NOS / Old Stock Tube experience

[Mike_LA]

The venerable 12AX7, a staple of most of our amps.

New tubes / Old Tubes, ah the eternal internet debate.


Just a quick take on my experience, owning (2) 6101s,thats 14 right there, a pair of 1 watt marshalls is another 8, need I go on?
From the musiciansroadhouse I developed a rather negative bias towards JJ tubes and I started buying NOS RCA and GE tubes on-line. The idea was to buy old glass but not go over what a new tube would cost. I ended up with about 25 (not counting the ones working in amps). About that time Pete posted his new top of the line tube tester rigs, so we made a deal, and I sent him all 25 for testing. Quite a few were labeled NOS (New Old Stock) but I have found, unless it's in it's original box with perfect lettering, it is no wheres close to New. I've been using what came back as good and they have all worked pretty well. Yah some sound less harsh than others.

Up until yesterday.
I've been firing up the 6L6 loaded 6101 almost everyday and it's been a joy to play.
Then, because no one was home I started to really push the amp. Wow, a couple of those creamy smooth sounding tubes were crazy microphonic. Tube testers don't usually generate enough power to test for microphonics . Great at low volume but not so much pushed . .
I went thru 8 finding a nice quiet set. Going to have a look at the new market once my stash runs out.

 

[Matthews Guitars]

I've found that it's rare to find tubes that have high gain, low noise, and low levels of microphonic behavior. They're gold when you find them. Since I don't usually play with blistering levels of gain, I pick tubes mostly by noise and microphonic levels.

In general I favor GE tubes for the V1 of a JMP era Marshall. They seem have a nice balanced tone.

 

[FleshOnGear]

I don’t hear huge differences between most of the vintage 12AX7/ECC83s I have. To me the standouts (out of the ones I’ve tried) are:

Long plate Mullards (mC1 and f91)
Smooth plate Telefunkens
Tesla E83CCs
Black plate Raytheons
Sylvanias (sideways plate? Not sure what they’re called)

These are the ones that seemed to sound most unique to me. My favorite is the Mullard, but the two long plate Mullards I have became microphonic at some point. I have yet to try them in my 4-hole amps, to see if they hold up ok in them.

I had a favorite current production 12AX7, which I thought sounded a lot like an I63 Mullard, but it was a Shuguang. I have enough vintage tubes to not bother testing any of the newer current production preamp tubes.

 

[Jethro Rocker]

The venerable 12AX7, a staple of most of our amps.

New tubes / Old Tubes, ah the eternal internet debate.


Just a quick take on my experience, owning (2) 6101s,thats 14 right there, a pair of 1 watt marshalls is another 8, need I go on?
From the musiciansroadhouse I developed a rather negative bias towards JJ tubes and I started buying NOS RCA and GE tubes on-line. The idea was to buy old glass but not go over what a new tube would cost. I ended up with about 25 (not counting the ones working in amps). About that time Pete posted his new top of the line tube tester rigs, so we made a deal, and I sent him all 25 for testing. Quite a few were labeled NOS (New Old Stock) but I have found, unless it's in it's original box with perfect lettering, it is no wheres close to New. I've been using what came back as good and they have all worked pretty well. Yah some sound less harsh than others.

Up until yesterday.
I've been firing up the 6L6 loaded 6101 almost everyday and it's been a joy to play.
Then, because no one was home I started to really push the amp. Wow, a couple of those creamy smooth sounding tubes were crazy microphonic. Tube testers don't usually generate enough power to test for microphonics . Great at low volume but not so much pushed . .
I went thru 8 finding a nice quiet set. Going to have a look at the new market once my stash runs out.

That one tube has an air leak, I assumed you saw that.
I find Chinese tubes, namely the National branded ones included with my 6101 work well in that series. Because each channel has it's own tubes I sorta cater to that. As I rarely use clean, any old tube works fine in there.
I love old tubes but find as well that many long plate tubes used in a high gain amp can be microphonic. I check em by running gain right up and turning up amp.
Found a few that way, however, they do make good PI tubes even if microphonic.

 

[Jethro Rocker]

I also find the lower gain amps like the 800s get along better with OS tubes.

 

[Georgiatec]

Yep. Old ECC83's / 12AX7's can test great but sound awful. Microphonic tubes being the worst let down if you're wanting to crank the amp they're going in.

 

[RLW59]

If you have a head, putting a folded towel on the top of the cab under the head, or moving the head off the cab entirely can sometimes eliminate microphonic feedback.

Silicone rubber O-rings rolled onto the tube can work. Sometimes even curing howling combos.

Worth trying if you like the tone of the microphonic tubes.
---------------------------
If you only rarely get to crank your amps, it might be worthwhile to swap back to the microphonic tubes for daily low volume playing, and only use the solid tubes for the occasional loud session.

The mica spacers that keep the guts in place can crush, flake, loosen up in response to vibration. Loose guts vibrating independently at different resonant frequencies (instead of all being locked together so they vibrate as one cohesive whole) is what causes the howling.

IOW, solid tubes can become microphonic with use.

 

[RLW59]

As far as NOS/UOS vs current production, I find the tonal differences pretty subtle. And when I do notice a difference, usually "tube A" is slightly better for somethings than "tube B", but worse for other things.

About 15 years ago I had a Frenzel single-ended Class A and an Orange Tiny Terror, and I was living where I could crank them. Both simple short signal paths that should reveal tube differences. There was still a lot of reasonably priced NOS available, so I rolled GE's, Sylvania's, Raytheon's, Telefunken's, etc against JJ's, Sovtek's, Sino's. Didn't find any Holy Grails, didn't find any I hated. Slight preference for NOS and JJ slightly at the bottom, but nothing I'd notice with a band and certainly nothing an audience ever noticed.

I saw a really good vid comparing a dozen 12AX7's, a mix of NOS and current production. Looped signal playing the same short segments through them, quick cuts between the tubes.

They all sounded different, but I only disliked 2 of them. I liked the other 10 pretty much equally, and none of them jumped out as my fave. I'd be happy with any of the 10, and the 2 I disliked weren't terrible, just a little harsh (which might actually have cut through a mix better).

 

[Jon Snell]

New Old Stock, is either stock that they couldn't shift due to noise, gain issues or hum, from faulty insulation between the heaters and the cathode ... but ... they could be Good old stock, stuck in a warehouse for years and years because they fell off the inventory.
A bit of a gamble, I am sure you agree but that is why people buy these good/crap items.

 

[Matthews Guitars]

In general I have noted that the bigger the plate structure, the more microphonic a given ECC83/12AX7 is likely to be. Watch for this and you'll probably start noticing the same thing.

I expect Sylvania 12AX7s to be microphonic in almost every case. So they don't get used in a high gain stage.

I've had totally mixed results with Chinese tubes. Once an early 5150 came to me and it sounded really BAD. It was full of Chinese 12AX7s. I pulled them all out and replaced all of them with a mix of JJs and Russian made tubes (EH, Mullard Ri, etc) and then the amp sounded fantastic. Literally nothing else was done. And all the Chinese tubes tested strong on my tube tester.

 

[mickeydg5]

I find strong tubes always sound good and lead in the crowd.

 

[Spanngitter]

That one on the very right side is toasted (has lost Vac, Getter fully consumed), get rid of it and do not reinstall
I have a stash of about 50-60 PreAmp tubes pulled from numerous repairs, from 50ties on up to NP which all still measure good but either crackle/pop, hum or are so microphonic that you cannot even use them in PI Position. Its thru all kind of manufacturers, from Telefunken over Ei, JJ, Svets, Mullards, Bugleboy, Brimar, younameit, they all share the same sickness. Surely could sell some of those easily on fleabay but I know that nobody would be happy with them and I want to retain my reputation good...

 

[mark123]

When someone is giving away an old organ I'll try to grab and harvest the tubes. Sometimes I'll get a little Leslie speaker out of it as well. My favorites are the Wurlitzer branded long plate 12ax7s.

It seems that organs are bought and displayed but rarely played and the tubes are usually good.

 

[Jethro Rocker]

When someone is giving away an old organ I'll try to grab and harvest the tubes. Sometimes I'll get a little Leslie speaker out of it as well. My favorites are the Wurlitzer branded long plate 12ax7s.

It seems that organs are bought and displayed but rarely played and the tubes are usually good.

I got a few Hammond (Amperex) 12aX7 and a bunch of AY7 (GE) from an old organ many years back.
Also have a nice 1963 aqldwin (Raytheon) AX7 long plate. Can get micro if run in high gain tho so I use in slots other than gain stages.

 

[Matthews Guitars]

Look for old, low value test equipment as well. It often contains useful tube types and often they have very few hours of use on them. But be careful to check the equipment's valuation before robbing the tubes out of what may be a very sought after piece of gear.

 

[StingRay85]

The Maxi Preamp 2 has RCA outputs, and besides RMS noise level you can hear with headphones for noise. When doing so, gently tapping the tube gives a good indication for microphonics. If the tap is amplified crazy loud, you know it's not a good tube for V1. It is indeed true that the long plate European tubes are more likely to be microphonic than the short plates

 

[Amadeus91]

Just food for thought, here is a cool 12AX7 variant that was made for
low noise and microphonic operation. I recently got an amp that was
made from a '60s tape recorder and uses these tubes, as stock.
The 12AD7, very smooth sounding and quiet. They were made by Sylvania and NEC (Japan).
Here are a spare pair, I got for the amp.

Here are 2 more spares one from Sylvania and the other labeled
Delco.
The Westinghouse is a 12DF7, another low noise, low microphonic
12AX7 variant.

 

[Pete Farrington]

Thanks, I wasn’t aware of those.

 

[Whatwhatringrang]

A good tube is a good tube period. Finding them can be a problem and you need to have a decent seller or just through different pulls with old ones . I love old tubes however they can still be crap as well. Like everyone one knows here .

I have had pretty good luck with old tubes lately . I collect them and mess with them often. It can bring a lot of happiness(escape from life or at worst a total distraction waste of time lol). I am a Total dork with it. Trying to learn what I can from a mind that is not so sharp.

Get the right combo of different tubes in the right spots in your amp or play someone’s else’s amp where they have stumbled on it and it is pretty amazing. When you find decent ones they can last a long time. I like 60’s and later generally for most ecc83’s. More so than 50s long plate Mullard types ones In guitar amps and even mid fi by a great amount . Telefunken from late 50s I have always had good luck with. I notice I have trouble with brimars . However when you do find a strong one there are my favorite for v1 in some amps.

It is too bad a lot or most of the older generations radio/ham/tube guys are not around anymore. I wonder if the people who helped cone up with the 40/50s rca,western electric tube books ever knew just what a impact they had in lots of different ways.

New amp designs might not really need nos or old tubes 12ax7s . They where designed without them and probably best to use nice new production for them. I don’t know . Save a lot of money and there can be decent stuff to find. Sometimes a tube will perform less than ideal in one amp and great in another amp also. Or try them in different positions within the same amp.

What sucks is when your amp kinda demands the great preforming examples old extinct ones to perform correctly. Some of the late 70s and early 80 gecs are the best I have found for power tubes (military numbers on them as well as regular with paint dot).Pretty amazing all the chemistry,brains ,machines, metals, everything else that went into these back in the day.

 

[Marcomel79]

I was playing my jtm45 micro today and was enjoying the nice creamy sound coming from the three Siemens 12ax7 pulls from mid 60's radios and tape recorders, when i thought id try a set of new JJ i had laying around.

What a fizz fest!!! Absolutely dreadful! Put them back in the drawer for nuclear holocaust emergencies....