That a great amp ! That is why I only use tubes for QRO SSB . The IMD is much better ! Like the new screen supply using IGBT . We got them in a broadcast transmitter . used in a different way. Plate modulated supply for AM. The screen done same way . Big power saver. Continental AM transmitter. Stations like WBCQ and WMRI are using them. Great tube life . That IMD test will get even better with a bigger cap bank. You need a bigger dummy load. What kind of amps that drawing from the mains ? Great way to stay warm in the winter ! LOL 73
Nice initial results there Tony. Looking forward to completing the Colorado Tsunami Project, thanks for leading the way on this build and smoothing out the speed bumps along the way.
That makes some noise . Needs to be in a soundproof room. Very slight cross over distortion. may be just a bias setting. Takes some testing and adjusting to get it right on. You need that Bird 10K load now. 73
Yeah it needs some minor tweeking. The bias voltage needs to be a bit higher right now the no signal bias current is at 0.4A and the circuit calls for 0.6A
Thanks man, I really appreciate it. That was one of the reasons I decided to start my channel a few years ago. Number one was to provide unbiased and honest info about amps. Number 2 was to provide an alternative for people to be able to see inside a box and to know what value components I have used. Unlike a few builders out there that forbid their customers from sharing pictures of the inside of their boxes. ( Must be some space tech in there, top secret first class garbage. Hahaha)
Thanks! I would have to say that border walls work good to keep undesirable things out of areas where they dont necessarily belong. RF is no different. Hahaha
That a nice circuit. That always best practice to use center tap on filament transformer. It it possible the transformer they had was not taped . But if you are having one made just ask for tap . I seen multi tap on primary. This is good to correct for line voltage. Naturalization can be done with triode' and pentode' as well . helps keep tube stable and clean on SSB. You still can cathode drive but loose power gain. That 9:1 UNUN is the same used in a random wire antenna . You can wrap with RG 400 or use trifeller wind of PTFE or mag wire. In this case you want better isolation and less RF leakage from UNUN. Coax much better , For multi band antenna the mix 61 ferrite works good for high power. Also type 52 and 43 ferrite also work. just pick for the bands you want. You will find this tetrode circuit more efficient for plate input power to watts out than triode amp. When you do full power test let us know current on the mains . 73
Very next level stuff Tony . Great video and very interesting . I’ll have to read into the original story . I love how challenging bets and bragging rights between smart people raise the bar and open up the door for the once impossible !
Glad you went over to TUBES, the LDMOS was a nice TRIAL Run, you stood behind your work with me and even gave ne a full refund after I was experiencing a lot of imd and harmonics with the LDMOS as well. It seems the LDMOs is hyped up to do so much power, yet it only handles clean power about half of its rated power.
@@DAVE_WHITE LDMOS has been discontinued at the beginning of the year. Being a very “Dirty” transistor is not the sole reason though. The reliability of these devices is worse the HG pills. Some NXP pill would blow up in under 10 min and some after a month with perfect running conditions. Running it at half power does make it cleaner however sometimes the transistor will just quit for no reason and no explanation. Tubes 100% now. With LDMOS in the trash.
great job i have built only small tetrode amps like a 4-400 a and 4-125a but never a big tetrode they are challenging ,at least they are for me compared to a triode for sure.great work your doing.
Your HV bench supply is to die for. Power On sequence and Screen/Plate protection circuit peace of mind. I've had small board pcb modules with screw terminals for wire connections loosen over time or worse yet,, tear the solder joint on the pcb bottom. Running a far smaller, homemade 4cx amp using the Tetrode Boards by g3sek, I appreciate all the circuit extras in your design
Hi Tony! You make an amplifier quickly. These tubes are not simple. Got good progress. Now you can test the tubes. Congratulations on your success! What is your AC voltage standard 110 volts or 220 volts? In Ukraine, the AC voltage standard is 220 volts. Phase and zero. Also in a private house you can install 3 phases and get 380 volts! To do this you need to obtain a special permit.
Standard voltage is 120V from Phase to Neutral. But every house has 2 Phases so you can have 240V. These phases electrically 180 Degrees out of phase with each other and Neutral is a center tap from your residential transformer.
That blower moves some air ! That change in line voltage is common across the US . Some of the stations hear are fed with a big transformer that is multi tap and can change taps under load. Quite costly. There's a back up as well. After so many tap changes . the transformer has to be serviced. You can use a buck-boost transformer on setup hear to correct that line voltage . The tube will be ok at lower plate just power out will drop . The filament voltage you do want that to stay with in spec for life of tube. With step down from mains that will stay close but plate supply is step up. That can change a bunch. You may want to meter the mains voltage. 73
Thanks. My filament runs at 74A and the datasheet calls for 75A +-5% which is good. Everything else seems fine. My power output fluctuates by about 800W PEP on my 3cx3000 depending on my line voltage all the time.
