Add Bluetooth to a Tube Radio without the buzz and noise. Bluetooth receiver board KRC-86B V4.0
Adding a Bluetooth receiver to a tube radio is a great way to increase its usefulness. You can either use an external one with a battery, or connect it to the internal power supply. The problem is that generally the latter option adds a lot of noise to the audio, in the form of an irritating buzzing. This video shows how to get around that issue.
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Have just added one of these to a tube radio I have restored and ran into the same issue of low voltage after rectification and smoothing of a heater winding output. This radio though has two heater windings. So the output across the two is over 12 volts but, they have a common chassis ground (single wires to tube heaters - ground return). This would result in shorting one of the windings when grounding the audio output. Bought one of the Mornsun B0505s -1w 5v-5v DC-DC converters mentioned by one of your viewers in the comments and placed it between the 78L05 and the BT unit and I can now safely ground the audio output while using both windings to feed a bridge rectifier. The BT works flawlessly and no noticable hum or buzz. Thank you for this video and also to the other viewer.
@electronicsoldandnew
Жыл бұрын
Good to know you’ve sorted it out 👍
Thank you!!!, I am in school currently for electronics repair. I honestly have learned SO much from you just build practical things. Hi from USA!
@electronicsoldandnew
3 жыл бұрын
Hi. Welcome to the channel. Hope you continue to get something positive from it.
I never knew it is so easy to create a aditional winding on an existing transformer. Very cool to see this is possible. Obrigado !!!
@electronicsoldandnew
24 күн бұрын
Prazer 👍
Nice idea. It wasn't really a ground loop problem. It was part of the capacitor charging ripple current travelling down the audio cable shield and therefore appearing in series with the audio output. It could probably have been reduced to an acceptable level by using a much thicker ground power input wire and putting a small resistor in series with the audio output shield.
Gotta be the best quality clearest explanatory video on KZread, thanks.
@electronicsoldandnew
4 жыл бұрын
My pleasure
@Andre-nx5xl
3 жыл бұрын
Agreed! :)
@electronicsoldandnew
3 жыл бұрын
😊
Brilliant Video, Quality and Explanation. Thank You for the time and effort you put into this. I believe the 100uF Capacitor that comes with the board is being used as a Bypass Capacitor to cut off the low frequency noise you may get from the supply. Perhaps you could have cut out more of the noise (before arranging the isolated supply) by also adding in a 0.1uF Bypass Capacitor to cut out the high frequency noise? Another alternative is to use a Boost Converter (essentially an isolated DC “transformer”) with an I/O voltage range to meet your specifications. You can buy tiny prebuilt ones off eBay for a few bucks. Cheers, great video!
@electronicsoldandnew
5 жыл бұрын
Simon Holl : good points. Thanks. I have since started using an isolated supply solution, which works very well. I did a video on it just last week.
Great video!! I wish you would have shown how to build that project board so newbies like me could walk through this whole project. But as is it gets me motivated to try this. Thank you!
@electronicsoldandnew
6 ай бұрын
👍
I love it. I love youtube for this kind of thing. thank you for a great video.
@electronicsoldandnew
5 жыл бұрын
My pleasure
Very useful info as i am restoring a 1967 Kenwood TK 66 reciever and would like to add BT in the process,thank you! also your instrucion is clear so a relative newbie like myself can easily understand
@electronicsoldandnew
5 жыл бұрын
Gearhead Ted: glad to be of assistance.
With the 78 series regulators the datasheet recommends 100nF caps on the IN and OUT pins to cut done noise and oscillation. Instead of a 78 series regulator a zener diode and series pass transistor setup will work. This way you don't have to add so many turns, just enough for 5.5 or 6 volts would be enough.
@electronicsoldandnew
6 жыл бұрын
Leland Clayton : good point.
You don't really need the resistor and second filter. The 7805 will actively filter any remaining ripple off your first 2200uf and the 100uf on the output will clean it up perfectly. Saves a step and the extra volt makes sure the 7805 input stays above the low voltage cutoff.
Thanks for the great explanation. Brilliant. I have a 1940 Philco I'm restoring and wanted to do this and you just showed me how. Love it.
@electronicsoldandnew
4 жыл бұрын
Good luck with the Philco
Excellent video. I have built a receiver that has valve amplification using a push pull circuit with EL84 valves that has a DAB FM radio using a Silicon labs SI4684 ic for the radio section it also features a touch screen control and a valve phono stage everything works perfectly except for the Bluetooth suffers with a buzzing noise and this video has given me the answer to the issue. The Bluetooth module i used only has one GND connection so it cannot be an earth loop the buzzing definitely sounds like some sort of digital signal being fed into the pre amp supply i suspected that i would need to provide a separate supply for the BT module. i am going to try this mod fortunately i wound my own transformer so it would be easy for me to add the extra winding. so thankyou for the info.
@electronicsoldandnew
9 ай бұрын
My pleasure. Good luck 🤞
Thanks, great video!!! I like your way of making separate AC source..
@electronicsoldandnew
2 жыл бұрын
👍
I am planning to install same bluetooth adapter in my old sony. It never crossed my mind to get rid of that buzzing. I will definitely think about secondary power supply for it. Thank you for the video ;)
@electronicsoldandnew
2 жыл бұрын
My pleasure
I don't know whether anyone else has mentioned this, but connecting both ends of the earth wire/screen in an audio feed lead is not normally done in older equipment. It causes an earth loop and or pickup of the hum signal. When you removed the supply earth the circuit still worked as it earthed through the audio lead screen. You still had a ground loop. I suspect that if you try the original setup with the audio lead screen connected to earth at one end only, the hum will reduce or disappear. Also you mentioned about care connecting to the correct point for the 6.3 volts on the heater circuit. It is worth noting some vintage tube radios and amplifiers have the valve heaters in series not parallel, meaning if at the wrong point you could have several times 6.3 volts A.C. More seriously in some cases the heater ciruit will have B+ as well on it. That is high voltage D.C. anywhere from 100V to 600V. Not just harmful to your BT board but the operator. Take care out there.
@electronicsoldandnew
2 жыл бұрын
👍
I've just done my first am only radio using this design.. Luckily i didn't have any hum issues.. Many thanks
@electronicsoldandnew
3 жыл бұрын
👍
I have done a similar thing but I used a simple 5 volt DC supply that cost a few dollars, which feeds directly into the Blue tooth board. Completely silent, no buzz or noise, I did, like you used a 100uF and a 0.1 uF across the power supply input If I was winding my own, I think I would have used slightly less turns and a full wave bridge. I bet that sounded good however, especially if you used a lossless audio file.
@electronicsoldandnew
7 жыл бұрын
+Michael Beeny : I've used separate supplies before, but they should be linear ones to avoid switched mode supply noise. A full wave bridge will give you about the same voltage ... actually less as it has two diode drops. The reason I used this one is that I already had the board built for the option if using the heater supply, so I left is like this. The sound is AMAZING!
@mmecanicafina3977
7 жыл бұрын
+ Michael Beeny: I was thinking along the same lines, I especially like a very compact one module (HLK-5M05) I have used in other projects with good results and I wanted to try it out for this.I wonder about the switching noise though. Did you actually use a switched mode power supply module or a linear one?
This is exactly what I've been looking for! In Norway they have shut down the FM-net, so I allso need to install a DAB-receiver and a display to show channels. :) I can't find anything on youtube, so I guess Norway was the first country to shut down FM :\ Great video!
@electronicsoldandnew
3 жыл бұрын
thanks
Very clever solution! You might also try a Mornsun B0505S-1W isolated dc-dc converter. You need a few additional filter components (see Mornsun data sheet) but I think that might allow you to use the original circuit that you came up with.
@electronicsoldandnew
7 жыл бұрын
+Glenn C : I actually ordered some of those a while ago. They're on their way.
@WaelSherif
5 жыл бұрын
or the Traco TMV 0505S
What if you used 4 diodes for full wave rectification and either removed or cut the resistor value by 25 percent between the first and second cap before the regulator. this should give you the extra voltage you need.
I be got a old radio like something like this that I listened to when I was small and needs a upgrade, from when they changed from 1979,and a few years ,ago.l had lots of other radio which has all broken down but my wooden radio still with me. great video now I can upgrade it.
Briiliant! I hope to do an old am radio this way, if the amp section still works.
@electronicsoldandnew
3 жыл бұрын
👍
Exremly usefull. Adding stuff like this in old tube radio's going to put those radio's info the this century, and ging them a new purpose.
@electronicsoldandnew
3 жыл бұрын
👍
Now *that's* clever stuff. Nice method! And, I might add: cool-ass handwriting.
@electronicsoldandnew
4 жыл бұрын
Thanks
I found the isolated 9.3vac transformer modification to be the most "Ah Ha!" moment for me! I would love to see a BT transmitter that allows the use of a BT speaker/headset for the radio output!
@electronicsoldandnew
2 жыл бұрын
👍
Thanks for making this, it will be very useful.
@electronicsoldandnew
4 ай бұрын
My pleasure
Great video. I have been trying to audio into my radios with an AM transmitter. The thought was I could listen to whatever radio was in the room I was in. Unfortunately, the transmitter has noise it sends with the signal that I haven't yet been able to get rid of. I am sure it is in the design since it is powered by a 9V battery. Till I find a suitable transmitter, this may be what I will have to do.
@electronicsoldandnew
Жыл бұрын
👍
Very interesting and clever solution how to create a new secondary coil to supply the necessary dc voltage prior a dc device to supply the necessary 5 dc output. The sound must be wonderful after having see the 4 speakers of the radio. I was missing the "final sound" result...! Thanks for the interesting video .
@electronicsoldandnew
7 жыл бұрын
+abele ballestri : you're welcome. I am just finishing up the cabinet repair to put this project to bed with a final video.
So glad to see this done properly ! It the radio a Telefunken Opus ?
@electronicsoldandnew
5 ай бұрын
👍
Very nice project. One thing I missed, how did you combine the L and R channels from the bluetooth module? Assuming of course that the radio is a mono one?
@electronicsoldandnew
4 жыл бұрын
Through 1k resistors.
Ok, good thought. I was not aware of that issue. I saw one method on you tube using that supply. I personally have not done it.
I wonder if the buzz was due to insufficient input voltage to the 78L05, and it not regulating properly. A half wave voltage doubler could be used to get about 15V DC for the input. Or use a low dropout version of the 7805. But otherwise, a separate secondary on the existing transformer is a good idea.
@electronicsoldandnew
6 ай бұрын
I tried many options with the same result: a buzz. I finally opted for the isolated option with good results.
How cool would this thing be if it was available in a 5 Pin Glass Tube to give it that valve radio look. 2 pins for power and your stereo audio output. You can easily tie the output together for Mono after the tube. Most radio chassis have a little extra room for another tube and socket
@electronicsoldandnew
Жыл бұрын
😊
Just did this. My logitech bluetooth adapter has a little higher output level than this one. Its otherwise ok. with 120hz sine wave at phone full volume: Logitech is 0.365 volts KRC-86B is 0.335 volts running it off the filament transformer winding caused it to buzz like hell. Then I noticed that the filament transformer is referenced to B- of the high voltage winding even though the schematic says its not. I then powered it from a battery and its good. I will try to figure out how to isolate this or just buy a small transformer to connect to this supply to isolate it. I did a little reprogramming of the chip on here and gave it a custom name.
Now that you have a non ground referenced supply from your new winding, can you now use a full wave bridge?
@electronicsoldandnew
2 жыл бұрын
yes
Clever solution on the the transformer winding. I wonder if you could use a DC-DC converter or if the switching noise would break through. I may have ago myself see if I can make it work. Wow those are incredible speakers!
@electronicsoldandnew
4 жыл бұрын
I use a dc-dc converter in other cases, but I use the isolated type to avoid the noise. The part number is B0505S-1W
@allthegearnoidea6752
4 жыл бұрын
Electronics Old and New by M Caldeira ok thanks for the heads up on the part number saves me trying various devices thanks. Regards Chris
Great video, as usual. Can you explain why you can't use a bridge rectifier? I didn't get that part...
@electronicsoldandnew
7 жыл бұрын
+James Kadosas : the final solution with the new wound secondary does allow you to use a bridge rectifier because it is floating. When I did the initial circuit, I was going to use the heater supply which has one end connected to the chassis (ground) so I cannot use a bridge rectifier as this needs the AC inputs to said rectifier separate from ground. One of the rectifier outputs is ground in that case, so you can't use it.
@kadosas
7 жыл бұрын
Thanks for the explanation.
This solves the exact problem I have of noise, thank you
@electronicsoldandnew
4 жыл бұрын
pleasure
That was more than useful for some old German Radios im going to work on.
@electronicsoldandnew
4 жыл бұрын
Glad to hear it. Have fun.
Try a LN-BT02 pull Pre/amp input and add the unit as an interrupt.
@electronicsoldandnew
2 жыл бұрын
👍
Great video Will be building one shortly into my radio. What is you reception range? Would it be possible to add external antenna? Kind regards
@electronicsoldandnew
6 жыл бұрын
Stephan C : you get about 10m or so, and you can place the antenna outside the unit.
What a great video and enjoyed the accent too. Going to do my mine differently with a seperate 240v/5v switchmode supply (so cheap on eBay) but this video has essentially thought me about the alternatives including pros/cons so thanks very much I have learned heaps!
@electronicsoldandnew
3 жыл бұрын
my pleasure. good luck with yours.
@simonflint5303
3 жыл бұрын
Thanks for the tip regarding the foam tape. I’ve been wondering how to mount these with minimal effort.
@electronicsoldandnew
3 жыл бұрын
pleasure
@RobsFixitShop
2 жыл бұрын
The switch mode power supply is going to interfere with the AM IF and make a bunch of noise. My 2 cents form personal experience. If you could find a PS with a transformer you''d be golden.
@electronicsoldandnew
2 жыл бұрын
I’ve added dozens of these to tube radios and get no noise induced into the AM IF. The only noise I sometimes noticed is on FM if there is an internal dipole antena. Some careful placement is needed if that happens.
I am doing the exactly the same at this moment. Adding the KRC-86B to a Philips tube radio with phono -input. I have managed the power for the bluetooth receiver, but I have a problem with the volume of the bluetooth signal. The audio-out signal of the KRC-86B is very low. So I have to turn the volume up very high. But when I switch to the radio, the volume blasts into my ears. So the amplification of the bluetooth signal and the radio signal is too much different. Do you have suggestions how to best solve this?
@electronicsoldandnew
4 жыл бұрын
All BT modules have the same symptoms. The phono cartridges used to have a much higher signal level I’ve tried pulling a preamp module after the BT But found that it added unnecessary complications. I’ve just got used to living with having to set the volume higher Bluetooth reception.
My external bluetooth adapter can last about 20 hours but an internal solution would also be a cool thing. You could probably use such isolated DC/DC converter modules to get rid of the noises. But the buzz sounds more like an issue with the unsymmetric load on the 6.3V supply to be honest. So not sure if this DC/DC isolation converter will actually help.
@electronicsoldandnew
3 жыл бұрын
It works perfectly with the DC/DC converters. I’ve installed it into literally douzens of sets so far.
@MultiWirth
3 жыл бұрын
@@electronicsoldandnew yeah also used this for a selfmade bluetooth speaker powered from a big lead acid battery but the noises i had were all high frequency rf noises from the bluetooth module, no static buzz like you had.
Very cool vid! Thank you. Solves a bunch of issues for me.
@electronicsoldandnew
2 жыл бұрын
👍
Did you try connecting only one end of the signal wire ground shielding? Both devices are referenced to ground on the heater supply so there is built in ground loop that you did not appear to consider.
@electronicsoldandnew
4 жыл бұрын
I’m not using the heater supply. I wound a separate winding on the transformer, so it is fully isolated. The only point of common ground is at the signal input.
@jonka1
4 жыл бұрын
@@electronicsoldandnew Thank you for your reply. I watched the video so I know about your arrangements for the power supply, however when you were powering it from 6.3volts you had two ground connections to the solid state device and when you disconnected the ground connection to the 6.3volts you had the ac feed going via the shielding wire. Both these conditions would create hum.
Excellent, thank for showing this. However, i got the exact same mini board and I was struggling on were to get 5V, This was a class A tube amplifier I just built and the closest I got was 6.3V. Then it down to me. one of this pone chargers that are a very small cube with a USB out with 5V... installed everything inside a small box at the rear of the top pd the chassis and it work fine. Thank you for the idea!! Mario
@electronicsoldandnew
7 жыл бұрын
+mtabernig : you're welcome.
Great solution. Tks for sharing.
thanks for the transformer trick ! very clever and will be useful to me ! only problem i suppose will be, it will put strain on primary coil, if current draw from secondaries are too high. but nice solution for measured requirements. :)
@electronicsoldandnew
6 жыл бұрын
iceberg789 : I’ve used this solution many times, but always for low current requirements only, so as not to overload the primary.
@jonka1
4 жыл бұрын
The power draw from this is so tiny it will get lost in the eddy currents of the core.
When you added the extra coil on the transfo. Did you use both ends of the wire (one 9v+ and one ground) on the circuit board? Or is that wrong?
@electronicsoldandnew
4 жыл бұрын
Yes. The two ends are used and you get the ac voltage across them. Neither is actually Ground, because you want an isolated voltage.
Hello, I have bought 2 KRC-86B Bluetooth modules from different vendors and both have terrible audio quality, for some reason the bass is almost non existent... did you notice this as well on yours?
@electronicsoldandnew
5 жыл бұрын
KatraOnline : no, I’ve had no problems with sound quality.
i liked your explanation. its very clear to understand. thank you. i have one question about bluetooth module. i have same and i have issue and its not only buzz noise - its very poor sound quality. its something like distorted vibrato effect over song. i connected it to a li-ion battery for test but same. and very poor bass also. when connect to bluetooth aux port - sound is great but when connect bluetooth -> noises and distorted sound. i used iphone 5s.
@electronicsoldandnew
6 жыл бұрын
allls firebird: it could me a problem with the module itself. These modules are very well priced but the problem is reliability. When I buy these from eBay, I usually order more than one just to ensure that at least one works. Good luck.
Watched it today.Really informative.
@electronicsoldandnew
2 жыл бұрын
👍
Hi, very clever, but I'm wondering whether the extra RC L section in the PSU really does anything that the 7805 can't already do by itself. I would have thought you'd be better off without the extra voltage drop and letting the regulator work a bit harder but with more headroom to play with. Nice solution though in the end. I have an FM tuner where introducing an MPX has caused a similar buzz, even though I've done the same thing to the same model dozens of time without problems. Might be time to dust it off and reconsider.
@electronicsoldandnew
Жыл бұрын
👍
@EJP286CRSKW
Жыл бұрын
And you can tone down the capacitance too. I use 1,000uF for a similar current drain. But I once fitted a similar-looking 10uF 450V cap by mistake and the thing still worked, no hum, except a horrible blast at startup.
@EJP286CRSKW
Жыл бұрын
In fact I'm not clear what the actual problem is. If it's digital hash from the BT module, how is that not being coupled into the output audio ground? And your later balanced voltage-doubler solution still seems to couple all the grounds together anyway. Isn't this really just a ground loop? Avoidable by using the chassis ground for power and lifting the shielding of the audio output cable at the target end? Or is it maybe caused by using the 6.3V ground, which is very dirty with hum?
@electronicsoldandnew
Жыл бұрын
It is a ground loop issue, aggravated by the digital noise from the BT. If you look at the current paths carefully, you’ll see that the digital noise is “left behind” and not passed on to the audio ground. You should experiment with it without this isolation. You’ll see that the issue is quite frustrating.
I want to make my living room wireless and thought I would need to buy a transmitter board for every device (vinyl player, DVD player, amplifiers and a tuner so four boards?) And then I need to get a receiver which will receive all the Bluetooth signals. I connect the output of the receiver to my speakers and subs at last and should be fine right? Please someone help me out with this I am so confused.. Thanks Fam and stay well oh and nice video btw
Brilliant! Great information. I am going to try it.
@electronicsoldandnew
5 жыл бұрын
Sam Calloway : it’s really great. Makes the device really useful.
Do you have a schematic or diagram of this treasure? Thank you. I'm trying to use either a 7.5 v wall wort transformer or the heater tap of the 35w4 whisk on this radio is connected through an .047 to ground since it doesn't have a bulb. Of course either way I'll have to rectify it. This is a G.E. model 930 without dial lamp.
@electronicsoldandnew
3 жыл бұрын
Only as drawn in the video. However, the more recent method I use is shown in a few videos on my channel, which uses a DC-DC chip to completely remove supply noise. Here is one: kzread.info/dash/bejne/o3iixcGYkb3ahcY.html
@sarahhoward9081
3 жыл бұрын
@@electronicsoldandnew thanks! That's the video I was looking for.
@electronicsoldandnew
3 жыл бұрын
👍
I realize this is a 5 year old video but I'm just viewing it so.... If I were to just add 17 turns to the transformer to reach 5v or so could I then connect straight to the bluetooth receiver directly, without the additional circuitry you designed, without any problems?
@electronicsoldandnew
Жыл бұрын
You’d need to rectify it to get DC and smooth it with the filter caps, then regulate it to give you 5V. Basically what the circuitry does 😊
How about a link for the Bluetooth device.
I wonder why didn't you use a bridge rectifier instead of this HWR config, so that you could avoid such bulky filters.. Some reasons related to the tube circuit scenarios?, what I'm totally blank about..
@electronicsoldandnew
4 жыл бұрын
I first built it to take the 6.3v heater supply, which has one point already connected to ground, so a bridge rectifier is not viable. I then changed that to a separate winding on the transformer, which could use a bridge rectifier and smaller filters, but I wanted to use the board I’d already built, so I went with this option.
@availablenowonwards
4 жыл бұрын
@@electronicsoldandnew Understood.. thanks for the clarification.
Have you tried re-programming this module (e.g. change it's name) ?
@electronicsoldandnew
6 жыл бұрын
YairAudioClinic : no I haven’t. That would imply going far deeper into this module than I wish to do.
@YairAudioClinic
6 жыл бұрын
Have you looked at modules such as CSRA64215 ? it is supposed to be programmable...
Did you ground one end of the new winding to chassis and the other one to the Bluetooth reciever to make it half wave rectification? And did you put 1nF cap in paralell with the 1n4007 diode?
@electronicsoldandnew
7 жыл бұрын
+Okhan Vatansever: No. That is not necessary and would probably create a ground loop. The system is connected to the radio's ground at the socket input only. The half-wave rectifier is the same. I left the 1n cap in place. Can't hurt. The system is dead quiet now. Works really well.
@OkhanVatansever
7 жыл бұрын
i will try this! And how did you wind the transformer? Do you hade to dissassembly The transformer?
@electronicsoldandnew
7 жыл бұрын
+Okhan Vatansever : No. It's explained in the video. You wind it through the space between the existing windings and the core.
Very neat solution! Thanks for sharing.
@electronicsoldandnew
7 жыл бұрын
1nformatica : thanks
I used the same circuit one year ago and I had the same buzz problem. I don't know what I did wrong, but my board smoked when I connected the output to the pickup input of my 1956 grundig radio. It still was working afterwards. weird. Any idea ? Thanks for the great tip with the transformer ! Very nice.
@electronicsoldandnew
5 жыл бұрын
eldontyrellcorp : you need to make sure the supplies are completely isolated, as shown in the video. That gets rid of the buzz. The smoking ... could you have had DC voltage at the PU input?
I bought such a unit and are testing it. The output of the unit clips 100% of the negative signal (I only get signal on the positive side of 0V from the oscilloscope). Do you get a similar result? Kind regards PS: I used a signal generator on my phone to test the output from the bluetooth unit.
@electronicsoldandnew
6 жыл бұрын
Stephan C : hi. No I don’t get clipping at all. Mine works perfectly. Sounds like the unit may be defective, but am not sure. I have had some failed units from the purchases on eBay.
Another solution to the independent power supply issue would be to buy up a bunch of these: www.jameco.com/z/MA14L-2001-0012-Fujitsu-9-V-200-mA-Unregulated-Wall-Power-Supply_2215460.html, cut the guts out of them and add a 78L05 and a couple of caps... would probably be hard to find bare transformers for less. Especially useful if your radio doesn't have a transformer in it, like a lot of the old AA5's and similar designs. I'm thinking about doing this to a Hallicrafters WR-600 I'm restoring, along with a couple of other radios without transformers in them.
What a great explanation, thank you.
how to solder an external antenna to it?
Hi. I have added this bluetooth board to a Braun G11 with the PCB board you made in an other video. It works great but I get a interferance on FM inbetween station even with audio to phone disconnected. It is still there with the bluetooth board disconnected but not as loud. Any idea on what could be the problem and how to solve it?
@electronicsoldandnew
3 жыл бұрын
If you use the internal FM antenna, it could pick up the nose from the digital section of the board due to proximity.
@maartenschapendonk6345
3 жыл бұрын
@@electronicsoldandnew Is there a way ti shield it and only leave the BT antenna exposed?
@electronicsoldandnew
3 жыл бұрын
Try moving it as far from the interior antenna as you can. That worked with me.
I like the idea. Instead of the rectifier, a voltage doubler could be used to get a higher voltage difference for the regulator. This would be an option for transformers that don't allow to add an extra winding. Anyway, nice restauration as always. I think you mentioned in the beginning that somebody gave that radio to you. Do you need to give it back or does it stay in your collection?
@electronicsoldandnew
7 жыл бұрын
+rotwang83 : a voltage doubler on the heater supply may make it necessary to use a decoupling capacitor at the output, which would certainly be an option. The main problem is to isolate the supply completely so that the noise is eliminated. I've tried many options here and the noise is never completely eliminated unless the supplies are actually isolated. This means that the only common ground becomes the audio ground connection at the audio input socket. This radio belongs to a friend, so unfortunately is has to be returned. Can't keep them all, I'm afraid.
@rotwang83
7 жыл бұрын
I agree that it's the best solution to have a separate, isolated voltage for the bluetooth device. In some radios, the heater winding is even not grounded on one side, there's a center tap in the middle for ground connection. Btw. modern electronics in tube radios: I have a Loewe-Opta radio with stereo amplifier and the usual mono radio section, BUT it is prepared for a stereo decoder. Here in Germany the tube radios were already like 10-15 years old until stereo on FM became standard, so actually nobody installed a decoder circuit. But it should be possible to install a circuit with one of these one-chip decoders. I'm planning to try this when I find some time. Perhaps I should stop watching youtube videos ;-)
@electronicsoldandnew
7 жыл бұрын
+rotwang83 : i think I saw a video or read an article sometime where they do exactly that, but I can't remember when. Should be interesting.
Can you please explain why the 6.3v becomes 8.2v after the diode? Why you multiply it by 1.4?
@electronicsoldandnew
3 жыл бұрын
Converting AC to DC. You need to do some research, for safety’s sake.
@EJP286CRSKW
Жыл бұрын
Because 6.3VAC is Vrms and when you rectify it you get Vp, which is 1.414 times Vrms.
I'm going to use the 6.3vac circuit and try a 6N137 Optoisolator between the 5vdc output and the bluetooth module. Anyone see an issue with that solution?
@royeubanks639
5 жыл бұрын
Oops, pardon my lack of knowledge on this. I just realized that this will not work.
@electronicsoldandnew
5 жыл бұрын
Roy Eubanks : that opto is only for data isolation. Will not work with supply.
Do you have any problem with RF noise from the Bluetooth module getting coupled into the RF or IF circuits of the radio?
@electronicsoldandnew
5 жыл бұрын
RayDT : no, because of the supply isolator used.
@drtidrow
5 жыл бұрын
@@electronicsoldandnew I was actually thinking about RF radiated out of the board and picked up by the radio's RF circuitry, which could happen even with a battery-powered unit. I suppose the BT module is running at too high a frequency for the radio to respond to, so it may not be an issue.
@electronicsoldandnew
5 жыл бұрын
RayDT : oh, I see what you mean. No, I get no issues.
Very interesting,good stuff .Has given me a few ideas . Cheers
@electronicsoldandnew
4 жыл бұрын
Glad to help
Fantastic. Love from Canada
@electronicsoldandnew
2 жыл бұрын
👍
@electronicsoldandnew
2 жыл бұрын
👍
Brilliant . Thank you
@electronicsoldandnew
Жыл бұрын
👍
@electronicsoldandnew
Жыл бұрын
👍
Nice video. I used a seperate 230V to 5V board and connected it to the main cables, so when I turn on the radio, it automatically tirns on the bluetooth board. No buzzzzz.
@electronicsoldandnew
5 жыл бұрын
Anton Lambooij : yes, those converters are now readily available and work great.
Nice project but you can buy a cable that makes the old Phono or Tape input conector to a normal 3.5mm stereo jack. So you could just buy that 4 dollar cable and plug it into a phone or a bluetooth reciver.
@electronicsoldandnew
3 жыл бұрын
Those cable normally just short the two channels together, which is best avoided.
@NinoJoel
3 жыл бұрын
@@electronicsoldandnew Interesting to know. I never bothered to check that since it works like a charm since 2 years with a logitech Bluetooth receiver. I'll look into it.
@electronicsoldandnew
3 жыл бұрын
👍
Very cool solution. 👍
@muddysledge
4 жыл бұрын
Genius. And explained wonderfully.
@electronicsoldandnew
4 жыл бұрын
Thank you.
The another easy way to power up this type of bluetooth module is using a 5volt/1Amp charger adapter for cell phone... ❤❤❤❤❤
@electronicsoldandnew
23 күн бұрын
That also works
Very cool idea to get a few milliamps of power for a parasite circuit.
@electronicsoldandnew
4 жыл бұрын
Yes, the transformer hardly notices it. Parasitic is the right word :)
Where does the 1. 414 comes from?
@electronicsoldandnew
28 күн бұрын
AC to peak calculation requires multiplying by this number (square root of 2).
Brilliant work!
@electronicsoldandnew
3 жыл бұрын
thanks
In the last solution you can use a real FBR (full bridge rectifier) :-) Is the regulator a low-drop-Version? And my experience with this regulators: I had to put on shortest way two 100nF ceramik capacitors to the in- and output pin to ground. These little beasts sometime dance alone with 20Khz and start cooking. And its nice to see, that you also know this old trick with the addon-secondary on the power transformer. In the meantime i'm really thinking about going back to the roots and restart electronics diy. Why for the hell have i found this channell?
@electronicsoldandnew
5 жыл бұрын
Alfred Neumann : i always check to ensure that I have no oscillations on the regulators. So far I’ve had none. As for getting back into electronics, be careful. It’s addictive!
@alfredneumann4692
5 жыл бұрын
Yes, i know, what i have made and built in the 80s and 90s. But the rails of live are sometimes guiding in other directions.
Usually regulators work about 6 volts above the supply. I am suprised that you went with 9V and not 12V as the input voltage to the 7805.
@electronicsoldandnew
4 жыл бұрын
The 7805 is spec’d at requiring 7.5V for proper regulation, so it needs 2.5V above, not 6V. It works perfectly.
I put together a similar board for a zenith console and powered it off the light circuit and it worked great (no noise). So I had a circuit made up. Sadly on the next one I did, the BT had all kinds of noise. Very clever about the transformer. I haven't gotten around to yet but I want ask some of my EE friends here at work if there is some affordable filtering that could be added to the circuit. Nothing I tried worked. Here's the video for the one that worked: kzread.info/dash/bejne/oJ6qxKiSkZfSo6Q.html
It's actually interesting that the 6.3V heater/filament supply is grounded. Normally this is floating so you won't have this issue.
@electronicsoldandnew
3 жыл бұрын
Not really. Most, if not all, of the german sets I’ve done have the heater grounded to chassis.
@EJP286CRSKW
Жыл бұрын
Normally it is either centre-tapped to ground or grounded at one end. You can't have floating heater supplies near cathodes.
This is brilliant
@electronicsoldandnew
2 жыл бұрын
👍
Nice 👍
Pretty in depth method of achieving the goal, however you could purchase a 5 volt supply from banggood.com for less than 5.00. It runs on 120 to 240 volts and is regulated. Pop it in and you are done.
@electronicsoldandnew
5 жыл бұрын
Mark Miner : you could, but ... Those are switched mode power supplies and tend to introduce switching noise into the receiver, so not an option for me.
@williamday7132
4 жыл бұрын
BEWARE!!! banggood.com has a history of never shipping your order and NO REFUNDS under any condition
@electronicsoldandnew
4 жыл бұрын
I don’t know where that history comes from. I’ve made countless purchases from them. When something arrived damaged, they promptly gave me a credit. When one order didn’t arrive, they shipped another out immediately. All the others arrived normally.
How do you tap in the wire for your windings
@electronicsoldandnew
5 жыл бұрын
Michael Byfield : not sure I understand the question. Should be clear from the video.
I think I’d rather have an USB type power supply than fiddle around with the valve heater circuit.
Why is this module delivered with the 470uF capacitor?
@electronicsoldandnew
4 жыл бұрын
Not sure. Probably for filtering supply.
@jonka1
4 жыл бұрын
Why do you need to know?
@Douwesiegersma
4 жыл бұрын
@@jonka1 Just curious. I cannot find a use for it in any documentation. Seems logical I wanted to know what it is for.
Nice!
@electronicsoldandnew
2 жыл бұрын
😊
An audio isolator might also do the trick right?
@electronicsoldandnew
6 жыл бұрын
Timon : possibly. Depends how you mean.
@timonarthur
6 жыл бұрын
M Caldeira I have a similar problem but I'll try to fix it by connecting an audio transformer between the Bluetooth modul and the amplifier. Hopefully it doesn't effect the sound quality. I guess I'll find out 😀
Will be performing this mod on my Othello 58 3D model.
@electronicsoldandnew
4 жыл бұрын
Nick Terence : you’re going to love the result.
@user-ht6qt6zv1c
4 жыл бұрын
@@electronicsoldandnew My bluetooth module is 12v. Should I be using a 47uF 16V cap across + & - feeding the module ? The isolator will be 12dc - 12dc. Luckily the Othelo has 12vdc available.
@electronicsoldandnew
4 жыл бұрын
Nick Terence : for a 12V supply, I’d use a 25v capacitor. 16v is within the limit, but too close.
@user-ht6qt6zv1c
4 жыл бұрын
@@electronicsoldandnew Much Thanks ! God Bless..
Brilliant !!
@electronicsoldandnew
4 жыл бұрын
thanks
what capacitor should be good i would not want to go overkill
@electronicsoldandnew
3 жыл бұрын
No need. Just use medium quality caps.
@Rainbow__cookie
3 жыл бұрын
@@electronicsoldandnew what uf do you think I should use
@electronicsoldandnew
3 жыл бұрын
anything above 1uF should do the trick
@Rainbow__cookie
3 жыл бұрын
also my radio have 6.3 seperated from ground its just 2 wires connceted to the fillament so i wont get a ground loop i hope
why not bridge rectifier- rectification ?
@electronicsoldandnew
4 жыл бұрын
I wanted a common ground on this winding (to chassis), so a half-wave rectifier was chosen.
@AVISIKTA1000
4 жыл бұрын
@@electronicsoldandnew is was necessary !!!. Iam watching yr ch in lockdown in india. thanks a lot.