Hello,
i wanted to design a small universal regulator board since there are some LM317 replacements out there (ldvor.com or sparkos regulators for example)
the sparkos seem interesting in that these are completely discrete... imo discrete opamps have some kind of magic for them, so i thought i make a board which can take LM317 based regulators and with a small circuit change is also completely combatible to the sparkos line up, since i kinda wanna research on which regulator sounds best easly swappable regulators seem awesome to have... i kinda wanna keep my dac build as universal as possible so i might swap certain things out in the future...
the current layout looks like this:
on the right there is the output cap missing im still searching for a good one
input cap will be currently WIMA MKS4 0,1uf, output cap probably nichicon or panasonic 100uf (both values recommended by the sparkos dev)
there is a challenge in that the recommend output cap value for a LM317 is 20uf and for sparkos 100uF but i rather go with sparkos recommendation because i probably wont use LM317 in the end and some aftermarket replacement should handle 100uF better than the LM317 i guess
both switches have to be engaged for the sparkos, this layout with GND connection might be also superior for a own board in the future...
What you guys think?
i wanted to design a small universal regulator board since there are some LM317 replacements out there (ldvor.com or sparkos regulators for example)
the sparkos seem interesting in that these are completely discrete... imo discrete opamps have some kind of magic for them, so i thought i make a board which can take LM317 based regulators and with a small circuit change is also completely combatible to the sparkos line up, since i kinda wanna research on which regulator sounds best easly swappable regulators seem awesome to have... i kinda wanna keep my dac build as universal as possible so i might swap certain things out in the future...
the current layout looks like this:
on the right there is the output cap missing im still searching for a good one
input cap will be currently WIMA MKS4 0,1uf, output cap probably nichicon or panasonic 100uf (both values recommended by the sparkos dev)
there is a challenge in that the recommend output cap value for a LM317 is 20uf and for sparkos 100uF but i rather go with sparkos recommendation because i probably wont use LM317 in the end and some aftermarket replacement should handle 100uF better than the LM317 i guess
both switches have to be engaged for the sparkos, this layout with GND connection might be also superior for a own board in the future...
What you guys think?
Last edited:
i ended up with rubycom yxj 100uf outputcap and 10 uf for the adj pin
i can get the modules assembled via jlcpcb, just the wima MKS4 cap is left
i also did another revision where i put the caps closer the LM317 pins, i have to keep in mind that lm317 replacements take up some space... with the new caps its also completely throughhole now
i can get the modules assembled via jlcpcb, just the wima MKS4 cap is left
i also did another revision where i put the caps closer the LM317 pins, i have to keep in mind that lm317 replacements take up some space... with the new caps its also completely throughhole now
Last edited:
You don't really need S2 as you can just leave the voltage reference section connected to the output for either regulator since it doesn't use much current.
S1 could also be replaced with a 3 pin jumper block to move the ADJ pin to either ground or to the reference point.
Simpler to configure and the jumper block is less $ than two switches.
S1 could also be replaced with a 3 pin jumper block to move the ADJ pin to either ground or to the reference point.
Simpler to configure and the jumper block is less $ than two switches.
hmm call it OCD but i used beefy switches because i think its in the end a better gnd connection for the sparkos... tho i could just add 2 solder joints for bridging them if you decide to permanantly use the sparkos
also with S2 i just wanted to make sure nothing unnessary is connected... i honestly just let the switch in to actually test it ...
but regarding something similar i made this change:
mind the position of C2 ... i think this is the better way todo it ... atleast for the LM317, so i can keep the caps as close as possible to the pins... i think for others it doesnt matter much and on sparkos mode both sides of the cap are grounded
mind the position of C2 ... i think this is the better way todo it ... atleast for the LM317, so i can keep the caps as close as possible to the pins... i think for others it doesnt matter much and on sparkos mode both sides of the cap are grounded
Just looked up the sparkos regulators - what a price!
TBH If I were going to spend that much on the regulator then I would build a board specifically for it without the unncessary switches and just dump the outgoing LM317 based version into the bits box for use on something else later.
If it absolutely has to be a drop in replacement then have the regulator board as a daughter board to wherever it is needed attached with, for example, a dupont connector like the Raspberry Pi GPIO daughter board connection. Pull your LM317 based daughter board out and drop the sparko based one in!
TBH If I were going to spend that much on the regulator then I would build a board specifically for it without the unncessary switches and just dump the outgoing LM317 based version into the bits box for use on something else later.
If it absolutely has to be a drop in replacement then have the regulator board as a daughter board to wherever it is needed attached with, for example, a dupont connector like the Raspberry Pi GPIO daughter board connection. Pull your LM317 based daughter board out and drop the sparko based one in!
not a unreasonable thought... i kinda agree
you mean as in make a 3 pin style socket for the sparkos on whatever board i need (dac board for example?) without daughterboard?
i kinda need a seperate daughter board for regulation after rectifier/smoothing board but if i will design something i will probably make it with a sparkos style connector
i actually just made this: https://www.diyaudio.com/community/threads/tps74a700-regulator-board.411299/
and yea i made them because the sparkos are that expensive, i still wanna try them tho, then i can decide if they are worth it or not
the TPS board will probably cost 5-10 euro to make, its a good price/performance chip i think
i didnt notice before that the ldvor board also use the ADJ pin as GND .... i would have probably really designed this board different but i ordered now 15, lol
tho since its designed this way, after soldering the switch pins together there shouldnt be much degredation than from a specialized board i think..
it might be interesting to test one, i just wanted to keep it simple, i will mainly feed them from a rectifier and smoothing board
you mean for the LM317? well since i use a 6x2 pinheader, i guess you can still attach a heatsink to the LM317
i will for now mainly use the diy regulators i posted above but it might be also interesting to really compare a LM317
how well does nearly 50 years old chip perform?i probably could have made really a dedicated sparkos adapter since these regulator i made also need to run in "sparkos mode" where adj becomes GND... maybe with rev2
Last edited:
For the heatsink I was thinking of this type which is available in different heights, same width/depth.
https://www.rapidonline.com/aavid-thermalloy-sw38-4-heat-sink-to220-10-2-c-w-36-0226
Any TO220 regulator could be used, whether adjustable or not.
https://uk.rs-online.com/web/p/common-mode-chokes/9040284
I know these require a larger pcb, but would widen the appeal I think. Cetainly, I keep looking on ebay and Aliexpress for a universal board.
The only other suggestion, would be for it to provide plus and minus regulated supplies.......
https://www.rapidonline.com/aavid-thermalloy-sw38-4-heat-sink-to220-10-2-c-w-36-0226
Any TO220 regulator could be used, whether adjustable or not.
https://uk.rs-online.com/web/p/common-mode-chokes/9040284
I know these require a larger pcb, but would widen the appeal I think. Cetainly, I keep looking on ebay and Aliexpress for a universal board.
The only other suggestion, would be for it to provide plus and minus regulated supplies.......
i already bought 15 of the boards with the new layout, i probably will try some kind of power noise filter on a seperate pcb for now and may do a second revision in the future
the question about the heatsink is wether i wanna specialize the board for LM317... i honestly just picked this design because there are some aftermarket replacements specially for the LM317, with the current 2x6 pinheader where both pin layouts for LM317 AND LM337 are directly beside eachother i couldnt even just add the heatsink footprint i think, best is probably to just attach a heatsink to the LM317 and plug it in
i will keep this in mind for a second revision, do you know which regulators would be of interest beside the LM317/LM337?
You mean at the same time? you can use two boards, one with LM317 and one with LM337 (or combatible replacement)
hmm these have non combatible pinouts, the only thing that would be possible is to make an adapter board between the 5 leaded TO220 and my LM317 design, this should work fine if these regulator play fine with my selected capacitors, or you might put new caps directly beside the LT3015/LT1965 on the regulator adapter board
but even with these regulators the adj circuit of the LM317 is fairly pointless, you could just go with the sparkos configuration in that case
i might really do a sparkos only board (i just tried to cancel my pcb order) and with the GND/IN/OUT layout you can pretty much adapt any regulator you like, good designs will need GND anyway
if the order cancel goes through i also add a CMC choke, do you just suggest a CMC or a CL (low pass) filter too?