Thank you Rick. for all the great tutorials you post. Has always I am looking forward to more videos,you take care.

Great explanation with neat diagrams! A few thoughts to add ^^:)1. At the turn on, filaments will take a few seconds to warm up for current to flow. Therfore, for the first 2~3 seconds full output voltage from the diode rectifier, regardless of the values of the series resistors (no current mean no voltage drop) will be imposed to the plates. This full voltage must be checked not to exceed the capacitor and plate maximum voltage ratings. Otherwise, capcitor may pop and tubes will degrade faster over time.2. Two diodes and center tapped transformer form a full wave rectifier, each diode conducting half cycle. So, two parallel 10W 300 ohm resistors can be replaced by one 20W 300 ohm in series with the 500//1000 ohm resitor.3. You could also use one diode and 10W 300 ohm resistor to bring the effective dc voltage lower (half wave rectifier confirguration) but at the expense of slight increase in ripple of course. If the capacitors are good, negligible increase in hum should be expected. Cheers,Terry

Thanks HardKnocks60, I'm happy that's all a shorting sparking rectifier tube did to the radio. I have been playing the radio for several more hours and it continues to operate great. If there is some malfunction down the road, I'll let everyone know about it. That's important also.

That's excellent Rick. Thanks again for all of the good stuff.

Hi Rick, good description of the valves (tubes) resistance. With regard to low emission from the output valve, on very large valves 20KW to 200KW when they started to fail we’d bump the filament voltage up to increase emission as the cost of replacement was enormous, the only trouble was they went downhill even faster and could give a bigger problem as they went into parasitic oscillation, as they say, 'its an old trick but it still works.' All the best ... Andy GWØJXM

Another great video, lots of info well explained and resource links, so I can go farther. I would have to say, that unlike many youtube videos, you resist the need to fit in as many words per second as possible and speak at a very pleasing pace. Thanks.

how awesomely cool that you're able to whip up a part like that!

Rick, Just a thank's for your time and effort!! Learning a lot from you. TDB3

Thanks very much. Your video has given me the confidence to try this myself on one of my own projects.

Great job, very interesting video, amazing difference in the sound of the radio after your very creative solid state rectifier replacement.

That was terrific. Very well done, with just enough math. I am currently working on a Zenith 8S653 which has the much-maligned 6X5 rectifier. Built a solid-state replacement will measure as you did to see if I need to modify the design.

Fantasic well explained and clever.we appreciate you in England cheers

It's really good watching your videos and a great lesson too! Thank You!

Very interesting Rick. First time seeing that done. Thanks.

Absolutely awesome work. Thank you for making all these videos 🙏👏👏

Thanks for the very interesting and instructive upload, it shows the real practice and everything you can meet when you want to do such an important adaptation. I once replaced a rectifier tube for a so called "U-radio" (the filaments -16 V or 18 V- are directly supplied via a series-resistor (temperature dependent type) from the mains, in Europe 230 V AC, the tubes are named with an U, so UY=rectifier, UF=HF, UL=audio end amp) with a diode. I also used a 1000 Volt Silicon diode (max 3 A) and a series resistor to limit the current to the plate, had the same experience. After all it worked.

Thanks Jordan, It probably was made by Howard's, it does a nice job of keeping the power transformer much cooler. It's really nice having that RCA console working again. With that large speaker, it really booms. I may listen to some shortwave with it, it has a very nice fine tuning control. Rick

Always very much helpful .... Best on line teacher i have ever met .....

Another great informative video, thanks Rick!

Thank you again, that makes it clear. Very much appreciated!

Thanks YQTFun I have done at least one video on why I have the tube testers I use. The bottom line is, choose a tube tester that will test most of the tubes in the radios that you have. I have one tube tester that will test 1920s tubes through the late 50s. Another tube tester I have will test the tubes from the 40s through to the 70s. They overlap nicely.

very clever Solution with the parallel Connection of the resistors internally of the original rectifier Tube 5z3. Thanks very muchfor the Lesson

You could try installing all those parts underneath and in the chassis, but I'm not sure I would want the extra heat in the chassis. Those resistors get very hot. On this radio the rectifier tube has a metal cover that slipped over it. So when I install the cover over the resistors and diodes, it looks the same.

That's why I make drawings and take pictures, it makes things much clearer, and with less talking.

Rick, another nice video. I have a Paco signal tracer. I'm trying to learn how to use it. I first thought you'd be injecting a tone into the radio but I guess you were using the tracer as an amplifier just amplifying the signal at the grid and the plate of the audio output. Is this what you did? What value capacitor is good to block the DC voltage and couple the audio to the signal tracer? You always take the time to answer questions. Thanks.

One simple way to stop switch-on HT overvolting is to make the main switch the HT switch, and keep the filaments powered as long as mains is connected. (That might mean adding a mains plug power switch, if plugs with switches are available.). I do this with most of my vintage valve equipment. Some equipment gets built this way by default.

Thanks nckeller, Yes you could put all the resistors on the plate side. But I did not have any 600 ohm resistors at 10 Watts. So with using four resistors, I thought this was the easiest way to get them all in the tube socket.

it's sometimes good practice when replacing rectifier tube with solid state diode, to connect an NTC thermistor in series. This simulates the slow turn on of the valve...prevents "cathode stripping".

I need to know what resistors I can use for a 5U4G to solid state conversion, my power transformer has a 400-0-400 secondary and with the rectification factor (with diodes) growns up to 560VDC, I only need 450VDC for my homemade guitar amp that uses 2 12ax7 and 2 6L6GC-STR. Thanks and still making good vids like this.

Stupid question: Have you considered putting thermistors in the circuit for some soft start warmup timing? There is also a schematic I have somewhere that uses an SCR and a capacitor that charges rather slowly allowing the SCR to close after a period of time.

Thanks Tony T.

Nice job!

Thanks Norman Walz

May I suggest that if anyone is planning to try this to do something to insulate the exposed high voltages. My first thought would be a short piece of PVC pipe glued to the tube base, maybe 3/4th of an inch higher than the highest component lead. A bunch of small holes drilled around the bottom would allow airflow to cool the resistors.

I have a USN TV-7D If I recall. It will test 20's tubes and more modern tubes. I don't have Ricks experience but I never had a receiving tube that it wouldn't test. You can find one on Ebay fairly cheap.

Greetings in North Carolina!

The one possible downside to doing this is that the B+ comes on immediately instead of ramping up like a tube rectifier would as it warms up. That could lead to excessively high voltages before the tubes start conducting, possibly exceeding the voltage ratings of some of the caps in an old radio. I've thought about adding some sort of delay circuit to this type of rectifier replacement, to avoid the turn-on transient.

That's the point, there's always unknowns and that's why large companies spend millions of dollars on their laboratories. In this example with the original resistor, I could have measured the current through each tube, do another calculation, and it would be wrong also because with the new resistor, changing the voltage drop, all the characteristics for all the tubes have changed.

I am interested how the original output tube would perform with 240v at its plate; it obviously suffered damage when the rectifier tube was 'playing up'. I remember a service history log of an AWA (Amalgamated Wireless of Australasia) B&W TV model 225 (1960 vintage) having to replace a 5AS4 rectifier every 2-3 years with daily operation. Your option of replacement with silicon rectifiers with series resistors would enhance the reliability of the radio greatly.. Thanks for the post..

nice fix, dose it warm up any faster with the new "tube" installed, or is it about the same?

Would it be possible to install these components on the underside of the chassis with the tube out of circuit except for the filament to keep it more original looking ?

very educational video thank you sir

very interesting,ty for the work.

Good information. Thanks

Hi Rick I keep repeating myself,,,,,,,, Great video! Regards

I think 'first base' is to use Ohm's Law, from typical operational data of the rectifier tube, as you have done. What was not known was the current needed by the other tubes to function to service specification, which turned out to be less than 'typical operational data' of the rectifier tube, so to 'second base', using Ohm's Law again, the required series resistance was applied, to get operating voltage/current correct. Perhaps 'Doogie Lindsay' was not factoring in the 'series resistance'..

If possible, could you do a video on choosing a tube tester, I see many types and brands in videos but don't know the specifics of features needed to test tubes. Thx

I don't know how I missed that one... getting old I guess :) thx.

Could you have increased the resistor value of the anode resistors instead of adding resistance from pin one to the cathodes?

this is beautiful

I was alarmed when you showed an indirect heated (one with a cathode) in your example. Indirect heated rectifiers are primarily used to control warm up time. You do not want full B+ until the load has heated up. I have seen solid state diodes used in guitar and stereo amplifiers in place of indirect heated rectifiers causing damage to the filter capacitors. What is your peak plate voltage on your output tube before it warmed up? There is more to consider than ohm’s law.

Rick is right. I would add that the more you know about the tubes you use, the better any tester will work for you, and the real test of any tube is the specific circuit it is used in. tone-lizard web site has his take, basic info and pros-and cons on loads of tube testers, good site! People like Rick, bandersentv, shango066 etc all have great insights too. IMHO, there is no "best", all have trade-offs, and it all depends on what you need to do.

I bought a solid State replacement on Ebay for about $6.00 which easily plugs in just like the old 6X5 tube and seems to work fine. What do you think about these. I think the seller has sold out of them as of now. I use them in several of my vintage tabletop radios, specifically a Setchell Carlson Model 58A radio and also have noticed that I have 2 Airline radios from the 1950's with the 6X5 in them also. Should these be replaced with this plug in solid state 6X5 rectifier being sold on Ebay?

Any updates on this project? How was the quality of sounds? Did it still have the “mojo” that everyone looks for in tubes? Very Interesting, thank you!!!!

HELLO,I SAW THAT YOY HAVE WHAT SEEMS TO BE AN OLD ATWATER KENT RADIO SPEAKER. I HAVE A MODEL 20 THAT I FIXED A YEAR AGO. SUDENLY IT STARTED LOOSING STATIONS AND 5 DAYS AGO IT STOP PLAYING. IT HUMS BUT DOES NOT GET ANY STATIONS. COULD THE 201 V TUBES BE BURNED OUT? THANKS.

Thanks Sr very educational

Is there anyway you could do what you do here and give me the resistance for a 5Y4g tube which is very similar to the 5Y3. It would really help me out...I am doing the same thing you were doing..but with a Philco 30-60 radio...that Im repairing for a friend for free..Thanks..

I guess with some tubes getting harder to find this could be the only option for some applications in the future

Now I understand why tubes sound better. very different rectifiers.

To help cool the power transformer

By 2:30 you have calculated the series equivalent resistance of the tubes, then how did you use this data to help you choose which diodes and resistors to use? and how many?

radio phono TV nut did a video wherein he said that diodes cause the filaments to see too much peak energy if that means anything to you, peak voltage.

May be a stupid question, but could you replace the transformer and supply a lower voltage to the input of the rectifier instead dropping voltage across a resistor?

Thanks MikellHildahl

Why is the 4 pin not connected...in the 5z3 tube..??? i want to do this with a 5Y4G tube...can you show me which way to connect the diodes..and resistors please...and which way do you look at the tube pins from the top looking down or from the bottom of the tube..and which way do the pins go left to right or right to left...sorry so many questions..Im just trying to use a SS tube replacement...in a Philco 37-610 radio..for a friend and need this just for a short time..then I will get the real tube..

Thanks jmcgatkinson

it's just me, but I would add a cap in there to smooth out the waveform

Thanks skycarl

Thanks maynardcat

Excellent. It's good to see these radios being used again. I wonder if you could use an "inrush thermistor" in series with the solid state diodes? This would limit the current and therefore voltage somewhat like a thermionic tube rectifier, and is actually designed for this purpose. The thermistor is around a dollar or so. It has very high resistance at first then the resistance drops as the radio becomes ready to receive full HT. The thermistor is type NTC+10D-11 and is available on various sellers here: www.ebay.com/sch/i.html?_from=R40&_trksid=m570.l1313&_nkw=NTC+10D-11+&_sacat=0

Thanks billybonewhacker

Thanks THEDOGBOYS3

Will the solid state setup last longer

Does the solid state rectifier sound better to your ears?

I forgot to look up the wire antenna.

wouldn't it have been better to give the diodes a little bit more space over top of the resistors, won't they get too hot and have a shortened life, or lose their value?

A true hybrid

There is more to consider than ohms law, because it didn't work. Full wave rectifier tubes start producing B+ before the other tubes start to function. The B+ is high until the other tubes start working. Of course diodes produce B+ much faster. With this diode set up the voltage reads about 407 V DC before the other tubes start to function. The capacitors I'm using are rated at 450 working volts DC.

Couldn't You find a replacement tube for that rectifier

Does this technic work for a mercury vapor rectifier like a type 83? This tube along with a 5Y3 is used in a Hickok tube tester.

Thanks thereelmaster . In this case there's not much difference. And that's because most rectifier tubes heat up faster than the other tubes in the radio. With this diode set up the B+ voltage is there almost instantly.

This is exactly why electronic companies spend millions of dollars on their laboratories, so a lot of very large companies fake it. The diodes have very low ohms in the forward bias and infinite ohms in reverse bias. There's always something unforeseen in complicated circuits. In this one I'm not sure why it took doubling the resistance to lower the voltage about 30 V.

......e-x-c-e-l-l-e-n-t! ..........

Well thats just great. You pick up audio, and its Obama. Hehe just kidding, badass video