Seven? For the volume control there is Main or lower board, right channel for balanced or Left and right for single ended, Upper Left channel for balanced, Rotary encoder board, and display board. That's four. And for input selector there is the input/relay board and the rotary control selector. That's two. So six total, if I remember right. 🙂
Here you go.
https://foilresistors.com/foil-resistors/list/product-63140/
chrome-extension://efaidnbmnnnibpcajpcglclefindmkaj/https://foilresistors.com/docs/63140/var.pdf
https://foilresistors.com/foil-resistors/list/product-63140/
chrome-extension://efaidnbmnnnibpcajpcglclefindmkaj/https://foilresistors.com/docs/63140/var.pdf
So my audio business friend decided to move out of Taxafornia and move to Texas where most taxes and costs are much lower. Left me with all the PCBs for the volume control so he can call me and ask for a build when needed.
In the meantime I am racking my brain for any good project to design and build for audio needs.
Any ideas, needs, or requests?
Have a good one.
In the meantime I am racking my brain for any good project to design and build for audio needs.
Any ideas, needs, or requests?
Have a good one.
I had an idea for making a power controller that would switch on and off all my components in sequence. I have three amps, a preamplifier, an active crossover, seperate power supply for vinyl pre-preamp, and then the sources, a DAC and an older FM tuner. The seperate power supply for my turntable stays on all the time. As you can see, switch all these off in the wrong sequence and it is a problem. Would be nice to be able to hit a switch or press a button on the remote and everything switched on in the correct order and off in the correct order. The amps are also fairly large amps so would need very large relays or active swithces.
I think something adjustable with timing between components would be awesome. Maybe 10 total plug-ins. Also, maybe more than one power cord so it could be provided power from more than one circuit. I have 3 20-amp dedicated circuits for my main audio/video area.
I think something adjustable with timing between components would be awesome. Maybe 10 total plug-ins. Also, maybe more than one power cord so it could be provided power from more than one circuit. I have 3 20-amp dedicated circuits for my main audio/video area.
I had thought about a small box that plugs into the wall and the unit to be controlled plugs into it. The box would take a 12v input signal to turn on or remove to turn off. And the Arduino in its own box with 12V lines that runs to each controller box. Then you can have a small set of relays that takes 5v to turn on by the Arduino controlling 12v outputs one button, push and it turns on everything in a sequence you choose, and another push to turn off in reverse order. But probably not a lot of call for on/off automation, I just walk about from component to component. 🙂
Just use a power sequencer from Baytech for instance.
It is IP controllable, so could integrate into an AMX or Crestron system or just telnet from a computer.
It is IP controllable, so could integrate into an AMX or Crestron system or just telnet from a computer.
Too easy. A home brew solution is more fun. Though, I am still old fashion and walk around to the components to power cycle them.
I made one. I'll post pictures when I have acess to my computer. It works well, looks good and is inexpensive.
I found pictures on my phone. The latest version has an earth ground post and a fuse. And shut off delay period is now set using jumpers, not a front panel switch. Attach cheap power strips to control multiple devices.
I have to comment on the mains wiring issues visible in that box. Especially in case anyone were to copy it and endager themselves and those around them. Several red flags...
The big safety error is that the protective earth wires should go to a solid stud on the case directly, not via the circuit board. The first major mains fault and the traces on the PCB carrying the fault current will vaporize, including protective earth - not good, especially as it will then potentially leave the outlets with earth, unbeknownst to anyone. Also its not clear if the metal case is actually earthed at all...
The connectors have faston tabs from what I can see - so why solder? Anyway you should have shrouded all the soldering to the mains sockets/plugs so they are finger-proof, very much in your own interest should you have to work on this unit in the future.
The big safety error is that the protective earth wires should go to a solid stud on the case directly, not via the circuit board. The first major mains fault and the traces on the PCB carrying the fault current will vaporize, including protective earth - not good, especially as it will then potentially leave the outlets with earth, unbeknownst to anyone. Also its not clear if the metal case is actually earthed at all...
The connectors have faston tabs from what I can see - so why solder? Anyway you should have shrouded all the soldering to the mains sockets/plugs so they are finger-proof, very much in your own interest should you have to work on this unit in the future.
Thanks for the input on that, @Mark Tillotson.
First off, I did not post this because I thought it would be copied as is, endangering people and those around them!
It's just pictures, not an invitation to self harm. No gerbers or schematics here.
Anyway, I posted the pictures only to show that such a device could be easily done. It was on topic.
I can assure you that this box, as built, with the lid on, endangers no one, will endanger no one, and works quite well.
But, FWIW, the latest rev has a few improvements that will make you happy. The boards arrived last week. I'll build it up when I get a minute.
Cheers!
First off, I did not post this because I thought it would be copied as is, endangering people and those around them!
It's just pictures, not an invitation to self harm. No gerbers or schematics here.
Anyway, I posted the pictures only to show that such a device could be easily done. It was on topic.
I can assure you that this box, as built, with the lid on, endangers no one, will endanger no one, and works quite well.
But, FWIW, the latest rev has a few improvements that will make you happy. The boards arrived last week. I'll build it up when I get a minute.
Cheers!
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Having worked with some of the regulatory agencies I absolutely agree, star ground to the chassis and power inlet ground.
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My observation: floor space in my projects is precious and vertical space frequently goes unused.
My suggestion: redesign your preamp control system into smaller, stackable boards. Leave open the possibility that a user might need two stacks (such as in order to fit the boards in a 1U chassis (40 mm vertical in a Modushop chassis). A board (or two) for attenuation, a board (or two) for input and a control board, perhaps?
Regards.
Last post because I don't want to hijack this thread, The next built version will have improvements, as said before, including a central chassis earth ground post. At this point I wish I had not posted the original picture! It really got a few of you going, but with good reason. I understand Cheers!
Hi @johnhenryharris,
your design is what I was looking for. If you can, I agree with the following:
Other features requests:
is it possible to center the balance once for all in software, in order to compensate for gain imbalance? For example tube preamplifiers with no feedback. Can this be done for each input?
Is there any room to implemnent a mono function? I don't listen stereo records in monoaural. I use the mono capability only temporarly, at the beginning of a disc, to center the acoustic scene through balance. Then I set stereo. This feature is very useful to correct imbalancies due to the listening room. It is simpler to correct in mono.
However, thanks for your work, very appreciated.
Regards,
Valerio
your design is what I was looking for. If you can, I agree with the following:
In particular, I'd like to separate the "digital portion", i.e. Arduino mega, from the analogic one, to be free in placing the analogic portion (i.e. attenuation board). To be extremist, look at the VTL TL7.5, where the encoder, and subsequent logic, is located into the PSU frame. Into another frame there is the proper preamplifier with the attenuation boards. This schema can be implmented also into one chassis, keeping, for example, PSU and digital boards near the front, and the volume plus preamplifier boards near the bottom.
Other features requests:
is it possible to center the balance once for all in software, in order to compensate for gain imbalance? For example tube preamplifiers with no feedback. Can this be done for each input?
Is there any room to implemnent a mono function? I don't listen stereo records in monoaural. I use the mono capability only temporarly, at the beginning of a disc, to center the acoustic scene through balance. Then I set stereo. This feature is very useful to correct imbalancies due to the listening room. It is simpler to correct in mono.
However, thanks for your work, very appreciated.
Regards,
Valerio
I stacked the CPU, left and right channel boards to save space inside the preamp. They can be mounted in any position and don't take no more than 1 3/4" vertical. The size of the boards are dictated by the size of the resistors. The larger resistors produce lower distortion due to current heating. If the smaller resistors only were used it would make the boards narrower by 1/2" but the relays and Trace width controls the length of the boards. Still a 3 1/4" x 8" footprint isn't bad such a quality sound.
I had thought about moving the CPU board farther from the analog section but after testing I could find no digital artifacts in the audio output.
The left and right channels are kept separate through the volume section, Balance is controlled by adjusting the volume of one channel against the other. The balance shift is no more than 3 db, I figure you need more than that then time to look at the other equipment or the room for a problem.
If you want a mono output then better to switch in and out a separate circuit before or after the volume control, something that won't affect the sound when used in stereo.
I had thought about moving the CPU board farther from the analog section but after testing I could find no digital artifacts in the audio output.
The left and right channels are kept separate through the volume section, Balance is controlled by adjusting the volume of one channel against the other. The balance shift is no more than 3 db, I figure you need more than that then time to look at the other equipment or the room for a problem.
If you want a mono output then better to switch in and out a separate circuit before or after the volume control, something that won't affect the sound when used in stereo.
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So, last week I had to change out my work laptop, which I was using for the Arduino programming, so I setup my personal laptop but downloading the latest version of the Arduino IDE then the volume control code and IR code for this thread, and it had the problem again of the left most balance LED not working. I traced it to the IR code then to which timer was being used and realized I had not uploaded the updated IR Code, so, don't use the code on post 606 or the one before that. So here is the proper code using timer 5 instead of 2 so the PMW for pin 9 works.