theamericanwinter
Member
How often should I change the 12AX7's? Are Mullards the best? or should I just use Mesa? What are my options?
Mark IV preamp tubes
- Thread starter theamericanwinter
- Start date
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Yes, replace all your pre-amp tubes with NOS Mullards. In six months you should replace them all again. As they will then be worthless, I will graciously take them off your hands for 50 cents a piece.
theamericanwinter
Member
Sorry, but I keep all my old pre amp tubes... between my old Mullards and the large vibrating egg I have near the bed, my wife stays always happy 
...
Besides, I prefer the TungSol...
...Besides, I prefer the TungSol...
mystidream
Well-known member
I just put Groove Tube 12AX7's in mine, and I love the way it sounds. I have 2 Mesa 6l6's in the inside sockets, and 2 Groove Tube EL-34's in the outer sockets. They give it a nice meaty tone. I've heard nothing but good things about Mullards.
Generally, NOS or Old Tubes are much much better in quality and tone. Preamp tubes last for ever, and rarely need to be changed. The only reason you should change a preamp tube is because it is going microphonic. NOS/Old tubes will last MUCH longer than any new production tubes. They just don't make them to spec these days, and for good reason; there is much less demand for tubes, and there are not stringent quality specs to be met.
Back in the day, the military used a ton of tubes, and manufacturers made more rugged tubes specifically for military uses. NOS tubes with a 'WA' 'WB' and 'WC' at the end were typically Military Spec tubes, and had extra reinforcement, were made to be structurally robust, possibly gold plated pins, and higher quality materials and of course much higher quality control. They are sometimes numbered differently, 12AX7A = 7052 = 6681.
New tubes with the "W" postfix are worthless, and usually no different than a regular tube. The problem with new tubes is that even if they are made on the same equipment from the 50's/60's (such as some chinese and russian tubes) the people who now make them are basically clueless to the old production methods. Workarounds for specific problems will be different now, and quality control is low.
Any modern company will try to make it cost effective to produce (read: cheap components = low quality) so that they can turn a profit. Coupled with simple economics (low demand = higher cost, as well as relatively low competition) you get crap tubes that sound nowhere near the real thing, don't last anywhere near as long, made of inferior components by people who don't understand the physics/mathematics of how tubes work.
Very few people know specifically how tubes are designed, why they are designed in such a way, as well as the necessary electronic knowledge to design new ones (or modify existing designs) or trouble shoot them. Most techs have a vague idea of how tube amps are designed, but most know only how to trouble shoot common electrical problems (read: component failures). Very few techs can design a new amp, or do a good job on mods, much less design their own mods. How many Analogman's or Keeley's do you see? How many Mike B's are left? And how many amps have you seen with botched mods?
To answer your question, NOS tubes are great, but can be a gamble. You may not be getting the "advertised" tube on ebay. Many sellers often know **** about tubes, and could inadvertently sell you what they think is a "rare" Mullard, but is actually a re-branded RCA. You also take a gamble on microphonics, tube life, and other factors.
In the long run it doesn't matter so much as you like how the tube sounds. I would suggest getting a handful of old tubes, nothing overly expensive so that you don't end up getting burned, and trying them in various positions in your amp. I was fortunate enough to have 6 such tubes given to me by a friend as a gift, and I treasure them (and use them) everyday. You can find relatively cheap NOS or Used Old tubes on ebay for cheap, or you can buy NOS tubes that have been tested from thetubestore.com or dougstubes if you feel like coughing up some extra dough for peace of mind.
You will find that different tubes sound different in different spots in your amp, and by mixing and matching, you can drastically change your amps tone.
12AT7s are great for the Phase inverter spot (or the V1 spots for gain)
12AU7's are great for overdrive and clean, but have MUCH less headroom and they suck for distortion since they lack gain (read: signal will be quieter)
12AX7s are great for high gain and are standard in every amp
NOS tubes will sound different based on what decade they were made in, what company actually produced them, what country they came from, the plate size/configuration, the shape of the getter, grade (Mil-Spec, High End British Tubes, etc), length of life (tho its is longer than any new production tube by leaps and bounds). Most NOS tubes are interchangeable, so a 12AX7 = ECC83, and can be swapped for a 12AT7, 12AU7, 12AV7, 12AY7, etc.
in my opinion, and from experience, Preamp tubes affect the overall sound more-so than power tubes. Powertubes have more to do with tone when overdriven, and when run clean (read: simply amplify the signal coming from the preamp) have very little effect on the overall tone. The amp being used, and therefore the basic circuit has a much greater impact on the tone. If you run a Marshall with the same tubes as a Boogie, you will not get anywhere near the same tone because the circuit is so radically different that the tubes effect on tone is minimal in comparison.
It is not that tubes do not matter, it is that there are OTHER factors that ALSO play a large (if not larger) role in determining your tone. One such example is your style of playing and technique. Fingers determine tone more than equipment.
::end rant::
Back in the day, the military used a ton of tubes, and manufacturers made more rugged tubes specifically for military uses. NOS tubes with a 'WA' 'WB' and 'WC' at the end were typically Military Spec tubes, and had extra reinforcement, were made to be structurally robust, possibly gold plated pins, and higher quality materials and of course much higher quality control. They are sometimes numbered differently, 12AX7A = 7052 = 6681.
New tubes with the "W" postfix are worthless, and usually no different than a regular tube. The problem with new tubes is that even if they are made on the same equipment from the 50's/60's (such as some chinese and russian tubes) the people who now make them are basically clueless to the old production methods. Workarounds for specific problems will be different now, and quality control is low.
Any modern company will try to make it cost effective to produce (read: cheap components = low quality) so that they can turn a profit. Coupled with simple economics (low demand = higher cost, as well as relatively low competition) you get crap tubes that sound nowhere near the real thing, don't last anywhere near as long, made of inferior components by people who don't understand the physics/mathematics of how tubes work.
Very few people know specifically how tubes are designed, why they are designed in such a way, as well as the necessary electronic knowledge to design new ones (or modify existing designs) or trouble shoot them. Most techs have a vague idea of how tube amps are designed, but most know only how to trouble shoot common electrical problems (read: component failures). Very few techs can design a new amp, or do a good job on mods, much less design their own mods. How many Analogman's or Keeley's do you see? How many Mike B's are left? And how many amps have you seen with botched mods?
To answer your question, NOS tubes are great, but can be a gamble. You may not be getting the "advertised" tube on ebay. Many sellers often know **** about tubes, and could inadvertently sell you what they think is a "rare" Mullard, but is actually a re-branded RCA. You also take a gamble on microphonics, tube life, and other factors.
In the long run it doesn't matter so much as you like how the tube sounds. I would suggest getting a handful of old tubes, nothing overly expensive so that you don't end up getting burned, and trying them in various positions in your amp. I was fortunate enough to have 6 such tubes given to me by a friend as a gift, and I treasure them (and use them) everyday. You can find relatively cheap NOS or Used Old tubes on ebay for cheap, or you can buy NOS tubes that have been tested from thetubestore.com or dougstubes if you feel like coughing up some extra dough for peace of mind.
You will find that different tubes sound different in different spots in your amp, and by mixing and matching, you can drastically change your amps tone.
12AT7s are great for the Phase inverter spot (or the V1 spots for gain)
12AU7's are great for overdrive and clean, but have MUCH less headroom and they suck for distortion since they lack gain (read: signal will be quieter)
12AX7s are great for high gain and are standard in every amp
NOS tubes will sound different based on what decade they were made in, what company actually produced them, what country they came from, the plate size/configuration, the shape of the getter, grade (Mil-Spec, High End British Tubes, etc), length of life (tho its is longer than any new production tube by leaps and bounds). Most NOS tubes are interchangeable, so a 12AX7 = ECC83, and can be swapped for a 12AT7, 12AU7, 12AV7, 12AY7, etc.
in my opinion, and from experience, Preamp tubes affect the overall sound more-so than power tubes. Powertubes have more to do with tone when overdriven, and when run clean (read: simply amplify the signal coming from the preamp) have very little effect on the overall tone. The amp being used, and therefore the basic circuit has a much greater impact on the tone. If you run a Marshall with the same tubes as a Boogie, you will not get anywhere near the same tone because the circuit is so radically different that the tubes effect on tone is minimal in comparison.
It is not that tubes do not matter, it is that there are OTHER factors that ALSO play a large (if not larger) role in determining your tone. One such example is your style of playing and technique. Fingers determine tone more than equipment.
::end rant::
