| Nuuk |
| Sorry, but what are we meant to be looking at? :scratch: |
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| carlosfm |
Gotta run.
Oh...
How do I get out of here?:bawling: |
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| carlosfm |
:eek: :bigeyes: :bawling:
That will not work.
I don't understand that signal ground.:scratch:
Take a look at Nuuk's excellent page, you'll find information there. |
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| Nuuk |
| quote: | | That will not work. |
Carlos has spoken ;) Actually I am not so sure. The only mistake that I can see is that pin 7 should be connected to the signal ground star.
When I originally did my GC, I connected pin 7 to the power star and got what sounded like too much bass!
| quote: | | Take a look at Nuuk's excellent page, you'll find information there. |
Carlos has spoken again and I can't disagree with him this time :) |
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| Nuuk |
| Correct me if I'm wrong but shouldn't a polarised input cap have the positive leadout facing the input? I hadn't thought about this on my GC as the Black Gate NX-Q is non-polarised. |
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| carlosfm |
| quote: | Originally posted by Nuuk
Correct me if I'm wrong but shouldn't a polarised input cap have the positive leadout facing the input? I hadn't thought about this on my GC as the Black Gate NX-Q is non-polarised. |
I've seen if both ways in commercial products.:dodgy:
What is confusing me here is the R2 resistor, the signal ground and the input.
The sketch is a little confusing. |
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| JOE DIRT® |
positive should be on the input side for the cap...atleast thats the way I`ve always arranged it
DIRT® |
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| Nuuk |
| quote: | | What is confusing me here is the R2 resistor, the signal ground and the input. |
Carlos, if you don't have a pot/attenuator as part of the GC circuit, powering it up without anything connected will cause problems.
So a resistor is soldered between the input and ground that takes the place of the ground leg of the pot/attenuator.
So, other than the ground connection from pin 7, which should go to the signal ground; and the polarity of the input cap, that circuit would seem to work fine.
If you want to refine it a bit, the input resistor could be put at an angle so that it mirrors the feedback resistor and the input cap could then be moved further up and closer to the chip, shortening the signal path.
Then R2 and the signal star ground could be moved closer to the chip as well making it possible to reduce the size of the PCB by almost half! :nod: |
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| S.C |
| So is this layout work, as long as I fix the Cap +/- position?:scratch: |
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| S.C |
| quote: | Originally posted by JOE DIRT?
positive should be on the input side for the cap...atleast thats the way I`ve always arranged it
DIRT? |
:clown: Hehe, I didn't know, cuz that sketch didn't say so. Thx. :devily: |
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| S.C |
| quote: | Originally posted by Nuuk
Carlos, if you don't have a pot/attenuator as part of the GC circuit, powering it up without anything connected will cause problems.
So a resistor is soldered between the input and ground that takes the place of the ground leg of the pot/attenuator.
So, other than the ground connection from pin 7, which should go to the signal ground; and the polarity of the input cap, that circuit would seem to work fine.
If you want to refine it a bit, the input resistor could be put at an angle so that it mirrors the feedback resistor and the input cap could then be moved further up and closer to the chip, shortening the signal path.
Then R2 and the signal star ground could be moved closer to the chip as well making it possible to reduce the size of the PCB by almost half! :nod: |
Look at the 4th one.
:nod: :nod: |
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| Nuuk |
S.C. have a good look at this.
I have shown a non-polarised cap on the input but as said before, the + side of a polarised cap is connected to the input socket.
Apart from that, you can see where the connections go to. Please note, pin 7 is connected to the signal ground. |
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| S.C |
| OK, I had corrected the Pin 7 problem. The 4 edition was done and I put it on the same link http://hk.geocities.com/solomon_choi/GC2.html. It is exactly half of the orignial. :) :cool: Still any comment, or mistake? :scratch: |
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| carlosfm |
| quote: | Originally posted by JOE DIRT®
positive should be on the input side for the cap...atleast thats the way I`ve always arranged it
DIRT® |
Me too.
| quote: | Originally posted by Nuuk
Carlos, if you don't have a pot/attenuator as part of the GC circuit, powering it up without anything connected will cause problems.
So a resistor is soldered between the input and ground that takes the place of the ground leg of the pot/attenuator.
So, other than the ground connection from pin 7, which should go to the signal ground; and the polarity of the input cap, that circuit would seem to work fine.
|
I know, but I use the 22k resistor from the inv. input to ground (soldered to the pin) and there's where I do the signal star ground.
You can imagine the board (and the signal path) will be much shorter.
Anyway, the 22k resistor I use is there to help the stability of the chip, even with no input connected.
So, I don't use a resistor before the cap on my power amp GC.
S.C., your circuit will work, it's just not optimized.
Make the things as small as you can or you'll have humm. |
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| Nuuk |
Yes, that should work OK.
If you want to fine tune it though, I would move PG and MG slightly to the left (they can go under the cap if necessary) and put the input where MG is now, run R2 from input to SG (which could go up slightly ) and then connect the input to the input cap. |
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| Nuuk |
| quote: | | I know, but I use the 22k resistor from the inv. input to ground (soldered to the pin) and there's where I do the signal star ground. |
Good morning Carlos. Der! I had never thought of that 22K doing the same job as the resistor to ground on the input but of course it does :ashamed:
But this is yet another reason to differentiate between the two versions of the minimised inverted GC circuit.
Now when I tried the 18K/22K to ground, the sound of my GCs was nowhere near as good as with the single resistor to ground and I couldn't understand why. Perhaps it was because I was using the 56K to ground as well! :idea:
This all goes to show that even with a circuit as simple as the minimised GC, the permutations are still vast! :nod: |
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| carlosfm |
S.C.,
Instead of trying to explain, I did some mods to your circuit, I hope it's clear enough.
They are in blue.
You should join the two PSU caps, don't run wires around.
With these changes you'll get around half the board size, and a much better layout. |
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| Nuuk |
| What's that blue thing? Portuguese censorship ;) |
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| carlosfm |
| quote: | Originally posted by Nuuk
What's that blue thing? Portuguese censorship ;) |
:D
That blue thing means that S.C. should join the two caps to make a ground star.
The way he had, with wires going back and forth to a "ground" point is not a good thing to do.
So, it's censured.;) |
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| Nuuk |
| quote: | | That blue thing means that S.C. should join the two caps to make a ground star. |
Yes, I agree, I hadn't noticed that before. Must be the heat :redhot: |
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| carlosfm |
| quote: | Originally posted by Nuuk
Yes, I agree, I hadn't noticed that before. Must be the heat :redhot: |
Yesterday in the news they were saying it has been hot in the UK.
30º C!
And it's raining here.:bawling: |
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| S.C |
OK, I will do the refine shortly after the summer school today. Thx alot ! ;)
P.S Man my parts from partsconnexionhadn't arrive yet T_T.:bawling: |
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| S.C |
| quote: | Originally posted by carlosfm
S.C.,
Instead of trying to explain, I did some mods to your circuit, I hope it's clear enough.
They are in blue.
You should join the two PSU caps, don't run wires around.
With these changes you'll get around half the board size, and a much better layout. |
Did I do that already on my 3th and 4th edition? There are 5 pics on that site. I will still refine it, but I just curious.
:cannotbe: |
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| carlosfm |
S.C.,
I have to give you sincere congratulations.
You investigated, made a layout of your own and before doing anything you asked if that was OK.
Now you're going to do your GC.
We are here to help, always feel free to ask.;)
It's better to do the way you did than an unexperienced person end up with a cap blown in his face.:devily: :eek: |
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| S.C |
| quote: | Originally posted by carlosfm
S.C.,
I have to give you sincere congratulations.
You investigated, made a layout of your own and before doing anything you asked if that was OK.
Now you're going to do your GC.
We are here to help, always feel free to ask.;)
It's better to do the way you did than an unexperienced person end up with a cap blown in his face.:devily: :eek: |
Thx carlosfm, I hopw I didn't annoying you guys about stuffs. I always ask some much, cuz I don't trust myself. It just like I always check the ans before I move on to next calculous question.
:( :bigeyes: :eek: :bawling: :dodgy: :scratch: :idea: :nod: |
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| S.C |
Damn, nice things always come at last. The final one is out ! 5th edition. The Ground under Cap really help me allot! Thx again for eveyone who helped me in this tread. http://hk.geocities.com/solomon_choi/GC2.html
P.S:bawling: Partsconnxion.com just charged me, that's mean I need to wait about a week to begin all this. T_T |
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| S.C |
| Damn, I just got my parts from partsconnexion.com. I always thought "The BlackGate" is a big *** components, but I was wrong. Edition 6 cut off 1/3 on the width. :):mafioso: same link. |
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| Nuuk |
Hi S.C. I second what Carlos said about your sensible approach to building your GC! ;)
I have looked at V6 and there is just a little bit more tidying up that I would do.
On the signal input, I presume that the circle shown off the PCB is the input phono socket. You show three wires coming from that to the PCB but you only need two.
The wire carrying the signal goes to a hole and then to R2 but you can also just put a track from that hole straight to the + terminal of C1. That means that you do not need the other wire carrying the signal to the PCB.
Finally, if you initend to earth any casework, you should do it via a 100R resistor with a small capacitor in parallel so you may wish to make provision for those items on the board. I would suggest they would be best put in on the bottom of the board near MG. The PCB would need to be made a little bigger but it is so small anyway, that will not be a problem. |
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| carlosfm |
S.C.,
Still one little thing to optimize, because you're giving unnecessary turns with wires.
Check this change I made.
I hope it doesn't look too bad, I almost ruined your sketch.:devily:
Make this correction on your sketch. |
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| Nuuk |
Good morning CFM!
That's a good idea but I would move the resistor SE a little to make sure it clears the caps. And of course the wire from the phono socket will need it's own hole.
BTW - how do you show your images when you don't have web space - or do you? |
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| carlosfm |
Hey Nuuk,
We were saying the same thing at the same time.;)
You hit "submit reply" before me because the sketch was too big to fit in the page and I had made some resizing.:dodgy: |
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| carlosfm |
| quote: | Originally posted by Nuuk
Good morning CFM!
That's a good idea but I would move the resistor SE a little to make sure it clears the caps. And you still don't need the two signal connections to the phono socket. |
Good morning Mr. Decibel.;)
Yes, well... I didn't do better bacause I had to delete part of the sketch.
Let's see what S.C. makes now, I think he got the piccture. |
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| S.C |
Good morning Nuuk, and Carlosfm,
I did the change, but now I'm doing a realiztic check. The resistior is kindla big. I rather need to change the layout to a little bit bigger or just simplly cut the un used led of LM3875TF. Which opion do you guys prefer? On the earthing case thing, is it I just connect the PG to a 100 Ohm resistor and a Cap (can it be 16v?) than to the MG or the case? |
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| jackinnj |
the pins of the LM3875 are not aligned the way you have them -- I guess you are using the freeware from www.expresspcb.com )there is a 3.4 mm (about 1/8th inch) space between the odd OR even pins as seen horizontally. They are spaced about 400 mills front to back.
They don't exactly fit on the expresspcb grid. Before you have your proto's burned, print out and make sure the parts fit.
In ultiboard I designed a custom device for the PCB layouts I use. Note also -- the width of the pins on these devices is a bit larger than a DIP IC -- you will have to specify
take a look at page 17 of the PDF from National. |
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| S.C |
| But I can put the LM3875 in this way, that's way I draw the layout like bez I put the LM3875 on first see is it fit. |
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| Nuuk |
S.G. The resistor between MG and the case connection should be 100R not 100K and the capacitor is in parallel with it and 0.22uF should be fine (use a small film type).
One end of the resistor/cap goes to MG; the other end is connected to the metal case. |
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| jackinnj |
| don't try to bend the pins to fit a 100 mil grid, they'll break. the pins for the 1876 -- (more pins than the 3875 I believe, but same layout) go something like this: |
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| S.C |
| Dip is a good idea, but I already bended the leg b4 I start this thread. It fit the board, but question is do you think it is a good idea to cut off leg 5?:scratch: |
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| S.C |
| V9 is on, I hope I understand what you say Nuuk. My English kindla poor too.:rolleyes: |
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| Nuuk |
S.C. This shows the resistor/cap in parallel connected to PG with a hole at the other end to connect a wire to the metal case. |
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| carlosfm |
| Some serious copper.:devily: |
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| Nuuk |
| quote: | | A Question about power supply, should I follow the LM3875 Data sheet's equcation to calculate the Max PS, or just use whatever. However, I don't know how to measure the Max V out of my laptop, MD recorder, and the CD player. |
S.C. if you are not completely worn out by drawing all those circuit diagrams, I would suggest building the 'standard' GC PSU as shown on my FAQ page .
Go with a 18-0-18 transformer and MUR860 diodes and you won't go far wrong.
And in all the posts that I have read about the GC, I haven't yet seen anybody complain that a device wouldn't work with the GC because of an impedance mismatch. ;) |
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| carlosfm |
S.C.,
The voltage for the transformer is 2x22V.
It's about the ideal, at least for me.
But from 18 to 22V you can use any.
If you're in for two transformers, 2x22V at around 160~200VA.
If you're going to use one transformer, 2x22V at 320~400VA. |
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| S.C |
| Ok, then I whatever I got that under 40V. |
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| S.C |
| quote: | Originally posted by carlosfm
Some serious copper.:devily: |
Is it good to have that much copper?:scratch:
On the previous post, I mean I need two around 35V, but whatever Amp I got. |
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| ronc |
IMO on any NC lead , it gets clipped off as close to the chip as possible, but all i use is P2P wiring.I have found out (the hard way) to bend any real functioning chip leg as little as possible or not at all.
ron |
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| carlosfm |
| quote: | Originally posted by S.C
Is it good to have that much copper?:scratch:
|
Yes, it is.
Good ground and thick tracks for the PSU pins.
This isn't a preamp... |
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| S.C |
| OK Let me try to send that to ADvcircuit, and had convertion of the ExpressPCB, then let them analyze too.:devily: Hehe, can't wait for the board. |
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| Nuuk |
| quote: | | I think I gonna send this |
Looks OK to me! |
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| S.C |
| Also plz help me out on the other pic which locat under the circuit pics. I don't know how to test those stuff, and Nuuk, your site that wiring tips won't help me. It is because the coloring code of the transfromer isn't the same.:scratch: |
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| Nuuk |
| quote: | | Also plz help me out on the other pic which locat under the circuit pics. I don't know how to test those stuff, and Nuuk, your site that wiring tips won't help me. It is because the coloring code of the transfromer isn't the same. |
Sorry S.C. I don't think that I can help you on this one. IF you know what you are doing, the only way to find out what those transformers are, is to connect them up and measure them. Even then you may not know what they are rated at.
And it should go without saying that you must know which are the primary leads and which are the secondary leads BEFORE connecting them to a mains supply. |
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| carlosfm |
| quote: | Originally posted by Nuuk
And it should go without saying that you must know which are the primary leads and which are the secondary leads BEFORE connecting them to a mains supply. |
You can look at the wires.
The primary wires are much thinner.
But if you have 3 wires on the primary (115, 230...) and no indication at all, you'll have difficulty in knowing which ones to connect. |
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| S.C |
| :bawling: :bawling: :bawling: :bawling: :bawling: :bawling: :bawling: :bawling: :bawling: |
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| Nuuk |
With a 25.2 secondary voltage, that transformer will cause the LM3875 to run very hot.
I would look for something between 18-22V and preferably a torroidal type. |
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| S.C |
| even if I had a heat sink? |
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| Nuuk |
| quote: | | even if I had a heat sink? |
Well, I have two PSU's, one with 27V rails and one with 36V rails.
On the smaller supply I have no problems but with the bigger one the thermal protection cuts in from time to time. I'm not using the biggest heatsinks due to the design of my small monoblock cases but it is 10MM thick! |
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| S.C |
| I think 25V will be fine, but I need a good Heat Sink. |
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| Nuuk |
| quote: | | I think 25V will be fine, but I need a good Heat Sink. |
Do you mean 25V secondaries or 25V rails?
The rail voltage will be the secoondary voltage multiplied by 1.414. |
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| S.C |
Secondery 20VDC x 1.414 = 28.28VDC rail Voltage.
I just finished the amp section at 3:30am. I hope it work.:goodbad: I used some copper foil tape to make my layout, it looks kinda ghetto and dirty , un or gan lize. :dead: hk.geocities.com/solomon_choi/GC2.html |
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| Nuuk |
| quote: | | Secondery 20VDC x 1.414 = 28.28VDC rail Voltage. |
Absolutely fine. :nod: |
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| S.C |
| Do you think I can test the amp section by connecting 3x9V=27V on each side of the Chip? and connect ground on a piece of metal. |
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| S.C |
| but where will the MG go? |
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| Nuuk |
| Pos rail (+ -)(+ -)(+ -) Zero Volts rail (+ -)(+ -)(+ -) Neg rail. |
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| S.C |
| I didn't hav a bridge yet |
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| S.C |
| I hook up the way you did, he speaker will Bi....... bu ubu ub ubbu ub ubuub ubub b. then stop. Then I connect the CD player and play. It is no sound at all like I didn't connected it . |
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| Nuuk |
S.C.
1 You don't need a rectifier bridge when using batteries as the output from batteries is DC already.
2 It sounds as though their may not be enough charge in those batteries.
3 Did you measure the DC offset on the speaker terminals before connecting your speakers? |
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| carlosfm |
| quote: | Originally posted by S.C
Do you think I can test the amp section by connecting 3x9V=27V on each side of the Chip? and connect ground on a piece of metal. |
What batteries are those?
Amp rating?
Anyway, with 3x9V batteries you can't test the amp.
If you connect them in series you'll get 27V.
But that's + and ground.
You can't test the amp this way, you would have to change the layout.
You could use two 9V batteries and join one + with another - and get +, - and ground.
But the voltage (+/- 9V) will be too low, I have doubts that the chips will even power on.
You should have above +/- 12V. |
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| S.C |
| I have an extra question about a power supply. Nuuk, did you remember my last thread had a weak power supply but only enough for one chip. I can use that. The question is the 0V = the COM port right? There is two +/- Out and a Com Port.:scratch: |
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| Nuuk |
| quote: | | I have an extra question about a power supply. Nuuk, did you remember my last thread had a weak power supply but only enough for one chip. I can use that. The question is the 0V = the COM port right? There is two +/- Out and a Com Port |
Sorry again. I have no idea. Perhaps somebody else can answer this one. :( |
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| S.C |
| Y...................................e.............................s ! I did it !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! The power just as I through, 0v to com port. and the left channel work @_@ ! Yes ! I better made a nice power supply n ow.:nod: |
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| Nuuk |
Well done S.C. Great feeling isn't it? ;)
Yes, it seems that it is time for you to make a decent power supply now! |
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| carlosfm |
Aaaaahhhhh...
This feels good.
Welcome to the club, S.C.;) |
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| S.C |
YA, it feel good. The sound as you guys said is tight and realistic. It didn't have too much colored sound.:bigeyes: I can turning it up to really loud .:cool: 24V rail will be an idle powersupply. 20-25V Supply is the way to go.:bigeyes: :devilr:
Thx a lot you guys, you guys have been helpping me a lot since I started this board. A guy call Jon wanted to produce some board out of this circuit, and good luck to him too. People enjoy. :) |
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| S.C |
A few more questions,
1. Do I connect all the ground to the Case any where? Even the ground from the PCB"the input ground" and the "To Case ground"? However, since the input RCA screwed on the case and ground, should I still connect "the input ground" from the PCB to the RCA pot or just the case? And should I attach the female power pot that ground to case?
2. I ordered a 330VA 25/25V TorXXX transformer with 4 wires secondart, how can I connect it to two bridge? and how to make 2 0V out of dual secondary?
P.S Man my transformer will be devilevr by Aug 13, and I'm gonna back to Hong Kong by 14.........T_T
:bawling: |
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| Nuuk |
Hi Solomon,
I would keep your phono sockets isolated from the metal case. Then connect the power ground star on the PCB to the case via a resistor and cap in parallel ( see the DDFAQ page).
To wire up your transformer for two rectifier bridges, connect each pair of secondary wires to the ~ connections on the bridges and then connect the -DC point of one bridge to the +DC point on the other bridge. The mid point of that connection is the 0V which should then be connected to the power ground star on the amp circuit. |
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| S.C |
| quote: | Originally posted by Nuuk
Hi Solomon,
I would keep your phono sockets isolated from the metal case. Then connect the power ground star on the PCB to the case via a resistor and cap in parallel ( see the DDFAQ page).
To wire up your transformer for two rectifier bridges, connect each pair of secondary wires to the ~ connections on the bridges and then connect the -DC point of one bridge to the +DC point on the other bridge. The mid point of that connection is the 0V which should then be connected to the power ground star on the amp circuit.
|
Nuuk thx for the reply,
but nuuk, didn't I already have a cap and a resistor parallel on my PCB? See http://hk.geocities.com/solomon_choi/GC2.html the "MG" pot and the "TC" pot on the right hand corner.
(MG=Main Gound=0V, TC=To Case) so just connect the case to "TC" pot, right? and "MG" to the 0V
After I isolated the phone sockets from the case and connect the ground to the "IG" right? (IG=Input Ground)
As you say I connect a wire from one +V DC bridge to another -V DC, but I have only one +/- left am I connecting it parallel to two Amp section? or what?
P.S: Do you have any tips for isolating the case from the phone sockets? That's why you guys using Al case.:bawling: |
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| GrahamnDodder |
Nuuk-
I have been learning from SC's thread, even tho I am going P2P wiring with my GC.
I have a little bit of confusion with the ground, too.
Power Gnd goes to case via a cap and resistor. Values? Wattage/voltage rating? I would hope there is not too much current/voltage assumed to be across this connection...
Also Power Gnd goes to Sig Gnd, straight connection.
But the thing I am most confused about is that if power gnd, which is a DC Virtual Ground, goes to the case via a cap and resistor, and the earth ground, which is a "true" ground, also goes to the case, is that going to cause me problems?
Or does the fact that one is an A/C earth and the other is a DC virtual, and they are separated by a transformer, make it okay?
Assuming his thingie works, I should have lots of good quality pix of the process when I am done.
Thanks,
GnD |
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| Nuuk |
Solomon. - sorry I forgot that we made provision for the resistor/cap on your PCB. In that case you only need to connect it to the case.
You can buy insulated phono sockets or make a panel from a non-conducting material to mount the sockets on.
This is the circuit diagram for using two rectifier bridges that used to be on the chip amp forum.
I think that it should work OK for two channels but perhaps somebody else can confirm that.
Graham, the values for the resistor and cap are given on the FAQ page at Decibel Dungeon. |
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| GrahamnDodder |
Nuuk-
Thanks.
I see that your diagram does not include the earth ground on the AC. Are you not using a 3-way plug? Are the different (2-prong only) over there?
But my main concern is still the idea of connecting both the AC earth and the DC virtual ground to the same chassis? Is that somehow okay becuse of the transformer isolating the two?
Thanks,
GnD |
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| Nuuk |
| quote: | | But my main concern is still the idea of connecting both the AC earth and the DC virtual ground to the same chassis? Is that somehow okay becuse of the transformer isolating the two? |
The case is connected to earth and the powerground star (0V) is connected to the case via the resistor/cap. If you connect directly, the case may act like an antenae.
We do have three pin plugs in the UK. I connect the earth wire to the power supply casing and then run a wire from there to the casing of the amplifier. |
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| S.C |
Sorry Nuuk, I think I didn't make myself clear. I'm planning to use one 330VA 25/25V transformer to power 2 amp section( Stereo)and 1 bridge each side.
Bridge 1- Right Amp section
+/- & 0V
1 transformer
+\- & 0V
Bridge 2- Left Amp section
How to do this?:dead: |
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| S.C |
| quote: | Originally posted by GrahamnDodder
Nuuk-
But my main concern is still the idea of connecting both the AC earth and the DC virtual ground to the same chassis? Is that somehow okay becuse of the transformer isolating the two?
|
I think your guess is right, cuz most of the Torxxx transformer grounding on the screw on the core. So you screw/blot on the case and following this  it grounded. Also if you using an AL case will not matter at all cuz it don't conduct electricity.:devily:
I think you come from Headfi/ headwize right?:devilr: |
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| Nuuk |
| quote: | | Also if you using an AL case will not matter at all cuz it don't conduct electricity. |
Solomon, I couldn't go to bed tonight without pointing out that aluminium DOES conduct electricity! :att'n: |
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| S.C |
| Opps, I thought my muti meter didn't bee...beee equal to no connection. Sorry, man have a nice sleep. It is 3:01 PM here. :bigeyes: |
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| carlosfm |
| quote: | Originally posted by S.C
Opps, I thought my muti meter didn't bee...beee equal to no connection. Sorry, man have a nice sleep. It is 3:01 PM here. :bigeyes: |
If your multimeter doen't bee...beee, it means that it's not conducting.
With a little luck, what you have there is anodized aluminium, and, more luck still, you made a hole, mounted the chip with thermal paste and a screw and it may not be touching anywhere that's not anodized (like the internals of the hole you made).
I have L-shaped aluminium bars, anodized, that simply don't conduct, only on the extremes where they were cut. |
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| S.C |
| I c, and yeah I just touched the Al surface only. Anyway, can anyone tell me how to connect one transformer to stereo Amp section, and one bridge per channel? or I just connect it like Nuuk said and parallel connect it to the stereo amp? |
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| S.C |
Problems appear:
My transformer, I connect it like you said and I got +/-38V. The fuse won't even blow at 3A fast blow. and I coonect two lights on it it lights up.
However, I started to connect two lights , one light neg ->neg and pos->0V, the second just oppsite. an parallel connect both amp section parallel to the +/-38V, and the 0V join together and connect it to the 0V. Now the fuse start to blow, even I dis connected the amp section. (even 3A slow blow)
I notice something when I close the light and start the amp, one of the bridge freshed and the fuse blow together in a sec after I turned on th amp. One time a light keeping light on thatt flashing side of the bridge, while the fuse already blowed. It keeps on for like 15sec.
Should I try the higher value, or sommething wrong with the bridge? |
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| Nuuk |
| quote: | | However, I started to connect two lights |
Solomon, what lights? I thought that you were building a hi-fi amp! ;) |
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| S.C |
I like lights hehe:cool: , and those are Max4.5V, 0.0030A same as your site. I used 10k+2k resister connect to the neg side. Help me plz, I really want to finish this before I go to Hong Kong. I need to go tomorrow night.
Is it suppose to conduct in the middle part of my bridge? http://hk.geocities.com/solomon_choi/GC2.html picture 4? |
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| S.C |
Oh god I think I burned the MUR860............ I checked the flashed side diodes only K have conduction with the screw hole, but A is gone. However, why there is light on that side when I blow my fuse everytime. The side of the bridge 2 out of 4 only K appear conduction with the screw hole, but not A. The 2 remained are able to make conduction from the screw hole to K and A
P.S Or my guess oppisite will be right?:bawling: :bawling: |
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| Nuuk |
| quote: | | Oh god I think I burned the MUR860............ I checked the flashed side diodes only K have conduction with the screw hole, but A is gone. However, why there is light on that side when I blow my fuse everytime. The side of the bridge 2 out of 4 only K appear conduction with the screw hole, but not A. The 2 remained are able to make conduction from the screw hole to K and A |
Solomon, I can see nothing on your site!
And I can't understand what you are saying about the rectifier bridges. Have you mounted the diodes on a heatsink? If so have you insulated them?
What is this 'conduction from screw hole' all about? |
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| carlosfm |
:scratch: :scratch: :scratch:
At this time the man must be in Hong Kong.
Without the amp!:bawling: |
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:goodbad: