If British Rail had made a breakout board, it would have been this one, with "the wrong sort of resistors on the line"! In the wrong position at least. Great work from you and Dave. Note to self, check bought in break out boards. Thanks for another educating and fun video. 73 G0ACE
When analyzing the operation of the board I noticed that something was wrong, I went to check the values of the resistors on pins 7 and 8 of the integrated, and there was the error. I went online to look for information about this problem, if anyone had already detected it, and I found this video confirming the assembly problem. Thanks! 73 PU3MSR!
Great when things are put together wrong at the factory - so glad that this has been picked up and hopefully word will spread. Looking at the other comments many people have already consigned their boards to the junk box! Nice work as always Nick!
Commented on your other video instead of here, sorry for the repeat. Great video! I bought two of those units and when tested they just performed like limiter amplifiers. I was short on patience and just thought they were Chineasium fakes and didn`t investigate further. I will pull them out of the piling system and have another go. Just a point about noise, (in any pre amp circuit using electrets), I filter the phantom power to the mic - +v supply through 1k res, 1000uf to gnd, then 4.7k to the mic. This helps a lot getting rid of noise on the supply getting into the mic line. Many thanks, Chris & the lads of 1977khz
Interesting video. Note the specification for minimum load on the output is 5k ohm (output Z is 145 ohms) according to datasheet. So if driving a diode double balanced modulator directly, then a unity gain opamp or emitter follower is probably recommended.
Thanks. Yes I measured about 100-120Ω output Z at 1kHz. You could do some matching (it's about 2:1 SWR) but to be honest as it is going through the W7EL audio diplexer the mixer port will still see 50Ω irrespective of the output impedance of the mic amp. It is certainly something to consider though. Thanks again. 73, Nick
I've never noticed the resistors in the wrong place on all of the boards I've used because I've always fitted pots and used the super-secret advanced technique of "twiddling it until it sounds right". But sure enough, the unused 3 modules I have in my microphone circuits bin have the resistors in the wrong place.
Good presentation of the SSM2167. Great IC from AD. However, I have seen some 10khz burst on the output (approx. 500ms) after audio silence on the input. I looks like the IC is very sensitive for noise / rippel on the Vcc input pin.
Those convenient holes in the board are perfectly spaced and sized for vertical multiturn preset pots, think I've had the discussion on the G-QRP mailing list some time ago.
Nick, have you tried any ferrite beads on your test equipment? Oscilloscope, power supplies, or function generator. It fixed a lot of noise by doing this. the power supply, use them on the AC input and the DC output the switching power supplies are very noisy even when not connected to the project. then if you want even better use a battery to power the project while testing. I picked up two boxes of the clamp-on type from Amazon. by the way I didn't stop with test equipment I put it on computer radios everything in my room. Hope this helps you as it did me!
Just a note I have about three of them on the power cord for my power supply and Ossiloscope. when I got to three it didn't show any more improvement with more. that's why I had to order two boxes and they come in many sizes in the kit.@@M0NTVHomebrewing
Hi Nick I wired one in to the mic of a ft-817, sounds fine on my Marconi 2955 test set,, seeing your video now, I had to have a look, and yes I had to change over the R1 and R2, Thanks for the great information, Dave 2E0DMB
Check the Analog devices data sheet It does not have a 470R in series with the supply but it does have a 10uF across the supply to ground That might just about provide enough current for the peaks. I f you want to add a bit of current protection just drop the 470R down tom 100R and add the 10uF Andy
I just have ordered a couple of these boards some days ago, will see if they also come with the wrong resistors. In any case, have you think about any way of modifying the resistor from the arduino? this will allow you to set the compression level from software depending on if you are trying some rare dx or just local ragchew. I've been thinking about it but haven't ended with any solution that i like yet.
Hi! No I've never considered doing this. I fear you would need a fairly complex switching bank of relays that would put in different values of resistance in each slot. For myself I'm happy to set it at a fixed level and then leave it alone but if you have an idea for a project then go for it! 73, Nick
Good day. I have a few of those little red board. I wanted to make a compressor for a dynamic mic. Is this possible or are these board limited to cb radios etc. Thanks a lot
Hi there, the boards are simply audio amplifiers with a compression feature. They can be used for any small audio signal. If you wanted to use it with a dynamic mic you'd have to adapt the design though. I only use condenser mics which require a DC bias hence the 4.7K resistor strapped across the VCC+ to the IN+. It is also why I had to include the 1uF electrolytic cap between the tuning tone output and the switch: I didn't want the DC bias getting back into the Arduino. Hope this helps. 73, Nick
Hi Kaden! As the output from a passive guitar pickup is so very small you might even need a pre-amp before this module. You'd have to try it and hear for yourself. Taking the DC supply down from 9V to 5V is a simple as using a 7805 voltage regulator with a couple of caps or maybe even an LM1117 based design. Just google them. Thanks for watching. Best wishes, Nick
Hi Kaden, I'm afraid I don't have any experience of those so can't really answer you confidently. You might be better off asking in a dedicated guitar electronics forum. I'm sure there are people who have done this and could probably help. Best wishes, Nick
Nick, please notice that your chart at 19:05 is misleading because you have fallen foul of an Excel quirk. Notice that your "X" axis (contrary to your "Y" axis) is not linearly spaced! This is because you have asked for a "line" graph. This merely places the "X" values specified at equal spacing, whereas they were not recorded that way! To do a proper comparison, you need to select "XY Scatter" plot which will give linear scales in both X and Y. 73 de Phil M1GWZ
Yes, I'm certain. Not everything green is an inductor. It is a 0.25W 1% Tolerance Metal Film Resistor (from Switch Electronics). It was the resistance that was the problem. 73, Nick
If British Rail had made a breakout board, it would have been this one, with "the wrong sort of resistors on the line"! In the wrong position at least. Great work from you and Dave. Note to self, check bought in break out boards. Thanks for another educating and fun video. 73 G0ACE
Cheers Ace! Hope you're doing OK. 73, Nick
When analyzing the operation of the board I noticed that something was wrong, I went to check the values of the resistors on pins 7 and 8 of the integrated, and there was the error. I went online to look for information about this problem, if anyone had already detected it, and I found this video confirming the assembly problem. Thanks! 73 PU3MSR!
Thanks Marcelo. It was another ham who alerted me to the issue. That’s the wonder of the internet. Glad you can resolve your issues now. 73, Nick
Great when things are put together wrong at the factory - so glad that this has been picked up and hopefully word will spread. Looking at the other comments many people have already consigned their boards to the junk box! Nice work as always Nick!
Thanks mate!
Commented on your other video instead of here, sorry for the repeat. Great video! I bought two of those units and when tested they just performed like limiter amplifiers. I was short on patience and just thought they were Chineasium fakes and didn`t investigate further. I will pull them out of the piling system and have another go. Just a point about noise, (in any pre amp circuit using electrets), I filter the phantom power to the mic - +v supply through 1k res, 1000uf to gnd, then 4.7k to the mic. This helps a lot getting rid of noise on the supply getting into the mic line. Many thanks, Chris & the lads of 1977khz
Thanks Chris! That's good advice about the filtering. 73, Nick
Interesting video. Note the specification for minimum load on the output is 5k ohm (output Z is 145 ohms) according to datasheet. So if driving a diode double balanced modulator directly, then a unity gain opamp or emitter follower is probably recommended.
Thanks. Yes I measured about 100-120Ω output Z at 1kHz. You could do some matching (it's about 2:1 SWR) but to be honest as it is going through the W7EL audio diplexer the mixer port will still see 50Ω irrespective of the output impedance of the mic amp. It is certainly something to consider though. Thanks again. 73, Nick
Good point, I use an emitter follower to drive ring modulators. Otherwise mine ended up sounding really tinny due to the mismatch.
I've never noticed the resistors in the wrong place on all of the boards I've used because I've always fitted pots and used the super-secret advanced technique of "twiddling it until it sounds right".
But sure enough, the unused 3 modules I have in my microphone circuits bin have the resistors in the wrong place.
I know! All mine were wrong too. If Dave hadn't reached out to me I'd still be none the wiser! 73, Nick
Good presentation of the SSM2167. Great IC from AD. However, I have seen some 10khz burst on the output (approx. 500ms) after audio silence on the input. I looks like the IC is very sensitive for noise / rippel on the Vcc input pin.
Thanks. I've not encountered any issues with the chip myself but your mileage may vary as they say. Thanks again. 73, Nick
Those convenient holes in the board are perfectly spaced and sized for vertical multiturn preset pots, think I've had the discussion on the G-QRP mailing list some time ago.
Hi there! Don't think I've ever come across those. Sound useful though. 73, Nick
Thanks Nick, a very useful video, I'll replace the resistors on mine now too.
Thanks Colin. It's certainly worth looking at. 73, Nick
Nick, have you tried any ferrite beads on your test equipment? Oscilloscope, power supplies, or function generator. It fixed a lot of noise by doing this. the power supply, use them on the AC input and the DC output the switching power supplies are very noisy even when not connected to the project. then if you want even better use a battery to power the project while testing. I picked up two boxes of the clamp-on type from Amazon. by the way I didn't stop with test equipment I put it on computer radios everything in my room.
Hope this helps you as it did me!
Thanks Curt, I've got a few of them on various leads in the shack but I could probably use some more! Thanks for the reminder. 73, Nick
Just a note I have about three of them on the power cord for my power supply and Ossiloscope. when I got to three it didn't show any more improvement with more. that's why I had to order two boxes and they come in many sizes in the kit.@@M0NTVHomebrewing
Hi Nick
I wired one in to the mic of a ft-817, sounds fine on my Marconi 2955 test set,, seeing your video now, I had to have a look, and yes I had to change over the R1 and R2,
Thanks for the great information,
Dave 2E0DMB
Cheers Dave! 73, Nick
Check the Analog devices data sheet It does not have a 470R in series with the supply but it does have a 10uF across the supply to ground That might just about provide enough current for the peaks.
I f you want to add a bit of current protection just drop the 470R down tom 100R and add the 10uF
Andy
Hi Andy, that sounds like a perfectly sensible option. Thanks very much. 73, Nick
I just have ordered a couple of these boards some days ago, will see if they also come with the wrong resistors. In any case, have you think about any way of modifying the resistor from the arduino? this will allow you to set the compression level from software depending on if you are trying some rare dx or just local ragchew. I've been thinking about it but haven't ended with any solution that i like yet.
Hi! No I've never considered doing this. I fear you would need a fairly complex switching bank of relays that would put in different values of resistance in each slot. For myself I'm happy to set it at a fixed level and then leave it alone but if you have an idea for a project then go for it! 73, Nick
Good day. I have a few of those little red board.
I wanted to make a compressor for a dynamic mic. Is this possible or are these board limited to cb radios etc. Thanks a lot
Hi there, the boards are simply audio amplifiers with a compression feature. They can be used for any small audio signal. If you wanted to use it with a dynamic mic you'd have to adapt the design though. I only use condenser mics which require a DC bias hence the 4.7K resistor strapped across the VCC+ to the IN+. It is also why I had to include the 1uF electrolytic cap between the tuning tone output and the switch: I didn't want the DC bias getting back into the Arduino. Hope this helps. 73, Nick
Thanks a lot
Can i make this into a guitar pedal that is a booster/compressor if so how can i put 9 volts into it or will i need a buck converter
Hi Kaden! As the output from a passive guitar pickup is so very small you might even need a pre-amp before this module. You'd have to try it and hear for yourself. Taking the DC supply down from 9V to 5V is a simple as using a 7805 voltage regulator with a couple of caps or maybe even an LM1117 based design. Just google them. Thanks for watching. Best wishes, Nick
@@M0NTVHomebrewing could i use one of those cheap 6j1 tube preamps as the preamplifier as you can use those with a guitar and it sounds pretty nice
Hi Kaden, I'm afraid I don't have any experience of those so can't really answer you confidently. You might be better off asking in a dedicated guitar electronics forum. I'm sure there are people who have done this and could probably help. Best wishes, Nick
@@M0NTVHomebrewing thanks for the help my guy i do appreciate it im off to guitar forums
All the best :)
Nick, please notice that your chart at 19:05 is misleading because you have fallen foul of an Excel quirk. Notice that your "X" axis (contrary to your "Y" axis) is not linearly spaced! This is because you have asked for a "line" graph. This merely places the "X" values specified at equal spacing, whereas they were not recorded that way! To do a proper comparison, you need to select "XY Scatter" plot which will give linear scales in both X and Y. 73 de Phil M1GWZ
Cheers Phil! Thanks for the advice. 73, Nick
I've redone the chart Phil and put a link to it in the video description. Thanks for spotting this and letting me know. 73, Nick
Μy personal opinion is better to desolder the 103 trimmer and add it front panel as Pot...tks for your design Dinos 73
That's certainly an option if you want to be able to change the output often. 73, Nick
what about pa0fri's design for a speech compressor
I don't think I've come across that one David. 73, Nick
Nick, that 470 ohm resistor looks like it has a green body. Probably a stupid question, but are you sure it's not actually an inductor?
Yes, I'm certain. Not everything green is an inductor. It is a 0.25W 1% Tolerance Metal Film Resistor (from Switch Electronics). It was the resistance that was the problem. 73, Nick
@@M0NTVHomebrewing Ah. It was, as I suspected, a stupid question. Sorry.
No worries at all. My favourite gaff used to be soldering in my transistors the wrong way around! 73, Nick