Even something lacking GAS can be bad enough

[suphuckers]

Well remember when I was asking you about current flow in tubes? The reason I was asking was that I was trying to figure out how a tube that tests good on a Maxi Matcher.......

I mean this guy was old, and had like 15 grand kids and etc.. I checked him out on Facebook (Without him knowing). He was pretty honest, and shocked that the tubes didn't work. In the end he took them back and even paid return shipping. ...and almost broke into tears for selling me bad tubes. Ive run into a few rip off idiots on eBay, but this guy wasn't one of them. So anyways.....

The Maxi Matcher tests the tubes @1ma. My tester that I was using (that actually showed the tube bad), was testing the tube closer to 3ma. The proof the tube was bad was in putting it in the amp. ...and like I said, it sounded like trash. The guy that sold me the tubes never put them in an amp. He only used the Maxi Matcher. ...and in his case the Maxi Matcher FAILED. Take it however you want. I'm just reporting what happened. Personally I wish the Maxi Tester was perfect, but I have seen 1st hand that it's not.

 

[suphuckers]

..and another thing. This same tester that caught those bad tubes... I used that tester to test that one JJ that failed in V2 that I mentioned earlier. It showed that tube as perfectly fine. Sooo I'm not saying my old testers are perfect either.... I'm saying for $2000 (I thought they were only $1000), but either way, you can keep those modern testers.

This is what I do for a living Rob. I analyze and troubleshoot electronics. I'm not gonna go into what kind, and that doesn't make me an expert on tubes, but I'm very familiar with test equipment and component analysis. (..and I'm REALLY good at it) If I were you, I wouldn't bet any money on that Maxi Tester always being right. That's all I'm saying. ...and I definitely wouldn't recommend that an avg musician or w/e go out and spend $1000 or $2000 on one of those. The $100 tester will work just as good for them. (As long as they get one that's working properly). In the end what matters is what happens when you put a tube in an amp.

The only point of using the tester is to widdle the pile of tubes down, so you don't have to listen to 50 tubes to find one good one. I bought my testers because I didn't want to be ripped off. A $100 tester can do a reasonable job of both of those things for the avg guy.

Just sayin

 

[Jaded Faith]

Well since we are just sayin, here's a few details you glanced over....

- The Maxi-Matcher tests tubes at 1, 2 or 4mA depending how you you set the Gain Type. You have to configure the machine to match the tube being measured.

- It's likely your seller was looking at no more than the gain data when declaring them "good". You have to look at more than that, paying particular attention to the transconductance as well. For example, I am working on a module right now and it had low output. The gain measurements of one of it's 12AX7's is great. The TC was rather low for it, thus this the tube is worn and not properly transmitting current. To make a blanket statement against a piece of equipment without knowing how it was used is inaccurate.

- To further expand on the last point, the Maxi-Matcher uses a cathode follower with a constant voltage low-impedance plate supply for the TC calculations. The cathode follower has very low input capacitance and a very high input impedance so it will not load down a previous stage, and very low output impedance so very little signal is lost even when driving a fairly low input impedance. Thus the current demands for testing are very low. Reference 12AX7 load lines for 200V and 1mA is quite sufficient for this test. Each triode plate in a pair is supplied with a constant voltage. A calibrated signal is applied to the control grid inputs and the resulting change in cathode current is measured. Samples are captured at the tube cathode every 150 milli-seconds, and the microprocessor then calculates the transconductance as Gm = change in Iplate / change in Vgrid. Data are averaged and then updated 4 times per second in the LCD display.

- I should clarify the $2000 for you. That includes the Maxi-Matcher, Maxi-Pre and various adapters needed to test many of the less common tubes found in older amps.

- There is no disagreement about the need for expensive test equipment. One can argue a simple Fender Champ clone to be a fantastic preamp tube tester, because it is! The best test gear is worthless if the user isn't thorough and knowledgeable about what they are testing.

Shall we agree tubes can be a gamble at best and test equipment can be useful in weeding out duds? That sums up my position on the subject fairly well.

 

[suphuckers]

yup, and as surprised as you might be, I was following what you said there pretty well. I didn't know that the Maxi tester had variable settings like the ones you described. ..and I've never used one myself. I asked the guy about his test conditions and his answer involved the 1mA I mentioned. I wasn't making a "blanket statement" I was describing a specific event that actually happened.

My response to what you said tho (and I'm really not trying to argue) but... Wouldn't you just likely set your tester at 1mA? Test the tube and call it good? Because that's exactly what he did. It didn't work out so well for him/me. That's all I was trying to say.

I probably agree with you more than disagree, and I'm not trying to debate too much of this. I'm just trying to point out... that, it's "possible". You could test a tube on your Maxi Tester, and then if you don't bother to test it in an amp afterwards, and just ship it out to a customer.... There's a "possibility" your Maxi tester could miss a bad tube.

For me, it's not worth all that money. I've got several other much cheaper testers that can miss bad tubes too I just wanted to tell you that... I had an experience with a guy who seemed fairly honest, who missed some bad tubes with that tester. That way if you get a call from a guy and he says "Hey these tubes you sent me are bad". Maybe you wont jump to conclusions and you might give him the benefit of the doubt.

As always, I'm just trying to share information/opinions/help. ..and as often seems to be the case, people react as if they believe I'm starting an argument. Can't figure that one out.

Why the hell do I care who uses a Maxi Tester? Or what tubes you sell people? LoL

 

[suphuckers]

So while we're discussing how awesome this Maxi tester your friend built is... (I'm poking you in the side there on purpose and it's kind of a joke OK ROB? heh) ...but Maybe you can give me some info on that tester. Will that tester detect and report a 750k Heater/Cathode leakage? Most testers won't, and I've had more than one situation where guys are selling tubes tested (Especially on old Hickok testers) that have 600-800k or so leakage. Then they want to argue with me how awesome their tubes are they sold me (That I'll just end up throwing in the trash).

 

[suphuckers]

Most testers that do a leakage test will report a tube as "good" if the leakage does not go below 500k. A tube (and you probably already know this but..) that tests at 750k is still "good", but it's certainly not a tube I'd want to put in an amp. I'm not aware of many testers that can report this information. I would be impressed if your friends tester reported actual leakage of anything below 1m. That's something I'd find very useful. Especially for testing NOS Tubes. (Or Old Worn Out. Whichever the case may be LoL).

 

[suphuckers]

Looks like No. I'm also looking at it, and I'm not sure you could test a 12AX7 with anything other than 1mA can you? I'll try to find a manual and read it later. Heading out for the night.

 

[suphuckers]

It is recommended that suggested Gain Type settings be used. While
other Gain Type settings than what is recommended on the front panel
may be used, spurious or out of range data may result. For instance,
measuring a medium-Mu triode such as a 12AU7 in the High range
setting results in an out of range statement. Using a low or medium gain
setting for a hi-gain triode such as a 12AX7 results in a mismatch of tube
impedance and power supply input resulting in incorrect measurement.
However, neither the tube nor the MaxiPreamp will be damaged by this
action, so it is possible to explore the various combinations of gain and
triode type

So basically the answer to this question of varying the current and observing the results is also a No on this tester. So again not trying to argue but.... smh.

I'm just going to attempt to walk away from this discussion because it seems as is often the case, there is an unshakable preconception. Hopefully you got my point I was trying to make earlier, and if it ever comes up in the future it'll be useful.

Nightdare, Sorry. ...and try those 803S's

 

[Jaded Faith]

You question regarding heater-cathode leakage is not one of great concern and there is a real reason for this: it doesn't really matter and most tests for it are irrelevant.

Heater-cathode leakage is a concern only when the heater becomes more negative than the cathode. In a common amplifier high/medium mu triode gain stage this scenario NEVER happens. The only common amp circuit where this scenario does occur is in a cathode follower stage, which is exactly why you see so many New Sensor tubes fail in that position. Thus, the widespread advice against their use as such all across the internet.

Testers like Eico 666 show amount of leakage on a meter. A person needs to set their own limits for this leakage when replacing tubes. Higher filament voltage increases leakage. New tubes usually won't register leakage on the meter.

The Maxi-Pre does not include a leakage test. It doesn't need one either. The consequence of heater-cathode leakage is hum. It only takes a quick sampling of the noise test on this unit to provide ample audible evidence of a leak significant enough for concern. You can adjust the gain type knob as noted in your last post to observe the tubes audible artifacts in each operating condition as well should that be a concern to you. Quite clever really.

As with most things in amps, math/numbers are great but they don't mean a thing if it doesn't feel right or it is too noisy. Good on paper isn't close enough for rock and roll my friend.

I know it's late and you just posted that you have checked out of this conversation. I bid you a fine evening and I hope this has provided you some clarification.

 

[suphuckers]

well I knew ...and then yeh I really need to get away from this conversation. Mostly because you seem to keep trying to rebut everything I say as if I have no clue what I'm talking about heh, but that's OK. ...and I really don't have any desire to argue or debate this. I only wanted to give you some 1st hand information that I have experienced. ...and I'm still in a good frame of mind... (for the time being heh) ...but I knew what the leakage caused.

Anyways, just to be clear.. the 666 isn't my only tester . ...and you might not find the leakage test so useless when you install 6 tubes in your system, and then you have a noise you can't find, that didn't show up until the 2nd day. Then you drive your self nuts switching out components trying to find it. I'd rather have not installed that tube in the 1st place. The leakage test not only lets you know about a potential hum, but it also gives you some kind of idea of the life left in the tube. That tube might test just perfectly fine and quiet during your 30 second test on your Maxi tester.

The leakage (as you should already know) is caused by a breakdown of the insulation. The insulation is normally so good that any leakage in a 12AX7 should be something to pay attention to. Noise or no noise (yet) It's a helpful tool to evaluate the overall condition and life expectancy of a tube. The noise test on the Maxi is not going to give you any of that information.

Also as I have suggested, and have also read... That tester is pretty much just testing the tube under one specific set of operation conditions. Yes you can flip a switch and get one or two other (incompatible) specific test parameters, but that's a far cry from being able to turn a dial and manually change every aspect of the test. (To whatever parameters you wish) They may be adequate conditions, but regardless, it's just one set of conditions.

This is the exact reason that guy missed those bad tubes. This is exactly why I was trying to get you the tell me the exact conditions that the tubes are under in the RM100. I tried twice to get a specific answer out of you about that. The 2nd answer was "around 1ma should be a good point to start" or something like that. I was trying to get specific answers (I'm a science guy, not a "sort of around" guy LoL) so that I could analyze why the Maxi tester failed to find these bad tubes, and my other testers found them easily. I still haven't gotten to the bottom of that, because I never found that specific information.

At this point I really don't care to spend any more time on it. I don't intend to buy a Maxi Tester. It would be nice to know why it failed. It's like you said... "know how to use the tester". If you know why it failed to find those tubes... that's how you get really good at using testers and testing tubes... not by saying "I stand by my tester 100%" Cause trust me Rob, That tester is not standing by YOU 100% LoL. They ALL have flaws. I was just pointing out one of the flaws in this particular tester. It would be nice to understand the cause of it. ...but nm LMAO

 

[suphuckers]

As with most things in amps, math/numbers are great but they don't mean a thing if it doesn't feel right or it is too noisy. Good on paper isn't close enough for rock and roll my friend.

I mean, and then I'm really gonna check out of this because I promised myself I would stay away from this kind of stuff. In the beginning all I said was "Beware my friend", and I had no desire to discuss it any further. I just figured I'd put that bug in your mind (to be helpful) and if you ever had a doubt about a tube, you'd remember what I said. That's really all there was to it. ...but, to your comment above. Here's a fact. Just because until now nobody has been able to quantify what makes certain tubes awesome (on paper) doesn't mean it can't be done. ...and I'm just gonna leave it right there. You can comment back if you want, (..and I'm still in a good frame of mind), but I think I'll force myself to refrain from commenting again. You can have the last word (if that's what you wish).

Peace out!

 

[Jaded Faith]

Well you sure do pop back in a lot for a fellow who constantly announces his exit! I do love a spirited discussion backed with solid facts from both parties, as debate has become a lost art in the age of the internet. So pardon my need to chime in once more...

I assure you as one who makes my living chasing ghosts in these machines that I would never be foolish enough to put all my faith in one tool. I have lots of tools, techniques and experience that help me track down problems. I can certainly appreciate your concern and warnings. I'll log those in the memory bank should they prove useful.

I also apologize if the replies I gave you on your RM100 were not satisfactory. I'll be perfectly honest that the questions or the way they were worded simply didn't make sense to me. It's entirely possible I couldn't understand you, but it just seemed like you were trying to indirectly ask something other than you did of were not clear enough on the subject matter to phrase your question properly. At any rate, I'm sorry if I wasn't helpful.

 

[audiomidijace]

Rob,
Don't waste another key stroke on this tool.
He's an untalented hack that thinks he's smarter than everyone else.
If we all just ignore him, he'll go away eventually.

 

[suphuckers]

Ya know Jace, I DON'T claim to know everything. If I did, why would I have come here to talk to individuals such as yourself? I'm here to hopefully gain some information. However, so far, I'm not having much luck. So Thanks for all of your useful insight and knowledge!

 

[suphuckers]

....and one more thing. Your Mom!

 

[JKD]

...

 

[JKD]

....and one more thing. Your Mom!

LOL...are you 12?

 

[suphuckers]

....and one more thing. Your Mom!

LOL...are you 12?

If Only that were true

 

[JKD]

....and one more thing. Your Mom!

LOL...are you 12?

If Only that were true

Heh....we are all maybe a little older than we'd like to be!

At least you are provoking activity...while we seemingly wait for new products.

 

[suphuckers]

The truth JKD is I don't know any other way to communicate with someone like Jace. I've tried to have reasonable conversations with him, but it's kind of like talking to my kids (before they were adults). So I just respond the only way that seems fitting.... like we're all 12. That seems to be the level a conversation with him ends up anyways. May as well just go right there in the 1st comment That way I save myself a lot of frustration.