How many extra tubes do you keep stashed per amp?

[Gear_Junky]

I figure that "polls" never cover every possibility, so it's better as a discussion. But I suggest the following data points (feel free to add your own):

1) Are you a weekly gig/rehearsal player or a hobbyist playing at home
2) How many sets of power tubes for each amp do you keep in reserve? (share which tube types)
3) How many sets of 12ax7 preamp tubes do you keep in reserve?

I'm the type that doesn't like to run out (i.e. I had a full box of strings from when I last played 8 years ago). And I don't like to pay shipping for when I need a small item in a hurry. But tubes aren't cheap and without testing equipment buying up a bunch of tubes to stash is risky (I won't know if I got a dud until later).

An extra set of power tubes per amp probably makes sense, but with preamp tubes lasting much longer it's probably not as important to have many extras? I have around 10 different 12ax7 in a box from when I decided to "audition" them. All different kinds (which turns out to be mostly Sovtek or JJ, there's one Chinese tube there). And I also have a Hammond 12au7 (pulled from an old organ), a 12ay7 and a 12at7 - when I was going to try lower gain tubes. My 4 amps need 8 12ax7 tubes total, so this is not unreasonable, I wonder if I need more

[nomadh]

Similar for me on preamp tubes. Maybe a few more. If you buy tubes always run them through your amps before you put them away as spares. Even a tube tester wont tell you if they sound good. Not even if they are microphonic.. power tubes are more likely to be needed. I always have at least a spare set not per amp but per type of tube. Really just el84 and 6v6 for me. I do need a couple other oddballs but I dont depend on those amps.
I was gigging my crate c30 but that probably wont be happening soon.

[andrewsrea]

How many do I recommend for a tube amp owner, or do I personally have in ratio to the amps I own?

[Gear_Junky]

How many do I recommend for a tube amp owner, or do I personally have in ratio to the amps I own?

I'll take both, please
I am trying to avoid spending money while also looking for an excuse to spend money
And there's also a tele switch that I can save a few bucks on by getting free shipping if I order nine 12ax7's. That's me - I save money by spending in bulk.

[Gear_Junky]

If you buy tubes always run them through your amps before you put them away as spares. Even a tube tester wont tell you if they sound good. Not even if they are microphonic..

Point well taken! And I figure it's cheaper to buy a little single EL84 amp than a tube tester, and more fun!

I always have at least a spare set not per amp but per type of tube. Really just el84 and 6v6 for me.

Same here - 6V6 for the SCXD and EL84's for the Palominos, but the V16 would need matched duets, while the V32 - matched quads, so I'd probably have a set for each one. But you don't figure you need more than one spare set? Who knows what the next "shortage" will be

[mickey]

I have three amps that use a matched set of 6V6's for the finals.
All three use 12AX7's.
I have a spare set of matched 6V6's.
No spare 12AX7's. You can always snitch one from another amp (that you aren't using at the moment.)

[Chocol8]

If you have almost enough* amps, then you generally have plenty of tubes to borrow from. I also save older but still working tubes to use as emergency spares, or to test amps I am working on. I never buy a new tube with the intention of it being a spare.



*Enough amps is defined as the number of amps you currently have plus at least one more.

[Gear_Junky]

I have three amps that use a matched set of 6V6's for the finals.
All three use 12AX7's.
I have a spare set of matched 6V6's.
No spare 12AX7's. You can always snitch one from another amp (that you aren't using at the moment.)

That is precisely why/how I have two SCXD's. One is currently loaned out to a friend along with a guitar. But I was thinking that stealing a tube from a second amp is twice the hassle/work

[mozz]

How many tubes do i hoard? Probably close to 8,000 or more. How many for guitar amps(old amps and new amps)? Maybe 500-1000, not sure. I use new stuff when i build amps, then dig through the boxes and put old stuff in when i'm sure it's not going to blow up or red plate. I do use Sovteks or JJ's but i don't put old Mullards or RCA's in a amp i am selling. If i was ever to play out again or just jam i would have a complete set or extras in my bag.
I don't count chinese/russian new production tubes.

common
6V6 165
6L6 27
6BQ5 33
6973 8
7189A 10
12AX7/A  92
12AY7/A  13
EF86    11
5Y3GT  55
5U4GB 87
5AR4/GZ34 9

uncommon
6SC7 21
6SH7  27
6SJ7 70
6SL7 41
6SN7 90
6AQ5A 96
6CZ5 6
6K6GT 66
5V4G 15
6P14P-K 60
6C10 4
6CA4 10
7C5 25
12AT7     308
12AU7/A   83
12AV7      26
12AZ7/A     12
12BZ7     12
5879 19




tubes i use to build with that people have no idea
6GK6 63
6AR6 36
6AN8 25
6AB4 10
6BG6G 25
75 35
6201 34
6211 154




tubes i have lots of and on the experimental list
6AU6/A 348
6AW8/A 271
6CL6 280
6DJ8/ECC88 64
6GH8/A 82
6J6/A    247
6U8A 131
12B4A       392
12BH7 45
12BY7A   55
2013 25
5517 25
5965/A    39
6414 17

[Gear_Junky]

How many tubes do i hoard? ...

The man with a list! Now I know it's serious

I made a spreadsheet of what I have (although mostly in single digits - tube types and actual tubes in stock), but it helps visualize what I have.

But you're a man to ask: I have a few Hammond tubes - a [presumably matched] duet of 6V6, a 12ax7 and 12au7. I pulled them from a working unit. Do these have any value? The 12's have a taller (longer) plate than guitar 12ax7's like JJ or Sovtek. Not sure of the hours, but as I understand they don't work as hard in organs vs. guitar amps.

[mozz]

Actually i think they work about the same. Chances are they are long plates 17mm or 19mm, i forget the exact "boutique terminology" . 12au7 is kind of useless in a guitar amp unless you are putting it in a fender reverb driver spot to tame it somewhat. Forget the matched bull. I can almost bet everyone here would prefer the sound of unmatched output tubes. Your phase splitter or driver is way more unmatched just due to design. Power tube distortion sounds good, you only get it when really cranked up. So if your output tubes are not matched, one side will clip before the other, thus causing distortion when not fully cranked. Really mismatched tubes could cause problems. If the tubes are of the same brand, that is as matched as you really need. Preamp tubes matched? Biggest line of bullshit ever. Look at the schematic, follow the circuit, there's nothing to match. Now if you are running a home stereo, and each side of the tube is split between channels, you would want it matched.

Buy a bias rite or other brand tube bias checker. You will see how far off they really are, but your mileage will vary due to your output transformer not being equal on each side and your phase splitter not being equal.

[Gear_Junky]

Forget the matched bull. I can almost bet everyone here would prefer the sound of unmatched output tubes. Your phase splitter or driver is way more unmatched just due to design. Power tube distortion sounds good, you only get it when really cranked up. So if your output tubes are not matched, one side will clip before the other, thus causing distortion when not fully cranked. Really mismatched tubes could cause problems. If the tubes are of the same brand, that is as matched as you really need.

I always value info like this. Question, does that still apply to Class A/B push-pull amps? Personally I wouldn't be overpaying for this, Amplified Parts doesn't charge extra for ordering "matched" duets or quartets (in fact, it might be a tad cheaper per tube). Perhaps they agree with you by giving the customers what they need while telling them what they want to hear - kudos to them for that.

Preamp tubes matched? Biggest line of bullshit ever. Look at the schematic, follow the circuit, there's nothing to match. Now if you are running a home stereo, and each side of the tube is split between channels, you would want it matched.

Yes, this much I knew, but still thank you. I saw on eBay today a set of tubes for Epi Valve Jr. (single 12ax7 and single EL84) advertised as a matched set

[andrewsrea]

How many do I recommend for a tube amp owner, or do I personally have in ratio to the amps I own?

I'll take both, please
I am trying to avoid spending money while also looking for an excuse to spend money
And there's also a tele switch that I can save a few bucks on by getting free shipping if I order nine 12ax7's. That's me - I save money by spending in bulk.

Lol. For a tube amp owner, I recommend spare output tubes or tube. If you have more than one, I recommend matched tubes for the inverter being unbalanced as [mention]mozz[/mention] mentioned. Do not travel with them, as jostling is one of the enemies of vacuum tubes.

If you like your tone, no need for spare 9-pin preamp tubes such as the 12A*** variety (the smaller tubes). Those are extremely durable. I have ones from the 50's that still test out great and sound exquisite.

If you are interested in trying different tones by changing out the 9-pin types, buy a few of different gain and current structures and roll tubes!

Like [mention]mozz[/mention] what I have in stock greatly exceeds what I require. In the mid-80's to around 2002, I was a repairman as a second income. I was quite sought after in the Philadelphia area, especially as the local gurus from the 50's and 60's retired. I was the primary repairman for seven music stores, being a certified Marshall, St. Louis Music (Crate, Ampeg and others) Gallen Kruger and Hughes & Kettner warranty repairman (Fender did not want me and Courtland Gray was a total douche to me when I applied for Peavey, so I did not continue with them). I was the first Groove Tubes distributor in the North East, having great conversations with Aspen Pittman and his top sales person at the time, Jim (I cannot remember his last name). I also have an Electro Harmonix account (Sovtek, EH Tubes, Tung Sol, Mullard, Gold Lion) and became well acquainted with Owen Mathews, founder Mike Matthews' son. Also at that time, old radio & TV repair guys or their widows would donate their stock.

With the help of a tube tester that [mention]golem[/mention] got for me and some other test equipment, I've sorted all the good stuff, the stuff I keep for repairing (that I don't mind if they blow-up) and divested the rest. The best of my stock (IMHO) are loaded into my amps.

IMHO and FYI: I believe there are really fantastic new tubes available today to the tube amp owner. Yes some of the old stuff can be stellar, but a lot of it is fake or used up. Unless you have a really credible source (like Mozz), I'd stick with new.

Hope this helps!

[golem]

I keep zero extra. I just get them from [mention]andrewsrea[/mention] when I need them. LOL.

[Gear_Junky]

One more question: any issue storing vacuum tubes near guitar pickups (magnets)? We're talking in padded boxes, so no risk of crushing damage, just magnetic field nearness? Thank you.

[andrewsrea]

One more question: any issue storing vacuum tubes near guitar pickups (magnets)? We're talking in padded boxes, so no risk of crushing damage, just magnetic field nearness? Thank you.

I don't believe that tubes are affected by magnetism. Shaking, vibration and temperature swings are the enemy of tubes. It causes the vacuum to weaken and once air is introduced, it creates shorts and burn-out.

Aspen Pittman once told me he though tubes would 'last as long' if kept 'on' in an amp operating to spec, as if they were NOS in boxes. He said heating and cooling were the #1 killer of tubes and #2 was enduring shaking when cooling.

[mickey]

Rob, you have reminded me that back in the tube era much top quality equipment (think Rockwell-Collins, H-P, Mackintosh, etc) had no way to turn the filament supplies off
(aside from unplugging them from the mains.)

[Gear_Junky]

I don't believe that tubes are affected by magnetism. Shaking, vibration and temperature swings are the enemy of tubes. It causes the vacuum to weaken and once air is introduced, it creates shorts and burn-out.

Aspen Pittman once told me he though tubes would 'last as long' if kept 'on' in an amp operating to spec, as if they were NOS in boxes. He said heating and cooling were the #1 killer of tubes and #2 was enduring shaking when cooling.

Awesome, thank you! Don't they still use vacuum tubes in space electronics? I thought Russians do. I could be wrong, I just thought I'd heard that somewhere.

[mozz]

Stolen from the web.
In the 1970's, it was discovered that vacuum tubes have about 10 million times more hardness against EMP than integrated solid-state circuitry.

About the shaking and colling, the same applies to headlights. If you are driving and turn them off, while they are cooling off the filament is at it's weakest. Potholes will shorten their life. Once cold they are stronger. Now cars with automatic headlights, you would have to manually leave them on until you parked.

[Chocol8]

I don't believe that tubes are affected by magnetism. Shaking, vibration and temperature swings are the enemy of tubes. It causes the vacuum to weaken and once air is introduced, it creates shorts and burn-out.

Aspen Pittman once told me he though tubes would 'last as long' if kept 'on' in an amp operating to spec, as if they were NOS in boxes. He said heating and cooling were the #1 killer of tubes and #2 was enduring shaking when cooling.

Awesome, thank you! Don't they still use vacuum tubes in space electronics? I thought Russians do. I could be wrong, I just thought I'd heard that somewhere.

The radiation in space is literally murder on standard solid state electronics, so they need to use beefed up shielded hardware, or something less susceptible.

[andrewsrea]

Don't they still use vacuum tubes in space electronics? I thought Russians do. I could be wrong, I just thought I'd heard that somewhere.

Yes. Traveling-wave tubes (TWTA's) for microwave communication frequencies. At least for American and European satellites.

Soviet and post-Soviet countries used tubes in other functions, as [mention]mozz[/mention] and [mention]Chocol8[/mention] mentioned, for their 'radiation hardness /survivability.' The problem, as we all know, is that tube-tech is exponentially heavier than solid-state. Especially today's micro surface-mount with digital switching, etc. I believe each extra pound of weight cost around $100K in today's dollars in the 70's, which caused the US to move to rad-hard solid-state components.

For example a design may use a dual op-amp like a RC4556 (just like a tube screamer), except high performance like a LM4562. They are coated in a doping which helps them survive and a lab would hook hundreds into operational test rigs and subject them to multiple 'environmental tests,' like shake, vibration, shock (about 32g force), high doses of radiation and electro-magnetic radiation. The samples that survived multiple e-tests are used in the spacecraft, tank, aircraft, etc.

Russians also used vacuum tubes with their bomber and fighter aircraft, the last being the MiG25. I actually replaced tubes in a MiG-21 an American person I met, bought from Poland. There were so many, that the tubes were considered the heat source for the pilot at high altitudes. That job was a challenge, as we had to get a translator to read the tube types & specs, then I had to translate those specs into American substitutes, just to test the tubes. We found the bad ones and found replacements, some Russian and some American.

[Gear_Junky]

Awesome stuff, guys! I never thought we'd be talking about that here
I saw that Tube Depot has a 15% off coupon (for 1st time email list subs), and I wanted their tele switch, which was a couple of bucks less than elsewhere and to get free shipping, so I went ahead and got nine 12ax7 JJ's. I wanted to retube both my Palomino amps, so it's really not excessive.

Power tubes I'll get from Amplified Parts as they have sets, better prices/selection and also free shipping over $89.

I've read in a few places that JJ 12ax7 are better made than anything Sovtek or Chinese in terms of being exactly like American 12ax7 spec. That supposedly the Soviet bloc tubes are approximations, not equivalents. I don't know if this is true at all, but for some reason JJ's are touted as more robust (not by sellers). Any knowledge on this beyond opinion/perception? And does this also go for power tubes like EL84 and 6V6?

[fatjack]

I don't keep any spares on the theory I'll have one tube and one solid sate amp to use until I replace what I need too. It's not like I'm gigging or recording an album to release.

[archetype]

One more question: any issue storing vacuum tubes near guitar pickups (magnets)? We're talking in padded boxes, so no risk of crushing damage, just magnetic field nearness? Thank you.

I don't believe that tubes are affected by magnetism. Shaking, vibration and temperature swings are the enemy of tubes. It causes the vacuum to weaken and once air is introduced, it creates shorts and burn-out.

Aspen Pittman once told me he though tubes would 'last as long' if kept 'on' in an amp operating to spec, as if they were NOS in boxes. He said heating and cooling were the #1 killer of tubes and #2 was enduring shaking when cooling.

Right. A typical magnetic field (guitar pickup, speaker) has no affect on audio tubes. In many amps, one or more tubes are within an inch of the speaker's magnet: this has no affect on the tubes.

[RayStankewitz]

I have 2 full sets for my Music Man HD130 bass head. 8 each 6CA7 power tubes, 2 each ECC83S phase inverter tubes. I was only going to get 1 full set so they could be used when the amp gets a cap job and bias set but a possible second MM, a 410 HD130 popped up for sale/trade. going to look at it this week. If it doesn't pan out, I have two sets for the HD130 head I already have.