Iconic 3-500z/g Tube, Plate Dissipation, Prices of New Amplifiers, Instead Consider a Used Drake L4b 

I hope someone a lot smarter than me can answer this question. I did use a small pencil torch and shoved in the solder to overflow. It was risky and I was aware I could cause permit damage like breaking the vacuum seal. Many years ago I did use a very large soldering iron successfully. Aaron I wish that I could give you better advice. Hopefully, advice will come from someone who knows the best way to fix the tube. 73, Jim

All good Jim. I would certainly be keen to hear from anyone else who has had success doing this should it come to pass again. Thankfully the current tubes are working fine, and I think I did help it with a little heat the other day when I had the amp open. I sure hope I did anyway because the Australian Dollar aint worth a lot of USD at the moment. Can't get a new pair of 3-500z landed in VK for less than $570usd at the moment, which is $900aud....thats some serious coin and a big further investment in a 35yr old amp, which has already had a lot spent on it (but I do love it, I must admit.) 73, Aaron

Sockets are the main problem of the solder leaking out on 500z ,not because lack of air.

If the diodes are original, change them too. You might want to buy one of those kits from Harbach. Change those equalizing resistors at the capacitors. Most importantly, have fun. 73, Jim W6LG

Oh, you should use it. Thoroughly test it on all bands. Watch my video on tuning up an amplfier. Give it a lot of use in the next few weeks. Always watch the grid current and never exceed the rated grid current. Enjoy it. 73, Jim

You can’t beat the price on a 811 tube. Very inexpensive and if your careful will last a long time.

Well that should sell while you are taking it out of the truck. It is a very popular amp. And, it has a good design. It was designed to run 1500 watts with ease. Someone is going to be very happy to buy that amp. 73, Jim

@@ham-radio buck a watt, $1,500

I used to have one and it would run 600 watts output easily, it was my first amp and I had a lot of use out of it virtually no problem. I then made a big mistake and bought a UK made amp with a single 3-500z that amp was junk in comparison to the old Yaesu G4VQH

All of what you write is very true and very good advice. The Drake amps, if you can find one, sell here for about $1200 if in good shape. A similar amp from MFJ is about $4000. If someone does buy a used Drake, they need to factor in the price of new tubes and some capacitors. Also, the construction of the Drake is much better. I think the value of a used Drake L4B is more than $3000,; much more. Your reminder about the dangers of high voltage is very important. When somone gets across that kind of voltage, they're dead. My prices are in dollars over here. I have no idea about pirces, values or costs in the UK. Thanks & 73, Jim

@@ham-radio thank you for the reply, sadly our prices are probably higher than yours despite the currency! I remember replacing an audio amp in a 12v rig, the rig burst into life as I soldered the new IC in as the power supply was accidentally left on. That grade of mistake would be a whole different scene in a 3KV amplifier. A few of the older amplifiers are great buys, and very maintainable. I bought an amplifier from a US ham living in the UK, he was moving abroad with his work. A bargain as it was on EBay at a very low price and attracting no bids. I drove to his home with cash in hand. Sometimes you can still find bargains.... 73

To touch on the prices of new HF amplifiers, they're simply in the stratosphere. I'm returning to radio after 5 years and I'm jaw-dropped at the cost of new (and used) amplifiers--they've easily gone insane. Remember when the AL-811 catch phrase was, "A Dollar Per Watt"?? 😂 I would hope every operator understands the dangers of HV. I can recall too many memories of the news of an experienced Ham losing to that dragon. Several years ago I upgraded the cap bank and bleeders in my AL-1200 (I sure wish I didn't sell it, but you knw....life happens). The scariest moment was hitting the power switch. But it came to life perfectly and I let run for an hour for new components to set in. I admire so many that can still service HV systems. And more so respect those that respect that kind of power. (The Ham that walked me through my cap upgrade is a SK now. He actually said, "it's easy...just make sure no electrons are still in there...short cap to ground....and keep a jumper clipped to the chassis--caps can build a charge...we want to make sure of the most important thing, YOU ARE SAFE!!" Tube amp builders/repairers are becoming extinct (like diehard CW ops)...and that's truly heartbreaking. As we rebuild our station we'll continue to be cautious of purchases and servicing. BTW, always enjoy these videos!! de N2QN.

The 3-500, 3CX-1200 and 811/572 don't require warm-up time. Plus, that lovely nostalgic glass tube glowwwwww 😁

Your original unedited email was sent to me for review. I was about to be delete it due to some unfortunate language that was a personal attack at me by you. Joe, when you say things like that (which I won't repeat here), it reflects more on you than it does me. It make you look good. Seems like our country has evolved into angry groups. So Joe, stick with the criticisms and corrections that you see necessary. They can be helpful to all. Do not include attacking the author; me. I am doing a new much more potent form of Chemo Therapy beginning on the 23rd. It will be one week of infusions and three weeks off. I will lose my hair and lots of weight. It will be brutal because the doctors believe that I have full blown Acute Leukemia and the outlook is grim. Confusion, memory loss and more nasty things are in ahead for me. Keep that also in mind when offering corrections. I did not forget. I have made about 200+ RU-vid videos and time constraints limit how much can be discussed. I did not forget about the 3-400z. I did own some L4's. The 3-500z in my view was iconic and was groundbreaking because that tube as compared to the 3-400z, was hugely popular. The 3-400z was in production a few years before the 3-500z was never as popular. Also, I did work in a store that sold Drake equipment while in high school and university. I am not aware of Art Collins having anything to do with either tube. I cannot remember Collins making any amp with either tube. By the way, I currently have 3 drake amps. Also, Art's son lived not far from me and I did inspections on his house as a County BI. You said, " Legal limit was 1kw DC output. Simple as that. Please don't mislead." Well, your statement about power is not correct. We were not restricted to 1KW DC output. First of all, no amp puts out DC. Output is AC. Second, the law then was 1KW input to the final stage in CW or 2 kw PEP input to the final stage when on SSB. AM was also 1kw. . With 2kw input to the final stage of the amplifier, the output, as I mentioned in the video, would be about 1.2-1.3 kw for Class B. A pair of 3-400z tubes did that when driven to their max ratings and about 800 watts of plate dissipation. From my tests over the years, the performance of the two variants was about the same. I have built many amplifiers using Eimac tubes since I was first licensed in 1964. I did meet one of the designers of 3-400z and the 3-500z. He said the latter was more like a 3-600z. All fun stuff Joe. 73, Jim W6LG