Joe Posted June 15, 2011 Share Posted June 15, 2011 I recently replaced tubes in my Peavy Delta Blues 1X15. This time I used Groove Tubes but after reading some recent posts, I think I may invest in a more expensive set next time.I was wondering if anyone here tests their tubes and replaces only the bad ones. The way I do it now is when the amp starts to buzz or hum I replace the whole set. Not a huge deal if your using less expensive tubes but is it wise to replace only the bad ones with a more expesive set? Thanks for any input. Link to comment Share on other sites More sharing options...
koula901 Posted June 15, 2011 Share Posted June 15, 2011 I think KBP810 will know the answer to your question. There was recently a thread regarding the pencil test. That may have been about whether or not the tubes are microphonic. Link to comment Share on other sites More sharing options...
Joe Posted June 15, 2011 Author Share Posted June 15, 2011 I think KBP810 will know the answer to your question. There was recently a thread regarding the pencil test. That may have been about whether or not the tubes are microphonic. I did see the thread describing the pencil test.I was thinking more along the lines of testing resistance. If resistance is the proper test. I was hoping KBP810 would offer some insite. Link to comment Share on other sites More sharing options...
DetroitBlues Posted June 15, 2011 Share Posted June 15, 2011 Just told him to check in with the HOC for this subject. Link to comment Share on other sites More sharing options...
kbp810 Posted June 15, 2011 Share Posted June 15, 2011 I did see the thread describing the pencil test.I was thinking more along the lines of testing resistance. If resistance is the proper test. I was hoping KBP810 would offer some insite. Aside from microphonic tap tests, there's not a lot more you can do test wise, sans a tube tester itself. You can't really measure resistance on a tube, or in essence the pins would/should all read open with the exception of the heater pins. Most errors can be detected by your ears - amp gets noisy, bad hums, loss of power, etc... usually if you can see or smell the problem, somethings has likely gone terribly wrong! If you start to hear a buzz or hum, it's best to start at the preamps and do a little trial and error by swapping one out at a time with a known good tube until you find the culprit (after a tap test of course, as that would likely be the tell)... usually, it's only one, but if two or more have gone south the above process could get a little frustrating Link to comment Share on other sites More sharing options...
FredZepp Posted June 15, 2011 Share Posted June 15, 2011 I remember the days of taking a bunch of tubes to the local Radio Shack (which had a tester for free) to test out the tubes. Always trying to keep straight what each one measured... Link to comment Share on other sites More sharing options...
DetroitBlues Posted June 15, 2011 Share Posted June 15, 2011 A local second hand shop around here has a tube tester. Its meant to test his stock of old tubes he has lying around, but I'm sure he wouldn't have a problem allowing you to use it for your own tubes. Link to comment Share on other sites More sharing options...
Joe Posted June 15, 2011 Author Share Posted June 15, 2011 I remember the days of taking a bunch of tubes to the local Radio Shack (which had a tester for free) to test out the tubes. Always trying to keep straight what each one measured... I remember seeing those in drug stores.That was a long time ago. Link to comment Share on other sites More sharing options...
Joe Posted June 15, 2011 Author Share Posted June 15, 2011 A local second hand shop around here has a tube tester. Its meant to test his stock of old tubes he has lying around, but I'm sure he wouldn't have a problem allowing you to use it for your own tubes. Where is that store? Link to comment Share on other sites More sharing options...
Joe Posted June 15, 2011 Author Share Posted June 15, 2011 Aside from microphonic tap tests, there's not a lot more you can do test wise, sans a tube tester itself. You can't really measure resistance on a tube, or in essence the pins would/should all read open with the exception of the heater pins. Most errors can be detected by your ears - amp gets noisy, bad hums, loss of power, etc... usually if you can see or smell the problem, somethings has likely gone terribly wrong! If you start to hear a buzz or hum, it's best to start at the preamps and do a little trial and error by swapping one out at a time with a known good tube until you find the culprit (after a tap test of course, as that would likely be the tell)... usually, it's only one, but if two or more have gone south the above process could get a little frustrating Thanks KBP. I guess I'm trying to make my world to perfect in these penny pinching times. Link to comment Share on other sites More sharing options...
pressure Posted June 15, 2011 Share Posted June 15, 2011 I used to go to the drug store to test the tubes for the TV. Link to comment Share on other sites More sharing options...
Guest HRB853370 Posted June 15, 2011 Share Posted June 15, 2011 I think KBP810 will know the answer to your question. There was recently a thread regarding the pencil test. That may have been about whether or not the tubes are microphonic. I thought the pencil test was for cleavage! Link to comment Share on other sites More sharing options...
kbp810 Posted June 16, 2011 Share Posted June 16, 2011 I thought the pencil test was for cleavage! It's one of those multitasking tools Link to comment Share on other sites More sharing options...
kbp810 Posted June 16, 2011 Share Posted June 16, 2011 Where is that store? I believe he was referring to Blues Airman, it's on Ford Rd near Merriman in Garden City, MI There's usually not much to look at there, but every now and then they get some neat stuff in - they usually have a box or two of used but working tubes for $5 a piece. I actually found a couple of old GE 12ax7's in there once that turned out to be solid tubes. Link to comment Share on other sites More sharing options...
DetroitBlues Posted June 16, 2011 Share Posted June 16, 2011 Where is that store? Brian beat me to it. Link to comment Share on other sites More sharing options...
schundog Posted June 16, 2011 Share Posted June 16, 2011 Brian beat me to it. Hey, Nice Truss Rod Cover in your picture! Link to comment Share on other sites More sharing options...
Joe Posted June 16, 2011 Author Share Posted June 16, 2011 I believe he was referring to Blues Airman, it's on Ford Rd near Merriman in Garden City, MI There's usually not much to look at there, but every now and then they get some neat stuff in - they usually have a box or two of used but working tubes for $5 a piece. I actually found a couple of old GE 12ax7's in there once that turned out to be solid tubes. Thanks for the info. I've only been in there once but I'll definetly take my last set of tubes in there.Should be interesting. Link to comment Share on other sites More sharing options...
H Posted June 16, 2011 Share Posted June 16, 2011 There are usually a few vintage tube testers on eBay at any given time. Worth the investment? Link to comment Share on other sites More sharing options...
Joe Posted June 16, 2011 Author Share Posted June 16, 2011 There are usually a few vintage tube testers on eBay at any given time. Worth the investment? I've been wondering about that myself.I saw testers on a tube website. I think they were about $190.00. Link to comment Share on other sites More sharing options...
DetroitBlues Posted June 16, 2011 Share Posted June 16, 2011 Hey, Nice Truss Rod Cover in your picture! Stiener and KBP810 found a place that makes them. I wasn't sure they be able to fix Detroit Blues in script on it, but I'm so glad they could! Can't wait to put it on my H-140. Its the final piece that makes that guitar uniquely mine. Link to comment Share on other sites More sharing options...
kbp810 Posted June 16, 2011 Share Posted June 16, 2011 There are usually a few vintage tube testers on eBay at any given time. Worth the investment? In my opinion... unless you are buying/selling a lot of tubes, it probably isn't The best test equipment for a tube is always an amp and a pair of ears A tester can tell if a tube is good and should work, but it's not going to do much in the way of telling you it's going to sound good... and it's also not really going to tell you if it's noisey and/or microphonic either. The only other best purpose I can think of is if you have a whole bunch of single power tubes that you want to pair up/match; but otherwise, I'd say you can probably easily live life without one. Just my one and a half cents on the matter Link to comment Share on other sites More sharing options...
Joe Posted June 16, 2011 Author Share Posted June 16, 2011 Just got back from Bluesairmen. Two power tubes from that set were bad.Got some good advice on tubes from the guys there. Link to comment Share on other sites More sharing options...
DetroitBlues Posted June 16, 2011 Share Posted June 16, 2011 Just got back from Bluesairmen. Two power tubes from that set were bad.Got some good advice on tubes from the guys there. Hopefully it was the owner and not that kid he has working for him. Link to comment Share on other sites More sharing options...
Joe Posted June 16, 2011 Author Share Posted June 16, 2011 Hopefully it was the owner and not that kid he has working for him. Yes it was the owner and thanks for the tip about him testing tubes. I found out what I needed to know. Link to comment Share on other sites More sharing options...
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