I just hooked up the protect circuit from post #8113. It works well except for a very slight hum.
I wonder if that is the AC line input coupling into the MOSFET relay gate?
I believe Thimios said he solved it with a separate power supply to the circuit. I haven't tried that yet.
http://www.diyaudio.com/forums/solid-state/162081-dc-servo-mosfet-amplifier-3.html
Maybe the dc servo mosfet amplifier power supply can be used has everything clip
dc and short circuit protection and its a tested circuit
Maybe the dc servo mosfet amplifier power supply can be used has everything clip
dc and short circuit protection and its a tested circuit
I have built a couple of those. They work well with the FX100. I just wanted to test the little MOSFET protection circuit with the FH11.
BTW, I hooked it up to my A/B setup and it sounds very good. For someone looking for a little more power from the FX8 circuit this is a good way to get it.
BTW, I hooked it up to my A/B setup and it sounds very good. For someone looking for a little more power from the FX8 circuit this is a good way to get it.
Thanks for the A/B test of the F11 Terry. What amp did you put it up against?
VSSA, DX Super A, SKA GB150. Held its own. It's a nice amp. I think if I was to do a layout for it I would put the MJE350 on the main heatsink or make room for a good size one.
That is the one Andrew mentioned.Maybe this is a good combo PSU and protect circuit for FH11?
The SKA GB150 is probably the closest comparable as it has the same 4 output MOSFETs. That's some good company to be able to hold its own against.
The best way is,using the contact of a relay power this circuit from dc and control relay's coil from ac using a diode and a small capacitor for rectifier.I believe Thimios said he solved it with a separate power supply to the circuit. I haven't tried that yet.
This way the power loss protection is still here
Last edited:
Hallo andrewlebon.
wich pcb layout Programm u use?
On weekend i have tested KICAD and Express PCB, but i am to dump to import files to
work on it or it is not possible.
I have seen in Juan clip- he works with Sprint Layout you can import files and rearrange
it.
For me it needs to much time to create a schema and work step by step- i am search a
short way to work on Bimos FX8 mod board for example.
If any other can give me advise- all is welcome- thanks.
Cheers Bangla.
Hi BanglaH,
only because I am using😀, you can try eagle, there is a good series of tutorials by Jeremy Blum on youtube. Its a difficult program to get around initially, but once you get the hang of it, it becomes simpler and because of backward compatibility with schematic, there is minimal chance of mistakes. ofcourse trial version is limited to a board size of 80mm x 100mm, but thats good enough for most single pair amps. sprint is way simpler than any program i guess, but does not have compatibility with schematic. you have to check each and every connection in sprint.
reg
prasi
Learn how to use PCB/Schematic drawing software is easy. But learn how to make good PCB layout is difficult.
VSSA, DX Super A, SKA GB150. Held its own. It's a nice amp. I think if I was to do a layout for it I would put the MJE350 on the main heatsink or make room for a good size one.
That is the one Andrew mentioned.
Use two MPSA92 instead MJE350 like on this schematic.
Attachments
Use two MPSA92 instead MJE350 like on this schematic.
Neat. So just adding one in series like that helps to cut the dissipation on one? Can you please explain how that works? To my untrained eyes, it seems that the same current would pass through both, thereby doubling the dissipation?
Neat. So just adding one in series like that helps to cut the dissipation on one? Can you please explain how that works? To my untrained eyes, it seems that the same current would pass through both, thereby doubling the dissipation?
Current is same but now we have only half voltage per transistor.
Current is same but now we have only half voltage per transistor.
Duh!! silly me, Ohms law.... 🙂
Hallo Bimo and Prasi.
My point is beginning to learn with Layout Programms to learn the rules.
If i can put in to Eagle, for example, a Layout i have a point for beginning in shorter time.
Thank you for advise Prasi- will test it on weekend, hope i understand simplicity it
works ;-).
I know that you have many experience in that doing.But learn how to make good PCB layout is difficult.
My point is beginning to learn with Layout Programms to learn the rules.
If i can put in to Eagle, for example, a Layout i have a point for beginning in shorter time.
Thank you for advise Prasi- will test it on weekend, hope i understand simplicity it
works ;-).
FH11 with modifications suggested by Mr. Miles.
@XRK, could you update schematic with modifications.
@Bangla H, I use sprint layout easy to use but more likely I make mistake while drawing layout. But it's fun once you get hang of it.
I started with eagle and still use it for digital layout.
@XRK, could you update schematic with modifications.
@Bangla H, I use sprint layout easy to use but more likely I make mistake while drawing layout. But it's fun once you get hang of it.
I started with eagle and still use it for digital layout.
Attachments
Let's call it FH12
Attachments
Last edited:
- Home
- Amplifiers
- Solid State
- 100W Ultimate Fidelity Amplifier