42 AM.
    I am learning. My posts should not be considered as expert advice or suggestions for you to implement... on the contrary, I am looking for expert advice!

  4. #4
    Noodle of Reality Steve Conner's Avatar
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    I agree with Enzo. If you swap one brand of 12AX7 or EL34 or whatever, for another tube of the same type but different brand, it makes about as much difference as guitar strings.

    As an example, I analyzed the differences between two 12AX7s in this thread, and posted sound clips etc. Revolutionary or just another try?

    You can achieve more of a difference by swapping a different type of tube in: a popular tweak is to substitute a 12AT7 or 12AY7 for a 12AX7. Or changing EL34s in your power amp for 6550s, etc. But be aware that power tube swaps sometimes need mods to the amp ("rebiasing") for safe operation. And, some swaps are just plain verboten: if you stuff an EL34 into a Champ, you'll burn out the transformer.

    You asked whether different tube manufacturers have different designs for the same type of tube:
    my answer is "Mostly not." However, the thread I linked above dealt with a tube design that was completely new and different, and even then, the differences were fairly subtle, although many people could identify them from the sound clips.

    I don't believe that changing the brand of capacitors makes the slightest tonal difference, and this point of view seems to be reasonably accepted, on this forum at least. But changing the VALUE of them does. If you swap a 0.1uF coupling capacitor for a 4700pF, it'll change the voicing of your amp radically.

    So, in order of influence on tone:

    1) Topology
    2) Resistor and capacitor values
    3) Tube types
    4) Tube brands
    5) ?
    "Enzo, I see that you replied parasitic oscillations. Is that a hypothesis? Or is that your amazing metal band I should check out?"

  5. #5
    Senior Member Enzo's Avatar
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    You will often read comments like this: "I replaced the Sovtek 12AX7 with a TungSol reissue and it made all this difference..." Maybe it did, but what I bet that same person did NOT do was try a differnt Sovtek tube of the same type. When you do note differences, you might just as easily see as much difference between two tubes of the same brand and model as between two different brands.

    Replacing a 12AX7 with a 5751 or 12AY7 is bound to sound different. The tubes have different gains and everything else. That is a separate isue from brands of one type tube.

    Some people are genuinely excited by changes in their amps, but they are not careful reporters. Numerous times I read reports that start out, "I swear by the orange drop caps, they made a tremendous difference in my amp." Then as we read on we find that not only did he replace all his caps with orange drops, he also changed values in his tone stack, performed someone's mod from some web site, put in a lower gain tube in the phase splitter, changed his speaker out for a hemp tone something. Added a bright switch and converted to cathode bias. Now how on earth can he say the orange drops made all this difference?

    The 12AX7 type tube has certain defining characteristics. Individual tube makers can build them as they see fit. Gather 10 different 12AX7 tubes and look through the glass at the innards. There are tall plates and short plates, different heater arrangements, and various things that may not meet the eye.
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  6. #6
    Pickup Maker yescaster's Avatar
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    I 'll disagree with one brand over another not imediately sounding different. It prolly depends on your listening. But I will also say...it seems no two tubes are identical, even the same make. Like guitars.

    An example... I had a 12ax7 EH tube...and I wasn't quite getting what i wanted from that amp.. the shop gave me a high end mesaboogie tube. It was very grainy, and seemed brittle in tone compared to the EH which was creamier.

    Tone IS subjective. but.. yea... get a bunch...pick a socket. True. I did. I presently have a 12ay or a 12au in place of the 12ax in the second socket (which is the reverb channel)... and i love it.. it gives alittle cleaner tone, and breaks up smoother than the full gain tube.

    I haven't experimented with switching power tubes as much (just a few)...because it is more more costly than swapping preamps... but yes...that would make a huge difference in the amps reactive character.
    Even changing the rectifier would change the character.
    compression or sag punch or warmth... yea.. tubes make a difference.

    one thing I will say I learned.

    You may like what a tube swap does at studio room volumes...or in a certain room... then take it out to a bar and crank it... and it may not do what you like in that room's accoustic scenario, or in a band mix. Because certainly the amp will respond differently when played harder than studio setting. Also power soaking from all the electrical draw at a bar will make a difference.

    One thing a fellow who is a Furman tech told me: "If you want the same sound always, use a power conditioner unit."
    That is true.... amp sounds different in every place i play, and also depends who i'm playing with.

    So tubes.. will get you in there. But crank it, and play as hard as you would when you play out.. because the tube swap will suprise you at the new character it gives the amp at higher volumes.

    I think push the amp, that is where you will see the difference easily, withoput squinting to hear a difference.

    anyway.. go for the preamps. it's cheap and values (ax, au, ay, 1575, etc..) can be swapped without rebiasing anything. It really amazed me how easily i could change the character of my amp.

    So far I can tell you I personally prefer an EH, or milspec, to a Mesaboogie pre.
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    Many 12ax7's sound different (mostly high or low balance and slight gain differences) this will make a difference but it's a very small one in all but the first preamp stage. Changing the V1 12ax7 can make a very marked difference IME and it's worth experimenting. Power tubes vary a bit too. Some break up a little sooner and, as mentioned, have different balance when overdriven. This can also be worth experimenting with IF you want that last 5% to 10% of polish on your sound. But, as mentioned, it's about YOUR sound. Your ears, your guitar, etc. The results are more subjective than "improvements". So, V1 and power tubes are where you'll really hear a difference. As for V2, PI tubes, reverb drivers, etc... Not so much unless you change tube type rather than just tube brand.

    Now. Steve mentioned that he doesn't think cap type makes the slightest difference in tone unless there is a change in value. This is true for the most part, but, if you were to change ALL the film caps in your amp with EXACT VALUE replacements of a different dielectric you MAY hear a SLIGHT difference. More significant are the dielectric characteristics. I use polypropylene caps because I got tired of my amps changing tone as they went from cold to warm to hot. Polypropylene caps in general have better temperature stability and I have noticed a significant improvement in this regard. So, since most amps that work do warm up I would say that different caps DO sound different. But it's not because of some fundamental difference in performance. It's because some caps change VALUE more than others as the amp warms up. As Steve said, a caps value can make a significant difference. That and cheap ceramic caps are best avoided all together.

    Chuck

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    Pickup Maker yescaster's Avatar
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    Quote Originally Posted by Chuck H View Post
    Changing the V1 12ax7 can make a very marked difference IME and it's worth experimenting. So, V1 and power tubes are where you'll really hear a difference. As for V2, PI tubes, reverb drivers, etc... Not so much unless you change tube type rather than just tube brand.

    Chuck
    why wouldn't you hear a difference swapping v2 in an amp?

    if you do play through the "normal" channel...and you play through the reverb or tremolo channel, then v1 is not your preamp.

    For instance. I've removed the V1 pre, at times altogether because I was not using that channel.

    If you use. V2 is for reverb side of (a "fender" amp for instance) your amp, and v1 is the normal side. You wont hear a difference swapping v1, or eliminating it, if you are playing through the reverb channel. maybe (and probably) a current/voltage character difference (because you are not heating v1 if it is absent), but the v1 and v2 positions are not both used unless you are jumping channels (using both channels) on fender amps (deluxe reverb as a plain example).

    I've never pulled v2 while playing through v1...although I wouldn't see that not working.
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    Seems like the general consensus is: for a given tube type the brand at best might make a marginal difference and two tubes from the same manufacturer could exhibit differences (due to variability in the tubes).

    It also sounds like there could be many other variables at play including the environment.

    Right now my weber 5e3 has the low cost chinese tubes in it. They sound pretty good to me. I switched the 12ax7 in v1 with an 12ay7 (EH tube). I could hear the difference... it help with headroom some.

    Well I was a bit skeptical anyway. I will probably not chase the elusive tube upgrade too much. Perhaps when I need to swap... I will try a different brand.

    Too bad there is not a try before you buy option... but then again, I suspect that would drastically reduce tube sales
    I am learning. My posts should not be considered as expert advice or suggestions for you to implement... on the contrary, I am looking for expert advice!

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    Steve, thanks for posting those examples comparing the Mullard to the Techtube (which unfortunately already seems to be OOP). I wish there were more audio examples A/B'ing alike tubes in different positions in different amps.

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    I probably shouldn't even be responding, but...

    Quote Originally Posted by yescaster View Post
    if you do play through the "normal" channel...and you play through the reverb or tremolo channel, then v1 is not your preamp.

    For instance. I've removed the V1 pre, at times altogether because I was not using that channel.

    If you use. V2 is for reverb side of (a "fender" amp for instance) your amp, and v1 is the normal side. You wont hear a difference swapping v1, or eliminating it, if you are playing through the reverb channel. maybe (and probably) a current/voltage character difference (because you are not heating v1 if it is absent), but the v1 and v2 positions are not both used unless you are jumping channels (using both channels) on fender amps (deluxe reverb as a plain example).

    I've never pulled v2 while playing through v1...although I wouldn't see that not working.
    In my example V1 represents the first tube in the signal chain regardless of what specific preamp you happen to be using. How else could you explain this phenomenon in this scenario without going through the specifics of every guitar preamp ever built? In the case of a typical two channel BF Fender, if you happen to be playing through the reverb or vibrato channel, my reference to "V1" is V2 of the actual circuit. If the poster is using a Fender 5E3 Deluxe my reference to "V1" would actually be V1. So, in the future, just assume when no specific preamp schematic is referenced that when someone says "V1" they mean the first preamp tube in the signal chain, ok.

    Chuck

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    Senior Member Enzo's Avatar
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    I'm with you Chuck. One shouldn;t have to explain that. Maybe we have to use terms like "input stage."
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    Pickup Maker yescaster's Avatar
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    Quote Originally Posted by Chuck H View Post

    So, in the future, just assume when no specific preamp schematic is referenced that when someone says "V1" they mean the first preamp tube in the signal chain, ok.

    Chuck
    ok. I misunderstood.
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    "You wont hear a difference swapping v1, or eliminating it, if you are playing through the reverb channel. maybe (and probably) a current/voltage character difference (because you are not heating v1 if it is absent)," Pulling the Normal Channel input tube reduces the effective value of the shared cathode resistor at pin 8 of both input tubes. This will noticably drop the voltage on pin 6 of the Reverb Channel input tube, voltage on pin 1 of the Reverb Channel input tube may well rise - this is what causes the marked change in tone, not the heaters.

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    True that. In fact, it's a common "mod" to simply pull the preamp tube your NOT using on a BF Fender. I missed that in light of the issue I covered.

    But Enzo is right. I should have said "input tube" or something like that as V1, V2, etc. actually IS how tubes are designated on schematics. I just wanted to recognize my part of the mistake here.

    Chuck

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    Senior Member Enzo's Avatar
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    I don't see it here as much. but over on the PV forum, we get a lot of confusion because the V numbers - which are schematic references - are not in straight 1-2-3-4 order across some amps - like the 5150 series. SO someone refers to tube #2 in the row as V2 when it isn;t.
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    Thanks for the comments. Very helpful.
    I am learning. My posts should not be considered as expert advice or suggestions for you to implement... on the contrary, I am looking for expert advice!

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    Senior Member Pedro Vecino's Avatar
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    If you compare the effect of changing one (or five) 12Ax7 in a amp with the obtained one by means of raising the gain 6db. in any frequency of a graphical eq, little relevance is going to be. But the tubes handle texture in the sound (timbre), when an equalizer will never do it.
    This effect in the texture the spectator is never going to perceive it in the majority of the occasions, but it will compose the element that you then will modulate playing the guitar. A "tactile" experience. And you, depending on the type of texture will play of different form.
    Like any other electronic component, the effect is dependent on what the circuit allows and of how it fits in it, but the texture that can generate an ECC83 RFT (it is an example) in certain overdrive circuit you will not obtain it with an ECC83JJ. And articulation and fluency that an real ECC83 Mullard generates cannot will obtain it with one 12AX7EH.
    Put five good ECC83 Tungsram in your Peavey 5150 and try to obtain it using tubes of current production. Before that it, you will achieve to make hamburgers with the texture and flavor of the best roastbeef
    Sorry for my poor english.
    Regards

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    I think your English was very readable and expressive, and your points were valid and important. We may hold hamburgers in higher regard than you do.

    I have the best luck just trying tubes. Even the same tubes from the same manufacturer vary quite a bit in gain, and this is especially important in the drive channel pre-amp.

    I have really good luck with used, re-tested RCA 12AX7s. They're frequently cheap on eBay. When you do a full re-tube on an amp, the preamp tubes probably have lots of mileage left on them, and you can try them later in different applications. Used tubes are a good option if you're working on your own amp. Even BugleBoys become somewhat affordable.

    You do need to be careful substituting a different member of the 12AX7 family (12AT7, 12AY7, 12AU7). The lower gain tubes can drive more current, and more importantly, their bias voltages are generally higher. For example, Carvin drives a reverb tank off the plate of a 12AX7 without a transformer in the BelAir, Nomad, Legacy and MTS. Substituting a 12AU7 (ECC82) with higher bias voltage into the circuit with the stock 220 Ohm cathode resistor boosts the bias current even higher, and can cause the 12AU7 to overheat, threatening the vulnerable heater circuit. If the cathode resistor is under 680 Ohms, beware. Most subs are safe, but the bias current can still change, altering the tube's bias beyond what would be expected from the gain change. I only point this out because lots of sites promote free exchange without caveats. With this proviso, the 5751, 12AT7 and the ECC81 are almost always safe lower-gain substitutes. For higher gain, most vendors will select high-gain outliers for a small premium.

    You can get more dramatic results messing with the associated resistors and capacitors than you can with a tube swap, and resistors and capacitors are much cheaper. In the case of the Carvin reverb drive, it's easy to adjust the reverb loop gain with resistor changes.

  20. #20
    Senior Member Pedro Vecino's Avatar
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    Quote Originally Posted by BackwardsBoB View Post
    We may hold hamburgers in higher regard than you do.
    Sorry! Sometimes one forgets these things... And handling so badly the English, I have very few resources.
    I also use 12AX7 RCA. Especially as first tube in the Mesa Marks. His articulation and bite are inimitable.
    Regards

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    If you were looking for crisp accurate reproduction then tube shoping would make more sense. In the case of guitar amps you are paying top dollar for tubes that were almost rejected for use in high fi equipment. Most of the qualities you are looking for can be obtained by changing bias, it is just easier to plug in diferent tubes. I think Fender is moving twords useing FET's as the first stage in their preamps to eliminate ground noise and then tubes to provide harmonics later. This is a little hard to accept if you really love tubes but it makes sense.

    The orange drop caps. They are mylar. Smash one, unwind the coiled up peice you find inside and pull. It streches like a sandwich bag. They are good caps and cheap to make. You can pay big bucks for them if you want but it doesn't change what is inside. The reason they are replaced with polycarbonate (it doesn't strech and is more like celephane) is it retains a small charge after a signal goes to zero. I don't think you will hear it. The absolute best choice would be a tefelon cap (if you know someone who works in the space industry). I would replace the monoceramic caps and electrolytic caps if you find them in the signal path.

    If you realy want to do the most to eleminate noise get away from carbon, use metal film. Cerimet pots are your best choice for low noise but are linier. Get one that is much higher value then you want and then put a metal film resistor in paralel with the wiper that is closer to the value you want. It wont be a log taper but it might be usable then.

    Now the disclaimer. This is stuff I've sold to people who like to expiriment with this sort of thing. I personaly like things the way they come out of the box.

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    Well seeing as most of this thread is discussing pre tubes, I'd like to put my 2Cs worth in about power tubes. I build Marshall clones mostly and so obviously they need tubes.
    For the past few years I've been buying used old stock EL34s, hooked on the idea that they are better, not only sound wise but reliability wise as well. Lately I've had an about face on these old tubes, I will say that Mullard XF2s are the best I've played, in saying that, the difference is both subtle and profound depending on your ear, taste, expectations etc.
    A couple of years ago I was working on a friends old Fender showman, 4 x 6L6 amp. I talked him into buying some NOS power tubes for it, he did, they cost him an arm and a leg, when he came around to check out the amp we first off played the amp with the old tubes then put in the NOS, we both agreed that we could not hear one iotas difference. I felt great for my friend here.
    That should have said something to me but no, I was still in NOS mode. They are hard to quit.
    Yesterday however I think the penny has finally dropped, I was putting a new and supposedly superior OT ( output transformer ) into one of my 100W Marshall clones, as I biased the amp I discovered one tube was dead and the others had drifted all over the place, this was a 1980s NOS set of Tesla EL34s ( not JJs ) that cost me heaps and had only about 5 hours on them, they were gone, all I had in stock was a new set of JJ EL34Ls so I put em in, I couldn't believe my ears, they sounded great, so much better than the "better" tubes, sooooo much better. Now obviously seeing as one of the Teslas was dead you would expect some improvement with a new set even if they were JJs right? Well that being true I must say, the Teslas to my ears sounded the same from day one, so now I have come full circle as far as power tubes go, I started out with JJs years ago, have been forking out rediculous amounts for old stock and now I am finally back where I started.
    Unless I get a good deal on some Mullards, yeah right, that'll happen soon, I won't be throwing any more dough away on old tubes. For the price, I think JJs are the go, next would be =C= another good sounding tube but cost 30% more, then nothin. AND, at volume it's even harded to hear a noticable difference, throw in a pedal and whadiya got.
    I will say though that I still prefer old pre tubes over new production but the difference for some may be slight at best? It depends on the price of the old tubes whether they're worth it or not IMO. Tweaking amps, whether it be swapping out one brand of cap for another, or using CC or CF resistors, or swapping out tubes, it's all very subtle, of course, it does add up and for someone who can actually build an amp I think it's all for the better but for the guy who just buys an amp and then thinks a new set of tubes will improve it, mostly this will only be the case if there is a bad tube in there to start with, of course, this isn't the case for everyone but on the whole, I'd say NOS is an extravagant venture for power tubes. Just my opinion after wasting so much on them. Far better to get the best speakers, the best pickups, a good lead etc etc than throwing money away on old tubes.

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    As a kid I helped repair TV's (yah, a long time ago). Most often my job was to walk a grocery bag of tubes down to the drugstore to test on the tube tester. I'd end up with a pile on one side that really moved the needle and a pile on the other side for the trash. In the middle there was always a little pile of tubes that were not good enough to keep or bad enough to toss. I wonder where they ended up?

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    Yep, that sounds like the mongrels I been coppin.

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    I built a 5f2-a awhile back and have been using it to compare 12ax7s specifically. So far I have acquired some telefunkens(rather pricey) , bugle boy amperex(rather pricey) , RCA(ditto), GE, sovtek, Valvo, Tungsol(current production, I got a good deal on a wad of these to use to fire up first trial new builds), mullard and raytheon, sylvania etc.. These are mostly NOS as advertised. My observations are that there is quite a difference between these brands in the only preamp position this amp offers, but I'm happy to say I like them all. There are also subtle differences within specific brands as stated by someone earlier.
    The best part of this is that it's fun to experiment. I found temptation to cut out of work to check the mail for an expected tube. I have one Valvo that breaks up really radical. I don't know if it's a defect or what, but very reminicient of Niel Youngs Live Rust solo on Out of the Blue(or Into the Black, The more violent sounding one). This tube exhibits the most varied tone from all the others. Kind of limited (in a super good way), but it definately will have it's place.
    Another good point is when you find ones you like for whatever tone, it's almost as easy as pushing a button to use them.
    One bad point is that like building amps, you get very addicted. You look up one day and theres flippin' tubes everywhere. I had to move some of my amps to make room for them.
    Final footnote: The Tungsols that I bought so I wouldn't have to blow my expensive purchases sound good too. Now I'm on to testing current production tubes.

  26. #26
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    You do need to be careful substituting a different member of the 12AX7 family (12AT7, 12AY7, 12AU7). The lower gain tubes can drive more current, and more importantly, their bias voltages are generally higher. For example, Carvin drives a reverb tank off the plate of a 12AX7 without a transformer in the BelAir, Nomad, Legacy and MTS. Substituting a 12AU7 (ECC82) with higher bias voltage into the circuit with the stock 220 Ohm cathode resistor boosts the bias current even higher, and can cause the 12AU7 to overheat, threatening the vulnerable heater circuit. If the cathode resistor is under 680 Ohms, beware. Most subs are safe, but the bias current can still change, altering the tube's bias beyond what would be expected from the gain change. I only point this out because lots of sites promote free exchange without caveats. With this proviso, the 5751, 12AT7 and the ECC81 are almost always safe lower-gain substitutes. For higher gain, most vendors will select high-gain outliers for a small premium.

    What about a 12au in v3 of the Blues Deluxe. Is there a possibility of overheating. I've been advised by many that there is no problem. it doesn't hurt to have another opinion.

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    The PI tube is usually more tolerant to lo mu tube subs, as the tube draws more current, plate voltage drops & dissipation accross the plate resistor rises, but also cathode/tail voltage rises to with respect to ground...evening things up a little.

    If you are concerned, measure voltages at the PI node, then pins 1 & 6, then subtract the voltage at pin 8 from previous measurements. Square the voltage drop accross the plate resistors & divide by their value in ohms to get W dissipation...theoretically should be under 0.25W to be "safe as houses"...but be aware that plate resistors in modern Fenders fail anyway, even with a 12AX7...so I'd say use the tube you like best & if a plate resistor fails sub it for a better quality 1W job, there's no guarantee it will last forever with a 12AX7 anyway.

  28. #28
    FXA
    FXA is offline
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    Great and complete answer. Since I am not an amp tech I like the second part of the answer best. It is a 1/2 watt resistor.

  29. #29
    daz
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    My experience is that tubes CAN and sometimes do make what I at least consider a big difference. Put it this way....from the worse to the best (from my ear's perspective as to whats worse and whats best) the margin is wide enough that i might sell an amp for how it sounds with the worse tubes in it, yet might consider it a very good am,p with the best in it. I do agree with Enzo in general tho, which is to say the majority of them are close enoufg so that most people won't hear the diff or won't care.

    As an example, if i HAD to use only the new tung sol 34's in my amp i would have to start using a different amp. With EH or several others i find my amp absolutly bonerific. There is that much difference to my ears between those. As for preamp tubes, i don't find as much difference as i do with output tubes, but enough that i can be somewhat disappointed in my tone with certain ones. But i could still use those and be relatively happy.

    There is no yes or no answer to whether or not tubes make a considerable difference. What it really comes down to is the individual and how sensitive they are to tone and feel and what thier expectations are.

  30. #30
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    I think it helps to think about this subject in terms QC and economics. I don't think the modern production plants can afford to pay sorters what they were paid 60 years ago and I doubt they can afford to keep their overall QC at the same level that giants like RCA and Western Electric could in their heyday. Poor performers came off the assembly line in 1945 and 1995. The modern market for tubes is a fraction of what it used to be and for all the plungers there's plenty who love the idea of a 'matched' quartet of 6550s at bargain bin prices. If someone is willing to take a chance on a Chinese special that costs 1/8 as much as modern premiums or NOS then it makes sense for a manufacturing facility to crate those up for sale instead of what may have happened to those same tubes in a different era - crush them.

    If some tube hawk has ten cases of a tube nobody would give a buck and a quarter for one day and within a week the market jumps to $50. apiece - count on hearing more marketing copy filled with just the right set of adjectives most seekers want to hear. The reasons behind the boom can be complex. Maybe a grain of it is based on some real world valid performance observation. Once it gets past a certain point the chasing mentality takes over and for some - I honestly believe there are those who simply choose to spend exorbitant amounts on whatever is currently top dawg on the must have list just so they can say they've got it - pure prestige buying. 800.00 for a piece of glass that has a tax value of 2 pennies.

    And lastly, a little pyschology. When someone drop 300 bucks each on some NOS 12AX7s and sticks them in their Marshall . . . they have to sound good if you know what I'm getting at. When faced with the reality that $900 worth of preamp tubes doesn't really sound that much better - if at all - than any of the dozens of modern X7s they've already 'experimented' with would be a hard egg to swallow.

    I do think there is some validity to the assertion that some NOS power tubes can withstand higher plate voltages than some modern equivalents, but I see that as more of a QC/ durability issue than tone or sound quality.

  31. #31
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    Make no mistake. There were tubes MFG'd back in the day that absolutely ARE superior in every way (including tone) than anything MFG'd today. That isn't to say that there aren't any good tubes being made today, there are. But you really need to pay extra or buy and weed yourself to get performance. Your comment about less $$$ for sorting is spot on. There are sellers that do the sorting and charge a premium... It's usually worth it. And the sound difference??? Well, it's hard to quantify. When every thing is just right you REALLY know it. And NOS (select brand, year, make) are the best you can do. But I can't afford the stuff that's become so expensive and I design with currently MFG'd tubes for this reason. I might quantify the difference as 5 to 10%. That can be a huge amount in the first preamp slot. The signal of which is often amplified some thousands of times. But for every other preamp tube I use currently MFG'd tubes. The Sovtek 12ax7LPS would be just great if it wasn't prone to microphonics. And it's all QC. Back in the day there were plenty of long plate tubes made that didn't squeal. But tone wise the LPS is just great and I do use it for most everything but the first position.

    JM2C

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