Sorry for double post. I forgot to mention that I'm building this for 8ohm speakers and I might use 30v transformer, I haven't decided which one to use.
Bring the two groups of three input/output connections to 0.2inch pitch. It allows use of three way terminal blocks or soldered joints.
Leave lots of space around the 4 caps just in case you want to use 40mm diameter.
Squeeze everything else closer to reduce the size of the PCB.
Increase the width of the high current traces by a factor of 4.
Add an optional snubber R + C across each diode.
Add a snubber R + C across the output.
Add a cap from AC to AC to absorb glitches/pulses coming from the transformer.
Think about adding pads for a resistor in each feed line both before and after the first capacitor. That's 4pair of pads. These pads can be for thermistors and/or inductors and/or resistors. This makes for a very multi-purpose PCB.
Leave lots of space around the 4 caps just in case you want to use 40mm diameter.
Squeeze everything else closer to reduce the size of the PCB.
Increase the width of the high current traces by a factor of 4.
Add an optional snubber R + C across each diode.
Add a snubber R + C across the output.
Add a cap from AC to AC to absorb glitches/pulses coming from the transformer.
Think about adding pads for a resistor in each feed line both before and after the first capacitor. That's 4pair of pads. These pads can be for thermistors and/or inductors and/or resistors. This makes for a very multi-purpose PCB.
30Vac sounds a bit (lot?) high for an 8ohm load.fr1s said:
30Vac can give >48Vdc if mains is running at +6% and the regulation is 10%.
Or, do you mean 30Vac centre tapped which is equivalent to 15-0-15Vac?
here u go 🙂
I found some 1n5401 diodes @ home, are they ok for this?
Also I found out that they are 3A, does that mean that on out put each of my amp's gonna get 3 A or just 1.5?
So if I'm gonna use these diodes does, do I have to get
"3A" +25 0 -25 transformer? (I'm gonna use 25v)
thx for help 🙂
An externally hosted image should be here but it was not working when we last tested it.
I found some 1n5401 diodes @ home, are they ok for this?
Also I found out that they are 3A, does that mean that on out put each of my amp's gonna get 3 A or just 1.5?
So if I'm gonna use these diodes does, do I have to get
"3A" +25 0 -25 transformer? (I'm gonna use 25v)
thx for help 🙂
You get, what your amps ask. If the sum is more than 3 A for more than a few ms those diodes will blow.fr1s said:
Did you read the datasheet? Max rail voltage is 60 V or ±30 V. How much is 25 V times 1,41 plus regulation plus mains fluctutation?fr1s said:
Well I guess I cant use em :/ that's ok extra few cents for 4 diodes wont hurt me.
ok pacificblue, so which diodes should I use then? maybe you can help me with transformer too?
Sorry I'm a bit of noob, I'm only 17 building my first chip amp 😎
ok pacificblue, so which diodes should I use then? maybe you can help me with transformer too?
Sorry I'm a bit of noob, I'm only 17 building my first chip amp 😎
So you do expect more than 3 A?
Start with reading the datasheet.
To make a nominal 20 W amplifier you need ~±22 V loaded with 8 Ohm speakers or ~±18 V loaded with 4 Ohm speakers.
That is ±25-26 V unloaded -> a 2*18 V transformer 1,6 A per channel for 8 Ohm or ±21-22 V unloaded -> a 2*15 V transformer 2,25 A per channel for 4 Ohm.
Use a transformer with 80-120 VA for a stereo amplifier. 40 VA would be enough, but has too high regulation.
Check: 2*18 V +25% safety margin for regulation and mains fluctuation times 1,41 minus 1,4 V diode drop = 30,3 V. One percent overvoltage at no load should be acceptable for a worst case assumption.
The 1N5401 will be okay, because a normal music signal will not lead to peaks that surpass 3 A for long enough to destroy them. Use them, if you already have them.
A good alternative would be a bridge rectifier. It is easier to connect compared to single diodes, thus avoids wrong connections. E. g. something like this.
Start with reading the datasheet.
To make a nominal 20 W amplifier you need ~±22 V loaded with 8 Ohm speakers or ~±18 V loaded with 4 Ohm speakers.
That is ±25-26 V unloaded -> a 2*18 V transformer 1,6 A per channel for 8 Ohm or ±21-22 V unloaded -> a 2*15 V transformer 2,25 A per channel for 4 Ohm.
Use a transformer with 80-120 VA for a stereo amplifier. 40 VA would be enough, but has too high regulation.
Check: 2*18 V +25% safety margin for regulation and mains fluctuation times 1,41 minus 1,4 V diode drop = 30,3 V. One percent overvoltage at no load should be acceptable for a worst case assumption.
The 1N5401 will be okay, because a normal music signal will not lead to peaks that surpass 3 A for long enough to destroy them. Use them, if you already have them.
A good alternative would be a bridge rectifier. It is easier to connect compared to single diodes, thus avoids wrong connections. E. g. something like this.
Well I guess I have to go do some parts shopping. 🙂
yea I wanna be a little bit more safe so I might go with more A.
I see BrianGT kits use 8A diodes MUR860 I guess those wont hurt me?
yea I wanna be a little bit more safe so I might go with more A.
I see BrianGT kits use 8A diodes MUR860 I guess those wont hurt me?
Dorry for double post but yea I might get my two VU connected to that power supply so i wound need probably more then 3A.
Hi,
I have four power amps that use 1n5404s as the bridge rectifier.
They charge up 20mF to 80Vdc.
None has ever blown.
I have four power amps that use 1n5404s as the bridge rectifier.
They charge up 20mF to 80Vdc.
None has ever blown.
Hi!
Is there any difference between 1n5404 and 1n5401?
I checked the data sheets and it looks the same to me?
Is there any difference between 1n5404 and 1n5401?
I checked the data sheets and it looks the same to me?
hello.
01 = 100volt maximum
04 = 400v max.
useful toy that lm 3915 n .
i think i will build that too.........
greetings........
01 = 100volt maximum
04 = 400v max.
useful toy that lm 3915 n .
i think i will build that too.........
greetings........
mjf said:
yea 3915 or 16 are fun 🙂 took me 20 minutes to put both of them on breadboard
got the schematics from this site
VU meter schematics
post25.
why have you deleted half the capacitance?
As it was is far superior and particularly, more flexible if you add the extra resistors/inductors as suggested.
why have you deleted half the capacitance?
As it was is far superior and particularly, more flexible if you add the extra resistors/inductors as suggested.
is that 47mF charged to <80Vdc from one 1n5406 bridge?MJL21193 said:
Maybe this would have benefited from a slow charge circuit.
An externally hosted image should be here but it was not working when we last tested it.
I guess it's better now 🙂 Yea if you think, you're right it's more flexible I can change the capacitance if I want.
- Status
- Not open for further replies.