Hey,
I would like to monitor and display real time data such as bias, filament voltage, hours of operation and other parameters from my tube amp. I have seen a picture of this done on a tube amp but there is real useful information other than pics. Also found some info on data logger but it doesn't seem to be applicable. I am not really sure where to look. Has anyone done this or have any pointers on how to do it?
thanks!
I would like to monitor and display real time data such as bias, filament voltage, hours of operation and other parameters from my tube amp. I have seen a picture of this done on a tube amp but there is real useful information other than pics. Also found some info on data logger but it doesn't seem to be applicable. I am not really sure where to look. Has anyone done this or have any pointers on how to do it?
thanks!
I started a thread a while back about this subject, but numerous other projects have taken precedence and I haven't done anything. Some good info was provided in the thread: https://www.diyaudio.com/community/threads/help-needed-interfacing-uprocessor-with-tube-amp.379145/
I was planning on using an Arduino-like board (Teensy), which makes things easier because you only need to plug in an Arduino compatible display, and library code is available to talk to it, rather than having to program the display at a low level. I was thinking the display would be updated in the main loop a few times a second, and an interrupt would be used to read voltages at appropriate parameters allowing accurate time-based calculations. Of course you have to scale the voltages appropriately to the range the processor can handle.
I don't know what you mean by data logger, but I would also add the ability to send data over USB to a PC, this could be in the main loop also, assuming the data has timestamps attached when collected in the interrupt routine.
I'm hoping to get back to this project, but I will probably start really simple and just take measurements of a tube operating in isolation rather than in an amp.
I was planning on using an Arduino-like board (Teensy), which makes things easier because you only need to plug in an Arduino compatible display, and library code is available to talk to it, rather than having to program the display at a low level. I was thinking the display would be updated in the main loop a few times a second, and an interrupt would be used to read voltages at appropriate parameters allowing accurate time-based calculations. Of course you have to scale the voltages appropriately to the range the processor can handle.
I don't know what you mean by data logger, but I would also add the ability to send data over USB to a PC, this could be in the main loop also, assuming the data has timestamps attached when collected in the interrupt routine.
I'm hoping to get back to this project, but I will probably start really simple and just take measurements of a tube operating in isolation rather than in an amp.
I use these two devices. I interface them with a thin-format flexible sheet made of fibrous cellulose. This stuff is amazing - you can make permanent or semi-permanent marks on it, and its self-datalogging! What will they think of next?
There are a whole bunch of symbols I've learnt that can be used to describe concepts, numbers, even imaginary stuff.
Anyway, once you get to grips with manipulating the pointy stick to make marks representing the symbols on the flexible sheet, you can record the information off the measuring device, then put that all into some dampware I've developed over the past 60 years to run the diagnostics!
Avant-garde eh!
There are a whole bunch of symbols I've learnt that can be used to describe concepts, numbers, even imaginary stuff.
Anyway, once you get to grips with manipulating the pointy stick to make marks representing the symbols on the flexible sheet, you can record the information off the measuring device, then put that all into some dampware I've developed over the past 60 years to run the diagnostics!
Avant-garde eh!
I think there is definitely a market here for some green thinking that would require the sort of monitoring described in this thread. I am thinking of two useful adaptions to the amplifiers I have:
1) Something a bit like the cutting off of the engine of a car when it is stationary. So if one has a Single Ended amp and there has not been music playing for a programable time period, then it sets the bias for a more quiescent state.
2) Because I hate to see the sight of glowing tubes first thing in the morning when I return to the room where my amps are located, because I stop playing music the night before then forget to turn off the amplifier, some sort of solution that powers down if the amp is quiescent for more than an hour, say.
Plus there could end up being a wealth of data on the usage profiles of different manufacturer's tubes, and with a really neat solution where different parameters can be shifted, say, by 10%, the tubes could be curve traced in situ at the operating point, with gm and internal resistance available continuously.
1) Something a bit like the cutting off of the engine of a car when it is stationary. So if one has a Single Ended amp and there has not been music playing for a programable time period, then it sets the bias for a more quiescent state.
2) Because I hate to see the sight of glowing tubes first thing in the morning when I return to the room where my amps are located, because I stop playing music the night before then forget to turn off the amplifier, some sort of solution that powers down if the amp is quiescent for more than an hour, say.
Plus there could end up being a wealth of data on the usage profiles of different manufacturer's tubes, and with a really neat solution where different parameters can be shifted, say, by 10%, the tubes could be curve traced in situ at the operating point, with gm and internal resistance available continuously.
This is something I've been wanting to put together for a while. A simple safety system to shut things down in case of red plating or loss of a fixed bias negative supply would be a sensible addition to any amp. I'm experimenting with ESP8266 datalogging when I get any spare time. This could easily be adapted to suit.
That's what I thought, at the moment I have two multimeters hooked up to make sure everything is on the up and up. As the tubes age and settle down, I would like to avoid getting out of hand particularly with expensive tubes so having an LCD showing the status would be nice.
To achieve your requirements, we need MCU, ADCs, voltage divider, and finally a LCD.
I recommend you to buy an RPi Pico, running Arduino Core as the MCU. Since it's easy to use when designing your own PCB.
https://github.com/earlephilhower/arduino-pico
If you don't care using Arduino development kits in your amplifier, the kits from Arduino such as Arduino UNO and Arduino Nano are more recommended.
The RP2040 could have somewhere incompatible when using Arduino Libraries. But it's much easier to write your program in an entirely new MCU comparing with ATmega328P which is used in Arduino Nano.
The ADC of RPi Pico has only 4 inpout channels, and I don't think the 12bit ADC of RPi Pico is accurate enough to provide monitoring of these parameters. An external ADC is recommended.
I'm using AD7124 in my filament ccs design, but I have no idea whether it's affordable and available for you.
When selecting ADC for the project, make sure its resolution and input channels are enough. Most importantly, there should be useable Arduino Library for such type.
Driving LCDs with Arduino Boards, you can find a lot of videos about it.
Sometimes the voltage you want to monitor does not have the same 'Ground' reference, which should be carefully consider building the voltage divider network.
You can learn how to connect ADC and LCD with an Arduino Board first. I think it's really easy
I recommend you to buy an RPi Pico, running Arduino Core as the MCU. Since it's easy to use when designing your own PCB.
https://github.com/earlephilhower/arduino-pico
If you don't care using Arduino development kits in your amplifier, the kits from Arduino such as Arduino UNO and Arduino Nano are more recommended.
The RP2040 could have somewhere incompatible when using Arduino Libraries. But it's much easier to write your program in an entirely new MCU comparing with ATmega328P which is used in Arduino Nano.
The ADC of RPi Pico has only 4 inpout channels, and I don't think the 12bit ADC of RPi Pico is accurate enough to provide monitoring of these parameters. An external ADC is recommended.
I'm using AD7124 in my filament ccs design, but I have no idea whether it's affordable and available for you.
When selecting ADC for the project, make sure its resolution and input channels are enough. Most importantly, there should be useable Arduino Library for such type.
Driving LCDs with Arduino Boards, you can find a lot of videos about it.
Sometimes the voltage you want to monitor does not have the same 'Ground' reference, which should be carefully consider building the voltage divider network.
You can learn how to connect ADC and LCD with an Arduino Board first. I think it's really easy
This sounds like something a basic Arduino could handle. There are modules which include a real-time clock with battery backup and SD or uSD socket. You can find tutorials on using those as a data logger. And hooking up an LCD display module is easy too.
Alternatively... there are dirt cheap digital voltmeter modules, and hour meters, if you want the simplest option. The cheap voltmeters I've used are based on microcontrollers, and aren't as accurate as the 7107 meters of our ancestors, but maybe good enough.
https://www.aliexpress.com/w/wholesale-voltmeter.html
https://www.aliexpress.com/w/wholesale-hour-meter.html
Alternatively... there are dirt cheap digital voltmeter modules, and hour meters, if you want the simplest option. The cheap voltmeters I've used are based on microcontrollers, and aren't as accurate as the 7107 meters of our ancestors, but maybe good enough.
https://www.aliexpress.com/w/wholesale-voltmeter.html
https://www.aliexpress.com/w/wholesale-hour-meter.html
An ESP32 or ESP8266 microcontroller might be a good choice with the wifi or bluetooth functionality. This would allow for easily automated integration into spreadsheets so you could record things without aardvarkash10's pointy stick thing. Time functions are nice and really easy to add and automatically update from the internet. And a big plus is they're really cheap!
There are sensors available that communicate over I2C and are isolated optically. There are also dedicated I2C isolation modules that use internal RF signals to communicate with a device. Adding an RF signal inside an amplifier does sound "wrong" but I've seen them used in a very well designed DAC without issue. The shielding is likely well thought out in the device.
There are sensors available that communicate over I2C and are isolated optically. There are also dedicated I2C isolation modules that use internal RF signals to communicate with a device. Adding an RF signal inside an amplifier does sound "wrong" but I've seen them used in a very well designed DAC without issue. The shielding is likely well thought out in the device.
I would use Bluetooth Smart advertising packets to be able to see some values without the need for pairing with the mobile phone. The amount of information is restricted to 37 bytes, but there is plenty you can pack there, If interaction is needed, then using "just works" pairing will make it easy to connect and exchange information in both directions.
So many dreams
So many dreams