M70 & M90 with hardwired bluetooth module mod.
- Thread starter blu_fuz
- Start date
^ Very cool to see that module in your M70. How is the signal range?
The module you have is just a little bit different, but pretty close. I can see your soldered the brown/yellow for the power in the same spot I used on the MMS board. Your orange and white audio signal wires, do you have any more info as to where you tapped the L/R line-out levels? I can see them soldered to the back of the main PCB.....
Nice job.
The module you have is just a little bit different, but pretty close. I can see your soldered the brown/yellow for the power in the same spot I used on the MMS board. Your orange and white audio signal wires, do you have any more info as to where you tapped the L/R line-out levels? I can see them soldered to the back of the main PCB.....
Nice job.
Michiel
Member (SA)
I think I've got the older BT 2.1 version of the board. It was slightly cheaper 
Power also comes from the MMS control board, like you did. The signal is inserted just before S502-1 on the Phono line. So the line-in is still functional as a back-up.
The signal range is sufficient, but not really impressive. About 10 meters I guess, just like normal modern BT speakers.
Power also comes from the MMS control board, like you did. The signal is inserted just before S502-1 on the Phono line. So the line-in is still functional as a back-up.The signal range is sufficient, but not really impressive. About 10 meters I guess, just like normal modern BT speakers.
Michiel
Member (SA)
You could consider mounting a Bluetooth antenna out of an old laptop, somewhere in the top of the box. From experience I know this may make a big difference! The standard antenna on the board is sooo tiny.blu_fuz said:^ this is what I was afraid of, only about 30 feet of signal range is not that impressive.
Thanks for letting me know.
Michiel
Member (SA)
Having a M90 on Bluetooth must be great! Gonna watch that! I haven't done it yet.
My project is putting an FM transmitter into the M70, connected to the line-out. So I can relay its output to other boomboxes via FM. Let's call it party mode haha. Only problem is that the transmitter I'm using at the moment has an output of 7 watts... Enough power to blow over the whole city lol. Glad it's a portable, because I'm sure gonna get big troubles if they find me... But I will get a transmitter with much less power, to avoid problems
My project is putting an FM transmitter into the M70, connected to the line-out. So I can relay its output to other boomboxes via FM. Let's call it party mode haha. Only problem is that the transmitter I'm using at the moment has an output of 7 watts... Enough power to blow over the whole city lol. Glad it's a portable, because I'm sure gonna get big troubles if they find me...
But I will get a transmitter with much less power, to avoid problems
I hope it is great. Should be no problem. The location of the BT module, it would be easy to solder a wire whip to the antenna and hot glue it around the inside perimeter of the rear case.
I think I got spoiled with that first BT module with that kick ass range. 140' is so great, and would be a nice feature to have on a great blaster. I hope to find more of the first BT module for this reason if I can't boost the other module antenna range somehow.
I think I got spoiled with that first BT module with that kick ass range. 140' is so great, and would be a nice feature to have on a great blaster. I hope to find more of the first BT module for this reason if I can't boost the other module antenna range somehow.
Running auxiliary 12v to the module right now for testing.
RCA solder pads are working great. Nice loud and clear signal.
Great position of the module on the rear case. Plenty of space and room to breath and stay cool.
Nifty green POWER led on the board
.
Again, only problem is the range .
Only about 20' away from the boombox with my body between the BT module and my ipod the signal starts to cut out. I'm going to add onto the BT antenna, maybe tap that into the regular radio antennas for hopefully a longer signal range and strength.
RCA solder pads are working great. Nice loud and clear signal.
Great position of the module on the rear case. Plenty of space and room to breath and stay cool.
Nifty green POWER led on the board
.Again, only problem is the range
.Only about 20' away from the boombox with my body between the BT module and my ipod the signal starts to cut out. I'm going to add onto the BT antenna, maybe tap that into the regular radio antennas for hopefully a longer signal range and strength.
I am giving it a full day of running right BT #3 now, going on the 5th hour and it is working great sitting at my desk.
Here is my final review of the 3 BT modules:
CPS brand BT module #1:
- Best range of 140ft un-ubstructed, 50ft ubstructed range
- price was decent at $34 shipped but was hiked up to $50 each and has been sold out since, can't get them anywhere
- inline fuse was a nice add on
- looks to be the most cheaply made
- RCA wire gauge is thicker than the Millenia brand
- little bit of a high pitch feedback though the speakers when module powered on with no BT music playing. High pitch noise dropped after the ipod was actually connected via BT. Keeping the ipod volume high during music playback helped clear this up high pitch noise, not just cover the noise. You notice it most during the pause in audio between songs.
MIL-BTREC Millenia brand BT module #2:
- average range of 60ft un-ubstructed and 20-30ft ubstructed
- price was about the same at $37 shipped
- hard case nicer than the CPS unit heat shrink case
- thinner gauge RCA wires than CPS brand
- again even more of a high pitch feedback through the speakers when module powered on with no BT music playing. High pitch noise didn't drop much at all after the ipod was actually connected via BT. Keeping the ipod volume high during music playback helped cover up the high pitch noise. You notice it most during the pause in audio between songs.
Sure Electronics brand BT module #3:
- un-ubstructed range not tested, but ubstructed range was only about 20-30ft
- best price at only $25 shipped
- looks to be built the best. Solder points, components, layout, mounting holes, all much nicer than BT #1 and #2.
- RCA jacks (not wires), 3.5mm jack, 12v DC jack, 12v wire terminals, and green power LED
- No high pitch noise from this module like the other ones. There is a distinctive hum in the speakers when the BT module is powered on but you are not connected via BT. Again, the hum is most noticeable during the pause between songs. I will be adding an auxiliary toggle switch to kill power to the BT module when not in use to get rid of the hum while I use an actual RCA cord plugged into the back of the radio. I did power this module with a 12v source outside of the radio and the hum was completely gone. Maybe there is a way to filter/shield the 12v power that is tapped from inside the radio to clear this up.
It's a tough choice to decide which is better, but I know the Millenia brand BT #2 I will probably stay away from. It's only nice feature is the hard plastic case, but the high pitch noise is annoying if you are listening for it. Ubstructed range was still only about 20-30ft.
I would snag a CPS brand BT #1 simply for the range, 140ft is amazing. Are the all like this? Who knows. But I can't get any more anywhere, all sold out.
So that leaves you with BT #3 Sure Electronics brand. Great price (get discounts when you buy multiples), great build quality, most connection options, nice power LED, no high pitch feedback but does have a audible hum, and nice mounting holes. If there was a way to add antenna to increase signal range, this one would be the BOSS.
I think it is a TIE between the CPS brand #1 and the Sure Electronics brand #3 depending on what YOU need. If you need range and more compact design, then go CPS if you can find it. If you need build quality and connection options, then go with Sure Electronics brand which is over 2x the footprint of the other modules.
Just a little update:
After testing the modules some more, all of the high pitch feedback and hum is caused from the power source in the radio. I have hooked up an external 12v power and all of the noise is gone. I'm not sure how to filter that noise out of the audio, if someone has an idea please let me know!
Here is my final review of the 3 BT modules:
CPS brand BT module #1:
- Best range of 140ft un-ubstructed, 50ft ubstructed range
- price was decent at $34 shipped but was hiked up to $50 each and has been sold out since, can't get them anywhere
- inline fuse was a nice add on
- looks to be the most cheaply made
- RCA wire gauge is thicker than the Millenia brand
- little bit of a high pitch feedback though the speakers when module powered on with no BT music playing. High pitch noise dropped after the ipod was actually connected via BT. Keeping the ipod volume high during music playback helped clear this up high pitch noise, not just cover the noise. You notice it most during the pause in audio between songs.
MIL-BTREC Millenia brand BT module #2:
- average range of 60ft un-ubstructed and 20-30ft ubstructed
- price was about the same at $37 shipped
- hard case nicer than the CPS unit heat shrink case
- thinner gauge RCA wires than CPS brand
- again even more of a high pitch feedback through the speakers when module powered on with no BT music playing. High pitch noise didn't drop much at all after the ipod was actually connected via BT. Keeping the ipod volume high during music playback helped cover up the high pitch noise. You notice it most during the pause in audio between songs.
Sure Electronics brand BT module #3:
- un-ubstructed range not tested, but ubstructed range was only about 20-30ft
- best price at only $25 shipped
- looks to be built the best. Solder points, components, layout, mounting holes, all much nicer than BT #1 and #2.
- RCA jacks (not wires), 3.5mm jack, 12v DC jack, 12v wire terminals, and green power LED
- No high pitch noise from this module like the other ones. There is a distinctive hum in the speakers when the BT module is powered on but you are not connected via BT. Again, the hum is most noticeable during the pause between songs. I will be adding an auxiliary toggle switch to kill power to the BT module when not in use to get rid of the hum while I use an actual RCA cord plugged into the back of the radio. I did power this module with a 12v source outside of the radio and the hum was completely gone. Maybe there is a way to filter/shield the 12v power that is tapped from inside the radio to clear this up.
It's a tough choice to decide which is better, but I know the Millenia brand BT #2 I will probably stay away from. It's only nice feature is the hard plastic case, but the high pitch noise is annoying if you are listening for it. Ubstructed range was still only about 20-30ft.
I would snag a CPS brand BT #1 simply for the range, 140ft is amazing. Are the all like this? Who knows. But I can't get any more anywhere, all sold out.
So that leaves you with BT #3 Sure Electronics brand. Great price (get discounts when you buy multiples), great build quality, most connection options, nice power LED, no high pitch feedback but does have a audible hum, and nice mounting holes. If there was a way to add antenna to increase signal range, this one would be the BOSS.
I think it is a TIE between the CPS brand #1 and the Sure Electronics brand #3 depending on what YOU need. If you need range and more compact design, then go CPS if you can find it. If you need build quality and connection options, then go with Sure Electronics brand which is over 2x the footprint of the other modules.
Just a little update:
After testing the modules some more, all of the high pitch feedback and hum is caused from the power source in the radio. I have hooked up an external 12v power and all of the noise is gone. I'm not sure how to filter that noise out of the audio, if someone has an idea please let me know!
JT Techno
Member (SA)
Great stuff Blu - nice work throughout this testing and great write up - food for thought as I will soon have my recent M70 acquisition in bits anyway for a good clean up and overhaul - may as well fit one of these Sure units at same time 
Re M70, Michiel, you say you took audio source from Phono stage on main board - is this phono level output or line level output before phono stage kicks in? Do you have any more detail for the novice solderer as to how I find the right solder points on the board to tap in to - will I need a PCB schematic or is it easy to tell some other way by markings on the board? Thanks in advance
Re M70, Michiel, you say you took audio source from Phono stage on main board - is this phono level output or line level output before phono stage kicks in? Do you have any more detail for the novice solderer as to how I find the right solder points on the board to tap in to - will I need a PCB schematic or is it easy to tell some other way by markings on the board? Thanks in advance
Michiel
Member (SA)
Nice write up Blu! Here my review of the 2.1 version of the Sure board... Ive got the same AC hum from the Bluetooth module. Its not loud and can only be heard when no music is playing. Its coming from the module, because the other channels (line-in, radio, cassette) are clean. The hum is gone when the box is powered by batteries. Ive got unmodded boxes that have a louder hum.
When I put the box really loud (full power) without music playing, I can hear digital noises. The intensity (not the loudness) of the noise rises when I swipe my ipod for instance. When I connect my laptop I get a different kind of noise. I think its kinda cool, it proofs how good the M70 amp actually is
Range is disappointing, but fits a class 2 bluetooth device I guess...
@ JT; I uploaded a low res picture on purpose. A novice should be really careful just copying the picture, because there are different kind of M70s! Basically you connect the module to the input of the function switch of the channel you want to sacrifice for BT. Its very basic and works on a lot of boxes. If its not clear you should do more homework
You can use the service manual to find the proper points, or just feed the box a signal and start poking with the oscilloscope around the function switch.
When I put the box really loud (full power) without music playing, I can hear digital noises. The intensity (not the loudness) of the noise rises when I swipe my ipod for instance. When I connect my laptop I get a different kind of noise. I think its kinda cool, it proofs how good the M70 amp actually is
Range is disappointing, but fits a class 2 bluetooth device I guess...
@ JT; I uploaded a low res picture on purpose. A novice should be really careful just copying the picture, because there are different kind of M70s! Basically you connect the module to the input of the function switch of the channel you want to sacrifice for BT. Its very basic and works on a lot of boxes. If its not clear you should do more homework
You can use the service manual to find the proper points, or just feed the box a signal and start poking with the oscilloscope around the function switch.
Your board design might be older, but this version of the SURE brand f'king sucks. I was literally 6 feet away from my boombox yesterday. One of my legs was between me and the radio streaming BT, my wife stepped between me and the boombox and it started cutting out. WTF, that is bad.Michiel said:
Something HAS to be done about this horrible range.
Also, you are correct that the module is producing this hum noise but because it is using the ground from the L/R audio to complete the power ciricuit. It isn't too bad honestly and you don't hear it when you are playing audio. The module will still power on and function if you remove the GROUND wire from it
. I believe the entire module is grounding through the L/R audio pad to complete the circuit for powering the module. In fact it must be, or the module shouldn't power on with the ground wire removed from the module.
Just a little update:
After testing the modules some more, all of the high pitch feedback and hum is caused from the power source in the radio. I have hooked up an external 12v power and all of the noise is gone. I'm not sure how to filter that noise out of the audio, if someone has an idea please let me know!
After testing the modules some more, all of the high pitch feedback and hum is caused from the power source in the radio. I have hooked up an external 12v power and all of the noise is gone. I'm not sure how to filter that noise out of the audio, if someone has an idea please let me know!