I once read an article in a 1960s edition of "CQ" magazine on building a "direct conversion" receiver. It was the first time I ever heard of such a critter. Their performance is amazing, the only downside being they're DSB, not SSB. Of course, they're great for AM, by zero-beating the oscillator.
Hello Michael.... It is WONDERFUL that you are taking this on...! I have had my eye on this project for years... Now we all get to see your "Modern," Professional take on this classic...! Please keep up the great work...! Best, Greg S.
It is going to be a challenge, Greg, but the goal is to make it a classic again! The home built inductors are showing excellent performance, comparable to the miniductor.
If you want to build a tube receiver, find a box and start putting likely looking parts into it for a few weeks. Then you can alter the design slightly to use what you have got. Many suitable components can be purchased or found on the Internet or junk sales.
I built a similar receiver back in 1962. I will enjoy how this project goes. my first novice receiver was a philco model 16 big console radio with an avc shorting switch/manual gain control/ q multiplier/ and bfo added by me. it worked ok and got me on the air.
Looking forward to this series. I found a schematic of the SimpleX Super in the 1959 Radio Amateur's Handbook. It's an interesting set that looks as if it would work fine for CW and SSB. On the other hand, in AM mode, it looks like a converter stage driving a grid leak detector. Apparently, the BFO can be switched off in WWV mode or switched off, if desired. That could limit its sensitivity to AM signals by quite a lot. That might not be much of a problem on 80m, with its relatively high external noise levels, but could be a bit of problem for 40m. This is confirmed by the Handbook article, "You will find this to be a practical receiver in every way for the c.w. (or s.s.b.) operator. " -- as it says in the text. But don't mind me too much. I'm an OT. I got my first ham radio license about 55 years ago, and to my mind, AM="Angel Music". If I were to build this receiver, I'd endow it with an IF stage, probably the classic circuit with a 6BA6. Interestingly enough, the next article in the Handbook is a 5 Tube Superheterodyne which has a front end that is practically identical to the SimpleX, but it's dual conversion (1700/100 Khz). Its detector is a non oscillating regenerative plate detector with a BFO that can be switched on or off as desired. It lacks the WWV option. Curiously, its 1700 khz. transformer is a homebrew design "(made from two Van i Loopsticks shunted by 100-µµf. mica capacitors. See text)".
One major difference between the MARK I and the MARK II is that the grid leak detector is converted to a Q multiplied grid leak detector which could improve AM reception - with the BFO switched off.
My introduction to radio and ultimately a career in electronic engineering started with assembling a Heathkit AR-3. I "surfed" the short wave broadcast bands at a time when short wave broadcasting was king. It was inspiration on steroids!!! And now we have the internet sewer pipe to contend with....
Great stuff. Love to see how this progresses. I was thinking i.f. transformers difficult to get, I do have two pairs out of old radios I took apart years ago. Other coils can be wound. I have a few o/p transformers and chokes, all kept as useful stuff. In the U.K. we call them radio rallies and there's always variable capacitors available quite cheap. I have two Jackson slow motion drives too. I made several receivers in the 1970's, making one then a few months later buy other valves and make a new one with existing parts. Circuits from Practical Wireless and Short Wave Magazine. No new one worked any better than the previous ones. I wish Denco was still producing items but homebrewing was already in decline by the 80's. G4GHB.
@@MIKROWAVE1 I'm not actually making it as I've other things going on here but I'll watch how yours goes. H/b tcvr to modify, RA17L to look at. Very soon when I get sunlight into the shack I'll do a video to disprove to C.B.'ers their 'magic tuned coax' is pointless using my VNA, tx, oscilloscope, 50 Ωdummy load, SWR meter and jumper lead. They really believe there is not one length of coax with a meter inserted as though the SWR meter is some kind of isolation device. They can obviously see two cables! 73, Bill, G4GHB.
I built an earlier version of a dual band receiver in 1959. The Radio Amateur's Handbook", 35tht Edition, 1956. Pages 116-120. "Two Band 5 tube Superhetrodine". Worked very well for my first Novice receiver. Never used it on 80 meters didn't have room at our rental house for an antenna that tall. Very stable receiver very low drift. Made a few changes to the design to save money, 85 KC IF transformers instead of the 100 kc noted. War surplus store near me had them for little money. Spare parts for the ARC5. Great to see someone still trying out tubes again.
Ok, now I understand the design better. I wasn't properly LISTENING the first time through and thought there was a two MHz shift of the LO when moving to 40 m; that would put (in my mind at the time) the image of the other ham band out of the IF passband. The original post was based on a complete misunderstanding of the design. I'm sorry, I wasn't paying attention. We can either delete or leave this trek into the pitfalls of multipliers as a cautionary warning to others, I don't care - it's a hobby to me (and I make mistakes all the time). Your choice. Thanks KC5UES - Chip
One way to overcome the lack of the 1700khz crystal is to use a 455khz IF filter. These ARE available as many ham rigs used double conversion down to a last IF of 455khz, and replacement crystal and mechanical filters are easy to find at hamfests and on ebay. You would have to add a second conversion from 1700khz down to 455khz, and the oscillator here can be free a free running L/C affair with a large C to L ratio. So, one extra tube. All of those mini inductor and IF cans can be replaced with toroid wound coils. I'd probably cheat and use solid state circuits, including an si5351a vfo with an arduino processor. So many of the classic tube circuits can be redesigned around the same block diagram to use older solid state devices. I don't know if I'd trust my kids to play around with the voltages used with vacuum tubes. I'm amazed I didn't kill myself as a kid building my own novice transmitter power supply.
In the first image the text mentions adding a transmitter. "* Or a 10, 12, 15, 17 or 10m Converter". Will you discuss those in a future video? What would that have looked like and what designs would someone have built back then for these additions? I'm curious.
The VHF manuals, 73 and CQ and QST, and the Handbooks, were full of simple converters. You could also buy them. The typical converter was an RF amplifier tube like a 6AK5 or a 6BZ6 into a dual tube like a 12AT7 or 6U8, with one section acting as a crystal oscillator and one as a mixer.
It will take several installments to produce the finished and tested box! But this is a proven (if old) project, which makes it less risky for the average builder.
I can feel that 12 year old boy excitement for electronic exploration coming on. But this time around I've got the money, the time, and the tools. I don't need this receiver but . . . I think I must build it. It's going to be a good series, Mike.
I built this receiver about 10 years ago. I found a crystal at a hamfest that was 1697kc,close enough. For the input coil I used a piece of 3/4 inch pvc pipe for the form. I had some wire that was 1/32 inch diameter, so I wrapped it around the form wery tightly. I made it longer than needed so I would have some extra form length. I then heated it with the heat gun till it just started to melt. After letting it cool I unwrapped the wire and had a form with threads in it. It took a couple tries to get it right. I then was able to use smaller sized magnet wire to make the inputcoils and oscillator coil. In the final build I used a smaller chasis so I used some junkbox adjustable coils for the input section and I used my home made oscillator coil.
Looking forward to that! My experience with toroids and tubes isn't that positive but there should be roads to solve problems like degree of coupling (very high in a toroid, often too high for tubes?). And the crystal I've been looking for too, no luck so far! Regards from Belgium, ON4SPK@@MIKROWAVE1
I love this project. I agree with most of your hard to get parts list but where are you going to get a 16 Henry AC filter choke. That type of pi network power supply isn’t used any more. I have an 8 Henry choke in my Johnson Viking Adventurer and that motivated me to recap the electrolytic filter capacitors because it still had the original kit electrolytic caps. If the had shorted it it could have ruined the filter choke.
Exactly. The most flexible part of this design is the power supply. It even changed between the MK1 and MK2 versions. Fortunately the receiver is happy with 200 to 300V, 40 mA. You could do a low current drain HV supply cheap, in any number of ways. I will be using a surplus CT HV transformer out of a discarded test box, two 1N4006 diodes and a small 2Hy choke with a single 100 uF 450 Capacitor. Much simpler - available parts. And yes the schematic will change of course, as I build.
Damn you got me thinking! I'd completely forgotten the fact you might be able to use a crystal on subharmonics with some luck... Well, that's a guess, I've seen regenerative detectors being swamped out on many subharmonics when the LC-circuit is coupled to the crystal by a pickup-loop. Is that the trick? Edit, nah looks like I was off by miles... Regards, Thomas
The crystals series resonance is the basis of a simple filter where the phasing capacitor nulls out the package capacitance, producing quite a sharp filter for CW. If you short out the crystal, it broadens so you can handle wider signals like AM without distortion. If you put a second crystal in place of the phasing capacitor, you for a proper half lattice filter where you can form a pass band more accurately.
What about using 3x 12AX7 Vacuum tubes as a Cross Coupled Double Balanced Mixer which will also operate as Local Oscillator will output the IF but not anything else.
Awesome. I was up early this morning troubleshooting why I get transmit signal feedback interfering with the VFO on my HW-8. It pulls the VFO with a switched capacitor to Net the transmitter to with the signal you have tuned offset with the Direct Conversion receiver. My kingdom for a SuperHet!
Direct conversion receivers do have some limitations, depending on the isolation between ports and the actual mixer type. And of course they do require a lot of audio gain which can perturb microphonics.
@ Yes I saw that in the original article. I often wonder with these things whether you should stick 100% to the original or deviate where there’s a much better modern option. Some have suggested using a cheap DDS board to get round the xtal limitations. Not sure…. I think I’m going to give this receiver a go…
In one of your early 2024 videos you mentioned building the SimpleX Super. I checked my 1959 ARRL Handbook and found the article. I added a 1.7 MHz crystal to my Hamfest shopping list. I attended Hamvention and 4 other Hamfests. No 1.7 MHz crystal to be found. Very few Ham band crystals to be found. I'm looking forward to your solution for the 1.7 MHz crystal. For the price of what FT-243 crystals are going for you could use a SI5351 and Arduino.
@@jagmarc The 2000 kHz crystal we will use as a filter was originally made as a microprocessor clock. It also could be a reference for a PLL, as you say.
Handy tip for novices with tuned circuits, beg borrow a grid dip oscillator to use (fet dip these days). To help get each tuned circuit into the ballpark one step at a time, ready for first switchon.
Thanks for a very informative and interesting video again! I have collected the parts for the Simple X, I managed find a 1640khz HC6-U type xtal. Also I have the stuff to wind the inductors. 73 de Juha OH8UBJ
Mike, thanks for your channel which I just recently discovered and have been catching up by watching your old videos, Now I'm starting to regret throwing out those old copies of QST.
Those aluminum chassis boxes have become outrageously expensive! So, why not "Think outside the (aluminum) box"? Find a sturdy cardboard box, and coat it with the epoxy/fiberglass auto body repair material sold at auto parts stores. It's also sold for repairing boat hulls. It's expensive, but a can of it will go a very long way. It will strengthen the box and protect it from moisture. For greater rigidity, wood furring strips can be screwed/epoxied to the underside. Now, cover the thing with metal tape! Copper is best, because it's easy to solder to, but the aluminum tape, sold for duct sealing at hardware stores, works, if you're clever. Just make sure all the pieces are connected together, electrically. Also, you may have noticed how god-awful expensive transformers for B(+) have become. But there are those "travel adapters" that convert 110/120V to 220/240V, and vice-versa. They're rated in Watts, and most models will satisfy any B(+) current requirement for a tube radio.
I always wondered if there was a solid state version of this circuit which would make it version Mark III. It really feels like it should exist. In any event you might should claim the "Mark III" moniker!
Yes 1958 and 3. I read the date wrong. The handbook had a similar image flipper 2 band receiver shown in 1958. The MARK I shows up in the Handbook in 1959, so shortly after and its in 60 and 61. The MARK II shows up in the handbook in 1962-65.
I once read an article in a 1960s edition of "CQ" magazine on building a "direct conversion" receiver. It was the first time I ever heard of such a critter. Their performance is amazing, the only downside being they're DSB, not SSB. Of course, they're great for AM, by zero-beating the oscillator.
This year I did a 10M DSB XCVR and used a direct conversion receive section. It required an RF amplifier before the mixer on 10, but it worked great.
Hello Michael.... It is WONDERFUL that you are taking this on...! I have had my eye on this project for years... Now we all get to see your "Modern," Professional take on this classic...! Please keep up the great work...! Best, Greg S.
It is going to be a challenge, Greg, but the goal is to make it a classic again! The home built inductors are showing excellent performance, comparable to the miniductor.
I'm really looking forward to this series. Been wanting to build one for years abut didn't due to the unobtainable parts. Now you've given me hope.
Yeah, it's a great project that just needs some practical updates on the parts approach.
If you want to build a tube receiver, find a box and start putting likely looking parts into it for a few weeks. Then you can alter the design slightly to use what you have got. Many suitable components can be purchased or found on the Internet or junk sales.
I built a similar receiver back in 1962. I will enjoy how this project goes. my first novice receiver was a philco model 16 big console radio with an avc shorting switch/manual gain control/ q multiplier/ and bfo added by me. it worked ok and got me on the air.
Wow! You souped up the grand old lady!
Hiya I like your new radio idea. Brings me back to my shock dates. So good luck to all why may build it with you.
73.
Paul.
Thailand.
That is simply shocking 😂
Brilliant :-) I've been looking at this design for some time now and this series should spur me on to building it.
Great - time to start collecting parts. Fortunately, there are not a lot of parts in this build.
Looking forward to this series. I found a schematic of the SimpleX Super in the 1959 Radio Amateur's Handbook. It's an interesting set that looks as if it would work fine for CW and SSB. On the other hand, in AM mode, it looks like a converter stage driving a grid leak detector. Apparently, the BFO can be switched off in WWV mode or switched off, if desired. That could limit its sensitivity to AM signals by quite a lot. That might not be much of a problem on 80m, with its relatively high external noise levels, but could be a bit of problem for 40m. This is confirmed by the Handbook article, "You will find this to be a practical receiver in every way for the c.w. (or s.s.b.) operator. " -- as it says in the text.
But don't mind me too much. I'm an OT. I got my first ham radio license about 55 years ago, and to my mind, AM="Angel Music". If I were to build this receiver, I'd endow it with an IF stage, probably the classic circuit with a 6BA6.
Interestingly enough, the next article in the Handbook is a 5 Tube Superheterodyne which has a front end that is practically identical to the SimpleX, but it's dual conversion (1700/100 Khz). Its detector is a non oscillating regenerative plate detector with a BFO that can be switched on or off as desired. It lacks the WWV option. Curiously, its 1700 khz. transformer is a homebrew design "(made from two Van i Loopsticks shunted by 100-µµf. mica capacitors. See text)".
One major difference between the MARK I and the MARK II is that the grid leak detector is converted to a Q multiplied grid leak detector which could improve AM reception - with the BFO switched off.
My introduction to radio and ultimately a career in electronic engineering started with assembling a Heathkit AR-3. I "surfed" the short wave broadcast bands at a time when short wave broadcasting was king. It was inspiration on steroids!!! And now we have the internet sewer pipe to contend with....
Kit assembly was the starting point for many of us
Great stuff. Love to see how this progresses.
I was thinking i.f. transformers difficult to get, I do have two pairs out of old radios I took apart years ago. Other coils can be wound. I have a few o/p transformers and chokes, all kept as useful stuff.
In the U.K. we call them radio rallies and there's always variable capacitors available quite cheap. I have two Jackson slow motion drives too.
I made several receivers in the 1970's, making one then a few months later buy other valves and make a new one with existing parts. Circuits from Practical Wireless and Short Wave Magazine. No new one worked any better than the previous ones.
I wish Denco was still producing items but homebrewing was already in decline by the 80's.
G4GHB.
The receiver has 3 shield can inductors. They are not actually transformers. They can be wound inside old IF Can forms.
@@MIKROWAVE1 Right, okay, tnx.
Looks like you are all provisioned for this project. Cutting the front panel today to just overlap the box width.
@@MIKROWAVE1 I'm not actually making it as I've other things going on here but I'll watch how yours goes.
H/b tcvr to modify, RA17L to look at.
Very soon when I get sunlight into the shack I'll do a video to disprove to C.B.'ers their 'magic tuned coax' is pointless using my VNA, tx, oscilloscope, 50 Ωdummy load, SWR meter and jumper lead.
They really believe there is not one length of coax with a meter inserted as though the SWR meter is some kind of isolation device.
They can obviously see two cables!
73, Bill, G4GHB.
RA17L and the Murphy Monsters are great! Well unless they fall on your foot!.
Wow! I learn all the time, watching your videos.
Thanks for taking the time to get through some of these!
I built an earlier version of a dual band receiver in 1959. The Radio Amateur's Handbook", 35tht Edition, 1956. Pages 116-120. "Two Band 5 tube Superhetrodine".
Worked very well for my first Novice receiver. Never used it on 80 meters didn't have room at our rental house for an antenna that tall. Very stable receiver very low drift.
Made a few changes to the design to save money, 85 KC IF transformers instead of the 100 kc noted.
War surplus store near me had them for little money. Spare parts for the ARC5. Great to see someone still trying out tubes again.
Wow that is very impressive! Real HBR project in the day!
👍Thank you sir.
Changing the oscillator frequency also took a strong ham band image out of the orher ham band. Great design!
I am a novice at spur searching. Please elaborate for the comments.
@MIKROWAVE1 (doing the calcs I see I'm wrong! -will replay until I fully understand what you're saying. - thanks.)
Ok, now I understand the design better. I wasn't properly LISTENING the first time through and thought there was a two MHz shift of the LO when moving to 40 m; that would put (in my mind at the time) the image of the other ham band out of the IF passband.
The original post was based on a complete misunderstanding of the design. I'm sorry, I wasn't paying attention.
We can either delete or leave this trek into the pitfalls of multipliers as a cautionary warning to others, I don't care - it's a hobby to me (and I make mistakes all the time). Your choice.
Thanks KC5UES - Chip
😂 Shooting down all the reasons why we cannot build a SimpleX Super. Excellent. Unobtainable parts? No, we SIMPLEy have to use our IMAGEnation.
One way to overcome the lack of the 1700khz crystal is to use a 455khz IF filter. These ARE available as many ham rigs used double conversion down to a last IF of 455khz, and replacement crystal and mechanical filters are easy to find at hamfests and on ebay. You would have to add a second conversion from 1700khz down to 455khz, and the oscillator here can be free a free running L/C affair with a large C to L ratio. So, one extra tube. All of those mini inductor and IF cans can be replaced with toroid wound coils. I'd probably cheat and use solid state circuits, including an si5351a vfo with an arduino processor. So many of the classic tube circuits can be redesigned around the same block diagram to use older solid state devices. I don't know if I'd trust my kids to play around with the voltages used with vacuum tubes. I'm amazed I didn't kill myself as a kid building my own novice transmitter power supply.
Let's do a solid state version.
In the first image the text mentions adding a transmitter. "* Or a 10, 12, 15, 17 or 10m Converter". Will you discuss those in a future video? What would that have looked like and what designs would someone have built back then for these additions? I'm curious.
The VHF manuals, 73 and CQ and QST, and the Handbooks, were full of simple converters. You could also buy them. The typical converter was an RF amplifier tube like a 6AK5 or a 6BZ6 into a dual tube like a 12AT7 or 6U8, with one section acting as a crystal oscillator and one as a mixer.
When are you putting up part 2 this build will be interesting👍.
Unless something comes up, I will have part 2 up next week.
Great Information!
It will take several installments to produce the finished and tested box! But this is a proven (if old) project, which makes it less risky for the average builder.
I can feel that 12 year old boy excitement for electronic exploration coming on. But this time around I've got the money, the time, and the tools. I don't need this receiver but . . . I think I must build it. It's going to be a good series, Mike.
I am going to try to make it a satisfying build and fun.
I built this receiver about 10 years ago. I found a crystal at a hamfest that was 1697kc,close enough. For the input coil I used a piece of 3/4 inch pvc pipe for the form. I had some wire that was 1/32 inch diameter, so I wrapped it around the form wery tightly. I made it longer than needed so I would have some extra form length. I then heated it with the heat gun till it just started to melt. After letting it cool I unwrapped the wire and had a form with threads in it. It took a couple tries to get it right. I then was able to use smaller sized magnet wire to make the inputcoils and oscillator coil. In the final build I used a smaller chasis so I used some junkbox adjustable coils for the input section and I used my home made oscillator coil.
Excellent story and this is essentially where I will go. I do want to show a toroid alternative solution as well.
Looking forward to that! My experience with toroids and tubes isn't that positive but there should be roads to solve problems like degree of coupling (very high in a toroid, often too high for tubes?). And the crystal I've been looking for too, no luck so far! Regards from Belgium, ON4SPK@@MIKROWAVE1
I love this project. I agree with most of your hard to get parts list but where are you going to get a 16 Henry AC filter choke. That type of pi network power supply isn’t used any more. I have an 8 Henry choke in my Johnson Viking Adventurer and that motivated me to recap the electrolytic filter capacitors because it still had the original kit electrolytic caps. If the had shorted it it could have ruined the filter choke.
Exactly. The most flexible part of this design is the power supply. It even changed between the MK1 and MK2 versions. Fortunately the receiver is happy with 200 to 300V, 40 mA. You could do a low current drain HV supply cheap, in any number of ways. I will be using a surplus CT HV transformer out of a discarded test box, two 1N4006 diodes and a small 2Hy choke with a single 100 uF 450 Capacitor. Much simpler - available parts. And yes the schematic will change of course, as I build.
Damn you got me thinking!
I'd completely forgotten the fact you might be able to use a crystal on subharmonics with some luck... Well, that's a guess, I've seen regenerative detectors being swamped out on many subharmonics when the LC-circuit is coupled to the crystal by a pickup-loop. Is that the trick?
Edit, nah looks like I was off by miles...
Regards,
Thomas
The crystals series resonance is the basis of a simple filter where the phasing capacitor nulls out the package capacitance, producing quite a sharp filter for CW. If you short out the crystal, it broadens so you can handle wider signals like AM without distortion. If you put a second crystal in place of the phasing capacitor, you for a proper half lattice filter where you can form a pass band more accurately.
What about using 3x 12AX7 Vacuum tubes as a Cross Coupled Double Balanced Mixer which will also operate as Local Oscillator will output the IF but not anything else.
Absolutely! Now you are bringing 70's style mixer technology back into the old girl for higher performance.
Awesome. I was up early this morning troubleshooting why I get transmit signal feedback interfering with the VFO on my HW-8. It pulls the VFO with a switched capacitor to Net the transmitter to with the signal you have tuned offset with the Direct Conversion receiver. My kingdom for a SuperHet!
Direct conversion receivers do have some limitations, depending on the isolation between ports and the actual mixer type. And of course they do require a lot of audio gain which can perturb microphonics.
With modern graphics programs and all sorts of printing options, could could probably make a very classy dial nowadays.
The original was not much more than paper and electrical tape.
@ Yes I saw that in the original article. I often wonder with these things whether you should stick 100% to the original or deviate where there’s a much better modern option. Some have suggested using a cheap DDS board to get round the xtal limitations. Not sure…. I think I’m going to give this receiver a go…
In one of your early 2024 videos you mentioned building the SimpleX Super. I checked my 1959 ARRL Handbook and found the article. I added a 1.7 MHz crystal to my Hamfest shopping list. I attended Hamvention and 4 other Hamfests. No 1.7 MHz crystal to be found. Very few Ham band crystals to be found. I'm looking forward to your solution for the 1.7 MHz crystal. For the price of what FT-243 crystals are going for you could use a SI5351 and Arduino.
We will try using slightly different crystals that are common clock frequency HC-49 types.
PLL?
@@jagmarc The 2000 kHz crystal we will use as a filter was originally made as a microprocessor clock. It also could be a reference for a PLL, as you say.
Handy tip for novices with tuned circuits, beg borrow a grid dip oscillator to use (fet dip these days). To help get each tuned circuit into the ballpark one step at a time, ready for first switchon.
Thanks for a very informative and interesting video again!
I have collected the parts for the Simple X, I managed find a 1640khz HC6-U type xtal. Also I have the stuff to wind the inductors.
73 de Juha OH8UBJ
Mike, thanks for your channel which I just recently discovered and have been catching up by watching your old videos,
Now I'm starting to regret throwing out those old copies of QST.
QST Magazine 1915-1969 on worldradiohistory .
There is some gold in them - before 1970 especially!
Those aluminum chassis boxes have become outrageously expensive! So, why not "Think outside the (aluminum) box"? Find a sturdy cardboard box, and coat it with the epoxy/fiberglass auto body repair material sold at auto parts stores. It's also sold for repairing boat hulls. It's expensive, but a can of it will go a very long way. It will strengthen the box and protect it from moisture. For greater rigidity, wood furring strips can be screwed/epoxied to the underside. Now, cover the thing with metal tape! Copper is best, because it's easy to solder to, but the aluminum tape, sold for duct sealing at hardware stores, works, if you're clever. Just make sure all the pieces are connected together, electrically. Also, you may have noticed how god-awful expensive transformers for B(+) have become. But there are those "travel adapters" that convert 110/120V to 220/240V, and vice-versa. They're rated in Watts, and most models will satisfy any B(+) current requirement for a tube radio.
I was waiting for this comment!
@@MIKROWAVE1 And I almost forgot....Filament xformer? "Wall-Wart"!
I always wondered if there was a solid state version of this circuit which would make it version Mark III. It really feels like it should exist. In any event you might should claim the "Mark III" moniker!
Lets do it with standard parts after the tube version. Something like MPF-102s and an LM380 for the speaker amp.
how many parts, ten?
Squared.
6U8 makes a good audio preamp and output tube (0.5W) as long as it's suppressed against VHF oscillations.
I made a fine headphone amp driver with the 6CG7 in a White Cathode follower, too.
Oh boy here we go, sifting the junk drawers and boxes. 73's Mike🎙KD9OAM🎧📻📡
I was going to order a Jackson vernier, and accidently spilled a box of dials and bingo there was one floating around in there!
@@MIKROWAVE1 You are my Elmer brother Mike
@@MIKROWAVE1 I do the same, I usually know what is on top of it and what side of the box or drawer.
Vernier drives and dials from mainline-group, who took over from Jackson Bros .
Very nice. I will check this out.
Not finding a simplex receiver in the 1953 jan issue. As stated in the video
Did find the first version in the dec 1958 issue.
Ah! @@daviddavidson1372
The Radio Amateur's Handbook", 41st Edition, 1964
@@ttucro2 The MARK II version was published in the Handbook for many years. I have a 1958 that has it already.
Yes 1958 and 3. I read the date wrong. The handbook had a similar image flipper 2 band receiver shown in 1958. The MARK I shows up in the Handbook in 1959, so shortly after and its in 60 and 61. The MARK II shows up in the handbook in 1962-65.
,👋👋👋🇨🇿🙂
7 years ago, I was chased by Krampus angels on St Nicholas night in Prague.
@MIKROWAVE1 😁😁😁 yeah yeah iťs a wonderful time
I built one in 1917.
Before you went to gay Paree?