I believe that 36V should be possible, but I need to check.
BTW Did you read Jack Walton's comparative power supply test, measurements and listening tests, in Linear Audio?
jan
BTW Did you read Jack Walton's comparative power supply test, measurements and listening tests, in Linear Audio?
jan
In the interest of reliability, the raw input voltage should not be higher than the total opamp allowed sypply. So for the most opamps that's 36V, but some allow 44V.
Anyway, if the raw input is 36V max, the Vout max should not be higher than (precision guess) 32V or so.
Some safety factor, limit Vraw to say 33V and Vout max to 30V.
Is that not enough for almost all applications?
jan
Anyway, if the raw input is 36V max, the Vout max should not be higher than (precision guess) 32V or so.
Some safety factor, limit Vraw to say 33V and Vout max to 30V.
Is that not enough for almost all applications?
jan
Opa627 will do 36v. What op amp were you considering? I'll try to start fiddling with schematic.
Hello,
What phono stage needs 36 volts anyway ? Is it AC coupled or a tube design? SOme of the lowest noise jfets with high gm will struggle with them voltages.
Most are under +/- 24volts DC...and even that can be pushing it
Kev.
PS. You can cascode the input CCS to waste unloaded headroom or change op amps.
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This should read a cascoded CCS with high gm mosfet output (or possibly pre-load the output) could be used to waste unloaded voltage headroom. I am going to dig out the original PDF and have a re-read. Make sure I am up to speed on it.
A small heatsink is advisable on top of the op amp also. You could also use very linear super-beta type transistors if it's just for a single positive rail.
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It's definitely impressive when an engineering effort "gets it right the first time".
Are you referring to the schematics of Figure 1 and Figure 2 of the article in "Audio Electronics", 2000 issue #4 (see http://waltjung.org/PDFs/Improved_PN_Regs.pdf ). I believe those circuits use a slightly modified version of the PWB layout shown in Figure 4 of the "Audio Amateur" article from 1995 issue #3 (see http://waltjung.org/PDFs/Regs_for_High_Perf_Audio_3.pdf ).
If that is the case, it should be fairly straightforward to simply replicate that layout into a file package that you could successfully send to most of the quick-turn PWB houses. Since the component make/model and basic mechanical layout have already been determined, I'd estimate about 1 - 2 man-days' work. Of course, modifications or "requirements creep" can exponentially increase that estimate.
Dale
Hello,
It would better if Jan designs it. I know he done tests/measurements (no easy task I hear)for Andy (ALW) and liked the PCB layout etc. I remember following the thread at the time. So he's best placed to design/improve it etc.
Kev
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Peranders boards are to be recommended. Here are the Old Colony boards which Jan designed:
At some point I will reconfigure to the shunt design WJ discussed a few months back in AudioXpress.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
At some point I will reconfigure to the shunt design WJ discussed a few months back in AudioXpress.
I've layed out a revised version, using the original circuit from the 1995 series updated with Walts 4/2000 article in Audio Amateur (all available on Walt's website).
I need to do some small tuning but will then place the Gerbers and stuff on my website for free.
Single board for pos and neg version which can be separated.
Such is the pleasure of a rainy Sunday afternoon 😉
jan
I need to do some small tuning but will then place the Gerbers and stuff on my website for free.
Single board for pos and neg version which can be separated.
Such is the pleasure of a rainy Sunday afternoon 😉
jan
Attachments
A Bruno-VC thread might be a stimulant.
e.g. BOM, tips on how to handle that buggar, possibly a component GB (+ang).
Just staring at the C-numbers makes me feel somewhat challenged.
Q1? Check the placement against the heatsink.
Notice also that you have acid traps (angles less than 90 deg) on the pcb, near J1 for instance. I don't use square pads very much. Pretty tight in some locations.
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Yeah I need to check those pinouts. The PCB faithfully reproduces the schematic, but those libs always have multiple pinouts for the same case. Standard procedure, I learned that the hard way 😉
jan
jan
It looks like you are using Altium Designer and if so I really do recommend that you make a pcb project with schematics and layout. Then you can also put intelligent net labels in the schematic and have a nice overview in the layout.