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Hard to beat the old school Dave Made amp ! Thanks for the video

Nice work as usual

I like the old Dave made ! Nice transformer ! I was wondering what 2879C would look on scope and spectrum test . I have totally re done that Xforce base amp. 2X4 . I converted to 1 MRF 455 driving 4- RFP 2SC2879. It had 2 PP 80 driving 2 PP 100 . all 4 pills blown and was class C . was a nice AB bias when I got done. this was years back now. And them China 30 amp SPMS hit the trash can. They will NEVER do 30 amps ! I changed so many of them . They just do not last . 73

Nice old amp ,, good job as always 👍

Thank you!! Great work.

Nice old amp. That bias looks too low and maybe due to lower voltage and the sag under load. changing bias diode and resistor should do the trick. if collector voltage stayed at 15 V the bias may be ok. I could not see what diode they used. but easy fix. ICA has better transformers for replacement if needed. has taps to select voltage . Also a better bridge rectifier can help with sag. mostly on 6 pill and bigger. that just a 2 pill. Sometimes a bigger filter cap is needed. ICA has some great ones. But on that amp the cap is biganouth unless it's bad. I scope test DC supply for ripple voltage. A weak cap really shows up when putting a load on supply. As long as not driven hard that supply is just fine. That splatter will clean up a lot with bias fix. It will get real bad with 120 HZ getting in from weak cap. not the case hear. I re did a 8 pill like that . was a blue one with pp 100 pills . so much work. does 2Kw PEP now but tad dirty. 1.2Kw clean power. Thanks to ICA transformer and caps . I get my 200 amp bridge from another source. Tony has been great ! 73

Awesome video! Great info as well ! DO EET!!!

is that a TC004 Thermal Imaging Camera ? how do you like it ?/

Thanks for the video, Great suggestion about others showing the results of their builds not to bash but it'd be good for the hobby..,.73

Thanks for the video. It would be nice in future tests to show a peak hold harmonic display out to the 9th?

Very nice work Tony . 73’s

Wow. That's a lot of punch for such a small platform. ✌✌

Looks great ! I was wondering how the 2879C would do on IMD test. When tubes biased right and tuned correctly they very good on SSB for the IMD test. I run FT8/FT4 WSPR all from WSJT-X software. you can decode with that program for the HAM bands . No licence needed to receive only . JS8-CALL and FLDIGI are outher programs for digital modes. You can use them on CB as long as legal power levels. Even SSTV . I sent and received pic's from NY to England on SSB CB. just watch them amps on digital . keep drive way down. It is the high duty cycle that heats them up. 73

Careful, you'll end up building boxes for FT8.

Are you willing to build for the public?

I’m late getting to the video ,, great work Tony !!

Super awesome to see a 2-tone IMD test for LDMOS, thank you for sharing! I tried connecting 2 separate pallets with ART2K0’s (Ampleon) together using a 1:2 ferrite combiner like you show in this video, and I measured -20 dB of 3rd order IMD using 2-tone audio test at 2kw PEP which agrees closely with your results. I totally agree with you: -20 dB is not a good IMD result and will definitely cause some unwanted audio splatter, especially with SSB modes. But then I tried connecting 2 ART2K0’s in parallel on a single, unified pallet just like the ham radio guys do (no combiner is used because drains of FETs directly connect together electrically using a 9:1 transmission line transformer). IMD was much better, -33 dB for 3rd order IMD and -42 dB for 5th order IMD with 2-tone test using 2kw PEP for pOut. Connecting the drains together electrically in parallel vs. using a 1:2 RF combiner was a big improvement in IMD that I did not expect, but glad I tried it. The only downside is the higher cost of buying a second FET which is an extra $226 for ART2K0. The extra cost might be worth it if a super clean signal is needed, especially for SSB customers.

Pretty cool, I can't wait

Bro thank you for explaining each part and it's job. I am learning to build and repair tube boxes and this was a gold mine ty bro

Nice testing. I did notice that LDMOS does have some IMD at full ratings. From what testing I have done dropping to 50% of rating cleans them up a bunch. Tubes when biased correct are buy far cleaner on SSB. Other FETS like IRF520 get quite dirty at power ratings. When you go back to BJT like 2SC2290 they pretty clean at rating's bias and tunes correctly. Something with FET transistors on SSB. now go to AM/FM/CW they much better . I did notice running LDMOS at 50% power on SSB they run quite cool . 73

Interesting, do you think the results are typical for that type of ldmos transistor?.. Thanks for sharing....73

Very cool. What do you use for your rf sampler that feeds your scope and spec-anny?

When does this LDMOS start compressing? Have you tested it on FM yet?

An you tell me who makes that 40kv 40amp blocking capacitor and what part number is please?

Fantastic information and demonstration it'd be interesting to see some of these popular Amplifiers being used today on same test...of course without names or finger pointing more of an example of what's commonly being used, thanks for sharing

That a great way to do that PTT keying. also works with radio that does not have PTT line. use foot switch to key radio on 1 jack and amp on outher . great for SSB. Also can use as a isolator for old tube amps like Collins ETC that have HV on PTT line . The last one I made was for a IC 705 radio that does not have 12V PTT. I used a opto isolator with small relay. works great . now someone made a bord for the IC 705 that fixes that issue. Icom does make a EXT one put $$ . The new board does USB C as well. Buy swapping out jacks you can easy make a Stryker radio or whatever you want to key a PTT line AMP. I did this inside my Cobra 2000 base radio. small relay inside and RCA jack on back. Great SSB ! 73

Good deal ✌️✌️

Awesome! Needle Bender 785, it was great chatting with you today WR0546 MN.

Awesome work as always in the Doc Brown Mad Scientist Lab !! My setup will definitely benefit from that Thanks NB-785 ,, looo fwd to putting it to use !

Dallas will put it to good use!! 73s !

Very nice.

Beautiful job!! Very impressive work for sure!!

Very nice Tony Look fwd to the new build in your Doc Brown mad science lab !!!!!

nice work. That SB 220 is clean as well. A clean signal gets out better ! Peek watts means nothing if distortion . Nice showing the wave forms. Starts with a clean radio . I had some tube amps to fix that where just driven too hard to long and tube flash Then lots more parts burned up. Watch for them Cheap China tubes like 811A or 3-500Z .They known to flash over. get good tubes like Penta Labs or RF Parts ones. Replace 811A with Penta 572/B . Some junk 8877 China ones on eBay . The Russian tubes are real good and getting hard to get for some. 73

Real cool Tony , you have my 100% attention, keepem coming

That dude is cool

I almost hate to hear that will be used on ssb. Awesome amp for sure✌✌

That's crazy power. Great craftsmanship. ✌✌

I believe UA-cam pulled a quick one again because I'm sure I was previously subscribed. Anyway, awesome build. Very clean and lacking of clutter. ✌✌

working great ! not too much sag on HV. nice transformer. That common on mains voltage. it will change threw out the day/night and year. mostly summer heat . that why I like AC mains meters . both volts and amps. great feed threw keying . want relay to latch up before drive. BBI did video on that. was transistor amp but the relay arc is the same. you never want a auto key on that much power. 73's

Beautiful work of art !! Brad said it would be ok if I came and picked it up , and broke it in for him , he’s still re-building his beam anyway ,,, so when you read this Brad. , just come to my house about mid July ,, it will be ready for you 🤣🤣

Awesome 👍... yep SSB testing, that'll let ya know.. some pretty cool stuff coming up. Thanks for sharing

Nice work as usual Tony 👍🏻

That's an SSB monster, and a clean build.

Very nice box I'm Youngstown where are U

Very nice Tony. Great to see how well you're doing and that you're having a lot of fun too because that's the main thing. Your buddy Joe in Gilbert, AZ. 2AZ8255.

6k is nice for am...what a nice box.

that working real nice. the Pi network in tube amps helps a lot with harmonics power supply holding up great under load. you could get more out but the duty cycle will drop a lot and transformer heating has to be taken in along with the tube. the user settings on his SSB set up will factor a lot in AVG and PEP ratings. very from person to person. nice base line testing.

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That is beautiful. You don’t really need any more than that. Kw ‘ otherwise everything starts getting complicated and expensive