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Post by steamroller on Apr 4, 2021 7:49:52 GMT -7
I reordered a matched set of JJ6v6 tubes for my Z-Plus. The tubes came in, and I installed them, and the noise problems I had been experiencing disappeared. But I noticed, too late to do anything about it, that there was various data printed on a label affixed to the base of my old tubes. I checked out the company name, and found out that APEX was a company that specializes in testing and matching tubes. Was I supposed to take into account the APEX information on the label when I reordered tubes? I believed that a matched set of tubes of the same OEM was the only requirement. Did I mess up? The amp sounds and behaves well?
-steamroller-
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Post by KeithA on Apr 4, 2021 8:10:51 GMT -7
The Z-Plus is cathode biased. So, the only recommendation would be to order a rating similar so that the tubes operate within the designed parameters.
In the old days, it was recommended that one get a set of tubes rated medium (4-7) under the Groove Tubes rating system.
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Post by perryr on Apr 4, 2021 8:54:43 GMT -7
Did you get the amp used, cause I didn’t think Z used Apex matched tubes? Either way, cathode bias is pretty forgiving and if it sounds good it is good!
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Post by daddyelmis (Greg) on Apr 4, 2021 10:27:36 GMT -7
The Z-Plus is cathode biased. So, the only recommendation would be to order a rating similar so that the tubes operate within the designed parameters. In the old days, it was recommended that one get a set of tubes rated medium (4-7) under the Groove Tubes rating system. Many people turned up their noses on the GT rating system, but I thought it was brilliant for 80%+ of players. Kind of like getting dressed using Garanimals 😁
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Post by zpilot on Apr 4, 2021 11:48:27 GMT -7
The Z-Plus is cathode biased. So, the only recommendation would be to order a rating similar so that the tubes operate within the designed parameters. In the old days, it was recommended that one get a set of tubes rated medium (4-7) under the Groove Tubes rating system. Many people turned up their noses on the GT rating system, but I thought it was brilliant for 80%+ of players. Kind of like getting dressed using Garanimals 😁 Yes, I agree. It was good enough for most players. Even Fender's red/white/blue rating is close enough unless you are really picky. Unfortunately I am one of the picky ones.
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Post by steamroller on Apr 4, 2021 13:34:01 GMT -7
perryr,
Yea, I bought the amp new, these were the origonal tubes.
My APPEX label shows, current:39 / transcend:3600 on both tubes. Then an ID#:0932752(P107) on one tube and an ID#0932749(P104) on the other tube.
Next time I order, should I request current:39? Actually I am going to purchase a backup set, I will inquire with Apex. The boxes my replacements came in had a sticker with 29 written on it.
-steamroller-
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Post by Seńor Verde on Apr 5, 2021 8:43:38 GMT -7
Antique Electronic Supply sells Apex Matched/Tested tubes. In one of Doc's AMA videos, link below, he stated that's where he gets his tubes. Doesn't say whether he uses Apex matched though. Looking on their website, you can click on Apex Matched tubes and there is more detailed information.
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Post by perryr on Apr 5, 2021 8:47:47 GMT -7
perryr, Yea, I bought the amp new, these were the origonal tubes. My APPEX label shows, current:39 / transcend:3600 on both tubes. Then an ID#:0932752(P107) on one tube and an ID#0932749(P104) on the other tube. Next time I order, should I request current:39? Actually I am going to purchase a backup set, I will inquire with Apex. The boxes my replacements came in had a sticker with 29 written on it. -steamroller- so ya, if you order Apex 6v6 the number 39 will be relevant, and a set of apex 39/3600 would be close to clones of the original set. Another set +/-10% on either number would likely perform pretty much the same. 39/3600 would not be relevant to other matching systems unless they use the exact same testing criteria (which I think is proprietary for apex). JJ likely measures with different equipment and a JJ 29/? May or may not be the same or similar in performance. the bulk of tubes produced fall in “average” range, so if they are both fairly “average” then their likely going to perform the same and sound great.. and if your ears say they are great and they aren’t glowing orange/red than you are golden.
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Post by steamroller on Apr 5, 2021 16:33:08 GMT -7
I am going to order another set, as a back up. I'll use Antique Electric next time, and give them the specks off my origonal Apex label. Do other tubes have specs. that I have to know about before ordering?
-steamroller-
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Post by jhen86 (jordan) on Apr 9, 2021 19:41:44 GMT -7
Apex prides themselves on having very specific and precise matching. Their site has info that is quite interesting. I think their whole angle is if you order a set of tubes with the same ratings as the one you pull, then there is no need for a rebias. But you obviously need to know that before ordering. All this is really only valuable though in a fixed bias amp.
Cathode biased amps don’t care much.
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