tube fanatic Posted August 30, 2015 Share Posted August 30, 2015 This is a controversial subject which comes up frequently. My answer is that, for most users of tube equipment, it is not needed (unless a person gets large quantities of tubes and wants to weed out those which are dead, shorted, or otherwise obviously defective in which case a lowly emissions type tester is quite adequate). Regardless of how a tube measures, its performance in a particular circuit cannot be predicted since designers often use operating parameters which are vastly different from those of the tester. I've had many tubes which don't test well but perform flawlessly in some circuits. The reverse is also true where a tube tests "better than spec" but turns out to be noisy or microphonic (particularly evident with our favorite Klipsch speakers). So, post your opinions on this! It will be an informative discussion.Maynard Quote Link to comment Share on other sites More sharing options...
FloridaBoy Posted August 30, 2015 Share Posted August 30, 2015 I think you nailed it Maynard. I just bought a single National Union VT229 that, according to the seller, tested new but it is so microphonic that is not listenable even with tube dampers. Quote Link to comment Share on other sites More sharing options...
joessportster Posted August 30, 2015 Share Posted August 30, 2015 Been using tubes for around 10 years now and never had a cause to own a tester, now if you hoard tubes and someday wish to sell and get rich a tester is a must When I swap out tube gear I have always let the spare tubes follow the gear and so I have no stash to worry with Quote Link to comment Share on other sites More sharing options...
ClaudeJ1 Posted August 30, 2015 Share Posted August 30, 2015 You should be asking if TUBES are a worthwhile investment. Quote Link to comment Share on other sites More sharing options...
jimjimbo Posted August 30, 2015 Share Posted August 30, 2015 Awww, Claude cmon dude!! You know they are! Your Super Heresy's/Baby Cornwalls sound incredible through an HH Scott setup... As for a tube tester, I would agree with Maynard. Buy the tubes you need, a backup set, and you are good to go. Testers are expensive, and very, very, time consuming....trust me on this..... Quote Link to comment Share on other sites More sharing options...
Guest thesloth Posted August 30, 2015 Share Posted August 30, 2015 For the normal person that might have a stereo or guitar amp with tubes I agree with the statement that a tube tester is not needed. For me I find mine useful because I buy lots of tubes new and used and I don't want to be putting a shorted tube in any of my equipment. As Maynard pointed out, the testers that test mutual transconductance often do at voltages lower then most circuits we see, so the results won't mean much. Also transconductance is only one part of the equation, plate resistance will effect the overall gain and insertion loss of that particular tube in a particular circuit. If I am restoring vintage equipment with original tubes the tester will give me a rough idea if the tubes are tired or not. Often times I will be testing different stages of a circuit and find that a stage will have less gain than it should. So I will pull the tube and test if, often times it will show low test results. 1 Quote Link to comment Share on other sites More sharing options...
ZEUS121996 Posted August 30, 2015 Share Posted August 30, 2015 You should be asking if TUBES are a worthwhile investment. Claude, the answer depends on the owner. I had an unbelievable setup of Mc tubes and sold it. The buyer hooked them up in an A/B comparison with a couple other tube amps. It was no comparison, the Mc gear smoked the others. Do I wish I had kept them? Yes and no, they were impressive. OTOH, with a good signal and solid state amps (I don't use any) the quality is still great. With my speakers if I buy an amp with 200 watts per channel, what am I going to do with the other 198 that I dont use? Maybe I'm satisfied with where I'm at but that's another question :D Mark Quote Link to comment Share on other sites More sharing options...
minermark Posted August 30, 2015 Share Posted August 30, 2015 Iv been playing with Tubes for 50+ Years. Reality: You sit down ready to listen to your Fav Tune(s), flip on the Amp(s), something is NOT there, something is missing, you suspect Tube. What do you do? I do not have ONE spare tube on site. I have a Hickcock, I test every tube, replace what is weak/bad. With all the years involved with tubes, iv learned if i can afford to be running tubes, i can afford the best (Most tubes coveresd) tester on the market. Why stock a bunch of tubes?, i did over the years, and when i needed a tube, id find i did not have it and had to buy it anyway. You and equipment will change over the years, you only buy one tester, one time. and only the tubes you need. Paid dam near a $600 for my Hickcock off the Bay some years back, today it goes for a Grand plus, so a quality tester is an investment, you will always get your money back. (tell That to the Wife). 1 Quote Link to comment Share on other sites More sharing options...
joessportster Posted August 30, 2015 Share Posted August 30, 2015 Iv been playing with Tubes for 50+ Years. Reality: You sit down ready to listen to your Fav Tune(s), flip on the Amp(s), something is NOT there, something is missing, you suspect Tube. What do you do? I do not have ONE spare tube on site. I have a Hickcock, I test every tube, replace what is weak/bad. With all the years involved with tubes, iv learned if i can afford to be running tubes, i can afford the best (Most tubes coveresd) tester on the market. Why stock a bunch of tubes?, i did over the years, and when i needed a tube, id find i did not have it and had to buy it anyway. You and equipment will change over the years, you only buy one tester, one time. and only the tubes you need. Paid dam near a $600 for my Hickcock off the Bay some years back, today it goes for a Grand plus, so a quality tester is an investment, you will always get your money back. (tell That to the Wife). Not poking sticks here , but am curious about calibration. In my experience all test equipment needs calibration at some point otherwise how would one know the results are legit ?? Quote Link to comment Share on other sites More sharing options...
Guest thesloth Posted August 30, 2015 Share Posted August 30, 2015 Most of the cheaper tube testers are not worth buying unless you are just checking for shorts. I agree they are an investment and hold their value so unless you bought really high you should get your money back at the very least, if not make a profit. Not necassary, but if you are into tube based audio as a hobby they are really handy to have. I would also like to say that tube testers need to be calibrated pretty regularly in order to be somewhat accurate, even still they are just a close approximation. I calibrate mine once a year, it's pretty easy if you have a scope. Quote Link to comment Share on other sites More sharing options...
mike stehr Posted August 30, 2015 Share Posted August 30, 2015 (edited) While I agree that some tube testers are glorified "no go" gauges, they are nice to have for testing unknown rectifier tubes. Around 12-13 years ago, I bought a sleeve of Mullard EZ81/6CA4 from that auction site. Listing said they were NOS, and never a mention of testing them. I wanted some Mullard EZ81s for my Magnavox single-ended 6BQ5 console amplifier. I had no tube tester at the time, so I tried them in the amplifier. Put in the first EZ81, hit the power switch...maybe a second goes by...FLASH! Like a camera bulb...heater to cathode short that blew a hole through the cathode tube. Took out my power fuse. So I went bought another fuse, stuck in another EZ81, hit the power switch....FLASH! So this is getting stupid...I went and visited a audio friend, who had tube testers. We found a couple more bad ones, and the good ones tested like new. I contacted the seller for the listing, told him of the situation, and asked if he had tested the rectifier tubes. He said no, because they were new old stock. Argh... Nonetheless, he replaced the bad tubes and everything was fine. But it's one reason why I bought a emission and transconductance tester. Edited August 30, 2015 by mike stehr Quote Link to comment Share on other sites More sharing options...
minermark Posted August 31, 2015 Share Posted August 31, 2015 Over the years anytime i get a new tester, i just flat out send it to my guy in LA to check out/tweek/adjust. Never really worried about Calib, i have a few "Tube standards" i plug in after warm up of the tester, it plugs into a socket and the meter should go 50%, not a test of complete working tester but it lets me know it's at least as good as it was last time. I guess im to old school to really care too much about matching tubes, gotta remember i was the kid in the neighborhood who fixed everybodys TV. http://www.alltubetesters.com/sales.htm 1 Quote Link to comment Share on other sites More sharing options...
tube fanatic Posted August 31, 2015 Author Share Posted August 31, 2015 Over the years anytime i get a new tester, i just flat out send it to my guy in LA to check out/tweek/adjust. Never really worried about Calib, i have a few "Tube standards" i plug in after warm up of the tester, it plugs into a socket and the meter should go 50%, not a test of complete working tester but it lets me know it's at least as good as it was last time. I guess im to old school to really care too much about matching tubes, gotta remember i was the kid in the neighborhood who fixed everybodys TV. http://www.alltubetesters.com/sales.htm Roger seems like an interesting guy. For those who are curious, his site has some articles (click on the tab on the right side), one of which is about how tubes work. It looks like an informative piece. So, when are you going to post a nice tube amp design on here Mark? You must have your favorite TV horizontal and vertical output tubes from which some nice amps can be made! Maynard Quote Link to comment Share on other sites More sharing options...
ClaudeJ1 Posted August 31, 2015 Share Posted August 31, 2015 Awww, Claude cmon dude!! You know they are! Your Super Heresy's/Baby Cornwalls sound incredible through an HH Scott setup... As for a tube tester, I would agree with Maynard. Buy the tubes you need, a backup set, and you are good to go. Testers are expensive, and very, very, time consuming....trust me on this..... As a former "tube guy," I was just trying to rattle a few cages here. LOL. I have had Mac 240's, Citation II's, Marantz 8B (my fave), Scott Integrated, Dynaco Mk II's, etc. but all in my 20's before all the SS amp designers paid attention to Matti Otala and TIM distortion. I actually spent about 30 minutes with Saul Marantz and he told me to use tubes on the top and solid state for woofers and subs. I had tubes on my Khorns for many years until the SS guys got it right, which they have for decades now. But tubes are sweet if you are willing to put up with replacement tubes and all the bias fussiness............I'm not. I'm actually sold on modern switching amps, which add neither dirt, nor "fairy dust." Quote Link to comment Share on other sites More sharing options...
Seadog Posted August 31, 2015 Share Posted August 31, 2015 A tube tester is a nice-to-have instrument for the casual tube gear user. For a serious tube guy (selling tubes, collecting or repairing tube gear), I would think it should be must-have instrument. An emission only unit is better than nothing, but leaves some to be desired. My brother has a Sencore Mighty Mite emission tester that was indicating good tubes that he had picked up on eBay. When I tested them using my B&K 747, they tested weak. I am a very casual tube guy, but I like the ability to do my own tube testing (I guess that is just the engineer coming out in me). Quote Link to comment Share on other sites More sharing options...
ClaudeJ1 Posted August 31, 2015 Share Posted August 31, 2015 Paid dam near a $600 for my Hickcock off the Bay some years back, today it goes for a Grand plus, so a quality tester is an investment, you will always get your money back. (tell That to the Wife). It's all part of the dedication, like stocking compression driver diaphragms. I do miss my Marantz 8B, but I think it's more nostalgia than performance. In 2015, it's really good to have a choice and to be able to use older technology with modern speakers (based on old school PRINCIPLES, not fashion). Quote Link to comment Share on other sites More sharing options...
JJkizak Posted August 31, 2015 Share Posted August 31, 2015 In the old days when tubes were $1.39 we would go through them like M & M's to cure local oscillators and distortion problems. JJK Quote Link to comment Share on other sites More sharing options...
Guest thesloth Posted August 31, 2015 Share Posted August 31, 2015 Around 12-13 years ago, I bought a sleeve of Mullard EZ81/6CA4 from that auction site. Listing said they were NOS, and never a mention of testing them. I wanted some Mullard EZ81s for my Magnavox single-ended 6BQ5 console amplifier. I had no tube tester at the time, so I tried them in the amplifier. Put in the first EZ81, hit the power switch...maybe a second goes by...FLASH! Like a camera bulb...heater to cathode short that blew a hole through the cathode tube. Took out my power fuse. So I went bought another fuse, stuck in another EZ81, hit the power switch....FLASH! So this is getting stupid...I went and visited a audio friend, who had tube testers. We found a couple more bad ones, and the good ones tested like new. I contacted the seller for the listing, told him of the situation, and asked if he had tested the rectifier tubes. He said no, because they were new old stock. Argh... Nonetheless, he replaced the bad tubes and everything was fine. But it's one reason why I bought a emission and transconductance tester. Hello Mike, maybe it was the amplifier that was the problem and not the rectifier tubes? What was the measured capacitance of the input filter cap? I think it should be 40uF but I have seen and measured up to 100uF. Also what was the power transformer secondary winding source resistance? The 6CA4 datasheet specifies 50uF for typical capacitor input filter value, I would use a 47uF. BUT you can still exceed the max peak current rating for the rectifier if the source resistance is to low, so it's a good idea to add 50-100 ohm resistors in series with the plates of the rectifier tubes, this will limit the inrush current so no flash over in the rectifier tubes. No worries in this amp for "sag" in the power supply with the added resistance because it's single ended and the current should not vary very much. Just saying it might be a good idea to go back and look at the amp. Quote Link to comment Share on other sites More sharing options...
minermark Posted August 31, 2015 Share Posted August 31, 2015 Over the years anytime i get a new tester, i just flat out send it to my guy in LA to check out/tweek/adjust. Never really worried about Calib, i have a few "Tube standards" i plug in after warm up of the tester, it plugs into a socket and the meter should go 50%, not a test of complete working tester but it lets me know it's at least as good as it was last time. I guess im to old school to really care too much about matching tubes, gotta remember i was the kid in the neighborhood who fixed everybodys TV. http://www.alltubetesters.com/sales.htm Roger seems like an interesting guy. For those who are curious, his site has some articles (click on the tab on the right side), one of which is about how tubes work. It looks like an informative piece. So, when are you going to post a nice tube amp design on here Mark? You must have your favorite TV horizontal and vertical output tubes from which some nice amps can be made! Maynard I did not know this guy was still in business, been the better part of six years since sending in my last tester. Amazing i still have the link, there are only a handfull of old school tube tester techs left. If you dig into his site a little, you will see that new fangled tester that is Pc based, i was all over these when they cane out a few years back, looking through what tubes it handled/test performed, it could not do a couple of tubes i wanted so i never looked back, Too bad, i was stoked and ready to buy, but i had the thought, if a tester does NOT do every tube you have experience with, they will not be in business long, this tester did some great tubes, but by NOT covering the spectrum they shut out the entire Ham Radio hobby. My circuit designs stopped at HamRadio hobby, Everything has gone SMT, throwaway generation. Quote Link to comment Share on other sites More sharing options...
minermark Posted August 31, 2015 Share Posted August 31, 2015 Found yet another usefull link in my bookmarks from the past. http://www.tubewizard.com/recommended_Hickok_testers.htm Quote Link to comment Share on other sites More sharing options...
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