You can see the same for lower current and 78xx/78xx compatible :
www.diyaudio.com/community/threads/the-dao-se-all-fet-class-a-zgf-headphone-amplifier.225577/post-4851725
Patrick
www.diyaudio.com/community/threads/the-dao-se-all-fet-class-a-zgf-headphone-amplifier.225577/post-4851725
Patrick
At the same time, we are also working on a suitable preamp for the Le Monstre.
It intends to use an equally vintage classic circuit from Linsley Hood.
The case matches that of the Le Monstre 3209 footprint. so that it stacks directly on top.
The rest of the elements uses the same common platform as the F5 Preamp.
www.diyaudio.com/community/threads/the-f5pi-f5p-voltage-gain-stage-m2-output-stage-perfectly-integrated.406024/post-7741027
The active preamp modules are mounted on heat spreaders, which in turn are fixed to the side with 4 screws.
Thus, one can easily swap the preamp circuit with compatible footprints.
Will open separate thread when ready.
Need to finish GB first of all.
Patrick
.
It intends to use an equally vintage classic circuit from Linsley Hood.
The case matches that of the Le Monstre 3209 footprint. so that it stacks directly on top.
The rest of the elements uses the same common platform as the F5 Preamp.
www.diyaudio.com/community/threads/the-f5pi-f5p-voltage-gain-stage-m2-output-stage-perfectly-integrated.406024/post-7741027
The active preamp modules are mounted on heat spreaders, which in turn are fixed to the side with 4 screws.
Thus, one can easily swap the preamp circuit with compatible footprints.
Will open separate thread when ready.
Need to finish GB first of all.
Patrick
.
Attachments
The amp modules have now been tested on the 3209 case heatsinks.
www.diyaudio.com/community/threads/hiraga-le-monstre-2024.413301/post-7818718
From cold to warm (after 1 hour), DC drift is less than 8mV, and is very stable after reaching steady state.
But the bias current can increase by 60%, though heatsink is only warm to hand.
This depends on your particular setup.
But it is wise to start with a low bias value.
To reduce steady state bias by 100mA, the bypass current should be increased by 100uA.
This corresponds to the ratio between the power resistor of the output stage (1R), to the drain resistor of the input stage (1k).
Patrick
www.diyaudio.com/community/threads/hiraga-le-monstre-2024.413301/post-7818718
From cold to warm (after 1 hour), DC drift is less than 8mV, and is very stable after reaching steady state.
But the bias current can increase by 60%, though heatsink is only warm to hand.
This depends on your particular setup.
But it is wise to start with a low bias value.
To reduce steady state bias by 100mA, the bypass current should be increased by 100uA.
This corresponds to the ratio between the power resistor of the output stage (1R), to the drain resistor of the input stage (1k).
Patrick
Family photo.
We like very much how they turn out. 😊
Patrick
We like very much how they turn out. 😊
Patrick
Remarkable cleanliness both in terms of the layout, implementation and design.
bravo!
bravo!
Fran already said he wants them both.
So they will go to him for measurements and listening.
We shall then publish all the details in a separate thread.
It is somewhat different from the F5Pre that we just published elsewhere.
www.diyaudio.com/community/threads/the-f5-preamp-2024.419289/#post-7833795
Not using any MCU to control the ladder attenuator.
As would have been the case in 1974. 😊
Below is a picture of the preamp (buffer) module, including local discrete regulators.
Patrick
.
So they will go to him for measurements and listening.
We shall then publish all the details in a separate thread.
It is somewhat different from the F5Pre that we just published elsewhere.
www.diyaudio.com/community/threads/the-f5-preamp-2024.419289/#post-7833795
Not using any MCU to control the ladder attenuator.
As would have been the case in 1974. 😊
Below is a picture of the preamp (buffer) module, including local discrete regulators.
Patrick
.
Attachments
If Industry builds like that , they go bankrupt in no time.
This is precisely the reason to DIY.
Not to save money, because it won't.
But to build something you can't buy.
😊
Patrick
This is precisely the reason to DIY.
Not to save money, because it won't.
But to build something you can't buy.
😊
Patrick
Great state of mind.
I start my builds like that. And my lack of skills bite me in the middle, and I finish limiting the scars...
I start my builds like that. And my lack of skills bite me in the middle, and I finish limiting the scars...
Anyone can build what we build.
Just need time, patience, and practice.
😊
Designing is another story.
Patrick
Just need time, patience, and practice.
😊
Designing is another story.
Patrick
How to DIY that front panel in post #264 ?
We got a special PCB made which is essentially a drilling fixture.
This allows you to position the PCB mounting holes and all the LED holes relative to the centre of the knobs.
We then drill through the panel first with 1.5mm as pilot drill.
Then drill out to size for the LEDs and the standoffs.
You can do it with am electric hand drill, with a bit of care.
Of course it helps a great deal to have a drill stand.
So anyone with a bit of DIY skill can do.
No CNC required.
Patrick
We got a special PCB made which is essentially a drilling fixture.
This allows you to position the PCB mounting holes and all the LED holes relative to the centre of the knobs.
We then drill through the panel first with 1.5mm as pilot drill.
Then drill out to size for the LEDs and the standoffs.
You can do it with am electric hand drill, with a bit of care.
Of course it helps a great deal to have a drill stand.
So anyone with a bit of DIY skill can do.
No CNC required.
Patrick
Some people can buy beautiful things and beautiful pieces, it is not for all that that they manage to implement them in a harmonious, efficient and aesthetic way.
Once again, my respects. 🙂
Once again, my respects. 🙂
Refer to our setup in post #252, here are some notes that might be useful as a reference.
Each heatsink is 300x50x80mm, with fins on 10mm pitch.
Over an hour, it doesn't really get hot, just nice and warm to hand.
Both channels have essentially the same bypass current.
So matching was perfect.
At cold start, bias was 0.6A, rising to 0.9A in 30 minutes, and settling at 0.96A after an hour.
DC offset drifts about 8mV from cold to warm, which is of course nothing for a power amp.
So for other builders, be sure you start with a lower bias, and allow for up to 60% rise in both heatsink and power supply.
Patrick
Each heatsink is 300x50x80mm, with fins on 10mm pitch.
Over an hour, it doesn't really get hot, just nice and warm to hand.
Both channels have essentially the same bypass current.
So matching was perfect.
At cold start, bias was 0.6A, rising to 0.9A in 30 minutes, and settling at 0.96A after an hour.
DC offset drifts about 8mV from cold to warm, which is of course nothing for a power amp.
So for other builders, be sure you start with a lower bias, and allow for up to 60% rise in both heatsink and power supply.
Patrick
Referring to Post #267, some progress with the distortion measurements.
Note that the Le Monstre only requires 0.3Vrms input and has 48k input impedance.
Figures show 2nd and 3rd harmonics of the preamp at 1kHz and 10kHz, with different amplitudes.
Distortion is practically identical between 2k and 10k load, and between 1kHz and 10kHz.
And about 3 to 5dB higher at 600R load.
3rd harmonics at 1kHz below 1Vrms are noise limited.
This version is with Onsemi JFETs and BJTs.
There are plans to test further versions with Toshiba devices, both through hole and SMD.
Some more work needs doing before ready for listening auditions together with the Le Monstre 2024.
Patrick
.
Note that the Le Monstre only requires 0.3Vrms input and has 48k input impedance.
Figures show 2nd and 3rd harmonics of the preamp at 1kHz and 10kHz, with different amplitudes.
Distortion is practically identical between 2k and 10k load, and between 1kHz and 10kHz.
And about 3 to 5dB higher at 600R load.
3rd harmonics at 1kHz below 1Vrms are noise limited.
This version is with Onsemi JFETs and BJTs.
There are plans to test further versions with Toshiba devices, both through hole and SMD.
Some more work needs doing before ready for listening auditions together with the Le Monstre 2024.
Patrick
.
Attachments
Question regarding the BOM, FMP100FTE52-200R is no longer in stock at neither DigiKey nor Mouser. Does it need to be 200r or can it also be 220r and what is the minimum wattage? I can buy 200r 0.5W Shikoh's but as that doesn't meet the specs, perhaps best to continue my search for a better alternative.
220R is just fine. And any 2W resistor such as Vishay PR02 will do.
It is there only to provide some load in case the output is disconnected.
No need to waste money on anything exotic.
Patrick
It is there only to provide some load in case the output is disconnected.
No need to waste money on anything exotic.
Patrick