I've got a 707 model. I bought it along with 500 or so vintage tubes for my guitar amp building. 226 bucks for the lot. What an incredible deal. I had to mod it to test 12ax7 properly. I'm told it's recently calibrated. Seems to work great, but lots of the sockets are worn . I have to find a good replacement for the octals . They're smaller than the belton I usually use.
I'm wondering is it ok to just press the Test button? I heard you need to check for shorts & then grid before hand & if the shorts lights up don't test any further. I tested a 12AX7 that had crackle & it lit the shorts light up. I forgot not to go any further & I pressed the grid button for a few seconds & it went into the bad range then realized I shouldn't go further. Now the tube doesn't light up the shorts light & the Grid Emission doesn't fail.. Do you think I damaged my tester?
@@proampsolutions Any thoughts as to why my B&K would show a short after I calibrated it & I press Grid Emission (which I know I shouldn't do) the needle went up 3/4 of the scale & when I pressed the shorts button again it showed no shorts?
Grid emission is a catastrophic failure in a tube. The tube is probably destroyed to the point where the short that existed may no longer exist. If your B&K is properly calibrated, you should test for shorts first, if you have a short test no further the tube is bad - period. You should never persist with a shorted tube, bad things happen. Also, good is relative! That is why there is a scale on the meter. A tube may sound just fine to the listener but in fact may only transconduct 65% of what a new tube does, but it still "works". A tired power tube will likely still work fairly well, it just might take less negative bias to run it at ideal idle dissipation. A calibrated meter is a good tool and should help you quantify results, not leave you with questions.
@@proampsolutions I calibrated my meter correctly & your explanation explains exactly why the Shorts isn't lighting up & I'll throw the tube out. As for the one Power Tube I'm a bit unsure as you stated previously the Orange tester isn't as good so the PT that fail in the orange tested good in the B&K but I heard crackling & the volume cut out so I guess the Orange found something the B&K didn't?
Yes I always test both plates on a dual triode tubes. One can be bad and the other good, or they can be significantly out of balance which may be important, depending on the application.
I've got a 707 model. I bought it along with 500 or so vintage tubes for my guitar amp building. 226 bucks for the lot. What an incredible deal.
I had to mod it to test 12ax7 properly. I'm told it's recently calibrated. Seems to work great, but lots of the sockets are worn . I have to find a good replacement for the octals . They're smaller than the belton I usually use.
That's actually a 747B (B for breaker)
I'm wondering is it ok to just press the Test button? I heard you need to check for shorts & then grid before hand & if the shorts lights up don't test any further. I tested a 12AX7 that had crackle & it lit the shorts light up. I forgot not to go any further & I pressed the grid button for a few seconds & it went into the bad range then realized I shouldn't go further. Now the tube doesn't light up the shorts light & the Grid Emission doesn't fail.. Do you think I damaged my tester?
The other question I had was I had an EL34 tested in an Orange VT1000 & it failed 2x's but in this tester it still showed good.
The Orange VT1000 tester has very limited capability and only gives you a general idea what is going on. I do not use one for this very reason.
@@proampsolutions Any thoughts as to why my B&K would show a short after I calibrated it & I press Grid Emission (which I know I shouldn't do) the needle went up 3/4 of the scale & when I pressed the shorts button again it showed no shorts?
Grid emission is a catastrophic failure in a tube. The tube is probably destroyed to the point where the short that existed may no longer exist. If your B&K is properly calibrated, you should test for shorts first, if you have a short test no further the tube is bad - period. You should never persist with a shorted tube, bad things happen. Also, good is relative! That is why there is a scale on the meter. A tube may sound just fine to the listener but in fact may only transconduct 65% of what a new tube does, but it still "works". A tired power tube will likely still work fairly well, it just might take less negative bias to run it at ideal idle dissipation. A calibrated meter is a good tool and should help you quantify results, not leave you with questions.
@@proampsolutions I calibrated my meter correctly & your explanation explains exactly why the Shorts isn't lighting up & I'll throw the tube out. As for the one Power Tube I'm a bit unsure as you stated previously the Orange tester isn't as good so the PT that fail in the orange tested good in the B&K but I heard crackling & the volume cut out so I guess the Orange found something the B&K didn't?
Do you always test both plates on those tubes?
Yes I always test both plates on a dual triode tubes. One can be bad and the other good, or they can be significantly out of balance which may be important, depending on the application.
Don't bother messing with those Shorts and Grid Emission buttons. No one needs those. LOL
Shorts? Bah! Just crank up the voltages. :-)
👇 *PromoSM*