I've been googling for practical (= complete with component values) AM detector schematics employing vacuum diode for the last two days with no success. There is plenty of theory to be found, many sketches but no components values anywhere.
While this isn't related to amplifiers directly I'm sure there are many of you who know of such schematics online and can hopefully point me in the right direction.
Thanks!
While this isn't related to amplifiers directly I'm sure there are many of you who know of such schematics online and can hopefully point me in the right direction.
Thanks!
I think you will find what you are looking for (and more) in the Radiotron designer's Handbook. Both the 1940's edition (350 pages) and the 1950's edition (1500 pages!) are online at http://www.pmillett.com/technical_books_online.htm
While you're there, you might also look at the book "Radio Reciever Design".
While you're there, you might also look at the book "Radio Reciever Design".
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Couldn't see any schematic in your last post.
I suspect you will find nothing about this topic on the internet, it stopped being an area of interest long before the internet ever happened, so why would anyone go to the bother of scanning old books, schematics etc and posting them?
I did quite a lot of R&D on this topic back in the late 60's, early 70's and got most of my ideas from the Radiotron Designers Handbook. The infinite impedance detector proved to be the best. Also suggest you take a look at the schematics for the Quad AM tube tuners, AM2 & AM3. That will give you a good working example of a diode detector - but the infinite impedance one sounds far better.
Regards, Allen (Vacuum State)
I suspect you will find nothing about this topic on the internet, it stopped being an area of interest long before the internet ever happened, so why would anyone go to the bother of scanning old books, schematics etc and posting them?
I did quite a lot of R&D on this topic back in the late 60's, early 70's and got most of my ideas from the Radiotron Designers Handbook. The infinite impedance detector proved to be the best. Also suggest you take a look at the schematics for the Quad AM tube tuners, AM2 & AM3. That will give you a good working example of a diode detector - but the infinite impedance one sounds far better.
Regards, Allen (Vacuum State)
Do you mean detector after the IF stage of a superheterodyne radio?
Here is a web page with full schematics and explanation for the All American Five radios.
All American Five - Detector Section
I also have a schematics of several German AM/FM tube radios that I owned.
I can post it if you are interested.
Raymond.
Here is a web page with full schematics and explanation for the All American Five radios.
All American Five - Detector Section
I also have a schematics of several German AM/FM tube radios that I owned.
I can post it if you are interested.
Raymond.
Not sure what your specific interest in tube diode based am detectors might be, but if you are planning to build an actual radio you might want to consider a triode based regenerative receiver instead.
http://www.lindsaybks.com/bks/twin/index.html Check out the Doerle Twinplex as an example of a radio that people are still building today.
There is quite a lot of stuff available online if you google for it, and Lindsay Books has republished a lot of the Gernsback radio series from the early 1930s and there is quite a crowd building these things. (Myself included)
Doerle Twinplex: http://dzabcik.home.texas.net/doerle.html
http://www.lindsaybks.com/bks/twin/index.html Check out the Doerle Twinplex as an example of a radio that people are still building today.
There is quite a lot of stuff available online if you google for it, and Lindsay Books has republished a lot of the Gernsback radio series from the early 1930s and there is quite a crowd building these things. (Myself included)
Doerle Twinplex: http://dzabcik.home.texas.net/doerle.html
Thanks for replies guys !
I already checked RDH (chapter 27). There is plenty of theory there but no practical circuits, alas I will look into this "infinite impedance detector" (which BTW sounds like something that uses an active, high-impedance input device, therefore not the thing I'm really after).
There are plenty designs using active device(s) (triode/pentode) described online. I'm not after these. I have a simple pentode-based regenerative receiver breadboarded, waiting for (ferrite) antenna + coil.
What I'm after are functional schematic od vacuum diode detectors. Why am I interested in these ? While I was bored and had nothing better to do over the course of the last weekend I came across serveral websites which outlined the history of vacuum tubes and/or electronics and they all mentioned (Flemming's) vacuum diode as the thing that started it all, alegedly allowing big advances in radio technology (this was in the days when crystal detectors were practical means of receiving AM with relatively low forward voltage drop). The only practical use for device with Vf of 100+V I see (mains rectifier/battery charger) has nothing to do with miniscule signals that aerial picks up so I'd like to see a couple of practical examples of vacuum diode AM detectors I was under the impression that DeForrest's tiode (Audion) was by far more influential so these schematics ought to prove me wrong.
The link I posted above has a simplified schematic right on top with components described in the text below. It shows up correctly for me but I want more schematics in order to be able to compare them.
That's all
I already checked RDH (chapter 27). There is plenty of theory there but no practical circuits, alas
I will look into this "infinite impedance detector" (which BTW sounds like something that uses an active, high-impedance input device, therefore not the thing I'm really after).There are plenty designs using active device(s) (triode/pentode) described online. I'm not after these. I have a simple pentode-based regenerative receiver breadboarded, waiting for (ferrite) antenna + coil.
What I'm after are functional schematic od vacuum diode detectors. Why am I interested in these ? While I was bored and had nothing better to do over the course of the last weekend I came across serveral websites which outlined the history of vacuum tubes and/or electronics and they all mentioned (Flemming's) vacuum diode as the thing that started it all, alegedly allowing big advances in radio technology (this was in the days when crystal detectors were practical means of receiving AM with relatively low forward voltage drop). The only practical use for device with Vf of 100+V I see (mains rectifier/battery charger) has nothing to do with miniscule signals that aerial picks up so I'd like to see a couple of practical examples of vacuum diode AM detectors
I was under the impression that DeForrest's tiode (Audion) was by far more influential so these schematics ought to prove me wrong.The link I posted above has a simplified schematic right on top with components described in the text below. It shows up correctly for me but I want more schematics in order to be able to compare them.
That's all
I am sure you will like it:
http://www.noding.com/la8ak/24a.htm
12P2000 pentode used as very sneaky detector.
Speaking of what started it all, it was a Silicon Carbide diode actually. That means, going for the earliest radio technology, you have to use the latest semiconductor one.
http://www.noding.com/la8ak/24a.htm
12P2000 pentode used as very sneaky detector.
Speaking of what started it all, it was a Silicon Carbide diode actually. That means, going for the earliest radio technology, you have to use the latest semiconductor one.
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Go to www.antiqueradios.com and look under the Archive section; there you will be able to download the whole Elements of Radio Servicing Book and learn all about detectors as well as superheterodyne radio theory.
If you want to look at random schematics, go to www.nostalgiaair.org; there you will find schematics for nearly every radio from the 20s, 30s, and 40s. I would look at random radios from Philco, RCA Victor, Zenith, General Electric, and Silvertone (Sears&Roebuck) if I wanted to see the most common practices.
If you want to look at random schematics, go to www.nostalgiaair.org; there you will find schematics for nearly every radio from the 20s, 30s, and 40s. I would look at random radios from Philco, RCA Victor, Zenith, General Electric, and Silvertone (Sears&Roebuck) if I wanted to see the most common practices.
A very good vacuum tube diode for AM or FM detectors would be the 6AL5/12AL5.. Equivalents 5726 and EAA91.
They are quite useful detectors and may be used as low voltage bias rectifiers in amplifiers if you must have all tubes.
They are quite useful detectors and may be used as low voltage bias rectifiers in amplifiers if you must have all tubes.
Thanks for replies guys !
I already checked RDH (chapter 27). There is plenty of theory there but no practical circuits, alas
There are plenty designs using active device(s) (triode/pentode) described online. I'm not after these. I have a simple pentode-based regenerative receiver breadboarded, waiting for (ferrite) antenna + coil.
What I'm after are functional schematic od vacuum diode detectors. Why am I interested in these ? While I was bored and had nothing better to do over the course of the last weekend I came across serveral websites which outlined the history of vacuum tubes and/or electronics and they all mentioned (Flemming's) vacuum diode as the thing that started it all, alegedly allowing big advances in radio technology (this was in the days when crystal detectors were practical means of receiving AM with relatively low forward voltage drop). The only practical use for device with Vf of 100+V I see (mains rectifier/battery charger) has nothing to do with miniscule signals that aerial picks up so I'd like to see a couple of practical examples of vacuum diode AM detectors
The link I posted above has a simplified schematic right on top with components described in the text below. It shows up correctly for me but I want more schematics in order to be able to compare them.
That's all
If you are interested in tube radios in general check two forums:
http://www.antiqueradios.com/forums/
http://www.theradioboard.com/rb/
If you need something quick - tell us where is it going to be used. I can hack few circuits for you in few minutes but I need to now things like RF signal source type, AF signal load type (basically impedance characteristics) and if AGC signal is needed.
http://www.antiqueradios.com/forums/
http://www.theradioboard.com/rb/
If you need something quick - tell us where is it going to be used. I can hack few circuits for you in few minutes but I need to now things like RF signal source type, AF signal load type (basically impedance characteristics) and if AGC signal is needed.
Again thanks for replies guys. I checked the Elements of Radio Servicing but it only touches detection as a part of the superhet receiver (where detector is preceded bby both RF and IF amplifier, allowing for plenty of voltage swing across the detector diode). I'm slowly checking out schematics on www.nostalgiaair.org now (slowly because I am unfamiliar with model names so I have to open each file up, check the schematics and move on).
Think about it this way: you were given hi-Z headphones/speaker, vacuum diode (single diode of your choice), a huge heap of passive components and you're expected to MacGyver MW AM receiver out of that pile. There are no active elements (triodes etc.) at your disposal but all the passives are there, as are batteries.
I imagine one would start with as long as aerial as practically possible, tuned circuit, perhaps followed by a step-up transformer, diode and ultimately headphones/speaker. I can't imagine what practical values (except for the tuned circuit) would be, given the extremely high source impedance of the signal. Things are much easier when one can stick an amplifier inbetween
Think about it this way: you were given hi-Z headphones/speaker, vacuum diode (single diode of your choice), a huge heap of passive components and you're expected to MacGyver MW AM receiver out of that pile. There are no active elements (triodes etc.) at your disposal but all the passives are there, as are batteries.
I imagine one would start with as long as aerial as practically possible, tuned circuit, perhaps followed by a step-up transformer, diode and ultimately headphones/speaker. I can't imagine what practical values (except for the tuned circuit) would be, given the extremely high source impedance of the signal. Things are much easier when one can stick an amplifier inbetween
The problem with the schematic in your post #2 is that heater circuit shunts RF via battery. Not good. If you want to use direct heater diode connect B+ to the other heater lead instead of the ground. Another option is to have diode in the ground return path of the headphones. Some report improved performance if a rheostat is used to control heater voltage - this allows some degree of detector impedance matching.
The circuit requires piezo-type HiZ headphones. You need a long areal and good ground to get decent performance.
Tube diode radios are rare - they do not offer zero power operation of a crystal set. Once you stick a powered device (tube) you can get vastly more enjoyable performance from a single tube regen.
The circuit requires piezo-type HiZ headphones. You need a long areal and good ground to get decent performance.
Tube diode radios are rare - they do not offer zero power operation of a crystal set. Once you stick a powered device (tube) you can get vastly more enjoyable performance from a single tube regen.
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