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EQUIPMENT FORUMS >> MINI TORII >> EZ 81 blown twice
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Message started by roggae on 04/30/12 at 03:04:39

Title: EZ 81 blown twice
Post by roggae on 04/30/12 at 03:04:39

So I've had two JJ tesla EZ 81s blow in the same channel. All stock tubes. All tested. Any idea what might be the problem? Both times it was idling. What should I do next?

Title: Re: EZ 81 blown twice
Post by Rivieraranch on 04/30/12 at 04:26:51

Not to make light of your situation, but the quality of JJ products right now blows.

Get a U.S. or European 6CA4/EZ81 and see if it blows, too.

Title: Re: EZ 81 blown twice
Post by Fireblade on 04/30/12 at 04:40:03

If you have another spare tube (or when you get it), just plug the one that was on the other channel into the channel in trouble, and the new one on the other channel . If it blows too, is not the tube.

Title: Re: EZ 81 blown twice
Post by roggae on 04/30/12 at 14:10:02

I have a NOS EZ 81 that has not blown. I used it after the other JJ blew too.

Title: Re: EZ 81 blown twice
Post by roggae on 05/01/12 at 00:35:27

Other than a bad tube, what could cause a tube to blow?

Title: Re: EZ 81 blown twice
Post by Donnie on 05/01/12 at 00:54:14

Now remember that I am not too technical, but a small explosive charge could blow a tube. Maybe Alpha or Gamma rays, I always forget which one is bad, maybe Stingrays?
It could be something to do with electricity, tricky stuff, avoid it like you would a tiger that looks hungry. Perhaps a short? Or possibly a long, it is hard to tell them apart.
I have always found the best way to fix a problem is to throw money at it, and if that doesn't work, shoot it with your largest caliber gun!

Title: Re: EZ 81 blown twice
Post by erik2a3 on 05/02/12 at 01:16:51

Donnie: LOL!

Title: Re: EZ 81 blown twice
Post by erik2a3 on 05/02/12 at 01:21:26

By the way, I made some ear extenders once. It can be amazing what lightly cupping one's ears can do for clarity in listening to music. I've known band directors who do that when listening critically to students playing their instruments (i'm a an art teacher, and would stop in the band room sometimes to listen. Some high school bands I've heard are really outstanding!).

Title: Re: EZ 81 blown twice
Post by Florida Boy on 05/02/12 at 13:17:37

Jim McShane has RFT EZ81's. Google and scroll down. Personally, I like Mullard or Amperex.

Title: Re: EZ 81 blown twice
Post by Rivieraranch on 05/02/12 at 13:39:59

I bought a pair from him. Another rectifier you could use is the EZ80.

Title: Re: EZ 81 blown twice
Post by HappyDwarf13 on 05/02/12 at 21:43:35

Just entered your forum. I love Steve's gear and own what will become seven items in his product mix within the next 12 weeks.

I suspect that I have the same predicament as some of you. I'm still breaking in a set of ZOB open baffles with the TORI mini amp. When I left for a meeting this morning things were sounding very pleasant with only about 28 hours on the system. When I returned to the office two and one-half hours later one side of the amp was out. Noticed that the rectifier tube wasn't heated.

Oh to be a tube dweeb. That's okay. To me a bit of reflection going back to all that ham radio equipment that I built in my youth using valves is pleasant. Too bad that I didn't realize how good (linear) tubes were for passing sine waves until about 18 years ago. I'm 60 now. From here on out it's vacuum tubes all the way--combined with high resolution digital recordings and of course my beloved LP collection.

Title: Re: EZ 81 blown twice
Post by Rivieraranch on 05/02/12 at 22:01:59

Is that another JJ failure?

Title: Re: EZ 81 blown twice
Post by erik2a3 on 05/02/12 at 23:55:04

A bit at odds, I guess, but I've always always had pretty good luck with JJ reliability. I've used a number of different rectifiers from them with long term success. I've learned in the past that some who are new to tubes have admitted to turning an amp on and off rapidly and repeatedly during swapping of tubes, and experienced a number of problems including blowing fuses and damaging rectifiers, etc. If you're one to constantly roll tubes, let the amp take a break for a bit before hitting the switch. It's not good to keep turning it on and off and on and off in quick succession.

Title: Re: EZ 81 blown twice
Post by roggae on 05/04/12 at 19:06:08

i've got a little more time now so i'll respond with a little more detail. i've had tubes for about ten years now. blew one tube in my previous amp as a result of a bad socket. the blown ez 81 happened after the amp had been on for a few hours and was the second time it had happened in the same slot under the same circumstances.

i'm not concerned just confounded.

Title: Re: EZ 81 blown twice
Post by HPDJ on 05/05/12 at 00:57:40

Hey,

I'm new to the forums so please excuse my jumping in on this thread. I'll briefly say that I had issue with my EZ81's with my Mini T. and ended up getting some NOS ones from Brent Jesse and have not had any problems since...I got my Mini in January. GREAT amp btw!

And I think others have had issues with their JJ EZ81's SO, it's not really Decware's fault (I know knowone has pointed fingers or anything) . I think there is an unreliable batch of EZ81's out there and some people are getting stuck with them. I tried 3 different batches of JJ's...they all were a no-go!

NOS rectifiers don't go for very much either and you can read a bit, or ask around about the different manufacturers who made them and see what flavor might work best for your set up :)

I've got a set from Valvo and I think Mullard.

Have fun :)

-H

Title: Re: EZ 81 blown twice
Post by Lon on 05/05/12 at 12:41:19

H, Welcome to the forum! Glad you're enjoying your MT and Trapeziums. Keep the impressions coming!

Title: Re: EZ 81 blown twice
Post by Rivieraranch on 05/05/12 at 14:39:59

Simply put, JJ quality BLOWS! Jim McShane wrote recently of a batch of JJ EL84's he received that were bad. The JJ EL84 was a very highly regarded tube. If they start mucking that up, do you think they are paying attention to quality control in their rectifiers? Hell no!

Jim McShane sells an RFT EZ81 that is a good bet. NOS US 6CA4 are available as well. If I am not mistaken you can also sub an EZ80 6V4 in there as well.

Title: Re: EZ 81 blown twice
Post by Florida Boy on 05/05/12 at 15:01:58

Just get a pair of quality NOS or lightly used RFT, Valvo, Mullard, GE
etc. They will seve you well. Like Erik posted, if you are rolling tubes let the amp cool a bit before turning it back on...especially if you are using JJ EZ81's.

Title: Re: EZ 81 blown twice
Post by roggae on 05/15/12 at 01:57:34

Blew another JJ. Different channel. Amp was idling. Put kids to bed. Came back. Tube was blown. What should I do?

Title: Re: EZ 81 blown twice
Post by HPDJ on 05/15/12 at 02:07:09

which tube was it? The EZ81's?......as others here have mentioned, your best bet is to ditch the JJ's (my 6V6's work fine still in my MT though) and get a more reliable NOS one...you probly got some JJ"s from a bad batch or something...

Title: Re: EZ 81 blown twice
Post by Fireblade on 05/15/12 at 03:17:12

If you still have that single survivor JJ tube that has not blown yet, it's definitely a bad lot. Try to take this with the seller, if you can.

Title: Re: EZ 81 blown twice
Post by roggae on 05/17/12 at 15:51:37

Pulled the trigger on a pair of the RFT EZ 81s and I also picked up a pair of 6v6gt reissues since Steve mentioned my out put tubes might be shorting. Any thoughts?

Title: Re: EZ 81 blown twice
Post by Florida Boy on 09/29/12 at 22:09:29

Rogge,

Were you using 6L6 types when the rectifier popped?

FB

Title: Re: EZ 81 blown twice
Post by roggae on 10/15/12 at 01:33:43

I'm pretty sure it happened both with stock tubes in place and other approved NOS tubes. Why?

Title: Re: EZ 81 blown twice
Post by Rivieraranch on 10/15/12 at 10:53:30

This is the main reason that the mass market migrated towards "solid state" in the 1960's. Tubes were somewhat unreliable. They can test fine but after a while sometimes a tube can go bad. Hopefully this won't happen to you again. With new power tubes and rectifiers, there is little chance that tubes will blow.

Title: Re: EZ 81 blown twice
Post by Lon on 10/15/12 at 13:34:33

Actually, I think the main reason that the industry moved to solid state was cost, transistors ultimately were easier to build, transport, and install all at a lower cost point. They could provide more power more easily, and it was easier to build powerful amps with inefficient speakers than lower powered amps with efficient speakers. Or so Ive read and been told by a few audio technicians.

What a shame really. . . Just think what fifty years of tube electronic development might have brought. And maybe we wouldn't have been hurled into this automated electronic nightmare we live in (or maybe just how I perceive it at times.) :)

Title: Re: EZ 81 blown twice
Post by Les Lammers on 10/15/12 at 17:55:22

Lon,

The chicken or the egg? LP's & CD's? Would Led Zep & ZZ Top have been the same with all tubes? The Japanese bought a lot of the old tube gear and tubes and sold us Pioneer and gave us perfect sound 4ever. :-)
I just sold a Sansui AU222 20 watt integrated from 1964-65 it sounded much like tubes and had a very good phono section. Actually, early SS was voiced to mimic tubes. The little amp was built like a tank. Industrial strength circuit boards etc. I wonder how it would stack up against a modern amp if it were fully restored?

Les

P.S. EZ80's sound great in the Mini. I got some Tungsrams and RFT's. They are not expensive tubes.

Title: Re: EZ 81 blown twice
Post by Lon on 10/15/12 at 18:01:59

When I listened to Zep and ZZ. . .I listened on a tube system. :) And those bands used tube amps.

The Japanese were smart to buy up that stuff. Most here didn't value them at the time.

I guess I blame transistors on miniturizing circuits and such things as smart phones and even the internet, both of which I begin to feel are polluting life and allowing the fabulously wealthy to . . . ah I'll just say I'm starting to be a bit of a luddite and enjoying my tubes.

Title: Re: EZ 81 blown twice
Post by Les Lammers on 10/15/12 at 18:27:01

I'm getting old(er) too. SS can sound very good but tubes do it for me.

Title: Re: EZ 81 blown twice
Post by Lon on 10/15/12 at 19:11:49

I prefer to think that we're both getting . . . wiser. :)

Title: Re: EZ 81 blown twice
Post by Les Lammers on 10/15/12 at 20:11:59

Speak for yourself...the jury is still out in my case. ;D