Eimac 4CX1000A Amp Changed to 4-400A/4-250A or Penta Lab PL-175 or PL-6775
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- Опубліковано 8 вер 2024
- Changing out the 4CX1000A amplifier chassis in the 1947 Collins Radio 30K-1 cabinet for an amplifier chassis that will use Eimac or Penta Lab glass tubes.
Love the Collins 310B. I have 1 and looks like it was built yesterday.
David, thanks for inviting us into your basement and attic. Your laboratory is top-drawer. Your designs and executions are empirical and first-class. Electromagnetism is a whole lotta love....
The passion for tubes is genuine, simply awesome'
Tubes have a soul that I can understand and there is something "alive" when 3500 volts is sizzling in the room. Thank you and stay safe.
I don't own a 30K1 but I do own a KWS-1 and matching 75a4 (gold dust twins) and a 32V1 and 4 other A series receivers. Great video I love the old tube rigs nothing like the smell of tubes :) .
Steve - your 75A-4 and KWS-1 is the jewel of jewels. I know a fellow close by that has the same and says it some repair but never uses it. I would give it anything it wanted and use it daily if I had one.
@@ElPasoTubeAmps I don't know how far you are willing to go to get one but these guys have a nice one they buy and sell silent keys estates and are located in North Little Rock , www.hamestate.com/product/collins-gold-dust-twins-75a-4-ssb-cw-receiver-kws-1-kilowatt-ssb-cw-transmitter-with-power-supply-312a-2-station-control-speaker-270g-3-speaker/
I usually come around for the audio stuff, but tubes in general are really cool. What a sharp radio rig!
I have no idea what you're talking about, but these things are fascinating...
I love vacuum tubes, and have tube guitar amps, and used to be into high-end audio, and nothing produces the kind of lifelike, holographic, 3D sound like a good vacuum tube preamp going into a high quality power amp, audiophile level power amp...
So, I love vacuum tubes, and have quite a collection of NOS and current production 12AX7's,
EL34's, and 6L6's currently, and still have leftover tubes of other types from when I was rolling tubes in my high-end audio system...
But I've never seen tubes like you have here... I'm just amazed at how large, and beautiful they are... I'll be watching more of your videos to learn more about them, what they are, and what they do... I've never seen anything like them...
They're pretty awesome... ;-)
Awesome David as always!! Love the basement shack. Be safe and stay well.
stay safe, I want to watch many more of your videos, they teach me so much
I wish I could build a audio amplifier that look that beautiful.
I am confident you can build anything you want to build. Stay safe, and thank you for your nice comments.
You are an Artist with tubes! Thanks for the fun.
I enjoyed this video very much......I have a few solid state amps but something about valves that pulls me in. beautiful equipment. especially that huge collins
You've got some very nice equipment
I actually have two NOS Penta Labs PL-4-400A Tubes. The were part of the estate of a retired Army Col.. I acquired them about 20 years ago. The boxes are stenciled with the description, like these were shipped from Penta directly to the military. The date is 4-58. (The date was hand written.)
Many of these old tubes are the best-of-the-best, that will never be made again at this quality and they may still work perfectly. I hope when I pass, some of my vintage estate is found by those that will appreciate it.
You are soo prepared. I can't believe that you had another switch. You must buy at least 2 of everything.
I do have a lot of parts on hand. What I have to be careful about is "reorganizing" my parts. These parts can lay around for decades but when I get in a mood and move them to a more "logical" place, that is when I lose them and it can take days to find them - if I am able to find them. I have to be very careful about that.
We are having so much wind and the weather report shows wind for the next 10 days. Maybe it will help keep people from congregating on Easter Sunday and make everyone a little safer from this virus. I think this event will go down in history , not to be forgotten soon.
@@ElPasoTubeAmps I'm the same way. I have tubs full of electronics and other items that I have collected over the past 40 years . I have them in the attic, garage, and 3 sheds. Like you, sometimes it takes me days if not longer to find something. Sometimes I don't find it and go buy another, and find it not long after.
@@ElPasoTubeAmps Also, my wind turbine might get a workout this week. Happy Easter by the way. I've only left my house to go to the hardware store in the past 2 weeks. Got to be able to do my projects. One thing, I'm getting a lot done. This will definitely be remembered for decades. Who knows how long it will actually go on. Will change everything for a long time.
That was great David!
Enjoyed the video Dave. Keep them coming and stay safe .
Always enjoy your videos; you have some cool stuff!
Hi David ! Beautiful work, excellent craftsmanship ! I loved your video and have subscribed ! Nice Collins cabinet !! 73, Mark, WN3SIX
Quite late comment , but I like TX Power Tubes stuff and High Voltage Equipment since I was 13yo (now 55...) Thanks for your Videos, last time I used tubes was in the 70's-80's building Pirate AM/FM TX in Greece. Now I collect Tubes and have plans to do build a 50-100W FM TX using own Designed HV Switch-mode PSU's & Digital PLL Exciter with RDS Data + an RF End Amplifier with a German WW2 Tube into a DummyLoad, just to combine Technologies from the 40's to nowadays. Thankyou, Cheers, Konstantin
Hi Konstantin, it is never too late for a comment and discussion on vacuum tubes. I just posted another video using WWII era tubes.
ua-cam.com/video/_MhHVXScFh0/v-deo.html
I also started at age 13 with my general class ham license and am now 71 yo. It went by so fast.
Good luck with your FM project. To me, it is certainly a lot more fun to build the whole thing than to buy it and put together a kit. In any case, please stay safe. Thank you for your comments.
Hello David, thankyou I already watched it! Btw, the FM Amplifier is not Build from a Kit :-) all the Building Blocks are/will be designed and Build by myself. I am in the Electronics Prototyping as a second Job.
The PSU is a Vin12-24V, Vout 50-800V/ 70(100W) with Digitally Controlled Vout & IOut.The 50W version of it almost finished, Stay Safe , Cheers, Konstantin
Nice basement.
Very interesting ! 👍
I see the roof in your attic is insulated. I take it that it doesn't get too awful hot up there. I wouldn't think extreme heat wouldn't be too good for the tubes over a long period of time. Even though they get hot anyway. The boxes wouldn't last as long.
It is insulated and has a roof vent with a wind turbine but it still gets pretty warm in the summer and it is really rough on the boxes you mention. They dry out really bad. I don't worry about the tubes as I figure they are not anywhere as hot as they run in equipment. They seem to be OK.
I've been looking for a very small tube guitar amplifier design capable of that lovely tube distortion yet keeping the max audio output under 1-watt or less, preferably less. I know it's challenging to find speakers that sound good at that low input but I think a bedroom type amplifier that can achieve a quality sound would be smashing. I don't know maybe there isn't any tubes capable of such a feat. I know of those fire fly, cricket amps but they don't quite do the job, oh well just a thought.
Thanks for the entertainment, you should have uncle doug back over, just stay 6' away from him, lol.
We kept seeing each other for a while and even going to the surplus store in Las Cruces but haven't seen each other in a year or so. I need to send him an email and see how he is doing.
Those power tubes look very very mean. I never actually got to build RF tube stuff and I don't really have much knowledge but I'd like to build myself a transmitter and do some CB fun in the future..first finish the tube amp, the tube microphone and then maybe I'll have some time to spare onto RF stuff.. man that collection tho. Lots of metal in glass. Big mean EIMAC tubes.
GREAT TUBES, GREAT VIDEO. STAY SAFE GOOD LUCK, BEST OF HEALTH DE 9H1GZ.
Thank you Mario. Stay safe..
I like to create working displays of vacuum tubes to bring them to life. My latest will be a 4-1000A. I can get the 7.5V 21A filament transformer no problem. Can you think of a way to simulate the loading? I guess that would require several thousand volts. I have the air system sockets and the chimney. This should be a good project.
I can't think of any way to simulate loading - I assume you mean 50 ohms at 2 KW?
I have had several 4-1000A given to me as pulls from WSMR but I ended up selling all of them. I wish I still had a couple.
Many years ago I did build a GG amplifier with the 4-1000A but my power supply was under 4KV and from everyone that I ever talked to that had an efficient amplifier ran their tube at 5KV or more. I could do it now but don't have the tube.
The 3-1000Z can run at 5-6KV for class-C or a modulator and do have a pair. Maybe you just gave me a project.
I might mention something else here - my grid driven and neutralized 833A RF amplifier (TGTP) runs as 1/2 of a pair for modulator and works great. I say this because there actually is a class-B RF rating for the 833A but I ignore it (it is a lower rating) and use the push-pull class-B ratings with only half the currents (running one tube) - hope I am making sense, and get 1400 watts (PEP) out of it.
I see the 4-1000A does not have a class-B rating. I assume you are going to run it GG ?
I also see on the datasheets that the 3-1000Z, running it as 1/2 class-B push-pull would only give me about 1800 watts and I already have three amplifiers that run at or close to 1500 watts so I don't see the gain there - you got me thinking...
Best of luck with your project - post it on YT - I would love to see it.
73
@@ElPasoTubeAmps I'm not building an amp or anything. It's just a powered display. I usually just light the filaments of the tube to be displayed. I've done one that had one 304TH and one 304TL. The filaments just lit up. All on an aluminum chassis one might build an amp out of. Sold it on etsy. I wanted to do the same sort off thing with the 4-1000A. I know they are prettier when the plate starts glowing (most tube are). I was thinking of a way to get the 4-1000 plate glowing. Or does the plate have a slight glow with just the filaments on? I think I could see a bit on some of your 400's. Might not be feasible for a small display unit.
Which tube of all the ones you've messed with do you think is the prettiest with just the filaments on? Maybe I could buy a tube marked as bad, but the filaments still work for a powered display.
@@pabblo6103 I understand now. You actually can turn the plate orange with pretty low voltage. It is done in an attempt to "degass" these tubes. I don't think it works as some people expect but take a look at this videos. You do have to put some voltage on it and it will get Extremely Hot...not sure you really want to do this but something to think about.
All of the transmitting type tubes are beautiful from the 4-65A, 4-125A all the way up.
Here is the video - be careful - ua-cam.com/video/w29uagNUGuM/v-deo.html ua-cam.com/video/rX87lrdc4jY/v-deo.html
Great video! Maybe you could look into getting an IR filter for your camera?
Fabulous
My pair of 4-400a’s at 3,600 will put out 1,500 but they’re grounded grid
PARABÉNS AMIGO 👏👏👏👏
In the video all tubes on the right seem to glow brighter than the ones on the left. Maybe there is a problem there that compromises the output power.
Howdy from 79936!
Mantaaaaaaaaaap
Are they emitting Xrays when plate V is up?
X-Rays do not become significant until plate voltages reach around 50,000 volts and more. So, no, there is not a risk of X-Ray emission in the 3000 to 4000 volt range
At what voltage does an x-ray tube work?
30 to 100 kilovolts
The tube consists of a source of electrons, the cathode, which is usually a heated filament, and a thermally rugged anode, usually of tungsten, which is enclosed in an evacuated glass envelope. The voltage applied to accelerate the electrons is in the range of 30 to 100 kilovolts.
I might also add that increasing the voltage does not increase the speed of the electrons - they mention accelerate the electrons... Increasing voltage increases the pressure of the electrons not the speed. Voltage is synonymous with pressure and current is synonymous with quantity (number of electrons)
Nice attic, lol
How about a 4-1000a with a roller inductor
why not add another 1000?
are the 400's better?
Happy New Year
That is a good question. The 4CX1000A amplifier was finished in 1983 and worked flawlessly for over 30 years. It will provide everything the Eimac data sheets says at 1680 watts output. The pair of 4-400A will do about 1200 watts. I suppose I just wanted something to do and had recently acquired a pair of 3-1000Z so the 4CX came out and the 3-1000Z went in and then just because I thought the pair of tubes were so nice looking, I put the chassis with the 4-400A's back in. I still have all these amplifier chassis and can change them out in an hour or two of work. Happy New Year
Do you sell the audio tubes ?
Has anyone built a HIFI amp with forced air cooling and runs 4CX5000A ceramic vacuum tubes, What was blowing the breakers was dodgy tubes.
Hello sir, can i ask you please- i have set 30w class A amp 845 tubes 1 tube per channel.
I notice that right channel 845 tube glow little brighter than in left channel.
Bias identical. At 15V
If i reverse the tubes, they glow identical but bias on left channel is 19V and right channal is 10V.
What it can be??
Thank you!
Well, let's think about this. Is the voltage across the filament pins exactly the same for both tubes? Possibly some voltage drop across the wires connecting the filaments? I am assuming the filaments pins for both tubes are wired parallel with at least #14 wire. Maybe the connection of the female pin on the tube socket is loose a little bit? Check that the socket female pins are snug around the tube pins. I am just guessing at things. If you have a meter that will measure resistance accurate to a few milliohms, I would measure the DC resistance of each tube filament. They could be different. I have seen in a few cases the actual filament wire that comes from the glass envelope of the tube have a bad solder joint in the male pin. That recently occurred with a vintage 811A in my Collins 30L-1 amplifier. I solved the problem by resoldering, heating up and adding more solder, to the filament pin of the tube. There is a quad of 811A's in the Collins 30L-1 and one of the filaments kept going out but I could slightly push on the glass part of the tube with a Q-Tip and the filament would usually come back on. I have had that happen to me in a few instances including some KT88's made in China. A similar thing happened with the screen pin of these same Chinese tubes. I was able to detect the bad screen connection by carefully measuring capacitance between the elements of a good tube then compare it to the bad tube. Once again resoldering the male pin on the tube fixed it. Again, I am just guessing at your problem but it could be something mechanical and I have found that some of the simplest issues are the hardest to recognize. Hope this helps.
@@ElPasoTubeAmps Thank you sir, i am new to tube, and all info you give, is wery hard for me, but i copy your text and show it to somebody who know more than me, - after quarantine, we try to check all, and i write to you!!
Thank a lot again sir.!!!!!!!
Also, with xlo testing disc, i found that channel with brighter tube have little lower power or so, becouse i have man who talk left channel,right channel, his voice not so clear in right channel, and when say voice center, i hear soundstage moving a bit to a left channel.
@@user-im3ry3it7e Thank you. I hope it helps and you stay safe thru this virus. God bless all of you.
@@ElPasoTubeAmps thank you!! Best wishes!
Hey I noticed that on the video one tube has I guess a radiation logo? Why is that. Do they actually produce x-rays in operation? I don't really think so since your not pushing 100 of kV into them. These are made out of Pyrex so it does let trough radiation to some extend unlike classic leaded glass.
They have the radiation warning on them because the filament has thorium impregnated into the tungsten. I have had the occasion to measure the filament and cathodes directly with my Geiger counters from busted tubes and I have yet to be able to detect anything whatsoever of radiation from the cathodes. (regular receiving class tubes do not use thorium in their filaments).
The old style Coleman lantern mantels that Walmart used to sell has (had) thorium in them to make them burn brighter - and indeed, they do burn hotter and brighter and they will definitely set off a Geiger counter. I don't get it about the filaments. There is so little thorium in then I can not measure it at all. Just like the lantern mantels, the thorium allows the cathode to run hotter and radiate electrons better.
@@ElPasoTubeAmps well if you cant measure it but it's there the warning labet might have been put on there for the same reason as today we see ROHS allover the place...because people kept licking it and poisoning themselves with lead ;)
@@adam207321 Yep, put a sign on the tube and say, "do not break open and eat the cathode" or "nothing inside of this vacuum tube is eatable" or "do not lick the tube" and so much more...
@@ElPasoTubeAmps big clive would taste test it anyways ;).
Do you have any eimac 3-500z tubes
Never had had any Eimac 3-500Z. I have plenty of 3-400Z and a couple of 3-1000Z but I save them for my projects. I made a video of a RF amplifier where I showed the difference between modern day 3-500Z and a 3-400Z and the Eimac 3-400Z outperforms the new 3-500Z.
Nice 73 kn4kbn
You're wasting a good tube. When you run a 4 or 5 element tube you run it driving the grid with screen voltage. Much higher effiency and alot more output. I see you have a Collins 310, so do I. Virtually no one knows of them.
Wow, Nice! Are those gg?
Yes, the 4-400A's are grounded grid and that is why I changed out the 4CX1000A which runs only AB1. I thought about getting serious and making the ALC work for the 4CX amp but it is just so much easier to run GG amps. The 4CX amp will deliver a full 1600 average watts to the antenna although I had it "cut back" to only 1 KW by lowering the screen voltage from 325V to 225V per a suggestion of a Collins engineer. I had no issue with the 4CX amp, I suppose I just wanted something to do and from pictures I liked the look of the two glass tubes the most. 750 to 800 watts is all it seems to deliver to the antenna but I get great reports on it.
@@ElPasoTubeAmps - Well, very nice work! Say, I work a broadcast station here in ABQ and it's run'n a Bauer 707. 1 of the finals is going soft in the RF. I can get a couple of 4-250s, do you think those wud hold up ok?
@@bob4analog I just looked up the manual for the Bauer 707 and I see it runs 4-400A's in the final and modulator. Looks a lot like a Collins transmitter. I would think the 4-250A's would work but they have a less plate dissipation so I doubt they would last long. I think I would want to put a lot of air flow on them in a commercial transmitter. Wow... you have the job from heaven running a transmitter like that. What are your call letters and frequency? I see Eimac 4-400A's on Ebay all the time and some of them "look" OK - of course they are likely to be a little soft but they might be OK. Let me know if I can help you. My direct email address for UA-cam is: TheAudioShop@SBCGlobal.Net.
www.ebay.com/itm/EIMAC-4-250-Power-Tetrode-free-shipping/283829223047
www.ebay.com/itm/EIMAC-JAN-8438-4-400A-VINTAGE-TETRODE-POWER-ELECTRON-TUBE/303145164417?hash=item4694dc1e81:g:cusAAOSwM4Rcz5Q7
www.ebay.com/itm/NEW-OLD-STOCK-UNUSED-EIMAC-8438-4-400A-HIGH-POWER-RF-POWER-TUBE/283817646942?hash=item4214d99b5e:g:rEAAAOSwIM5eYGtd
@@bob4analog Here are two available that look good to me.
www.ebay.com/itm/NEW-OLD-STOCK-UNUSED-EIMAC-8438-4-400A-HIGH-POWER-RF-POWER-TUBE/283817646942?hash=item4214d99b5e:g:rEAAAOSwIM5eYGtd
I got,I got, I got.
I Got!l got,I got.?
You're not driving them hard enough. Take the pair up to 800-900ma plate current and load heavy enough to keep the grid current under control. 1500 plus out, no problem.
I agree with you. Today I used a little Heathkit antenna tuner and my RigExpert to match the transmitter (32S-1) to the input and got 850 watts output from the beautiful Eimac 4-400A's that are somewhat weaker than the Penta Lab PL-175's. I put the older Eimac 4-400's back in because the are just so beautiful with the logo facing the front of the amplifier but I am confident now that I can get 1 KW with the PL-175's with a full 200 mA of grid current. Also, I think 80 watts of drive, which is necessary, it pretty much the limit of the 32S-1. I have know for years that just the small amount of loss in RG-58 can make a difference and in the past when I have changed that coax out to LMR-400 I can get more drive but the big coax is so stiff. I need 200 mA of grid current (my grid meter is measuring 2X the current on the meter face). The tuned circuit in it right now is simply a parallel LC circuit so I really need to change it out for a Pi network - either that or leave the Heathkit tuner inside the cabinet. It is a little bit of a pain to pull the amp chassis out particularly disconnecting the front plate lead from the blocking capacitors so I have to pump myself up a little bit to get back in and work on it. It works beautifully and I get great reports from it having several QSO's today. The antenna is King but power matters also, especially with lots of QSB. Thanks for your comments and suggestions. 73
I am glad to report that tonight I put the Heathkit HFT-8A antenna tuner between the input of the amplifier (mounted it with rigid male/female PL-259 connectors right at the chassis which apparently helped) and the coax driving it. I first tuned the internal LC circuit but could not get the input SWR below 3:1. Apparently, I don't have that simple parallel LC circuit as it should be. Anyway, I am using the RigExpert to make these adjustments with only the filaments on and I got the input SWR (of the Heathkit which surely made my 32S-1 happy) to pretty close to perfect, 1:1 with the Heathkit. Then I put the Collins exciter in Lock Key mode, peaked everything to max, etc and finally tuned the Heathkit for maximum output and it is exactly 1100 watts output with a full 200+ mA of grid drive. The plate current is a little below the nominal value of 660 mA but I am running it at 3500 V instead of 3000 volts. You were right that I did not have enough drive and I was a little concerned my 6146's in the 32S-1 might be a little soft but all is perfect . I am happy with 1.1 KW output. The tubes I am running are the 4-400A's with the Eimac showing thru the front of the cabinet. I probably would get another 100/150 watts or so from the Penta Lab PL-175's like I did last night but these Eimac tubes with the logo in just the right place are so beautiful I will leave it along. The difference was made by adjusting the Heathkit while the transmitter was in full drive and output and I had to slightly adjust (increase) loading (to get the grid current down to 200mA) which I tried the other night and it was set for max output. The old radio handbooks will tell you that you can make tuning adjustments with only the filaments lit and it will get you close but not perfect unless the transmitter is in full drive and loading.
I have to tell you a story. As I was swapping out tubes and making the final adjustments with the Heathkit for max power, just after putting the 4-400A's back in (I had just before installed the PL-175's and got the same power but forgot to touch up loading and was only getting about 925 watts), I usually put a dowel rod across the bottom of the cabinet to hold the door interlock switch in but this time I thought I would just jumper it out so I connected a jumper lead to one of the terminals and then for some dumb reason clipped the other lead to ground. Everything was off when I started this. I turned on the key lock in the front and noticed that the left hand 4-400A filament was not lit. It has happened before and all I have to do is wiggle the tube so that is what I did - I stepped around to the back of the cabinet and put my hand on the tube and rocked it slightly and the filament came on. My right index finger barely touched the plate lead of that tube and I felt the very slightest of shocks. I wondered why but a few seconds later, I noticed the tube plates were red. Holy cow... now I realize that by clipping the lead to ground I enabled the HV, 3600 volts and I touched it. Thank God I was not touching anything else or I likely would have been killed on the spot. This is real and I am still shaken that I did this. I always work with one hand and always avoid touching anything, anywhere when working around equipment although in most cases it is probably excessive but that habit surely saved my life a few minutes ago. I am still shaking my head in amazement of my carelessness. After seeing the plates red, I stepped around in front of the cabinet I saw it was in full operational transmit condition. Surely all the lights came on when I turned the key switch on but I did not notice. This is just another example of simple safety practices that I have used for years that kept me from getting hit by 3600 volts and probably killed on the spot. I never thought I would be so careless but it goes to show what can happen when when we change our procedures and interlocks are jumpered out to do live testing. Enough for one night. 73
@@ElPasoTubeAmps Omg!!!! I was glad I came back to the comments, happy that you achieved the higher wattage output, wishing that you had recorded and posted a video of the procedure. Then read what happened next... Fortunately you WERE NOT messing with a camera too, when that 'mishap' took place! I often hear your words about safety when working on a live amplifier, and I see how meticulous you are placing Warning Labels, Double door interlock switches, Key activated and Lighted Switched HV, and maybe most important are the production quality schematics you draw, to refer to, for all your projects... I can't believe that happened.. Thank Goodness your okay.. If you get bored, I'm sure many would like to see a short video of the 4-400A''s keyed up cranking out 1100 watts. Be safe, Tom
Check yo watt meter
the tubes dont look matched. the one on the right gets hotter
I have a pair of Eimac tubes in it right now that can be seen here. www.qrz.com/db/WA4QGA