12V regulator
Hi
I just built tho regs +-12V using LM 317 / 337 and can not get more than 11V on the 317 and -8V on the 337.
I used 5% resistors 120ohm R1 and 1k + 47ohm R2.
Can anyone help on this matter ?
what seems to be the problem ?
I really would apreciate some help.
Ricardo
Hi
I just built tho regs +-12V using LM 317 / 337 and can not get more than 11V on the 317 and -8V on the 337.
I used 5% resistors 120ohm R1 and 1k + 47ohm R2.
Can anyone help on this matter ?
what seems to be the problem ?
I really would apreciate some help.
Ricardo
Was it the raygulators from post on the previous page?
If so, R1 (LM317) and R3 (LM337) should be 1.5K, while R2 and R4 respectively should be 120 ohms...
If so, R1 (LM317) and R3 (LM337) should be 1.5K, while R2 and R4 respectively should be 120 ohms...
Ricardo,
What load have you got on the outputs when you're making the measurements ?
Cheers,
Jon
What load have you got on the outputs when you're making the measurements ?
Cheers,
Jon
Hi,
None, in that case no - I was thinking about the output dropping under load.
The 120R should be enough for the regulator to actually regulate.
What volt drop are you getting across the transistor and the zeners ?
Cheers,
Jon
None, in that case no - I was thinking about the output dropping under load.
The 120R should be enough for the regulator to actually regulate.
What volt drop are you getting across the transistor and the zeners ?
Cheers,
Jon
JonHarrison said:
I am not using any transistors or diodes... only two resistors and a 10uF Tant cap.
Please see the original layout from Ray
Regards
Ricardo
RCruz said:
I got it right now.... The tant caps where innadecuate so I am using 120uF Pana between the common and the output in both cases and the output is now +-12V
Thank you
Ricardo
Muting relays?
Back around post 4711 or so (page 189), there were a couple pictures of a muting relay circuit (Rays?). Any particularl realys you guys find that work well? I'm putting a realy muting circuit into my Rotel RCD855 (along with a discrete I/V stage) and had planned on using an Omron G6A-234P-ST-US-DC12 http://oeiwcsnts1.omron.com/ocb_pdf...86929DE586256FC7006173ED/$File/D20G6A0305.pdf, but will switch to something else if this one isn't fast enough, etc. Thanks for any help!
Chris
Back around post 4711 or so (page 189), there were a couple pictures of a muting relay circuit (Rays?). Any particularl realys you guys find that work well? I'm putting a realy muting circuit into my Rotel RCD855 (along with a discrete I/V stage) and had planned on using an Omron G6A-234P-ST-US-DC12 http://oeiwcsnts1.omron.com/ocb_pdf...86929DE586256FC7006173ED/$File/D20G6A0305.pdf, but will switch to something else if this one isn't fast enough, etc. Thanks for any help!
Chris
Hi Chris,
This one looks good. For muting, it's best to use a so called 'small signal' relay, with gold plated contacts. Most of the times you will not be switching any signal (that's called 'dry' switching), and this way the contact resistance is low enough to make sure the output is properly clamped to ground.
Regards,
Ray
This one looks good. For muting, it's best to use a so called 'small signal' relay, with gold plated contacts. Most of the times you will not be switching any signal (that's called 'dry' switching), and this way the contact resistance is low enough to make sure the output is properly clamped to ground.
Regards,
Ray
RCruz said:
Hi,
The 10uF tants should be fine, I use them in my rayregs. Sounds like you maybe didn't get the polarity correct when you fitted them and they blew.
Regards
Pete
HiChivvyp said:
maybe that´s true ... or maybe the caps where already faulty when I monted them.
Right now I am using 120uG Pana linking the outputs to the common ground in the regulators.
I am not following Ray´s schematic because I always noted a big drop in output whenever I placed the cap parallel to R2. in the LM337 -12v reg.
Can you comment on that ?
Best Regards
Ricardo
RCruz said:
Beware that you have the polarity correct. For the LM337 the plus of the capacitors goes to GND.
Ray
6h5c said:
Thank you Ray
I am using the correct polarity but my schema is different from yours.
I did not put the cap in parallel with R2 as you indicated because I noticed a big drop in the output.
I decided to put the cap between pins 1 and 3 in the 337 with + linked to pin 1 (common ground).
I would like your comment on this setup before I install it in the CD53.
Best Regards
Ricardo
Not good!
The cap must be parallel to the 1k05 resistor. If you have a drop in output voltage that way, then something else must be wrong. Are you sure you used the right pinning? LM337 is different from LM317! Try adding a 10...47u output capacitor. Maybe you have an oscillation problem.
Regards,
Ray
The cap must be parallel to the 1k05 resistor. If you have a drop in output voltage that way, then something else must be wrong. Are you sure you used the right pinning? LM337 is different from LM317! Try adding a 10...47u output capacitor. Maybe you have an oscillation problem.
Regards,
Ray
I've finally got my discrete stage finished and fitted and it does sound good, especially considering that I have only used standard resistors and 7812/7912 regs.
One thing I am concerned about though, it is very, very quiet. About half as loud as with opamps, is this normal?
Lee.
One thing I am concerned about though, it is very, very quiet. About half as loud as with opamps, is this normal?
Lee.
6h5c said:
Thank you Ray.... I added an output cap and now I have 12v sharp.
The 10uF is still parallel to the 1k05
Note:
I just replaced the opamps and want to remove the output caps.... but I have a 0.022V dc offset.
Can this value hurt my Meridian 101 PreAmp ?
Regards
Ricardo