Controlling power on/off offset with output cap?
post-1409577
Post #16 of 30

Garbz

Headphoneus Supremus
Joined
May 19, 2004
Messages
3,573
Reaction score
11
Joined
May 19, 2004
Posts
3,573
Likes
11
now that would even keep my main amp going!
 
     Share This Post       
post-1411119
Post #17 of 30

Garbz

Headphoneus Supremus
Joined
May 19, 2004
Messages
3,573
Reaction score
11
Joined
May 19, 2004
Posts
3,573
Likes
11
Ok here's the latest. The powersupply pre regulator sits at 25.8v. At power-off it takes almost a full second to drop below 4v (i'm running a 12v time delayed relay circuit through a resistor divider so 4v becomes the new critical switchoff votlage).
However post regulator where my newly installed 2200uf cap is still drops too quickly and when i turn off I still get a massive power spike. I can only conclude that 2200uf is not enough to keep this running long enough.

Is there anyway to cause the voltage pre-regulator to drop more quickly so the relay gets triggered earlier? If no i'll have to start whipping up a simple logic board to controll the power-on/off.
 
     Share This Post       
post-1411248
Post #18 of 30

rickcr42

Are YOU talkin' to me?
Joined
Jun 21, 2001
Messages
13,874
Reaction score
13
Joined
Jun 21, 2001
Posts
13,874
Likes
13
take the relay voltage right after the rectifiers and before any filter caps
 
     Share This Post       
post-1411391
Post #19 of 30

Garbz

Headphoneus Supremus
Joined
May 19, 2004
Messages
3,573
Reaction score
11
Joined
May 19, 2004
Posts
3,573
Likes
11
firstly i don't think that's possible since the capacitor, bridge, and input of voltage regulator would elecrically all be the same point.

To make matters worse i'm using a 24v wallwart, and I am taking the juice direclty from the switch.
 
     Share This Post       
post-1411564
Post #20 of 30

rickcr42

Are YOU talkin' to me?
Joined
Jun 21, 2001
Messages
13,874
Reaction score
13
Joined
Jun 21, 2001
Posts
13,874
Likes
13
Quote:

To make matters worse i'm using a 24v wallwart, and I am taking the juice direclty from the switch.


I had meant to say before the rectifier and just add a single IN4001 from the transformer but the all in one wallwart kinda kills that idea.looks like you are screwed but



What is the deal with your AC going "brown out" on you all the time ?

grid related ? House ? Apartment building with too low a service ?

Maybe instead of a bandaid you need a cure dude
 
     Share This Post       
post-1411638
Post #21 of 30

rickcr42

Are YOU talkin' to me?
Joined
Jun 21, 2001
Messages
13,874
Reaction score
13
Joined
Jun 21, 2001
Posts
13,874
Likes
13
BTW-I think a rechargable Lead Acid Battery supply is your only true fix here.The only time AC is connected is during the charge stage when you are not listening and if designed correctly could give you ten hours or more of continous listening without any shut downs or glitches
 
     Share This Post       
post-1412210
Post #22 of 30

Garbz

Headphoneus Supremus
Joined
May 19, 2004
Messages
3,573
Reaction score
11
Joined
May 19, 2004
Posts
3,573
Likes
11
yeah lead acid batteries are heavy, but it does sound like the way to go.

No idea why our AC browns out all the time, but it's most probably grid related. It's rare that I take my 10min walk to the train without seeing some Energex guys clinging to a pole messing with some wires.

But the point of this problem here is when my computer will get taken to LAN parties. As soon as some ******** brings in his custom water cooling unit all so he could get a few more Hz from the chared remains of an over overclocked ****box, the power goes out! It happens about 6 times during the day at these events.


We actually activily banned one person's rig who had such troubles after he killed the power during a competition, and told him he'll only be allowed in next time AFTER his computer has had a complete inspection
 
     Share This Post       
post-1412274
Post #23 of 30

Garbz

Headphoneus Supremus
Joined
May 19, 2004
Messages
3,573
Reaction score
11
Joined
May 19, 2004
Posts
3,573
Likes
11
actually i'm not quite prepared to throw in the towel yet.

http://www.garbz.com/amp/prot-circuit.pdf

This is something I just whipped up which may help. It's very similar to the last circuit I used with a few key differences.

A zener diode will in theory increase raise the turn-on voltage for the darlington pair, correct? I don't mess with them much so it wouldn't surprise me if that is wrong.

Secondly, rather then letting the cap discharge through the 47-300k that charged it up, a diode and 10r resistor is inplace which will kill the cap instantly.

I figured if this still doesn't cut it i'll raise the cap value, after that it's to that lead acid batter
What you'r opinion on it rick?
 
     Share This Post       
post-1412536
Post #24 of 30

amb

Member of the Trade: AMB Laboratories
Joined
Apr 1, 2004
Messages
4,933
Reaction score
39
Joined
Apr 1, 2004
Posts
4,933
Likes
39
Quote:

Originally Posted by Garbz
A zener diode will in theory increase raise the turn-on voltage for the darlington pair, correct? I don't mess with them much so it wouldn't surprise me if that is wrong.


Yes it would.

Quote:

Secondly, rather then letting the cap discharge through the 47-300k that charged it up, a diode and 10r resistor is inplace which will kill the cap instantly.


I don't think that diode and resistor would actually help much. If the +12V supply actually falls fast enough to make that work, then it should have dropped below the disengagement threshold of the relay even without discharging the cap.
 
     Share This Post       
post-1412785
Post #25 of 30

Garbz

Headphoneus Supremus
Joined
May 19, 2004
Messages
3,573
Reaction score
11
Joined
May 19, 2004
Posts
3,573
Likes
11
Ok guys fixed


I put a diode in series with the powersupply before the regulator. That when when i flick the power off that pre-diode section looses power instantly. No more juice bleeding out of the regulator.

Flick the switch and the relay click off instantly, no more problems! I get a thump of about 2mV


Time for dinner then i need to neaten this mess :S Thanks for everyones help. Especially rick. I still love your capacitor el grande idea
 
     Share This Post       
post-1413757
Post #26 of 30

Garbz

Headphoneus Supremus
Joined
May 19, 2004
Messages
3,573
Reaction score
11
Joined
May 19, 2004
Posts
3,573
Likes
11
Heres a wiring job to scare off rick




 
     Share This Post       
post-1413823
Post #27 of 30

rickcr42

Are YOU talkin' to me?
Joined
Jun 21, 2001
Messages
13,874
Reaction score
13
Joined
Jun 21, 2001
Posts
13,874
Likes
13


love the top plate layout man,very unique thus cool


the bottom part....um....errr......what was the question ?

oh yeah...............


[size=large]buy some terminal strips dammit !!!!!!!!! [/size]


 
     Share This Post       
post-1413955
Post #28 of 30

Garbz

Headphoneus Supremus
Joined
May 19, 2004
Messages
3,573
Reaction score
11
Joined
May 19, 2004
Posts
3,573
Likes
11
Then i'll have them floating around, because i don't have any glue


Anyway it works and is all good. I'll post the final one next week when it's assembled in my computer.
 
     Share This Post       
post-1414001
Post #29 of 30

rickcr42

Are YOU talkin' to me?
Joined
Jun 21, 2001
Messages
13,874
Reaction score
13
Joined
Jun 21, 2001
Posts
13,874
Likes
13
Quote:

Then i'll have them floating around, because i don't have any glue


they don't sell mounting hardware down under wise guy ?


i see two unsuded holes in the top plate that look like ideal for terminal strip tie downs.

BTW- i do hope you plan to cover those exposed mosfet leads,just looking for a short if you accidently drop a pen or something on them

PFFFFFFT ! Release the magic blue smoke from the box !
 
     Share This Post       
post-1414448
Post #30 of 30

Garbz

Headphoneus Supremus
Joined
May 19, 2004
Messages
3,573
Reaction score
11
Joined
May 19, 2004
Posts
3,573
Likes
11
Yeah i will. I'm waiting on a trip to jaycar where i'll buy some liquidised electrical tape which i'll smear on. Also around the insides of thoes slits i've cut incase a pin gets bent.

The 2 holes were for doing something creative, i'm not sure what yet but I think i'll mount a disc halfway up the tube just for visual effect which will be bolted into thoes holes.

Either way considering the ammount of movement this thing will get I'm going to stop just short of dunking the entire thing in silicon
 
     Share This Post       

Users Who Are Viewing This Thread (Users: 0, Guests: 1)

Top