JJ glass is becoming infamous for either loss of vacuum or cracking like an eggshell under normal use. It’s not all of the tubes obviously, but it happens enough to be a real problem. It’s a shame too, they made some of the more durable tubes previously. For new power tubes, the best out there right now are TAD Redbase and an EL84 is part of the lineup. I’d probably go find a quad of good used Mullards/Brimars and leave new tubes alone in that amp. A failing tube could have been the cause of the pops and crackles.
Weird. I'm on multiple large forums daily and I've seen no rash of jj tubes busting and losing vacuum and going bad out of nowhere prematurely. And you can bet that's where they would Complain if it was happening. Especially at TGP & TDPRI. Yeatzee knows all about that lol.
@@J.C... When you talk to techs that work on hundreds of amps a month and they say it’s a problem, it’s a problem. JJ has been swamped and QC slipped, and I don’t blame them entirely. If you want JJ’s, buy them “burned in”. It’ll save on the crib death/glass problems
Yeah I hadn't heard about it on forums either but more than one tech has told me they've seen that type of failure a lot with them. Frustrating! And vintage glass is soooo expensive now. I think I'll end up just going with new tested stuff with a warranty if it's going to get gigged. Since I changed the screens and grids as well I'm not as worried about running modern tubes.
Yep it's a problem, I just stopped using them entirely. It's been 50/50 for me if the base cracks or not. Lyle has had the same problem and so has Brad, and many many other techs. They have a problem with annealing or their glass supplier is having QA issues.
You may want to increase the 47r cathode resistor for the EL84s to be kinder to these modern production tubes. You can double it and sitll be fine (91r) or pick something in the middle like 68r. It'll run the tubes cooler. Would be good to run that amp into a bucking transformer / brown box type thing because even when new the 115 was really 110 so plugging into 120v+ gives you some meaningfully high voltages in the amp you'd best avoid with new manufacture power tubes. You can get Welwyn 14 watt vitreous enamel resistors from Mouser.
It's actually got a 75ohm cathode resistor right now 🙂 The previous episode I check the bias at both 112v (6.3v on heaters) and 120v with the 75ohm resistor and at 120v it biased at just under 100%. I've got a 68r and and 60r iirc on the way to try 😎👍
"National" tubes are rebranded tubes that could be from just about anywhere. There was a USA based manufacturer called National that specialized in manufacturing large, expensive transmitting and industrial tubes, but as solidstate equipment was taking over most areas of electronics, National was bought by another manufacturer of industrial tubes, Richardson Electronics (still in business making microwave and x-ray tubes and other industrial tubes), who repurposed Richardson as a marketing and relabeling brand for tubes imported from all over the world and occasionally from the US. They came in distinctive red and white boxes with the symbol you see on them; some were high quality German or British tubes and some were from China or India or who knows where. Unfortunately they weren't above relabeling the tubes to show a different country of origin then where they were originally manufactured, And so quality could be a little bit of a crap shoot. However, National branded tubes were likely to be a notch better than IEC Servicemaster tubes which were typically absolute garbage. Back in the 1930s and 40s there was also a company known as National Union that made tubes for radios and amplifiers, lgenerally pretty decent stuff, But I don't think they lasted long enough to even get into making 12AX7'S or other similar miniature 9 pin tubes.
@@YeatzeeGuitar , Ned Carlson at Triode Electronics said that when they first started buying tubes from National/Richardson it was kind of like Forest Gump's box of chocolates where you never quite knew what you were gonna get! Might be Telefunken, Siemens or Mullard, and it might be Chinese junk !
National Union operated in Orange NJ making replacement tubes (about 300 types) and a few dozen different radios. The tube factory was sold to Sylvania in 1954. Since you mentioned it, i have only seen five pin and Octal tubes carrying the National Union label.
Thanks! I've got a video on my channel about the guitar, it's an old one. The model is G6136T-LDS I believe. Nitro finish, fully hollow full body size with dynasonic pickups.
Well the good news is that the amplifier sounds incredible! As for the noise...it almost sounded like a static electricity crackle. But as others have mentioned, it could have been the tube. Also, it happened when your right hand was not on the guitar so that doesn't look like static electricity buildup on your pickguard was the culprit. Hopefully it was just that tube & now you'll be good to go. As for matched tubes I wouldn't worry about it as much in a guitar amp. As long as the quad is within about 10mA of each other you are probably fine. Lots of people think a slight mismatch sounds better in guitar amps. HiFi equipment is where you have to take the matching more seriously. YMMV
I've now played the amp several hours since this and yeah zero pops or crackles so I *think* it's fixed. Just bummed about the video, but it sounds insane in person!
Sounds great! My first amp and I used it many years straight in and surf the volume and tone. Especially with a 50's wired LP. They never need to go above half way as you mentioned. I find it just turns to mush anyway. My favourite thing about these is how much they like to feedback and how controllable and usable that is. Especially with a semi hollow .. ruclips.net/video/kE8HmxU8mSg/видео.htmlsi=ar9hLyJtu81XbiU3 ^ It really can be extremely musical.
@@YeatzeeGuitar They were cheap in the 90's. Everyone wanted Marshalls because Guns n Roses haha. I still have it. Also funny reading the other comments about JJ glass being crap. I've had the same (complete) set of JJ's in mine since 2015. They are so ridiculously over-biased it sounds like a Corvette cooling off and pinging for 10 mins after a jam. I guess Rona screwed up supply and demand outstripped supply so standards fell?
This thing sounds amazing, thanks for video.
Getting there!
Couldn't have gotten this far without you! Thank you!
Got to love a well maintained AC30 cranked :)
I'm actually surprised by how much gain it has! I haven't got it past halfway and it's more gain than I'd ever really need!
Sound amazing!!!
JJ glass is becoming infamous for either loss of vacuum or cracking like an eggshell under normal use. It’s not all of the tubes obviously, but it happens enough to be a real problem. It’s a shame too, they made some of the more durable tubes previously.
For new power tubes, the best out there right now are TAD Redbase and an EL84 is part of the lineup. I’d probably go find a quad of good used Mullards/Brimars and leave new tubes alone in that amp.
A failing tube could have been the cause of the pops and crackles.
Weird. I'm on multiple large forums daily and I've seen no rash of jj tubes busting and losing vacuum and going bad out of nowhere prematurely. And you can bet that's where they would Complain if it was happening. Especially at TGP & TDPRI. Yeatzee knows all about that lol.
@@J.C... When you talk to techs that work on hundreds of amps a month and they say it’s a problem, it’s a problem. JJ has been swamped and QC slipped, and I don’t blame them entirely. If you want JJ’s, buy them “burned in”. It’ll save on the crib death/glass problems
Yeah I hadn't heard about it on forums either but more than one tech has told me they've seen that type of failure a lot with them. Frustrating! And vintage glass is soooo expensive now. I think I'll end up just going with new tested stuff with a warranty if it's going to get gigged. Since I changed the screens and grids as well I'm not as worried about running modern tubes.
Yep it's a problem, I just stopped using them entirely. It's been 50/50 for me if the base cracks or not. Lyle has had the same problem and so has Brad, and many many other techs. They have a problem with annealing or their glass supplier is having QA issues.
What's your go to now?
That's what a real Vox sounds like. Would be cool if you demonstrated your amp compared to the modern AC30 being sold now so kids new what's up.
That’s a nice sounding amp!
You may want to increase the 47r cathode resistor for the EL84s to be kinder to these modern production tubes. You can double it and sitll be fine (91r) or pick something in the middle like 68r. It'll run the tubes cooler. Would be good to run that amp into a bucking transformer / brown box type thing because even when new the 115 was really 110 so plugging into 120v+ gives you some meaningfully high voltages in the amp you'd best avoid with new manufacture power tubes. You can get Welwyn 14 watt vitreous enamel resistors from Mouser.
It's actually got a 75ohm cathode resistor right now 🙂 The previous episode I check the bias at both 112v (6.3v on heaters) and 120v with the 75ohm resistor and at 120v it biased at just under 100%. I've got a 68r and and 60r iirc on the way to try 😎👍
@@YeatzeeGuitar NICE - missed that bit, great work!
@@zeroamplification thanks! Getting there!
"National" tubes are rebranded tubes that could be from just about anywhere. There was a USA based manufacturer called National that specialized in manufacturing large, expensive transmitting and industrial tubes, but as solidstate equipment was taking over most areas of electronics, National was bought by another manufacturer of industrial tubes, Richardson Electronics (still in business making microwave and x-ray tubes and other industrial tubes), who repurposed Richardson as a marketing and relabeling brand for tubes imported from all over the world and occasionally from the US. They came in distinctive red and white boxes with the symbol you see on them; some were high quality German or British tubes and some were from China or India or who knows where. Unfortunately they weren't above relabeling the tubes to show a different country of origin then where they were originally manufactured, And so quality could be a little bit of a crap shoot. However, National branded tubes were likely to be a notch better than IEC Servicemaster tubes which were typically absolute garbage.
Back in the 1930s and 40s there was also a company known as National Union that made tubes for radios and amplifiers, lgenerally pretty decent stuff, But I don't think they lasted long enough to even get into making 12AX7'S or other similar miniature 9 pin tubes.
Great insight!
@@YeatzeeGuitar , Ned Carlson at Triode Electronics said that when they first started buying tubes from National/Richardson it was kind of like Forest Gump's box of chocolates where you never quite knew what you were gonna get! Might be Telefunken, Siemens or Mullard, and it might be Chinese junk !
National Union operated in Orange NJ making replacement tubes (about 300 types) and a few dozen different radios. The tube factory was sold to Sylvania in 1954. Since you mentioned it, i have only seen five pin and Octal tubes carrying the National Union label.
Amazing sound. I own a 65 AC30….Which Gretsch is this? (Pickups?)
It’s a Falcon with DynaSonic pickups.
Thanks! I've got a video on my channel about the guitar, it's an old one. The model is G6136T-LDS I believe. Nitro finish, fully hollow full body size with dynasonic pickups.
Well the good news is that the amplifier sounds incredible! As for the noise...it almost sounded like a static electricity crackle. But as others have mentioned, it could have been the tube. Also, it happened when your right hand was not on the guitar so that doesn't look like static electricity buildup on your pickguard was the culprit. Hopefully it was just that tube & now you'll be good to go. As for matched tubes I wouldn't worry about it as much in a guitar amp. As long as the quad is within about 10mA of each other you are probably fine. Lots of people think a slight mismatch sounds better in guitar amps. HiFi equipment is where you have to take the matching more seriously. YMMV
I've now played the amp several hours since this and yeah zero pops or crackles so I *think* it's fixed. Just bummed about the video, but it sounds insane in person!
@@YeatzeeGuitar Grats! That's definitely a keeper
It sounded great! Apparently we have almost the same Falcon, mine has melita bridge
Nice! Yeah I installed a Compton on mine, highly recommend.
@@YeatzeeGuitar that’s what everyone does, I do like the Melitas though
Sounds great! My first amp and I used it many years straight in and surf the volume and tone. Especially with a 50's wired LP.
They never need to go above half way as you mentioned. I find it just turns to mush anyway.
My favourite thing about these is how much they like to feedback and how controllable and usable that is. Especially with a semi hollow ..
ruclips.net/video/kE8HmxU8mSg/видео.htmlsi=ar9hLyJtu81XbiU3
^ It really can be extremely musical.
What a first amp!!
@@YeatzeeGuitar They were cheap in the 90's. Everyone wanted Marshalls because Guns n Roses haha. I still have it. Also funny reading the other comments about JJ glass being crap. I've had the same (complete) set of JJ's in mine since 2015. They are so ridiculously over-biased it sounds like a Corvette cooling off and pinging for 10 mins after a jam. I guess Rona screwed up supply and demand outstripped supply so standards fell?