How many extra tubes do you keep stashed per amp?

[Tonray's Ghost]

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.

With the Russia sanctions you may need to travel to the international space station to restock

[LancerTheGreat]

When I was gigging and having weekly practices, I kept a heaping 0 backup tubes.

Now that I'm not gigging or having band practice every week I'm up to a whopping none lol.
I could stand to pick some up, but I've been (and still am) too broke to pick anything up as a spare.

[BatUtilityBelt]

I only have 8 to 10 odd tubes around for swapping, and I'm not going to worry about it.

Here's an example of why. I have an Edison phonograph from the 1920's. We occasionally play records on it and don't worry about it. We can still buy needles, and if the spring were to break, I would be able to buy a replacement for that too. Where there is demand, there will be supply, just not necessarily as cheap as its lowest point.

[andrewsrea]

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.

I haven't seen too many Music Man HD130's and only worked on a few. Wonderful amp.

[JimyTheAssassin]

I only gig a couple of my amps (the others stay home) so most of what I have is for fun or tube rolling. I always carry a spare set after getting to a gig and realizing a sovtek 12ax7 died from being put down hard. It happened when a friend carried it for me. Whoops.

I have a stash of tubes that would be fun to build with (someday) but like mozz listed, many aren’t typical types. I guess you could say I started collecting them but only because most are overlooked and cheap or free. Someday I’ll finish my VHT 36 watt Handwired amp but it will probably have 6gk6 and 6eu7 instead of el84 and 12ax7.

As for the common types of power and preamp tubes, I have a plethora that I’ve gotten cheaply over the years (Mullard, amperes, rca etc.). Lots of 6v6 tubes but not many power tubes bigger than that.

I took a good look at what I didn’t have any backups of and purchased them more so because prices will likely jump and I have cash now.
Those I rarely/never come across but wanted are EL34, 6ca7, 6550, 12ay7, 12dw7 and 5751.

I’ll be completely honest. I have way too many tubes for my needs but it won’t stop me from buying more if the price is right. One day when I’m not so busy growing a family, I hope to wade through them all

[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.

I haven't seen too many Music Man HD130's and only worked on a few. Wonderful amp.

I love the stupidly huge overhead all of the MM amps have. My favorite combo for bass is a MM HD130 with a pair of the 212 Reflex Horn cabinets, top cab up side down for effect. They move stupid amounts of air, to the point you don't want to stand in front of them at a gig. I can still hear my band mates screaming for me to turn it down! I never had to dime my amp to keep up with our drummer or the lead guitarist. I play it on "2" channel, "5" master in my music room. Mine is also a tube inverter amp using an ECC83S for that duty.

Next project that will be on the bench is a Kay 703C "Widowmaker" amp. Needs a recap of that multi-cap, isolation transformer and three conductor cord. I'm just hoping the tubes are okay, since if I remember right, they are real weird tubes. The filaments are all in series, connected to 110V with a resistor to limit voltage.

[mozz]

Just did a widowmaker, put the tubes in series, the rectifier was used as a dummy and put solid state diodes in for the bridge. Isolation transformer was from Mouser about $20.

[JimyTheAssassin]

Just did a widowmaker, put the tubes in series, the rectifier was used as a dummy and put solid state diodes in for the bridge. Isolation transformer was from Mouser about $20.

So it went from having a half wave rectifier to a full wave essentially? Would that improve the sound any in your estimation. All else being equal


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[Rollin Hand]

I have no backup tubes, but I changed the preamp tubes in the Classic 20 a while ago, and the 6505MH shouldn't need any yet.

I hope.....

[mozz]

Just did a widowmaker, put the tubes in series, the rectifier was used as a dummy and put solid state diodes in for the bridge. Isolation transformer was from Mouser about $20.

So it went from having a half wave rectifier to a full wave essentially? Would that improve the sound any in your estimation. All else being equal


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Actual B+ voltage went up a bit so i did have to add a resistor, still a little higher than the schematic penciled voltages but i'm fine. Series filament voltages had a resistor also and i had to up that a bit to get a even 150ma draw on all the tubes. Ended up being a 10 watter because it was pretty warm. Being a class A single ended amp, no difference to the sound, slightly less hum with my CRCRC filtering. 2.3 watts only goes so loud but my friend wanted it for recording mostly. All the way up with single coils it does start to get a little bit dirty.

[Tonray's Ghost]

We used to have an old Emerson tube radio (circa 1950s) in my mom's kitchen, I don't ever recall keeping spare tubes and that thing was still working (although the tuning knob was a bit dodgy) when we sold mom's house in 2003.

[Rollin Hand]

I have no backup tubes, but I changed the preamp tubes in the Classic 20 a while ago, and the 6505MH shouldn't need any yet.

I hope.....

I should add that I do have a box of my dad's tubes from when he was a TV/radio repairman. I have no way of testing them (I sold his tube tester, and even then, I didn't know how to use it), but they are in a box in my basement.

[andrewsrea]

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.

I haven't seen too many Music Man HD130's and only worked on a few. Wonderful amp.

I love the stupidly huge overhead all of the MM amps have. My favorite combo for bass is a MM HD130 with a pair of the 212 Reflex Horn cabinets, top cab up side down for effect. They move stupid amounts of air, to the point you don't want to stand in front of them at a gig. I can still hear my band mates screaming for me to turn it down! I never had to dime my amp to keep up with our drummer or the lead guitarist. I play it on "2" channel, "5" master in my music room. Mine is also a tube inverter amp using an ECC83S for that duty.

Next project that will be on the bench is a Kay 703C "Widowmaker" amp. Needs a recap of that multi-cap, isolation transformer and three conductor cord. I'm just hoping the tubes are okay, since if I remember right, they are real weird tubes. The filaments are all in series, connected to 110V with a resistor to limit voltage.

IMHO, the tube inverter amps are the best of that model!

[JimyTheAssassin]

Just did a widowmaker, put the tubes in series, the rectifier was used as a dummy and put solid state diodes in for the bridge. Isolation transformer was from Mouser about $20.

This may be off topic but I was brainstorming the other day on “what if” you wished to put a full wave rectification in one of these widow makers. It’s line level so even if you add an isolation transformer to make it safe, you still need a center tap. Right? Am I crazy here I was staring at schematics and I couldn’t find an example where a transformerless widow maker had a full recto. Understanding the reasons of using a half wave rectifier for filament and cost, could a full wave be added hypothetically without creating a headache ?


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[mozz]

Isolation transformer can have a center tapped secondary, or not. Easiest thing is using a bridge rectifier.

[backinit]

I actually have quite a few 6L6GC and EL34 tubes. Not so many preamp tubes, but a few and some retro valves as well.

[Partscaster]

I just keep some extras for the more used amps. 12ax7s' I probably have 4-6 in a drawer. Probably 1 or 2 12ay7s in that drawer.
I may stock a full set for one amp with unusual tubes i.e. 6973. I think those are NOS RCAs.
If a more used amp goes down I have some fairly close redundancy amps to fill the time it takes to get what I need. The switch would do me good.

While Russian sources may be a trouble, I found one seller who buys from a Ukrainian that bought a Ukrainian warehouse full of Russian tubes.

[tonebender]

There might be some tubes out there in the garage somewhere in a box. I will just say none. I have a few small tube amps and if one goes down I sub in another. Then I order tubes if need be but I normally take the amp in to my guy. If only had one amp, I would definitely keep a set or two of spare tubes.

[mickey]

I thought for a moment there that after years of being A.W.O.L. that @Gear_Junky had returned!