@oddiofyl that's right, testers are great for weeding out shorted or bad tubes, not so much for tube life or even for matching. Testers don't test tubes at real world operating voltage and current.
DON:T WAIT! Replace Those Old Power Tubes!
For several years I've cobbled together the required quad of 6L6GC power tubes for my Raven Audio Integrated amp. I say 'cobbled' because out of two sets I culled four which would perform what I perceived as reasonably decent sounding. Being on the last best four I feared one more failing tube would put me out of the music. So, I ordered another quad from Raven Dave (Thomson). At first I thought to just saved them for an emergency but on a whim I decided to just put all the Chinese New Old Stock (NOS) in place. APPARENTLY, and obviously, my smorgasbord set in place previously had various quirks including but not limited to: hum, occasional buzzing, and a bloated`slow tone. My wife immediately stated: I don't hear anything in the background. Indeed there isn't anything but dead silence. NOS tubes are always a "Russian roulette" deal but their unique and amazing "real-ness" is worth the gamble. (IMO) So if you have been waiting until you absolutely have to, DON'T WAIT any longer. The improvement is profound. These tubes are as old as I am! Only difference is I've not been in a box traveling around the world for over 60 years!
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Some testers, like the Amplitrex, do test at full power and do give one an idea of how much life is left in the tube. This tester, if attached to a computer, will curve trace the tube. Someone who owns dozens of modern and vintage testers told me that he likes the E-Tracer which is bought from Taiwan as a kit; it too curve traces and delivers very close readings to the Amplitrex. Another supposedly good tester/tracer that comes as a kit is the Sofia tester. A local shop uses a TV7 tester as its main unit. It is good for finding bad tubes and weak ones, but, it tends to be a bit generous in its rating—it will give strong readings for tubes that the Amplitrex says is not that strong. This shop also uses a modern, very compact tester called the Orange, but they mainly use it for small signal tubes. |
The Raven Audio amps seem to be tough because due to my overuse of nano contact enhancer on tube pins I shorted out, red plated a couple power tubes. Very scary when a tube glows bright red in the main body of the tube and a horrific howl blasts from one's speaker. Being a complete novice and never even knowing about or ever seeing such an event I was both terrified and intrigued. Immediately put it off. let it cool, removed offender and "kept calm and carried on". (All nano enhancer has been cleaned off now on tube pins TIP: Use sparingly, extremely sparingly) Occasionally a tube would begin to "red plate" I will shut off unit, reseat tube, and it will act normal again. But as I said, these amps can withstand a lot of user misuse.My normal idea of learning by experience may be on my tomb stone. "Experience Is The Perfect Teacher to He Who Lives Forever" (For mere mortals, read the instruction book) |
@allears4u Do Raven amps still use tube sockets mounted directly to the circuit board instead of being mounted on the chassis? If you are doing a lot of tube rolling, you may have cracked solder joints causing operating failures like you mention. Intermittent red-plating should not be happening as if it was a matter of course. |
I'm not sure how the tube sockets are attached but after I cleaned off the nano contact enhancer which can move around a little with heat and getting these NOS power tubes no more problems with any thing. As usual its my fault for over using the nano stuff and being too cheap to just get new power tubes which I suspected I needed for a while. (Didn't;t realize just how much I needed the new tubes) AND, I was always changing around tubes to discover the best sound with each combination. So intriguing to hear the changes as I try different preamp tubes especially from all around the world and from different time frames of manufacturing. All NOS in this amp. If anything could crack I surely would have cracked it by now. Did have one of the 9-pin tube leave behind one of its pins before and I shoved another right along side of it! Iy played but was a little weird so I checked to discover the extra pin lodged in a slot. Not good. Raven Dave is sending a free replacement as if he's personally responsible for all things Raven Audio which I appreciate endlessly of course. May I say Raven Audio (as many here have confirmed) is profoundly committed to personal customer care. Chris Botti CD playing right now beautifully. Over and out |
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