A Good New 12AY7?

[wizard333]

Seven of the last Eight EH 12AY7s I've ordered from Tube Depot and CE have been bad. Seems they have a heater/grid leak and all hum like no tomorrow no matter what circuit you put them in. Thats a failure rate thats completely unacceptable, I have to conclude that the EH 12AY7 is complete crap; unless you're willing to buy 100 and keep 12 of them its just not worth messing with.

Unfortunately, I cant find ANY other new 12AY7 out there. Anyone know a source for CONSISTENTLY usable 12AY7s? Not interested in NOS since 1) They are too expensive to justify to most of my customers, 2) I've had mixed results getting decent NOS tubes as well.

[txstrat]

If you don't mind the shipping.
TAD 12AY7/6072A Premium Selected TAD TubeAmpDoctor

Don't know if they're different, but you might contact 'em and ask. Might be a better choice than what you got.
Frankly that's the only other 12AY7 I could find.

[Diablo]

Seven of the last Eight EH 12AY7s I've ordered from Tube Depot and CE have been bad. Seems they have a heater/grid leak and all hum like no tomorrow no matter what circuit you put them in. Thats a failure rate thats completely unacceptable, I have to conclude that the EH 12AY7 is complete crap; unless you're willing to buy 100 and keep 12 of them its just not worth messing with.

You make me feel like I've hit the jackpot. I bought three EH 12AY7s for my 5E8A clone from Triode Electronics, and they all work just fine. I don't understand why the 12AY7 should be any more difficult to manufacture than any other dual triode. Perhaps EH had a run of bad tubes?

[tubeswell]

Yep - what Diablo said. I've never had any problem with EH12AY7s yet (touch wood) either. Maybe you struck a bad batch

[MWJB]

Must be a bad batch, the EH is the most reliable 12AY7 I have found, sounds good too.

[wizard333]

Maybe its a bad batch, but they weren't all ordered at the same time. That makes me believe its more than just a bad batch.

[Bruce / Mission Amps]

Maybe its a bad batch, but they weren't all ordered at the same time. That makes me believe its more than just a bad batch.

I've only had four or five bad 12AY7EHs in the last 350 tubes.
I dare to say it but I bet I use as many or more 12AY7EHs as anyone else.
Truthfully, over the last 4 or 5 years, USPS, UPS or Fedex has broken way more then I've had any bad ones.

[wizard333]

Where do you get them? Maybe my suppliers are just bad. Half of what CE has sent me for all tubes in the last 4 months has been bad, and we're talking a lot of tubes.

[Bruce / Mission Amps]

Where do you get them? Maybe my suppliers are just bad. Half of what CE has sent me for all tubes in the last 4 months has been bad, and we're talking a lot of tubes.

When I want a lot of say 50 to 100 I go to New Sensor.
If I'm ordering a bunch of other parts and just need a dozen or two I'll get them from MOJO.
I've only ordered large numbers of tubes a few times from CE and mostly it is just JJs or CED/Svetlana tubes

[Trout]

Speaking of 12AY7's, specifically EH's.

I have had repeated problem with those purchased from CE as well.
But on another issue/question.

Are these tubes more vunerable when running elevated heaters? I had 3 go bad in the past week.

Kind of bugs me because they sound great, but they are only lasting about 2-3 hours then they suddenly sound like a guitar cord with broken ground connection.

Any insight?

[wizard333]

I think they have heater/cathode leak issues, and given that, having weak heater elements wouldn't shock me.

So far as I know, all these tubes come from the same factory, only difference is how much checking and rejection each vendor does. From what I gather, CE does basically 0 checking of anything, leaving that to you. That gets really old when you're rejecting 50-80% of what they send you and having to send it back (pay for return shipping) and re-order.

Their prices are decent if you buy in quantity, but the number of bad tubes I've been getting from them lately is making it just not worth it.

[Trout]

I think they have heater/cathode leak issues, and given that, having weak heater elements wouldn't shock me.

So far as I know, all these tubes come from the same factory, only difference is how much checking and rejection each vendor does. From what I gather, CE does basically 0 checking of anything, leaving that to you. That gets really old when you're rejecting 50-80% of what they send you and having to send it back (pay for return shipping) and re-order.

Their prices are decent if you buy in quantity, but the number of bad tubes I've been getting from them lately is making it just not worth it.

I suspect that you are correct on the heater/cathode issue. Seems to me they had a similar problem with the 12AX7LPS's as well.

Tell you what, CE seems like on some items they are outstanding, and really, the only tube issues I ever get from them are always the same tubes.
EH 12AY7's, & JJ GZ34's I swear 75% of the GZ34's they have are bad!

The only other issue I have ever had would be the guys packing the boxes. They have no clue when it comes to packing mixed items with tubes. You simply can not pack tubes and transformers in the same box!

[tubeswell]

I suspect that you are correct on the heater/cathode issue. Seems to me they had a similar problem with the 12AX7LPS's as well.

Then don't elevate them much (say 20-40V, not 80-90V) - a matter of working with the clay that you've got.

[soundmasterg]

The vintage spec for the 12AY7 is 90v max heater to cathode. I have no idea if the EH's are the same or not. I elevated the heaters in a Silvertone build to 70v with about 320v on the plate with an EH12AY7 and it is holding up after several years......

greg

[jrfrond]

You know, I have a theory on all of this.

If you want E-H or Sovtek tubes, get them directly from New Sensor. I've had issues with new (not NOS) tubes that seemingly pass through too many hands and shipping departments winding up defective. We are in NYC and so is New Sensor, and we RARELY get defective tubes, but I HAVE gotten defective tubes from places that were geographically farther away.

I submit to you that new tubes don't like to be excessively handled or shocked. NOS tubes are much hardier, it would seem.