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Into my VTA -120. Sorry if this isn't the right forum but since I did mentio it here I will post what I found out today.I was getting ready to toss this bad JJ GZ34 rectifier when I noticed like white or silver dots on the glass. I thought it was on the outside but seen it was on the inside. When I turn the tube upside down all those little particles went to the bottom of the inside of the top silver part of the tube.
Does anyone know what these particles may be?
I still think the JJ GZ34 sounded the best but too bad it can't handle the current draw like the Mullard GZ37 can that I have in my VTA-120. Btw, that VTA-120 is around 50-60 hrs. burned in now and is starting to really open up and with nice depth on the sound stage.
This has turned out to be a very good buy/kit. I did changed some parts but it just has added more to this already nice tube amp.
Edits: 11/27/16Follow Ups:
Hopefully you can see what I'm talking about.
I don't think they'll harm the operation of the rectifier.
It flashed in my VTA-120 and then when I put it in the Woo Audio WA6 headphone amp, it flashed again. With the other rectifiers, the GZ37 in the VTA-120 and the Shuguang 274 rectifier in the WA6 and Mullard GZ34 in the VTA-120 before GZ37, no flashes til now and everything is working fine.
mt
Exactly! At least it wasn't an expensive paperweight, like I have heard or seen in other threads.
Before you "toss" the tube, try the series SS diode tweak. Very frequently, the "fireworks" stop and the tube serves well. My bias is towards UF4007s, instead of 1N4007s. The idea being less switching noise, from the outset, can't be bad. However, regardless of which "sand" diode you use, the vacuum rectifier blocks switching noise from entering the B+ rail.
Eli D.
When I was building my VTA-120. I did get a bad set of Gold Lion KT88's from Partsconexion. So that may have damaged this JJ GZ34. I sent them back for refund. Bought the next set of GL's from Kevin Deal at Upscale
Perhaps you did damage that JJ 5AR4. However, all of JJ's Octal production is suspect. :> ( You could have been sold "floor sweepings".
Eli D.
Eli - I take exception to your statement of, "However, all of JJ's Octal production is suspect." Although I agree about the JJ GZ34, I am on my second set of JJ 7591's and upgraded my Dynaco ST70 from German EL34s to JJ KT77s (for the higher plate and screen grid ratings) with no problems.
I said suspect, not junk. Sadly, far too many JJ made Octal tubes are trash. IF you get good tubes, great. The lack of consistent quality is a significant issue.
I wonder if JJ's better efforts are not shipped to North America. It's pretty well established that the Jamona plant is capable of manufacturing very nice products.
Eli D.
Their tubes quality are suspect and not great in QC. The tube that I posted here about has terrible build quality. The top a bottom round plates that are touching the glass are way out of whack uneven really bad. I have never seen any other tube with build quality that bad.
I bought four JJ GZ34s that all arced in a 2A3SE amp running 250V and 50mA total including the driver. Seems like it should be safe, right? It never had a problem before or since with Sovtek 5AR4s.
Vendor said they were sale items and non-returnable. I will never buy another JJ tube on principal.
Very nice sounding!
With the SS diode tweak, Sovtek 5AR4s are fine.
Eli D.
5AR4 labeled as 5V4GA. I've used several of these and they test as 5AR4/GZ34. Are very good tubes. And last.I used this 5AR4 in my 1971 Fender Vibrolux Reverb, for four years now. Air the amp out, about 2-3 times a month. No problems.
Edits: 11/27/16 11/27/16
As comparison to mislabeled tube.
Edits: 11/27/16 11/27/16
nada aqui
--------------------------
Buy Chinese. Bury freedom.
A picture would be wonderful, but it sounds like the tube has lost vacuum. The getter turns white under such circumstances.
I wish. LOL!
But I was not able due to the light. I will try tomorrow to post a pic. The tube didn't loose vacuum.
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