Coytee Posted January 24, 2005 Share Posted January 24, 2005 I have rolled my first tube compliment. I have the Jolida 502B and decided to try out the KT90's and at same time put some Sylvania 12AX7 (I think "a" variety?) Anyways as I was checking the bias on the KT's, the wires get in the way and one of the wires hit one of the 12AX7's. I clearly heard a "tink" on the right side speaker. Intrigued, I let the wire (gently) bump it again.......... "tink" hmm... So I repeated it "tink tink tink" I cranked the volume WAY up, the volume of the tink stayed essentially the same. I might add that the tube itself made a tink sound so I wasnt sure if I heard the tube reacting to the wire, or the speaker somehow picking it up. Soooooooooo, I "hit" the other 12AX7 for the left channel and the sound was WAY different. yes, the tube still had a tink to it when struck (again, this is gentle) Now, with the left channel, the speaker seemed to NOT display the tink sound. Right did, left did not. I might add that one of these tubes (I think it was the "tink-erbelle" tube) seemed just a tad loose in the socket such that if I wiggled it (EVERRRRRRRRRRRRRRRRR so gently) I'd hear a scratchy kind of sound out of that side. I adjusted the pins some to make them grab tighter and the looseness seems to have all but disappeared. This tinking sound, has me curious. I had a small screwdriver (just a gram over the size of a paperclip, so no one needs to worry that I'm using a hammer) I took the small screwdriver and gently tapped it against ALL the tubes (KT's and 12AT7's too) The only singular tube that seemed to display a reaction over the speaker was the one 12AX and not the other. Might that recently bought) tube be bad or is that part of the world of tubes? I received these tubes less than a week ago from Tube Depot. Do they usually carry any warranty (presuming the tinking is something to be concerned about) Thanks Tinkerbelle Quote Link to comment Share on other sites More sharing options...
3dzapper Posted January 24, 2005 Share Posted January 24, 2005 Tinkerbelle, Thats called "microphonics". Some tubes are more sensitive to it than others. If they sound good, avoid hitting them up side the head in the future. Rick Quote Link to comment Share on other sites More sharing options...
dodger Posted January 24, 2005 Share Posted January 24, 2005 It is not a good idea to tap on tubes while in operation. You can cause damage within the tube, or if you loosen it you will be greeted by all sorts of wonderful noises that can damge speakers. Now, as tubes heat, you will hear a tink from the tube as heat expands the glass and inside filaments. Some tubes will carry a tapping sound but are alright. A tube that is very slightly microphonic would react as described. But the microphonic problem may increase over time. If there is a warranty, call and check about a return policy. dodger Quote Link to comment Share on other sites More sharing options...
Coytee Posted January 24, 2005 Author Share Posted January 24, 2005 Thanks for the comments. I think for the price I paid for them that I'll just let them ride and see what happens. Besides, with my Peach just sitting around currently gathering dust, I need to focus more on getting the $$ for a pair of 2A3 amps that I can plug in. Fret not Peach lovers, it's not really gathering dust, but since the wife doesn't yet know I bought it (camera flashes to "ET" scene with ET in the closet next to all the stuffed animals) It's still in its original box, next to a bunch of other boxes I've moved as we prepare to finish the basement. I'm banking that by being so out in the open, like ET, she simply won't see it. So far my devious plan is working. If however, I fail to ever post here again, it's possible I was ratted out. Quote Link to comment Share on other sites More sharing options...
D-MAN Posted January 24, 2005 Share Posted January 24, 2005 One of the problems with microphonics is that they can do that when the volume is cranked up and the tubes vibrate from the SPL. Tube sleeves may lessen the effect. DM Quote Link to comment Share on other sites More sharing options...
JJkizak Posted January 24, 2005 Share Posted January 24, 2005 Oh yes' I remember now, yes, the old ones, yes I remember now, they were glass and they glowed and they were hot. I now hold in my hand a chip that is the equivalent of 1 billion tubes. What am I missing here? JJK Quote Link to comment Share on other sites More sharing options...
3dzapper Posted January 24, 2005 Share Posted January 24, 2005 ---------------- On 1/24/2005 7:44:17 PM JJKIZAK wrote: Oh yes' I remember now, yes, the old ones, yes I remember now, they were glass and they glowed and they were hot. I now hold in my hand a chip that is the equivalent of 1 billion tubes. What am I missing here? JJK ---------------- The Unguintine!!!! Rick Quote Link to comment Share on other sites More sharing options...
JJkizak Posted January 25, 2005 Share Posted January 25, 2005 I was just trying to be funny. JJK Quote Link to comment Share on other sites More sharing options...
ZAKO Posted January 25, 2005 Share Posted January 25, 2005 JJKIZAK.....You are right . theres too mutch obsessing about tubes. Quote Link to comment Share on other sites More sharing options...
DRBILL Posted January 25, 2005 Share Posted January 25, 2005 As a high school student and radio repair technician (no TV's in S. Arkansas, yet!) in the 50's, one of the most used tools on my bench was a #2 pencil with a fresh eraser for administering the "tink test." The order was eyeball, tap, tube tester. You don't have to whack it, just a gentle tap. No microphonic tube should remain in any gear. This is especially vital in quality audio gear. I recently sent back two out of six Russian 12AX7's that failed the tap test. DR BILL Quote Link to comment Share on other sites More sharing options...
Coytee Posted January 25, 2005 Author Share Posted January 25, 2005 Casual update, I called the tube vender and he said they might need some time to burn in, I said no biggie. Unrelated to this vender, I'd called Jolida a week ago about (yet) another tube that I was curious of. Seems I'd had one tube "cherry out" on me and they replaced it. On replacing it, I remembered I had another tube that I thought odd... seems no matter how high I adjusted the bias, it could never reach 50. After talking to them, I swapped the tube and the problem moved with the tube. I called Jolida back talked to the tech guy and he said he'd just send another. Well, "another" arrived today. Another INTEGRATED AMP, not a TUBE!!. They sent me the whole shebang!!! I'm convinced that between his decision and the shipping department someone messed up as we clearly decided it was the tube. update to this evening: I decided to swap out the amps anyway and swapped out all the tubes also. I remembered Tinky, so rather than strike it, I wondered just how sensative it really was. I placed my little fingers fingernail on the tube and simply moved the fingernail up and down. I could hear the movement of my fingernail over the right speaker. When I'm not messing around with the tube I can't hear a thing. the guy at the tube store said I should be ok since the tube wasn't in a guitar amp getting feedback (K-horns? ) I'm not unhappy with that logic. I thought I'd only paid $5 for the Sylvanias but he informed me they were about $25/each. Only money right? Amp is swapped out, tubes are swapped out (with the funky tube back in the box) I'll send the amp back to them tomorrow. Amazing to me how much tinkering can go on with tubes. I realize they are not all the same. I think in over 25 years of owning my Yamaha, I had it to the shop one time and that was to replace some burnt out bulbs on tuner, and to replace the power switch. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.