Integrated 4 channel class D-amp in JVC vintage housing
Hi together. I am planning to build a "new" integrated amp into an old nice vintage housing and have some questions to the experts.
As you can see on the pictures, i want to create a four channel "main" amp, made of two Wondom Modules. In addition, I want to use a small one-channel Kemo Amp for some quick speaker measurements (there's a nice line-in on the front i want to use for my soundcard).
A miniDSP 2x4 HD will drive the two Wondom Modules, a motor-driven Alps-Potentiometer reduces the incoming signals of a DAC-Board, a Bluetooth-HD-Board and a Creek phonoamp. I don't want to use Dirac or the digital imputs of the miniDSP 2x4 HD.
In addition, the Alps motorpotentiometer drives an unfiltered pre-out on the back.
As power-supplies, two 150 watts linear power supplies (Ebay ;-)) are going to supply 24 Volts DC to the amp modules, as well as the phonostage, which needs 24 Volts too.
For the rest (DAC, DSP, Bluetooth and potentiometer) I need 12 Volts DC. A Kemo step-down converter is going to do this job.
As you can see, I want to put a lot of stuff into the old housing. Therefore, i asking myself, which is the best way to avoide noise and hum.
For now, i want to use a single ground point for the power supply and the amp modules and try to decouple the inputs from the housing ground (i will need other cinch sockets, the gold ones on the picture are too big and touch the steel back).
Is this a proper way to avoid hum and noise? This the main point i am worrying about.
Is it a better way to put the whole power supply for the 12 Volt into a separate housing?
Or do you see mistakes I'm not aware of yet because of limited experiences?
Advice welcome.
Regards Ludger
Hi together. I am planning to build a "new" integrated amp into an old nice vintage housing and have some questions to the experts.
As you can see on the pictures, i want to create a four channel "main" amp, made of two Wondom Modules. In addition, I want to use a small one-channel Kemo Amp for some quick speaker measurements (there's a nice line-in on the front i want to use for my soundcard).
A miniDSP 2x4 HD will drive the two Wondom Modules, a motor-driven Alps-Potentiometer reduces the incoming signals of a DAC-Board, a Bluetooth-HD-Board and a Creek phonoamp. I don't want to use Dirac or the digital imputs of the miniDSP 2x4 HD.
In addition, the Alps motorpotentiometer drives an unfiltered pre-out on the back.
As power-supplies, two 150 watts linear power supplies (Ebay ;-)) are going to supply 24 Volts DC to the amp modules, as well as the phonostage, which needs 24 Volts too.
For the rest (DAC, DSP, Bluetooth and potentiometer) I need 12 Volts DC. A Kemo step-down converter is going to do this job.
As you can see, I want to put a lot of stuff into the old housing. Therefore, i asking myself, which is the best way to avoide noise and hum.
For now, i want to use a single ground point for the power supply and the amp modules and try to decouple the inputs from the housing ground (i will need other cinch sockets, the gold ones on the picture are too big and touch the steel back).
Is this a proper way to avoid hum and noise? This the main point i am worrying about.
Is it a better way to put the whole power supply for the 12 Volt into a separate housing?
Or do you see mistakes I'm not aware of yet because of limited experiences?
Advice welcome.
Regards Ludger
Attachments
Last edited:
After a year has passed, it's time for a little update. This project get's way more complicated then planned, but that's the way it goes. So let's dive into the pics.
A view into the old JVC, i was surely the first one to lift the cover.
Be happy that you can't smell what I had to, this amp really stinked.
First thing to do: making a plan how to use all the in- and outputs. Endless possibilities, that was fun!
I love this front so much - even when I was working at a crossover I put it in sight to have always a look at it. Strange? No, real enthusiasm. 🙂
Next step: drilling the loudspeaker connections into a plastic plate used as a base for the banana plugs.
To get the right dimensions of the steel plates for the components, i used some plywood boards.
A quick look on the components. DAC-board with AKM 4490 and additional analog input:
Bluetooth APTX-HD board.
The analog input selector is this one:
https://www.ebay.com/itm/143739704686
I removed the sockets to save space, and it really works well.
Testing the functions and connections of the speaker selector.
Then it was time to get the right lengths of the dc wires.
All internal components are working with 12 V DC. So i can feed them with a seperate power supply.
A detail shot of the power switches for DSP, headphone amplifier and Bluetooth board.
https://abload.de/img/dceinausmjkr1.jpg
more to come...
A view into the old JVC, i was surely the first one to lift the cover.
Be happy that you can't smell what I had to, this amp really stinked.
First thing to do: making a plan how to use all the in- and outputs. Endless possibilities, that was fun!
I love this front so much - even when I was working at a crossover I put it in sight to have always a look at it. Strange? No, real enthusiasm. 🙂
Next step: drilling the loudspeaker connections into a plastic plate used as a base for the banana plugs.
To get the right dimensions of the steel plates for the components, i used some plywood boards.
A quick look on the components. DAC-board with AKM 4490 and additional analog input:
Bluetooth APTX-HD board.
The analog input selector is this one:
https://www.ebay.com/itm/143739704686
I removed the sockets to save space, and it really works well.
Testing the functions and connections of the speaker selector.
Then it was time to get the right lengths of the dc wires.
All internal components are working with 12 V DC. So i can feed them with a seperate power supply.
A detail shot of the power switches for DSP, headphone amplifier and Bluetooth board.
https://abload.de/img/dceinausmjkr1.jpg
more to come...
Attachments
Last edited:
Thanks mate.
Here are once again the pics, something didn't worked.
Dac-board:
APTX-HD Bluetooth:
Naked housing:
DC-power switches:
DSP with pots and input board. Shouldn't have solder the DSP at least, big mistake caused handling problems:
Inputs, DSP, additional amp and power supply without front and rear plates
Function test of input section and dsp
Bright green light: Bluetooth is working
Bright red light: DAC on fire
Dimmed green light: input selector ready
To be continued...
Here are once again the pics, something didn't worked.
Dac-board:
APTX-HD Bluetooth:
Naked housing:
DC-power switches:
DSP with pots and input board. Shouldn't have solder the DSP at least, big mistake caused handling problems:
Inputs, DSP, additional amp and power supply without front and rear plates
Function test of input section and dsp
Bright green light: Bluetooth is working
Bright red light: DAC on fire
Dimmed green light: input selector ready
To be continued...
