it's done
It took a little longer to write the descriptions.
I hope my English is good enough for the descriptions to be understandable.
If you have any questions, I will answer them, of course
first the minimal configuration:
PCU -> Preamp – Control - Unit
minimal configuration (Main board, Display OLED or LCD)
with the minimal configuration
(without the pcb for multiple input channels)
the following functions are available:
-volume
-balance
-gain (for values bigger than 0 the pcu works as an preamp)
also all standard functions like:
the real-time clock
startup volume configuration
remote control as well as controlling with rotary encoders.
and here now the complete PCU with all possibilities
Preamp - Control - Unit
the pcu is a modular expandable preamp-controller unit,
working with the muses72320 audio chip.
all functions and sectors of the pcu, as well as the digital and analog sections are separated across different pcbs, to avoid unwanted noise in the audio signal path from the digital section. the pcu can also work as a preamp itself, according to the digital selectable gain value. because of the modular design, many different expansion states and configurations are possible. going from a simple volume regulation up to full functionality including phono-preamp (mm/mc), subwoofer control unit, different input channels, oled display, smartphone as remote control over bluetooth and an ir-remote (learnable). furthermore you can select different grades of operational amplifiers for the preamp functionality, which can also be swapped at any later time. an upgrade is always possible, so that you are also able to use future hardware developments and connect them simply to the pcu. extra functionalities can also be unlocked with a new software. the power supply is handled by specially designed low noise power supplies. you have the possibility to install software updates on the processors, to always get the latest fixes and new functionalities/options.
Main-Board:
digital and analog section are completely isolated. high quality parts used in the audio signal path, to prevent signal distortion. muses72320 chip for volume, balance and gain control. muses01 operational amplifier (highest opamp configuration) with digitally configurable gain for the preamp. software can detect, if an audio signal is present (i.e. to control the standby of external devices, threshold adjustable). emi filter in the audio and power signal paths against noise in the frequency range of cellphones or wlan. high quality smb-connectors for lossless signal transmission. all extension boards share the same connector to connect them to the main-board. because of this a confusion of the connectors is not possible. a security mechanism exists, to prevent damage from wrong connected boards; no electrical damage can occur. updates can be installed with an optional usb-software-updater and included software for mac or pc. every input channel can be given a custom name, an offset of the volume and gain adjust is also available separately for each input channel, to hold every channel at the same base volume and select different preamp values. the time, how long a channel is active, is saved (i.e. to monitor the playtime of phono cartridges). when switching to another input channel, the volume gets faded down first, the input signal get galvanic isolated (mute), only now the actual channel is switched and the volume fades back up. the startup volume is adjustable (or use the previous volume from last power on). subwoofer: an extension board to control a subwoofer is available. the cutoff frequency and phase (including graphical rendering of the functions) for the subwoofer signal can be digitally adjusted. however,
no digital parts are used in the signal path.
digital section: automatic detection, which extension boards are connected and which configuration is present, without manual adjustment. this enables easy plug and play. monitoring of all critical components and extension boards to show the user a warning if incorrect wiring or defect components are present. setting current time and date, real time clock chip included. the clock will pre preserved during power down. status and error display using seven segment display and leds. monitoring of all voltages in the system, over and under voltage protection. monitoring of the current in the system. if an over or under voltage case is detected, the protection circuit will shut off every component to prevent electrical damage. polarity protection, temperature protection and monitoring. every board can be shut off separately and the digital sections can be put into a deep sleep mode to enable standby functionality. if connections for the power supply are missing, the user will get an according error message and all components and extension boards will not be started to prevent electrical damage.
now I make the descriptions for the power supplys
+/- 15 V (PCU)
24 V (Nutube)
It took a little longer to write the descriptions.
I hope my English is good enough for the descriptions to be understandable.
If you have any questions, I will answer them, of course
first the minimal configuration:
PCU -> Preamp – Control - Unit
minimal configuration (Main board, Display OLED or LCD)
with the minimal configuration
(without the pcb for multiple input channels)
the following functions are available:
-volume
-balance
-gain (for values bigger than 0 the pcu works as an preamp)
also all standard functions like:
the real-time clock
startup volume configuration
remote control as well as controlling with rotary encoders.
and here now the complete PCU with all possibilities
Preamp - Control - Unit
the pcu is a modular expandable preamp-controller unit,
working with the muses72320 audio chip.
all functions and sectors of the pcu, as well as the digital and analog sections are separated across different pcbs, to avoid unwanted noise in the audio signal path from the digital section. the pcu can also work as a preamp itself, according to the digital selectable gain value. because of the modular design, many different expansion states and configurations are possible. going from a simple volume regulation up to full functionality including phono-preamp (mm/mc), subwoofer control unit, different input channels, oled display, smartphone as remote control over bluetooth and an ir-remote (learnable). furthermore you can select different grades of operational amplifiers for the preamp functionality, which can also be swapped at any later time. an upgrade is always possible, so that you are also able to use future hardware developments and connect them simply to the pcu. extra functionalities can also be unlocked with a new software. the power supply is handled by specially designed low noise power supplies. you have the possibility to install software updates on the processors, to always get the latest fixes and new functionalities/options.
Main-Board:
digital and analog section are completely isolated. high quality parts used in the audio signal path, to prevent signal distortion. muses72320 chip for volume, balance and gain control. muses01 operational amplifier (highest opamp configuration) with digitally configurable gain for the preamp. software can detect, if an audio signal is present (i.e. to control the standby of external devices, threshold adjustable). emi filter in the audio and power signal paths against noise in the frequency range of cellphones or wlan. high quality smb-connectors for lossless signal transmission. all extension boards share the same connector to connect them to the main-board. because of this a confusion of the connectors is not possible. a security mechanism exists, to prevent damage from wrong connected boards; no electrical damage can occur. updates can be installed with an optional usb-software-updater and included software for mac or pc. every input channel can be given a custom name, an offset of the volume and gain adjust is also available separately for each input channel, to hold every channel at the same base volume and select different preamp values. the time, how long a channel is active, is saved (i.e. to monitor the playtime of phono cartridges). when switching to another input channel, the volume gets faded down first, the input signal get galvanic isolated (mute), only now the actual channel is switched and the volume fades back up. the startup volume is adjustable (or use the previous volume from last power on). subwoofer: an extension board to control a subwoofer is available. the cutoff frequency and phase (including graphical rendering of the functions) for the subwoofer signal can be digitally adjusted. however,
no digital parts are used in the signal path.
digital section: automatic detection, which extension boards are connected and which configuration is present, without manual adjustment. this enables easy plug and play. monitoring of all critical components and extension boards to show the user a warning if incorrect wiring or defect components are present. setting current time and date, real time clock chip included. the clock will pre preserved during power down. status and error display using seven segment display and leds. monitoring of all voltages in the system, over and under voltage protection. monitoring of the current in the system. if an over or under voltage case is detected, the protection circuit will shut off every component to prevent electrical damage. polarity protection, temperature protection and monitoring. every board can be shut off separately and the digital sections can be put into a deep sleep mode to enable standby functionality. if connections for the power supply are missing, the user will get an according error message and all components and extension boards will not be started to prevent electrical damage.
now I make the descriptions for the power supplys
+/- 15 V (PCU)
24 V (Nutube)
here is a photo of my Korg Nutube Preamp with the PCU Preamp-Control-Unit
I will upload more photos today
I will upload more photos today
Hi Jürgen,
This looks like an impressive project!
It seems all was already well planned even for future possibilities.
I read it through, and all was clear, bar perhaps the following:
1- If no gain, are you making absolutely sure the Muses volume chip doen't activate its internal output op-amp, as that would clearly degrade the sound?
2- For those who want it, do you have a function enabling the display to go completely off say after 10s of course only if no order is given, and then goes on again as soon as one touches the remote? Display on can degrade the sound and also distract even if it can be dimmed
3- well, that point is more personal, but with all these functions and nice boards and various PS regulations I am unsure what the minimum cost would be for someone wanting just a passive (no gain) volume control... on the positive you seem to use the 24V from the Korg, if that can be done without polluting its sound, the better!
4- do you have the possibility to have a source out function, that is after source selection the ability to get it out before it gets to any volume control? Kind of monitoring output, could be useful for those wanting to integrate RIAA and DAC with this preamp while being able to evaluate individualy all tweaks or compare with other units these modules stand alone
5- Following the same idea, perhaps having 2 switchable outputs could be nice to control 2 different amps as suited (or have the B1K on one output and direct output on the other)
6- what will you use for the source selection? I guess that needs to be a very pure selection mean and reliable... relays or else?
Thanks for all this, it looks like an impressive project, far more a modern modular pre-amp control with many convenient functions than a simple volume control.
MFG
Claude
This looks like an impressive project!
It seems all was already well planned even for future possibilities.
I read it through, and all was clear, bar perhaps the following:
1- If no gain, are you making absolutely sure the Muses volume chip doen't activate its internal output op-amp, as that would clearly degrade the sound?
2- For those who want it, do you have a function enabling the display to go completely off say after 10s of course only if no order is given, and then goes on again as soon as one touches the remote? Display on can degrade the sound and also distract even if it can be dimmed
3- well, that point is more personal, but with all these functions and nice boards and various PS regulations I am unsure what the minimum cost would be for someone wanting just a passive (no gain) volume control... on the positive you seem to use the 24V from the Korg, if that can be done without polluting its sound, the better!
4- do you have the possibility to have a source out function, that is after source selection the ability to get it out before it gets to any volume control? Kind of monitoring output, could be useful for those wanting to integrate RIAA and DAC with this preamp while being able to evaluate individualy all tweaks or compare with other units these modules stand alone
5- Following the same idea, perhaps having 2 switchable outputs could be nice to control 2 different amps as suited (or have the B1K on one output and direct output on the other)
6- what will you use for the source selection? I guess that needs to be a very pure selection mean and reliable... relays or else?
Thanks for all this, it looks like an impressive project, far more a modern modular pre-amp control with many convenient functions than a simple volume control.
MFG
Claude
PCU Preamp - Control - Unit
Hi Claude,
here the answer
#1
for the gain an extra CHip is installed, also from Muses.
each input is individually programmable by the user
if the gain is "0" the signal is passed through
#2
after an adjustable time the display goes into sleep mode and switches back on as soon as any key is pressed
#3
No, you need +/- 15V fort he PCU
#4
is individually programmable by me
#5
is individually programmable by me
#6
High quality meder relais
Hi Claude,
here the answer
#1
for the gain an extra CHip is installed, also from Muses.
each input is individually programmable by the user
if the gain is "0" the signal is passed through
#2
after an adjustable time the display goes into sleep mode and switches back on as soon as any key is pressed
#3
No, you need +/- 15V fort he PCU
#4
is individually programmable by me
#5
is individually programmable by me
#6
High quality meder relais
Hi! An audio opamp is used for amplification. What is the use of the tube then?
I am very curious what the audible result is by connecting the Muses opamp output to the output RCA connectors directly (the opamp is always in the path anyway). It saves an effect generator, 3 electrolytic capacitors and 2 buffers per channel. Maybe even lower output impedance, better drive capabilities, lower output offset voltage and lower noise? You can then also omit the electrolytic output capacitors of the muses01 board and DC couple to the output. That will save 4 electrolytic caps per channel, all gone out of the signal path which can not have any negative side effect to put it mildly 😀 If the power amp does not have input caps then the output caps of the Muses01 board can be Wima MKT film caps which sound better than electrolytic caps.
Less can be "way more" in this case 🙂
I am very curious what the audible result is by connecting the Muses opamp output to the output RCA connectors directly (the opamp is always in the path anyway). It saves an effect generator, 3 electrolytic capacitors and 2 buffers per channel. Maybe even lower output impedance, better drive capabilities, lower output offset voltage and lower noise? You can then also omit the electrolytic output capacitors of the muses01 board and DC couple to the output. That will save 4 electrolytic caps per channel, all gone out of the signal path which can not have any negative side effect to put it mildly 😀 If the power amp does not have input caps then the output caps of the Muses01 board can be Wima MKT film caps which sound better than electrolytic caps.
Less can be "way more" in this case 🙂
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jean Paul,
the muses opamp is modular, but even if it is installed, and the gain is "0", the signal is passed through.
at the nutube preamp the opamp is not built in!
what you eventually installed is a matter of experience
regards juergen
the muses opamp is modular, but even if it is installed, and the gain is "0", the signal is passed through.
at the nutube preamp the opamp is not built in!
what you eventually installed is a matter of experience
regards juergen
Cryptic.... When the gain is not 0 then it will be bypassed? So when not set to 0 then the opamps AND the tube are having gain? If I understand you correctly the possibility exists to set the gain of the opamp to the gain that the tube has. Then still the comparison can be made with and without the extra board.
I mean your design looks very good but the question arises if it really needs the "Kram" behind it. To me it looks like your design can be used on itself with excellent results probably.
I mean your design looks very good but the question arises if it really needs the "Kram" behind it. To me it looks like your design can be used on itself with excellent results probably.
Last edited by a moderator:
hi jean-paul,
if you want to use the opamp, it is of course in the signal path, if you do not need the opamp, it is not in the signal path. this detects the software and reacts accordingly. it is simply an option also for future applications.in the nutube preamp the opamp makes no sense, therefore it is not installed. simply an option.
if you want to use the opamp, it is of course in the signal path, if you do not need the opamp, it is not in the signal path. this detects the software and reacts accordingly. it is simply an option also for future applications.in the nutube preamp the opamp makes no sense, therefore it is not installed. simply an option.
Watching this thread with interest. The programming side of things causes me a bit of concern at my level of expertise.
Would you consider the assembly and programming to be accessible to someone that can follow clear instructions and has a bit of electronics and PC knowledge? Does it require coding - or are all software / firmwares ready to go?
Thank you for starting the thread and providing your solution.
Would you consider the assembly and programming to be accessible to someone that can follow clear instructions and has a bit of electronics and PC knowledge? Does it require coding - or are all software / firmwares ready to go?
Thank you for starting the thread and providing your solution.
hi its allinmyhead,
if someone wants to use the PCU, then there are several options.
You can only get the boards with the soldered and programmed controller,
all components for soldering yourself,
or even a complete assembly.
the things that are to be programmed individually are made via a menu on the display and with two encoders.
It's very simple.
regards
juergen
if someone wants to use the PCU, then there are several options.
You can only get the boards with the soldered and programmed controller,
all components for soldering yourself,
or even a complete assembly.
the things that are to be programmed individually are made via a menu on the display and with two encoders.
It's very simple.
regards
juergen
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The thought arises that it can be the other way around but forget it. Functionality is what counts here.
Last edited:
Mant thanks for your kind and detailled reply, Jürgen.
It is more complex and bigger than what I was personaly looking for - for my specific use- but let's see the cost as it offers many possibilities.
bb
Claude
It is more complex and bigger than what I was personaly looking for - for my specific use- but let's see the cost as it offers many possibilities.
bb
Claude
PSU
Power supply for the Preamp-Control-Unit
The “Model L” power supply is a symmetric (positive, negative rail) linear supply, which provides stable and clean output voltages from milliamp range up to amps thanks to the partial shunt regulation design. The toroidal transformer prevents unwanted emissions and radiation is minimized to suppress noise in sensitive analog circuits. Both voltage rails can be precisely adjusted with a potentiometer.
Features
-High security: Primary and secondary side are fused
-Suppressing house power line noise (from microwaves, motors, …) by using a special mains filter
-Different output voltages selectable by switching resistors. Fine tuning using potentiometers
-Big capacitance to stabilize short power pulses from the load
-Protection against big capacitive loads
-Overvoltage, overpower and over temperature protection
-Exact output voltage independent from the connected load by using a specialized partial shunt regulation. Therefore the power supply doesn’t need a minimum load to be stable and can power very small loads with low noise.
-Ultra fast diodes to prevent ringing
-Different filters, including inductive ones, to prevent low and high frequency noise
-Specialized filters to suppress 50Hz mains noise
The default version of the power supply is adjusted to +/-15V. The maximum current per rail is 2A. Peak load up to 2.2A. For different voltages and/or higher currents, feel free to contact me.
Transformer
The toroidal transformer must be configured as follows: Primary 1x 230V, secondary 2x 15V 3.5A, 105VA (please adjust power and voltage according to desired output voltage and power of the power supply; you can get information about this by contacting us). The secondary windings will be connected in serial on the power supply PCB. Please pay attention to the polarity of the windings!
Power supply for the Preamp-Control-Unit
The “Model L” power supply is a symmetric (positive, negative rail) linear supply, which provides stable and clean output voltages from milliamp range up to amps thanks to the partial shunt regulation design. The toroidal transformer prevents unwanted emissions and radiation is minimized to suppress noise in sensitive analog circuits. Both voltage rails can be precisely adjusted with a potentiometer.
Features
-High security: Primary and secondary side are fused
-Suppressing house power line noise (from microwaves, motors, …) by using a special mains filter
-Different output voltages selectable by switching resistors. Fine tuning using potentiometers
-Big capacitance to stabilize short power pulses from the load
-Protection against big capacitive loads
-Overvoltage, overpower and over temperature protection
-Exact output voltage independent from the connected load by using a specialized partial shunt regulation. Therefore the power supply doesn’t need a minimum load to be stable and can power very small loads with low noise.
-Ultra fast diodes to prevent ringing
-Different filters, including inductive ones, to prevent low and high frequency noise
-Specialized filters to suppress 50Hz mains noise
The default version of the power supply is adjusted to +/-15V. The maximum current per rail is 2A. Peak load up to 2.2A. For different voltages and/or higher currents, feel free to contact me.
Transformer
The toroidal transformer must be configured as follows: Primary 1x 230V, secondary 2x 15V 3.5A, 105VA (please adjust power and voltage according to desired output voltage and power of the power supply; you can get information about this by contacting us). The secondary windings will be connected in serial on the power supply PCB. Please pay attention to the polarity of the windings!