Max V for amp
Is the module capable of operating up the max rating of the LM3886? I have two 30V transformers that will give about +/-40VDC. The Max operating supply voltage for the LM according to spec is +/42V
Is the module capable of operating up the max rating of the LM3886? I have two 30V transformers that will give about +/-40VDC. The Max operating supply voltage for the LM according to spec is +/42V
Re: Max V for amp
No, for a couple reasons. That voltage will likely cook the turn on delay circuit. It will also make the resistors in the zener shunt regulators for the LM318 too hot. You could likely make some adjustments to handle it, such as a higher voltage relay, etc.
glt said:
No, for a couple reasons. That voltage will likely cook the turn on delay circuit. It will also make the resistors in the zener shunt regulators for the LM318 too hot. You could likely make some adjustments to handle it, such as a higher voltage relay, etc.
Thanks, Brian,
Can you point me to the module's schematic? The other thread is too long and after 30 pages or so I could only find the schematic of the circuit which does not include the zener regulator or startup circuit
Can you point me to the module's schematic? The other thread is too long and after 30 pages or so I could only find the schematic of the circuit which does not include the zener regulator or startup circuit
Take a look at the first post in this thread. It's not perfect but is very close to what is actually on the board.glt said:
If someone has an updated schematic that corresponds precisely to the board, now that would be svelte.
peter
Got the board stuffed. My parts arrived today. Everything fits well now 🙂 You have to push the LM3886T a little bit and the pins just come flush with the bottom side. This is fine as the solder flowed around the pins and filled the hole as well as came out the other side so a good connection is made. The proto is done in immersion silver and the thickness of this silver is 2 mils. What that means who knows but maybe its thicker than the regular HASL that they flow over the traces. Either way I am happy with the board up to this point.
I am working on the enclosure and power supply. Remember I was having transformer trouble and bought a new one from Antek. 600VA so I will be using a huge thermistor CL60 to avoid a bad inrush. So I have some pictures of what I have been working on while working for my parts to get here. Check em out please 🙂
Uriah
Added 3 more pics to the MyRef album. They are all just about the same, but anyway everything fits. I decided to pop some terminal blocks on the input and LED. I could have just soldered, which frankly would be better, but when doing a proto I didnt want to unsolder anything when I remove it.
http://picasaweb.google.com/udailey/MyRef#
Then check out my giant enclosure:
http://picasaweb.google.com/udailey/MyRefEnclosure#
I am working on the enclosure and power supply. Remember I was having transformer trouble and bought a new one from Antek. 600VA so I will be using a huge thermistor CL60 to avoid a bad inrush. So I have some pictures of what I have been working on while working for my parts to get here. Check em out please 🙂
Uriah
Added 3 more pics to the MyRef album. They are all just about the same, but anyway everything fits. I decided to pop some terminal blocks on the input and LED. I could have just soldered, which frankly would be better, but when doing a proto I didnt want to unsolder anything when I remove it.
http://picasaweb.google.com/udailey/MyRef#
Then check out my giant enclosure:
http://picasaweb.google.com/udailey/MyRefEnclosure#
I'm considering using either a single 300Va trafo from Antek or 2 100Va trafos. What are the advantages or disadvantages of either setup? Are there potential grounding issues if I run 2 transformers off of a single mains line?
pete
pete
Pete, I think Brian or Russ might have the best answer there, or AndrewT if he is watching. Andrew always has good advice for that sort of question. Nevertheless, my opinion is that the 100VA wont be enough and the 300 will be fine. If you still go with dual toroids I dont think you will have any problem running them from the same mains power, but I think I would individually fuse them and I dont think it would matter if you use one or two on/off switches. After the switch treat them totally individually except for the shared ground.
Uriah
Uriah
There wouldn't even be a shared ground. they would be totally separate other than primary wiring.
We prefer PayPal. What if something goes wrong and there is a refund in order? Very Very easy with paypal. Not easy with a money order. Consider that this should be as easy as possible for Peter and I as it is already quite a task. To do special jobs for everybody really gets to be a hassle. We were even considering not shipping to other countries before we announced the Group Buy. Easy is the word of the day for this group buy.
Uriah
Uriah
I have a few wires to make up and then I can fire her up. The only thing stopping me tonight is a freaking screw. I dont have one to fit the threads in the heatsink. Off to the hardware in the morning, fired up before noon.
Uriah
Uriah
Well, I got the transformer to hum but the LED is not coming on. I have an AndrewT saftey bulb wired in, no glow on it. I will write back within the hour.
Uriah
I know its not AndrewT's bulb, but I think he has adopted it with more dedication than anyone and lets every newb know to use it.
Uriah
I know its not AndrewT's bulb, but I think he has adopted it with more dedication than anyone and lets every newb know to use it.
LED is lit. Transformer secondaries were tied in wrong. 2 blue and 2 green had the wrong blue and green matched up.
So LED is lit but no music.
Uriah
So LED is lit but no music.
Uriah
Hi,
these bulbs are clever.
You wired the secondaries wrong and the transformer still works on re-wiring and the fuse didn't blow. Magic!
I found the bulb trick on this Forum.
these bulbs are clever.
You wired the secondaries wrong and the transformer still works on re-wiring and the fuse didn't blow. Magic!
I found the bulb trick on this Forum.
But the light never lit and my fuse is intact and only a 2 amp fuse. Its a 150W bulb and I have seen a lot of people using 40W but I knew the inrush current would be high so I got a higher wattage bulb, but under the limit for the fuse.
By the way no resistors ever poofed. Nothing it up except the LED.
Anyway I am doing some tesing with the DMM and will post some observations in the next post.
Responses would be greatly appreciated.
By the way no resistors ever poofed. Nothing it up except the LED.
Anyway I am doing some tesing with the DMM and will post some observations in the next post.
Responses would be greatly appreciated.
start with a low power bulb. If it glows and you have checked that all is working correctly, only then do you swap in a higher power bulb to allow near full voltage to pass to the transformer.
So I did some continuity checks.
First, I checked my RCA for a short. No short on the RCA from Signal Pin to GND.
The next are measurements from Power GND to several points.
POINT CONTINUITY
OGND NO
OUT NO
Signal NO
SigGND YES
Pin7 YES
From Pin 3 to OUT
YES
Arg. This circuit is giving me trouble because of all the caps getting in the way of my continuity checks. Anyone mind giving me some points to check? I have my power supply wired correctly to the board so if you would like me to check for voltages please list them.
Uriah
First, I checked my RCA for a short. No short on the RCA from Signal Pin to GND.
The next are measurements from Power GND to several points.
POINT CONTINUITY
OGND NO
OUT NO
Signal NO
SigGND YES
Pin7 YES
From Pin 3 to OUT
YES
Arg. This circuit is giving me trouble because of all the caps getting in the way of my continuity checks. Anyone mind giving me some points to check? I have my power supply wired correctly to the board so if you would like me to check for voltages please list them.
Uriah
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