Feel I've Been Had - NOS

After spending quite some time on this board and other places reading about the "virtues" of the great NOS tubes;
I went to "stealbay" (probably a big mistake) and took the plunge investing something like $350 on a bunch of "NOS".

Heres what I got for my Mark IV (a/b) baby:

1-12AX7 Mullard Hammond (Gr. Britian/Blackburn) NOS paid: $31.86
1-12AX7 Tungsol JAN Box marked: 2/64 NOS NIB paid: $41.00
2-12AX7A ECC83 RCA Gr. Britian KD NIB NOS NIB paid: $23.55 each
2-12AX7WA Sylvania JAN Box marked: 6/70 NOS NIB paid: $40.00 each
6-5751/12AX7 GE JAN Box marked: 10/1967 NOS NIB paid: $14.43 each
and finally
1-12AT7 CV4024 Mullard Balanced NOS NIB paid: $33.50

Now: I received the 12AX7 Mullard the night before a gig and threw it in V1 for the show. 1st set it was crap and then in 2nd set the amp just lit up and I was sooo happy. Seemed to be a "good" thing I was doing.

During the next week I received all the rest of the tubes and got down to testing them all.

I one at a time put each one in V1 and did the pencil "tap" test.
Every stinking tube listed above EXCEPT the Mullard 12AX7 was NOISY. Some caused a crackle noise when struck, some jangled a little, some did both. Grrrrrr.

None of the groove tubes I had in the amp before make these noises.

Is this normal???
Should I complain to the sellers?
Do I leave positive feedback?

I just feel bad somehow.

Perhaps I have just learned a very expensive lesson here...

all comments welcome.

Topcat , yeah ive bought some microphonic tubes on ebay too and it is annoying, the most frustrating thing is they all sounded great just too noisy.. Im no expert and look forward to hearing other posts here.

But can you rock them out and get a good sound without tube noise? I'm not convinced just noise is a problem when you bang on a tube. I mean hell, you're banging on a tube. But if there's actual mechanical noise, is it coming through when you play?

If they crackle when moved or tapped, it's more likely to be dirty or corroded tube pins than a problem inside the bottle - they can get like that if they've been stored for a long time ... they are of course NOS, so they have. Or are they? A lot of private sellers call any old tube "NOS" either not realising or deliberately ignoring that N stands for New. (As in unused, other than testing.) You can usually clean off dirt of corrosion with a shot of contact cleaner and then move the tube around in the socket a bit. The fact that the first tube you tried sounded crap until it got thoroughly hot may also indicate a bad contact with the socket.

Secondly, tube testers do not test for microphonics and noise, so even if a tube "tests good" it may still be useless in an audio sense. Worse, a lot of NOS tubes sold privately have already been through several owners who have all tried them for audio, found they weren't very good, and re-sold them... as "test good", which they still do. When you buy off Ebay, this is the chance you take - which is why the prices you paid were not as high as you would expect for most of those tubes. It doesn't mean that NOS tubes are no good, or even that all the tubes you bought are no good, but you need to be aware that you get a different level of service from a proper vendor, and that's one of the reasons you pay more.

What to do for now - if you don't feel like complaining to the sellers, and to be honest you don't have much of a case unless the tubes actually don't work, if they were not specifically described as "not microphonic" - is to put the least microphonic tube in V1, and the others where it's less important, as it is the further through the amp you go. Almost all tubes are microphonic to some extent and I always keep the ones that are bad enough not to really work in early gain stages for PI, reverb and FX return stages etc - just because they're no good for V1s doesn't mean they're no good. In fact, I honestly think that a small amount of microphonics (as long as it doesn't cause ringing or other problems) is a genuinely good thing because it gives the sound a bit of life.

A lot of my old-stock tubes (almost all acquired used or cheap) are less than perfect in ways like this, but I wouldn't trade them for quiet new-production ones, ever. Be patient, look for bargains and buy more than you need (you already did), sort through them yourself, and save some money - but accept that some of them won't be great or might only do for spares. Or, pay the big money up front from a recognised NOS tube vendor who offers a warranty.

Test for musicality? Bang on it.
Advice? Sell amp. Buy drums.

Yeah, I've learned to question the seller whether they've been tested for microphonics AND noise. It also helps to buy from eBay sellers with return policies...some do. I've found good eBay sellers whose tubes are pretty reliable.

Wow! Lots of great feedback here!

Special thanks to 94Tremoverb! Lots advise in that post that I will be following.

I now consider myself better educated on the subject and don't feel quite so bad about my purchases.

Sooo... I'll play with my cocktail of tubes and find whats most pleasing to me and go with it.

I'm commencing to hit tube pins with contact cleaner for starters.

Positive feedback going out to all the "sellers" since all the tubes do actually "work".

If anyone else has input its certainly welcome here - even dumb drummer remarks!

I LOVE MY MARK IV!!!!!!

find one type that you like, or two, different ones out of the bunch..then buy a few more. try and set a limit of what you'll pay per tube, based on how much you want it.

i got my cv4024 for much less than yours. and it was NEW old stock guarunteed.
i know this sounds dumb, but look at recent (last month or so) feedback from who you're considering buying from..if theres a lot of greys, or reds, this is a big red flag......people hate giving negative feedback, because they can be given negs back...so, the feedback doesn't always tell the real truth. read the comments and look at ratings.

personally, i have two different tube types that i absolutely KNOW that i love..and i look for them specifically. this, after having bought about 20 different kinds.

and, the rest of the ones i have that i dont like, will go back on ebay, listed truthfully.

getting Mp tubes is a pain in the ***.

yeti said:

getting Mp tubes is a pain in the ***.

Click to expand...

...meaning what?

micro-phonic

I have been very lucky with regards to buying old tubes. I have bought all mine off eBay, but they were all from guitarists that I could actually ask questions to and find out why they are selling. All of my old tubes are dead quiet, but typically I won't worry about noise unless I hear crackling while not playing on the clean channel. I effing HATE that!!!!

sometimes you luck up as well. I recently purchased an advertised NOS Sylvania 12AX7 from an estate sale. When it arrived, it was an RCA blackplate 7025. Currently residing in V1 of my Heartbreaker. Sweeeeet!

i hate that crackling/tickling noise. but, nothing touches the ruination of excitement that a microphonic tube renders.

maybe a smelly vag upon depanty-ing, but, even then, you can get by.

thunda1216 said:

When it arrived, it was an RCA blackplate 7025. Currently residing in V1 of my Heartbreaker. Sweeeeet!

Click to expand...

I just got 2 RCA 12AX7A for about 1963 and they amazing!!!! My favorite preamp tube by far!!

yeti said:

i hate that crackling/tickling noise. but, nothing touches the ruination of excitement that a microphonic tube renders.

maybe a smelly vag upon depanty-ing, but, even then, you can get by.

Click to expand...

BAAAAAHAHAHAHAHAHAHAHAHAHAHAHA!!!!! I almost spit my coffee onto my keyboard.

MrMarkIII said:

Test for musicality? Bang on it.
Advice? Sell amp. Buy drums.

Click to expand...

An electrical engineering friend of mine recommends tapping the tube lightly with the eraser end of pencil. You are not testing for musicality nor are you testing for noise. You are testing for microphonic tubes. If a tap on the tube sets it ringing or oscillating, then any vibration will likely start the tube ringing. This type of microphonic tube will be annoying, especially in high gain usage.

cscotto said:

MrMarkIII said:

Test for musicality? Bang on it.
Advice? Sell amp. Buy drums.

Click to expand...

An electrical engineering friend of mine recommends tapping the tube lightly with the eraser end of pencil. You are not testing for musicality nor are you testing for noise. You are testing for microphonic tubes. If a tap on the tube sets it ringing or oscillating, then any vibration will likely start the tube ringing. This type of microphonic tube will be annoying, especially in high gain usage.

Click to expand...

My point was that the OP did not test any tube beyond the pencil tap test.
It was his only criterion for determining the tubes value.
As stated above, microphony is not the be-all and end-all in tube-testing.
One might actually consider the sound.

you can still use a MP tube in the PI position and it can be fine.

or in a tube based pedal.

MrMarkIII said:

cscotto said:

MrMarkIII said:

Test for musicality? Bang on it.
Advice? Sell amp. Buy drums.

Click to expand...

An electrical engineering friend of mine recommends tapping the tube lightly with the eraser end of pencil. You are not testing for musicality nor are you testing for noise. You are testing for microphonic tubes. If a tap on the tube sets it ringing or oscillating, then any vibration will likely start the tube ringing. This type of microphonic tube will be annoying, especially in high gain usage.

Click to expand...

My point was that the OP did not test any tube beyond the pencil tap test.
It was his only criterion for determining the tubes value.
As stated above, microphony is not the be-all and end-all in tube-testing.
One might actually consider the sound.

Click to expand...

well, actually I had tested the Mullard 12AX7 - I mentioned that I used it at a gig - sounded awesome for 2nd and 3rd sets.

Testing of the rest is in progess.....playing them in my living room at master vol=1 class A Tweed won't really show what they will do I'm thinkin'. I'm starting to rotate different tubes thru the amp now at gigs. My original concern was having a monophonic tube or 2 or 3 at a gig on a live stage with drums and bass and the black shadow in the combo all jiggling things. Not the time to mess with that.

This weekend went with:

v1=mullurd 12ax7
v2=RCA 12ax7
v3: RCA 12ax7
v4 Groove Tube 12at7
v5=mullard 12at7

unfortunately it was a very low volume gig so the jury stays out for now.


I'm a NOS NOOB soaking up the electrons.

Thanks for your input and please keep it coming.

cscotto said:

MrMarkIII said:

Test for musicality? Bang on it.
Advice? Sell amp. Buy drums.

Click to expand...

An electrical engineering friend of mine recommends tapping the tube lightly with the eraser end of pencil. You are not testing for musicality nor are you testing for noise. You are testing for microphonic tubes. If a tap on the tube sets it ringing or oscillating, then any vibration will likely start the tube ringing. This type of microphonic tube will be annoying, especially in high gain usage.

Click to expand...

Excellent explanation of that test. Thanks, cscotto.

anyone try tube dampers in combos?

i bought some of that clay window sealant..it's supposed to settle things down.
mortite, i think it's called?

that hiss rattle that tubes do drives me batty!