Preamp Control - Volume, input, mute, remote

last night I took the last step and measured the standby and active current draw from the batteries. Between the first design and the second there is no difference. I was hoping the changing from a 555 to a 7555 timer and upping the resistor and lowering the cap values, and changing from a bipolar to a MOSFET driver would lower the standby current losses. The drain in standby, the encoder asleep and the 7555 not active and current leakage through the MOSFET, added up to 0.3 ma. With a button pressed it uses 30 ma, most to drive the Infrared LED. At that rate the 3 AAA alkali batteries would be drained in 4.5 month but drop below useful voltage after 3 months, which is why I put a on/off slide switch on the remote.
I was hoping for better battery life but no time now to investigate more.
 
Tonight I tested a mod to the remote. I cut three traces on the new PCB and wired the incoming power to the buttons only then I wired the rest of the board power to the output of the four diodes D1-4. Pressing a button powers everything up and transmits the code. No standby power is used when a button is not pressed. What is interesting is before the remote drew 30 ma when a button was pressed, now it only draws 13 ma. Seems the diodes may be limiting current somehow, though they are rated for 400 ma. With less power to the Infrared LED it limits the transmission distance, it still worked up to 15 feet, 5 meters, so should not be a problem. I will post a revised remote schematic, a new gerber and a cut and jumper drawing for current Rev 2 remotes.
 
Attached is the updated remote control schematic and the new gerbers for it. I am still experimenting with why the transmit current is only 13 ma vs 30 ma for the unmodified board, until I find out why I would keep the R2 remote unmodified and use the on/off switch. The R2b works fine by the transmit distance is limited right now. The new board with thicker power traces might be the cure but I will test.
 

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Finally receive my parts order, FedEx delayed due to bad weather. Built up one of the new remote transmitter boards last night but no time left to test. Hopefully tonight or tomorrow I can test the current draw and transmit distance. If not as much as I would like there is one cut/jumper mod to try which might boost power and range if needed. if not there are still other things to try.
 
I tested the new remote PCB tonight and it performs like the first board which I modded. Pushing a remote button drew 13ma and the transmitter only worked out to about 12 feet, 4 Meters. Changing one connection had the current up to 19ma and transmitting over 15 feet, 5 meters, as far as I could back up in the room. So I am happy with the design, no power usage until a button is pushed and good distance on the remote. I will post the new schematic and gerbers soon.
 
Hi Samoloko,
The main board hasn't changed and if you don't need a remote then the Display board also from PBN Audio are good. I still have the five original boards, Main, display and remote, built up and tested for sale, see post #1. And I think Roy may have some to sell as well. Will be turning new display and remote boards which are needed for the new encoder/decoder chip so they will eventually be available from PBNaudio.com as well, probably not for a few months, and more expensive than a large buy but good for one offs.
 
Samoloko,

I have about 20 sets of working boards which I will be making available now that I have had a chance to test that they operate correctly by making three sets. I will be selling them at cost, which is $17 per set plus shipping. ($7.00 in the US).

The remote board, however, it not from the newest Gerber, RemoteR2c. I have the earlier version which uses the surface mount encoder/decoder chip. The difference between the newest version and the one I had made is the life expectancy of the remote control battery and should be used with an on/off switch to conserve battery life.

I personally will be using mine with a universal remote control and will have a few built remotes that I can lend purchasers to "train" their universal remotes after they have their main and display boards working properly.

From my experience, the build is fairly straight forward with the exception of the ribbon cable between the main and display board and the surface mount chip.

I would purchase a few extra connectors to make sure that you get a good cable connection. If your are not very experienced with surface mount work, I would also purchase extra surface mount chips and something like Chipquick for easy removal if you run into problems.

For those of you that want board sets just start a list on this thread.

Regards,

Roy
 
thank you
please do not think that I want to push you
I preffer to wait but everything to be checked and OK

would you please once again explain what does pcb sets Include
1 pcs main board - can we use for balanced stereo
1 pcs display with receiver
1 pcs remote
Is there hard to find parts which you can offer
 
samoloko,

The boards you listed are correct. I don't think that their are any unobtainable parts remaining with the new encoder/decoder surface mount chip for the display board and the remote board.

As I live in the US, I purchase primarily from Mouser and then from Digi-Key, if it is not available from Mouser. Everything required was available from one of the two. From what I have seen, you have equivalent distribution in Europe.

One issue, in my most recent purchase, the RN65 series resisters used in the volume control section were out of stock with a long delay for restock so I substituted Holco. Those resistors are a generally subjective decision anyway so use what you like best.

Regards,

Roy