That would be red-yellow-brown-brown or red-yellow-black-black-brown, for a 1% four or five band resistor.
Ray
Ray
ezdual
Got it working now!
I popped in 2x 100ohm resistors @ R3 & R5 and get +15.10 / -14.40 volts out.
I believe the resistors were within 5%. Should that do? Or should I get some resistors @ 1%?
Thanks,
JG
Got it working now!
I popped in 2x 100ohm resistors @ R3 & R5 and get +15.10 / -14.40 volts out.
I believe the resistors were within 5%. Should that do? Or should I get some resistors @ 1%?
Thanks,
JG
I think I found my case...
HiFi Audio DIY Aluminum Chassis Aluminum Case - eBay (item 190353281526 end time Dec-27-09 07:38:50 PST)
20cm x 29.5 cm x 8cm internal dimensions.
I got to lay out my components and see if they'll fit.
I'd prefer to find something locally.
HiFi Audio DIY Aluminum Chassis Aluminum Case - eBay (item 190353281526 end time Dec-27-09 07:38:50 PST)
20cm x 29.5 cm x 8cm internal dimensions.
I got to lay out my components and see if they'll fit.
I'd prefer to find something locally.
That's great, just two resistors then. The voltage doesn't have to be exactly +/-15V, as long as it is >2.0V higher than the 12V output of the next regulator. 14.4V is a bit lowish, but the 4% tolerance of the LM337 and the 5% of the resistors could lead to 9% in total. If you want an exact voltage with LM317/337, it's better to use a trimmer instead of the 1k1.
The case looks good, but all the way from Hong Kong must mean $$$ shipping...
Ray
The case looks good, but all the way from Hong Kong must mean $$$ shipping...
Ray
These ones from Hammond (Guelph is pretty close to home, eh?) actually don't look too bad, though maybe not big enough if the power supply is in the same box.
Hammond Mfg. - Extruded Aluminum (Metal End Panels) - 1455 Series Enclosures
p.s. How's the weather there these days?
Should I use a couple of trimmers? I believe there 2x 1k1 on board.
I should use only the wiper and one end of the trimmer right?
If you'd like to tune the voltage, sure, but it's not really needed in this case. If you do, connect the free end of the trimmer to the wiper.
Ray
So, I should be ok with +15.11v / -14.40v going into the opamps?
The ezdac schematic says +12v / -12v.
The ezdac schematic says +12v / -12v.
No, that voltage doesn't go to the opamps. This is the voltage that supplies the on-board LM317/337 regulators, and they will in turn regulate down to +/-12V.
Ray
Ray
Right, thats what I meant. 😀
Anyways, I should be good to hook up my ezdac - I'll need a fuse I think, thats about it (and a case) - the 2 smt bypass capacitors can be mounted eventually.
Anyways, I should be good to hook up my ezdac - I'll need a fuse I think, thats about it (and a case) - the 2 smt bypass capacitors can be mounted eventually.
guys, I put my name down on the interest thread for this round of PCBs (2 x dac boards and a PSU) and I followed up as well. I have never received any reply or any indication of what to do. I have most of the parts sitting around and really wanted to see if I could modify one of these for portable battery operated use as well. what do I do?
Hi everyone, have a good 2010!
Battery operation for the ezDAC shouldn't be a problem. You can use two 24V batteries and the ezDual to regulate this down to 15V, and then feed that to the ezDAC board. The on-board regulators will provide the needed 3.3V, 5V and 12V. You will need to tie V1, V2 and V3 together.
Second approach would be to use two 12V batteries and no ezDual. I would tune the LM317 and LM337 for the opamps down to say 8V (that will still give plenty of headroom and allows for the batteries to run low) and connect them directly to the ezDAC board. Well, with a fuse in series of course 😀
Ray
Battery operation for the ezDAC shouldn't be a problem. You can use two 24V batteries and the ezDual to regulate this down to 15V, and then feed that to the ezDAC board. The on-board regulators will provide the needed 3.3V, 5V and 12V. You will need to tie V1, V2 and V3 together.
Second approach would be to use two 12V batteries and no ezDual. I would tune the LM317 and LM337 for the opamps down to say 8V (that will still give plenty of headroom and allows for the batteries to run low) and connect them directly to the ezDAC board. Well, with a fuse in series of course 😀
Ray
yeah I was going to probably go the second route; if I can actually get a board. time to contact the man again and see if I can get the boards. thats what I meant by 'what do I do' but thanks anyway 😉
http://www.diyaudio.com/forums/group-buys/136169-ezdac-group-buy-interest-27.html#post1990658
I'm getting ready to send them out this week, so please get in touch soon. If you e-mailed me earlier, I'm sorry that I didn't get back to you. I've got a lot of plates to juggle these days.
That's o.k., as long as there is no closed metal circuit formed by the mounting bolt through the centre. That happened to me once, when the bolt make contact with the top shell of a metal case. The transformer ran very hot within a few minutes!
Regards,
Ray
Regards,
Ray
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