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ElPaso TubeAmps
United States
Приєднався 6 тра 2008
PL-259 Connectors on RG-400 or RG-58 Coax Cable
Everyone has their own favorite way of putting PL-259 connectors on coax, be it RG-58 or LMR-400 or whatever. In this case I am dealing with RG-400 coax which is a double shielded, silver plated coax the size of RG-58. The center wire dielectric is PTFE (Teflon). Good stuff - a bit stiff though. In any case, all the official ways of putting PL-259 connectors on small coax and using the reducer UG-175/U with new, high quality, PL-259's ends up shorting the braid to the center conductor. The problem does not exist on the vintage connectors for reasons shown in the video. The solution is an easy one and I hope it helps you safely and effectively install PL-259 connectors on your RG-400 and RG-58 coax cable. 73 WA4QGA
I mentioned in the video I used a #6 size nylon washer - this relates to a 8x3x2 mm washer.
I mentioned in the video I used a #6 size nylon washer - this relates to a 8x3x2 mm washer.
Переглядів: 808
Відео
Tickling The Dragon's Tail
Переглядів 3,7 тис.8 місяців тому
"Tickling The Dragon's Tail", is a movie about some guys "playing" with a Plutonium bomb core, also named, "Demon Core", in 1946 and an accident occurring. It cost them their lives in a horrible way. I know this is a little odd video but during the building of complex pieces of equipment like an AM transmitter that requires power supplies, in this case only a HV supply and not a screen and bias...
McIntosh MC225 Quick Review
Переглядів 1,8 тис.8 місяців тому
A beautiful condition McIntosh MC-225 power amplifier undergoing simple power and THD measurements.
T/R (Transmit/Receive) Switch External Control Box For "SEND" Connections
Переглядів 1,1 тис.10 місяців тому
In the beginning I said, "iCom 736 and meant to say, iCom 7300". The purpose of this video is to show how to build a simple relay box that can control external devices like linear amplifiers, especially vintage and homebrew amplifiers, and other devices that need to be controlled by the SEND relay in the iCom 7300, and other modern day tranceivers, that have a maximum allowable voltage of aroun...
Bird Power Analyst 4391 Quick Overview
Переглядів 88010 місяців тому
A quick as possible overview of how to set the switches for different power slugs on the Bird Power Analyst.
Building A Demodulator To Monitor AM and SSB Transmissions
Переглядів 1,6 тис.10 місяців тому
I wanted a simple way to listen to my own AM and SSB transmission over the air without having to use a receiver. By sampling a bit of RF off the coax line and putting it into a diode demodulator, I can clearly hear what my AM and SSB signals sounds like over the air. To demodulate a SSB signal it requires an additional RF generator to inject carrier into the diode demodulator.
Grounded Grid, Class-C, Plate Modulated AM Transmitter Using Eimac 3-400Z High mu Triode
Переглядів 1,6 тис.Рік тому
I love to build high voltage - high power transmitters. Grounded Grid (GG) amplifiers for SSB amplification is very common and run class-B and are classified as linear amplifiers. These linear amplifiers can be used to amplify an AM signal and they can sound good. Their efficiency is low and even very large (1500 watt PEP) GG amplifiers can usually not provide more than 300 watts output. Of cou...
General Radio (Genrad) Model 1666 Precision DC Ohm Meter
Переглядів 989Рік тому
A beautiful precision DC ohm meter capable of measuring resistance values from one (1) micro ohm to one (1) tera ohm (a trillion ohms) still in good working condition after I cleaned up the battery goo in the battery compartments. Uses eight D-cells - four to run the electronics and four to supply voltage to the probes.
Fender Blue Junior III "tinnitus" Issue
Переглядів 2 тис.Рік тому
An attempt to calm a Blues Junior III issue with a very sensitive front end tube - the first 12AX7 - seems to have a tendency to oscillate and cause acoustic feedback from mechanical vibrations in the cabinet apparently at high frequencies and was described at "tinnitus" (a very high frequency ringing sound). I tried numerous brands of vintage 12AX7 tubes and settled on a vintage military versi...
Stereo Williamson 7591 Amplifier Repair
Переглядів 2,9 тис.Рік тому
This is a beautiful performing amplifier I would call a "perfect" 15 watts per channel using 7591 and 6SN7 in a Williamson design and running a pair of UTC LS-57 output transformers. I have it run hours per day but a few days back it blew a fuse and smelled something burned. Just wanted to show how I go about repairing the equipment that I build. Hope you enjoy.
Plate Modulating The Mighty 833A
Переглядів 2 тис.Рік тому
Update: 8/10/2023 I backed off this project and turned to modulating an already built grounded grid (GG) amplifier built for class-B, SSB amplification. The amplifier was biased for class-C and plate modulated. It turned out surprisingly well and I have been using it on 40M and 20M AM. Making one of my favorite amplifiers that runs class-B for SSB to run class-C and high-level plate modulate it...
Checking Modulation On An AM transmitter Using Two Different Speech Amplifier Drivers.
Переглядів 1,1 тис.Рік тому
I used three methods of measurement in this experiment in an attempt to determine modulation bandwidth of an AM transmitter. One is the SDRPlay unit to visually see speech modulation using the spectrum analyzer function at different carrier levels in relationship to the noise floor. One carrier level is at about S8 and the other at 20/S9. A second unit of visual measurement is an oscilloscope d...
High Voltage Megger Used To Check Capacitors
Переглядів 3,8 тис.Рік тому
I have recently needed to measure leakage current in high voltages devices like transformers and purchased a modern digital Megger. This video is about the high voltages that are at the tips of the megger probe and how you should be Very Careful if you use it to measure capacitors. BTW - these meggers can be used to check very high ohmage resistors (Gig ohm level resistors) just like any ohm me...
Radio Transmitter High Voltage Transformer Repair/Replacement
Переглядів 1,6 тис.Рік тому
UPDATE: 11/26/2022 Power Transformer Replacement It happened again and this time I gave up on using the transformer that I "floated" and replaced it with another large transformer. 3700 VAC into a SS bridge (Goodby beautiful MV rectifiers...). The original transformer arced again and I suppose went from secondary to case to primary. Time to recycle 50 pounds of copper and steel. Plate current "...
Svetlana SV572-10 SET Amplifier Before Rebuild
Переглядів 2,6 тис.Рік тому
An attempt at a high-end SET amplifier using the interesting Svetlana SV572-10 triodes. Plate load was a 20H choke, impedance matched to speaker load with a UTC-LS output transformer. Plate voltage was 1000 volts and the tubes ran at a dull red plate color - extremely hot. Performance was poor and the amplifier is very heavy. I never did make it work good enough to warrant keeping it as a usabl...
Vacuum Tube Gain & Gm Calculations & Some Insight Into Transformer Inductance and Impedance
Переглядів 6 тис.Рік тому
Vacuum Tube Gain & Gm Calculations & Some Insight Into Transformer Inductance and Impedance
Heathkit WA-1 Audio Amplifier Performance Using 5V4, 5U4, Solid State & Mercury Vapour Rectifier
Переглядів 2,2 тис.Рік тому
Heathkit WA-1 Audio Amplifier Performance Using 5V4, 5U4, Solid State & Mercury Vapour Rectifier
Revisiting the McIntosh MC40 Amplifier
Переглядів 3 тис.Рік тому
Revisiting the McIntosh MC40 Amplifier
Cleaning RCA Connectors And Vacuum Tube Sockets
Переглядів 5 тис.Рік тому
Cleaning RCA Connectors And Vacuum Tube Sockets
First Attempt at Hydrogen Line Detection at 21 CM
Переглядів 1,2 тис.Рік тому
First Attempt at Hydrogen Line Detection at 21 CM
A First Radio Telescope For The 1.42 GHz Range
Переглядів 1,1 тис.Рік тому
A First Radio Telescope For The 1.42 GHz Range
Microwave Antennas & 21 cm Radio Telescope (1420 MHz)
Переглядів 1,5 тис.Рік тому
Microwave Antennas & 21 cm Radio Telescope (1420 MHz)
1.42 GHz Hydrogen Line Resonate Frequency Radio Astronomy & The Search For ET
Переглядів 2,9 тис.Рік тому
1.42 GHz Hydrogen Line Resonate Frequency Radio Astronomy & The Search For ET
AM (Amplitude Modulation) Radio Transmitters From The Ground Up
Переглядів 4,1 тис.2 роки тому
AM (Amplitude Modulation) Radio Transmitters From The Ground Up
Checking Out Some Beautiful Eimac 304 TH Tubes
Переглядів 2,3 тис.2 роки тому
Checking Out Some Beautiful Eimac 304 TH Tubes
Williamson Stereo Amplifier Using 7591 and Stereo 300B Amplifier Compared
Переглядів 3,9 тис.2 роки тому
Williamson Stereo Amplifier Using 7591 and Stereo 300B Amplifier Compared
hi,im a french and the traduction on you tube is terrible,When you plug your variac on the primary transformer you dont use the tap if i understand well.If i understand well with the 16 ohm i should have 32,400 ohms on the primary,so if i obtain 16,200 ohms on the primary how to know if its 8 ohms secondary .Probably if i have 4 leads black is ground no problem and the 8 ohms would be the number calculation between the 2 others ,i hope you understand my question ,i have three color on the secondary yellow ,brown and green which is 8 ohm!i dont understand
In vintage vacuum tube amplifiers, the secondary connections of the output transformer were often color-coded, and while there could be variations depending on the manufacturer, a common standard was: Black: Common (ground) Yellow: 4 ohms Green: 8 ohms Brown: 16 ohmss You could verify this by making some low voltage ratio measurements between these connections and the primary. Be sure to use a low voltage signal generator so as to not develop any high voltages across the high impedance primary (the wires that go to the vacuum tube plates and B+) remembering that voltage ratios are the square root of the impedance ratios. Hope this helps. There are other ways if this doesn't make sense or help.
hi my out put transformer is a hammond threre is little plate with a number 1664 thanks i will try @@ElPasoTubeAmps
Update 8/24/2024 - just had a bad connector on the end of my 20M hexbeam LMR-400 coax. I disconnected it when a thunderstorm was nearby and when I connected it up again today it was shorted - it was soldered braid thru the holes in the PL-259. About a year ago, I had a similar issue but this time it was on the 40M coax and in this case the center conductor was broken and open, (as I remember)... Obviously, I did a poor job on these connections. We learn from our own mistakes often times.
ElPaso, I've watched many of your videos, love them! I have an HP 8903a because of you all configured with the PMillet software - works great. One of my favorites. Anyway, I really would like to get an audio freq spectrum analyzer and I'm wondering if you have any insight on a CURRENT FFT that would provide a comparable replacement for one of these old HP 3580 or 3582s? I currently have a Siglent SDS 1202-X-E but it really doesn't do it. I saw your comparison with the Tektronix and the ARTA software these seem a bit dated now. Any insight would be appreciated. Thx, Ben.
Hi Ben, The one I have that I like is TrueRTA. Here is the link. trueaudio.com/rta_down.htm I think it is worth the price for the license beyond the free version because it prints beautiful images with your name exactly as you put it in when you install it. Another one is SpectraPlus but it is very expensive. Here is a video where I use it and show the very nice printouts. ua-cam.com/video/eU62EfGWNHg/v-deo.html There is another one called ARTA as seen in this link below but they just went out of business as of March 2024. ua-cam.com/video/BBQyoHsmwL8/v-deo.html Hope I got these right... Thank you so much for your kind words. It makes all this effort worthwhile. The 8903A and Pete's software was a challenge.... but it still works. I had a leak in my shop a few years back and it leaked water on one of my PCs and I lost one of my most important PCs but fortunately was able to move the hard drive into another PC. Now I get constant - this is not authorized software - or something like that - from Microsoft but it does work. I just keep that PC off the Internet. I still have my 3580A also as it is such an icon of a SA. As you know, it is brutally slow on low frequency signals. As I searched for FFT software, it seems like much of it is going away. What is our world coming to? 🙂 In another 20 years, it seems there won't be many of us that like to do this stuff, still around. Lastly, I forgot to mention about the first software I listed - you need and external USB sound device but I am sure I show it in some of my video. Again, thanks for contacting me. I don't do many videos anymore. Time is sneaking up on me and it is hard to get the energy to do them. Best wishes to you, always. David Beard
@@ElPasoTubeAmps David Thanks for the quick reply. Please don't quit making videos. I've learned so much from your material and many others refer to your work. Blueglow electronics mentioned your HP 3580 and I've had several conversations with other hobbiests who also have pointed to your work.
In my quest for Spectrum analyzers I could use some insight from you. Currently I have an HP 8590a which I received first very cheap and supprisingly it work great. Then I got an HP 8560a (not so cheap) which goes down to 50hz and up to 2.9 ghz. I was thinking that these might cover both some audio work and RF work which I'd like to do soon as I get the courage to start aligning am and fm receivers. But I'm not sure either of these will really work properly. The 8590a only has an RBW of 3k which I learned does not allow me to zoom in enough. The 8560a is a much better spec going down to 50 hz and an RBW of 10 hz but to get the span down to see that resolution it is almost a crawl. Do have the opportunity to return the 8560a for a full refund so I need to make a decision. (the 8560 does not perform as nice as the 8590a, the image is a little choppy and blurred but its good enough for the RF work not sure of the audio work. The HP 8560a came to $470 with shipping. I'm wondering if my money would be better spend on another better solution. I know you have a similar device I can't remember the model but I remember you trying to calibrate it. What do you use your for? Any insight on if I should keep or return this HP8560a 50hz to 2.9 ghz and pursue another solution I'd appreciate it. I might sell the 8590a too but it is so damn nice...
@@bendec2969 I went that path also trying to get an RF SA to work at audio and it is not a good choice. The old style analyzers like the HP 3580A, utilize a technology based on swept-tuned heterodyne receivers rather than the Fast Fourier Transform (FFT) approach used in modern digital spectrum analyzers. I love my HP RF analyzer, works great up into the GHz range, but for audio the PC based FFT analyzers are far better - in my opinion - although the 3580A is an icon of a swept-tuned SA. With that said, I have to thank you for reinitializing my interest in my PC analyzers. After your comments from last night, I got my TrueRTA program going again - had to look back for a few years in my email to find the code to make it work properly and then "reinvent" how to make the USB sound cards work again - I have always disliked PC's but know I need them nowadays. I am planning on making an audio video using a stereo amplifier - a Williamson design - and making measurements with one channel using 6L6 beam power tubes and the other channel using EL34 (pentodes) and try to document the harmonic profile of the so-called, British sound, of the EL34. Supposedly, the EL34 has more pronounced high order harmonics and gives it that bit of a "rougher" sound of the amplifiers like the Marshalls vs the smoother Fender. I figure it is time I give some attention to my audio fans. I will break out my 3580A and hope it still works. Thanks again. Stay safe.
David, I'm glad I got you going again. Looking forward to seeing that. I recently acquired two EICO HF-22 Monoblocks for a song!! But they are in rough shape right now but have everything. The original tubes test marginal but they'll do for now. Currently they use the 6L6 and I was wondering if I could upgrade to EL34 since there is a similar model that uses the EL34. I didn't consider the performance details just the fact that I have EL34's seem more available and I have several since I use them in an old Traynor Bass amp. Get that video out!!! I think I'm going to watch some of your videos on my 75" TV right now!
I wish you would put this into production. I would buy one!!
The brushed aluminum dhd amps was korean made and they did good power used the same exact boards as many other brand names amps used.
Looks just like a alpine knockoff most of the dhd amps are korean built.
How did you manage to obtain the MX-117 knobs for your lovely MX-113? Great look by the way.
I never noticed the knobs were different from other MX-113. I just looked both models up on Ebay. I have had it for years and bought it used and it came that way. I also have the MX-112 and see they originally had the same style knobs. Oh well... I might mention that I had a very intermittent issue with this MX-113 where the FM audio would randomly go in and out and it turned out to be a dirty MUTING control on the top of the unit. Apparently, a dirty wiper on the pot. I mention this as it was so random and intermittent it took me quite a while to find the issue. Thanks for your comments.
Can I use this for my headphones?
I think I would put a lot of insulation between my headphones and my ears if something with 5000 volts was driving my headphones. 🙂 Thanks for your reply...
@@ElPasoTubeAmps YOLO
I don't know what I am watching but... it's pretty dope.
I dont think ypu are a licensed ham radio operator. Other hams usualy identify with their callsign KA5WZY
Most hams identify themselves ??
I have to make a correction here - at about 2:30 where I show how to take the unit out of the case is WRONG... It is the two Philips inner screws on the front top - just to the left and right of the side screws that should be removed. Sorry for showing the wrong way to remove the outer case. 73 WA4QGA
nice mam god tranceivers 73 py2low
Excellent
Oh that is so neat and what a beautiful pair. Nicely done really love it. Many thanks for sharing this classic vintage exciter and amp. 73s wb7qxu
I run 2 275 in mono block this happen Several time it is alway the same thing a Bad Tube Thinking of going back to Solid State as I am getting Older and the expense of Replacement every couple of years is getting Pretty high.
I understand what you say. I have a Williamson amplifier that I put 7591 in and now they are $52 each - just too much - I will probably change them out (have to make some socket wiring changes) to 5881 that I have lots of. Of all the solid state amplifiers I have, I like the McIntosh 2100 the best. 105W per channel and for some reason like it better than the huge 2205 at 210W per channel. I doubt I will get rid of any of my tube amps but tubes, along with everything else, and taxes, is just going thru the room.
Shu Guang in Chinese means "Aurora" and is pronounced "Shroo 'Gwaang," with the stress on the second syllable. To be closer to the original "Shroo" should be pronounced with the tongue rolled back slightly as if you're going to say "roo" but instead you say "shoo." The firm has been in valve manufacturing for over 60 years.
Yes yes yes 100% correct. The center tap and all power supply electrolytics must be grounded at a single point. Then a ground buss may run from that single point across rhe chassis
Totally agree - the comment at the top, transcribed from the Mullard document agrees with us also. Thanks for your comments and confirmation.
You do have beautiful stuff. Very nice build quality. Just curious why not use a little JEWELRY ? they have LED VU meters for little $ that would have taken a huge box just to build the meters. Lots of very nice lighted analog VU meters. Its always nice to have a visual view of your output. Beautiful jewelry for very little. They even have full spectral displays for $ 50. Anazing. KA5WZY
You have a good point. I like to spice up the equipment some time. I joke that most of my equipment looks like surplus equipment from a cold war underground bunker with the grey chassis. When I get really fancy, I paint my chassis blue like the headphone amplifier I built for my grandson. 🙂 I do like symmetry try to dress the under-chassis wires along the sides of the chassis rather than direct - although sometimes short, direct connections can be the best. I do hope to build some more audio amplifiers soon. Thanks for your comments.
One thing I would like to say about this amplifier is, in the ARRL schematic, they directly wire all the screens together. I found that separating the screen connections from one another is a much better way to go. Everything works better when each screen has a little wiggle-room. I don't see it in this video but I believe I added 470 ohm 5W resistors in each screen lead right at the socket. It did wonders for stabilizing it and improving the output.
You do have a nice stash of transformers and chokes
If you are such a ham radio enthusiast ? Why dont you use your callsign ??KA5WZY
My most serious interest does always come down to amateur radio and RF but my YT channel was initially intended to be primarily for audio equipment so I thought it would be more appropriate to have a name not specifically for ham radio.
Have you ever built with the bendix redbank tubes ? Highest military quality but quite rare. KA5WZY
Awesome stuff. Wish i had met you when i lived in Spilver City NM i am sure we have seen each other at hamfests. I use to go to them all i am building a williamson with bendix red bank output tubes. KA5WZY
Your work is superb.
What are you doing with ypur screen grids ? Do ypu have UL taps. Resistor divided ? Or regulated
This amplifier does have screen taps and are used. It evolved into a much more powerful 6550/KT88 amplifier. Not sure but I think I made a video of that version using the 5U4 rectifier and then a solid state rectifier. A good bit more power with the higher voltage from the SS rectifiers. Being very conservative with vacuum tube rectifiers, a 5U4 is really only good for an amplifier of about 30 watts output. I do still have this amplifier.
Looks good KA5WZY i have a PPP 1625 modulator built from the 1965 arrl manual
This was my first modulator to modulate a pair of push-pull 812A tubes in a 1947 James Millen amplifier. It was too small and I ended up with, and still use in my AM transmitter, a modulator using Eimac 4-125A and a BC-610 modulation transformer. This one does a great job of modulating the Millen amplifier. I mostly keep it at 7293 KHz so maybe we will meet on the air some time for a QSO.
Obvious you like sprague orange drop caps
Good stuff. Ka5wzy
Howdy. Pity and Mercy again ! The Forefathers' Spirits are still angry ... Regards.
Very nice amp and presentation 😊 K9XOK
Hi David, add about 3 uH on a switch for 40m :)
My brother. Do you use the same comb for cables and mustache ? UA-camrs gotta know. Lol. And great job on video. 73 EVERYONE.
🙂 Absolutely... that solder resin keeps the mustache under control and comb the cats with it too ... 🙂
@ElPasoTubeAmps Well played, my friend. Make it a great day . Til next time. 73. DESPERADO 56 north of Tampa FL. When conditions are right.
I have one just like this built from the 1962 ARRL handbook. The arrl version did use an interstage. KA5WZY
hy , what hardware do you use for probing?
I use an external USB sound card like, in this case the Behringer or maybe a Focusrite or whatever you might have that the ARTA software can connect to thru the USB port. I am confident it can find any USB unit. If the external sound unit has mic input you can use that for high gain, if you need it, or use the line level mode for higher voltage levels from the device you are measuring plus some attenuation network, etc. to get the input signal to a level the sound unit can handle.
@@ElPasoTubeAmps ok, can i use such thing for measure the gain of smps ? I develop resonant converter whixh need to explore the mag gain
@@endremurti Sure, if you can measure the input accurately and then the same for the output or you can do 10*log of the power ratios with a volt meter. I am not sure the dynamic range of this FFT device is adequate to measure input accurately but I may be wrong. You will just have to try. I can give you an example. Suppose your driving voltage is 1.5 volts across an input load of 500K (you convert this to input power and get 4.5 microwatts) and your power output is 50 watts, the gain would be 10*log (50/4.5E-6) = 70.46 dB. Hope this helps.
David, there is concern about the maximum first capacitor size before the choke in a power supply when using these gas rectifiers. What is the value of the first capacitor? Is it about 40-60uf or so that would be used for a 5U4 or 5AR4? I bet these things can take that as they are rugged. Some say only a few uf can be used. Others say only a choke input power supply for these gas rectifiers. Also when using the 3B22 since you are using only one, wouldn't that be only half wave rectification in that case? Thanks for all these insightful videos over the years. I have learned a lot from you.
Tom, per all the specs on Hg rectifiers, only a choke input filter is recommended but I have used these rectifiers with capacitor input filters and in voltage doubler circuits which by design has capacitors at the output to the rectifier - running them at 4KV output - and never had any issue. I would keep the size of the input capacitors relative small, as you mention, at 40 uF or below. You are right, these Hg rectifiers are tough. I like to call them the solid-state rectifiers of 1930... voltage drop is constant at about 15 volts regardless of the load. As for the 3B22, it is a full-wave rectifier so you need only one. Thank you for your kind comments. I learn something from you all every time I post a video and have met many very nice people over the years on UA-cam. Stay safe...
@@ElPasoTubeAmps Thanks again for such a thorough response. Regarding the xenon gas 3B22 would you say it also could tolerate a 40uf first capacitor in the power supply? Since it only is rated for 725V PIV have you run it past that? I suppose a 1N4007 in series with it would help.
I was inspired by this video to run a test. I ran two tests, one with dual 649/5834 mercury vapor rectifier tubes and then dual 3B22 xenon rectifier tubes in a full wave CT arrangement on a Hammond 278cx power transformer. I coupled them to both a 2000 ohm load and then a 1000 ohm load, representing approx 250ma and 500 ma loads as might be expected in higher power amplifiers. The filter network I used was a 100uf capacitor, then a .5mh choke then a 120uf capacitor. I certainly exceeded the piv rating as I had over 1000V piv. Neither the relatively large first cap nor the piv spec busting did I notice any problems. They even withstood switching (after warmup) into completely discharged caps without arcing. They also, as you show in your video, have much less voltage drop than vacuum rectifiers. The 3B22 xenon tubes had less voltage drop than the mercury tubes. I intend to use these tubes in my next tube amp.
@@tomlang6480 I have experienced similar performance. The PIV rating is very conservative and so is the current rating. I used 866A rectifiers in a voltage doubler circuit raising 1800 VAC from a 700 mA transformer to 4KV for an 833A RF amplifier and never had an issue. The ratings of Hg rectifiers are always into a choke input filter and the voltage doubler by design is capacitor input to the filter. I turn the HV on during transmission of off during receive so there are many cycles of on/off and I never had an issue with the Hg rectifiers charging a 40 uF capacitor at the input of the Pi filter network. I don't have as much experience with the 3B22 but I figure it is just as tough. Thanks for your information and comments. Stay safe. Here is a link for vintage components you might like. n4trb.com/AmateurRadio/RCA_Ham_Tips/rca_ham_tips.htm
@@ElPasoTubeAmps No kidding about staying safe! I notice after all these years (decades) I automatically put my left hand in my pocket around this stuff.
I just got a comment and watched this video again. (7-14-2024) I can't hear much if any difference in the video but I trust and respect each of your judgements. I also want to let you know the way I balanced the volume of the two amplifiers is by using pink and white noise generators I got from the Internet download and a high-end General Radio sound level meter measuring the SPL (sound pressure level), and going back and forth between the two amplifier and adjusting the volume on each. I did not adjust the volume controls using music. Even now I am amazed I was able to balance so well. I remember reading years ago that in comparing amplifiers or speakers, the difficulty is getting the volume exactly the same because the one that is a little louder will almost always be chosen as the preferred one. And now that I am rereading all the comments below, it seems preference is about 50/50 and with extended listening I also hear more brightness in the SET and more command of the lows in the Mac. Nothing technically surprising there as it is what we would expect. Thanks for all your comments. This is where the rubber-meets-the-road as the saying goes and in the end it is all about, "how does it sound"? Best regards, David Beard
Number 1 was more refined sound, more clean.
Thank you for your vid, I learned from it
Thank you for your comments. Been a while since I have used this device but still have it in good condition. I don't know if I mentioned it in the video, the cables from the amplifier socket to the test jig may introduce instabilities in some amplifiers if the amplifier is swept with a sine wave. I bought ferrite cores to put around the grid an plate wires but never got around to it. Also some small bypass capacitors in the 100 pF range might help quell any parasitic events but for static measurements it is really handy for matching tubes. Stay safe...
Thank you!
Very good stuff. Love your audio projects from a fellow Texan. Audiophile and ham Radio operator KA5WZY
Love the Collins 310B. I have 1 and looks like it was built yesterday.
I've done it this way for 40+ years. It's the best way to do it.
Preferred amp 1 and hears when you switched them! Very cool!
Beautiful amplifier. Appreciate you taking the time to take us through it. Looks amazing. 🎶😊
Gr eat video. I have d 104 about 70 yo. No bottom on base and no switch on stand. I need to update mic. How is this possible without everything it doesnt have? Harry, w3wkx
I think you need another base and switch assembly that you can take parts off of to save your heirloom microphone. They are not too expensive on Ebay. I have one similar that was bought for me in 1963 when I got my general class license - 61 years old - and is special to me. I keep them going and have acquired several heads to experiment with different mic elements. I have also found that the inexpensive condenser mics sold on Ebay and Amazon have a QC problem. Some work much better than others so a simple method of evaluating them would be good. I just ordered some more... 🙂 and will work on a method to sort the good ones from the weak ones and plan on making a video. Thanks for your comments. I hope you can save your 70 yo microphone for another 100 years. 73 WA4QGA
worked like a charm! Thanks!
Very nice work!
Today is June 26, 2024, and I've been working on these D-104 heads again. I’ve found a great solution by placing three small, inexpensive microphones in a triangular pattern inside the D-104 head. By wiring the three positive terminals in parallel and the three negative terminals in parallel, treating them as one microphone, it works marvelously. I now have two heads set up this way and consistently receive unsolicited compliments on the audio quality. There are no other changes in the setup, just wiring the three mic elements together. This setup works beautifully with my KWM-2A and 32S-1. However, when I wired one of the mic stands with an 8-pin connector for my Icom 7300, it didn’t work well at all. Despite my efforts, I haven’t found a better microphone for the 7300 than the stock mobile-style hand mic it came with. I continue to receive wonderful compliments on the audio quality of the 7300 with its stock mic. I also want to take a moment to thank all of you for your kind comments and good wishes. 2022 was a tough year. Not only did my two cats pass away, but the love of my life, my wife Marilu, who I was married to for 45 years, came down with pancreatic cancer and passed on June 19, 2022. It has been a difficult journey. I now have six cats, and I believe Marilu sent them to me because she knew I needed them. I am deeply grateful for your kindness and support. God bless you all. I’ve been posting since 2008 and have met so many wonderful people through this UA-cam channel. 73, WA4QGA.
Super tip, thank you!
This is super interesting and your cat is a cutie. Is your receive antenna directional? Appears to be. Love the video!
Thank you. You are very kind. Here are a couple of additional videos when I got more serious about it. Yes, the antennas are very directional and need a good size tripod to mount them on. ua-cam.com/video/KLhxggZbsVc/v-deo.html ua-cam.com/video/SDLm1N10fTI/v-deo.html