This is GW preamp with no global NFB used, in SMD technic and increased output power to drive even low impedance hedphones.
It is dual mono, used separate power supplay per channel.
Output amplifier uses CFP with mosfet transistors and it's powered by capacitanse multiplier incorporating overcurrent and DC offset protection.
Gain block is a current conveyor and it's powered with shunt regulator one per channel.
Damir
It is dual mono, used separate power supplay per channel.
Output amplifier uses CFP with mosfet transistors and it's powered by capacitanse multiplier incorporating overcurrent and DC offset protection.
Gain block is a current conveyor and it's powered with shunt regulator one per channel.
Damir
Attachments
This preamp is DC from the input to the output, no capacitor in signal path (someone will say all caps are in the signal path 😉)
So, volume Pot P1 is floating and connected to the U1 servo output.
I am not sure you actually built this or it is only a simulation exercise.
I am not sure you actually built this or it is only a simulation exercise.
I have not built this SMD version yet, but used the same way with one of mine though hole version and it works perfectly.
Probably I am not the right person to ask for the purpose (not function).
Useful answer would be to increase the internal impedance of the output ?
Useful answer would be to increase the internal impedance of the output ?
No, try to find explanation abouth current mirrors and current conveyours (output impedance of a current conveyour is quite high).
SMD technic is not DIY friendly. Doing it without SMT stecil is not easy, even with stencil placing by hand is not easy.
I did some SMD soldering using stencil and hand placing, and used hot plate to solder it (look attached photos).
I tried ones to order soldering at JLCPCB but they did not have all component I wanted to use(specialy semiconductor) and I gave up.
Now i have a question, how to proceed wird this project?
I do not have intention to offer gerbers for now (to much work and effort in it).
1. I can offer pcb and BOM.
2. I can offer pcb ansembled with SMD components without through hole components (this could be more costly).
Let me know what you think abouth it. This is not ready yet, I have to recheck the layout very carefuly as from the experience I do some erros on it.😳
Damir
I did some SMD soldering using stencil and hand placing, and used hot plate to solder it (look attached photos).
I tried ones to order soldering at JLCPCB but they did not have all component I wanted to use(specialy semiconductor) and I gave up.
Now i have a question, how to proceed wird this project?
I do not have intention to offer gerbers for now (to much work and effort in it).
1. I can offer pcb and BOM.
2. I can offer pcb ansembled with SMD components without through hole components (this could be more costly).
Let me know what you think abouth it. This is not ready yet, I have to recheck the layout very carefuly as from the experience I do some erros on it.😳
Damir
Attachments
Hi Damir,
SMD soldering is laborious but it can be done. I think the price will be decisive
1, The price per bare board?
2. The price per board with SMD components?
SMD soldering is laborious but it can be done. I think the price will be decisive
1, The price per bare board?
2. The price per board with SMD components?
Damir, hot air gun works well,but on a small scale,
you don't want to do a groupe group buys?
personally I would like the option pcb ansembled with SMD components without through hole components.
Thanks for this beautiful project.
you don't want to do a groupe group buys?
personally I would like the option pcb ansembled with SMD components without through hole components.
Thanks for this beautiful project.
What are the package sizes for the resistors, etc. If they are 0805 or so, those are pretty easy by hand with a soldering iron. I can do down to 0603 without much issue. This project (https://www.diyaudio.com/community/threads/ugs-muse-preamp-gb.277355/) is mostly SMD and I built it by hand without much issue, and I'm 70 years old. The CPU wasn't much fun, and the two Muse chips as well. But doable. If you can get JLPCB to do the SMD stuff, that would be good if they have the parts and don't charge thru the roof.
Agree with Pars, while this project has many smd components they are not stressful packages to solder. (DFN! 
)
Will the layout in the first post be the board that is offered?
)Will the layout in the first post be the board that is offered?
I am using two types SMD resistors MELF 0204 and thin film 1206, but there are very small package for double transistors in one package like BCM846/856(SOT363) for current mirrors, very hard to solder with a solder iron.
Attachments
Last edited:
Yes, but I have to recheck it very carefully.Agree with Pars, while this project has many smd components they are not stressful packages to solder. (DFN!
Will the layout in the first post be the board that is offered?
