Did you lay those PCBs out yourself? Looks good.Finally the pcbs for the blowtorch arrived
Your preamp looks great! You nearly have me convinced to do 2 encoders instead of 1 w/pushbuttons. Would you have a CAD or FPE file for the front you would be willing to share?
Also, did you do your own layout for the Blowtorch pcb?
Thanks,
Chris
I built up one of the shunt boards yesterday and tested it last night. I did not put in the thermistors yet, but I wasn't really noticing much drift at all, but only ran it for a few minutes testing it. Note I did use the RG Susumus for all (including the 270R) instead of the RR. The glass-encapsulated RGs are supposed to be more stable than the RRs are.
I do wish you would have used 0805 packages rather than the 0603, as those are pretty much at my limit as far as SMD work goes. Putting in 20 270Rs, I only lost 2
I bought 100 of them, so unless I start losing them at a faster rate, I should be good for doing 4 boards.
Also, the transistors (BC857/BC847) case size of the chosen part numbers (SOT323) in the BOM are nearly too small for the board footprint. I wonder if an SOT23-3 part would fit better?
I do wish you would have used 0805 packages rather than the 0603, as those are pretty much at my limit as far as SMD work goes. Putting in 20 270Rs, I only lost 2
I bought 100 of them, so unless I start losing them at a faster rate, I should be good for doing 4 boards.Also, the transistors (BC857/BC847) case size of the chosen part numbers (SOT323) in the BOM are nearly too small for the board footprint. I wonder if an SOT23-3 part would fit better?
I didn’t share the file with only the encoders because I was thinking to keep it somehow unique(only for me) but if you insist I will send a pm with that one.
The minimum vdrop for the shunt is 6-7v even more. You need at least 5v across the ccs and the rest to account for the mains variations.
With a 26v ps you can set the shunt for 20v.
The minimum vdrop for the shunt is 6-7v even more. You need at least 5v across the ccs and the rest to account for the mains variations.
With a 26v ps you can set the shunt for 20v.
Oops, I had missed that post. Good idea, and will keep this in mind instead of cutting traces.
It mostly depends on what you have after the transformer and also mains variation.
For the digital part I used 6v/800ma because I used the smd ldos on the power supply pcb. These are low drop so 6vac can do it.
If you use the through hole ones, these have a higher vdrop so you need a bigger ac voltage and you need also to use heatsinks for them.
Same thing for the analog part, you want your ps to give you at least 31vdc when loaded, 24vout+ 7vdrop for the shunt. If you count in for -10% mains variation you will want to add 2-3v for a total of 33-34v.
If you use the ac/dc pcb from the gb it has some ptc fuses in the secondary of the trafo that will lower a bit the ac voltage.
You want your ac winding current to be 3x the dc current.
Try to make a simulation with psu designer first of ordering the transformer.
For the digital part I used 6v/800ma because I used the smd ldos on the power supply pcb. These are low drop so 6vac can do it.
If you use the through hole ones, these have a higher vdrop so you need a bigger ac voltage and you need also to use heatsinks for them.
Same thing for the analog part, you want your ps to give you at least 31vdc when loaded, 24vout+ 7vdrop for the shunt. If you count in for -10% mains variation you will want to add 2-3v for a total of 33-34v.
If you use the ac/dc pcb from the gb it has some ptc fuses in the secondary of the trafo that will lower a bit the ac voltage.
You want your ac winding current to be 3x the dc current.
Try to make a simulation with psu designer first of ordering the transformer.
Think I figured out the regulators, etc. from my previous question.
For Eric's PSU, the Schottky rectifiers proposed (MBRS4201T3G) are on extended backorder. I came up with the following Micro Commercial Components SK4200L-TP, which seems to have the same parameters (Mouser 833-SK4200L-TP). Any thoughts, or does anyone have a better sub for these?
For Eric's PSU, the Schottky rectifiers proposed (MBRS4201T3G) are on extended backorder. I came up with the following Micro Commercial Components SK4200L-TP, which seems to have the same parameters (Mouser 833-SK4200L-TP). Any thoughts, or does anyone have a better sub for these?
I think I am going to use the std. regulators on the Logic Supply board, and go with a 4x24V 2x8V transformer. Any comment? The current limit on the LDOs bothers me a bit.