Hi guys, I'm just after someone to look at my schematic for running to amp chips from one power supply, so here is the power supply
I was told that this will be powerful enough for 2 amps, got it for $10 so I got it, now here are the details of the amps
now I basically took the schematic for one amp and split the output into 2 (please excuse my drawing, it's the first one I've ever drawn)
The amp kit tells me I need one bridge rectifier and 2 2200uf 50v caps, so I got a set for each amp, 2 bridges and 4 caps, can someone please tell me if this will work? I'm just not sure if it's correct or not
two chipamps @ 50W each fed from a 174VA transformer will work well.
BUT !!!! your 35-0-35Vac transformer will blow up the chipamps.
It's the wrong voltage.
You need a 18-0-18Vac to 26-0-26Vac transformer.
You may get away with a 27-0-27Vac, if you check your mains voltage NEVER goes too high.
35-0-35Vac will give around ±50Vdc when powering typical ClassAB amplifiers and can rise as high as ±53Vdc, when mains is high and current load is low.
Save the 174VA transformer for another project.
Buy the correct transformer to power the chipamps.
The BOM states:
"MT2114 25 +25V 160VA toroid"
It is my view that using ±2200uF for a chipamp will impact adversely on performance.
I recommend at least ±10mF per channel and I use ±20mF for my own 8ohms channels.
BUT !!!! your 35-0-35Vac transformer will blow up the chipamps.
It's the wrong voltage.
You need a 18-0-18Vac to 26-0-26Vac transformer.
You may get away with a 27-0-27Vac, if you check your mains voltage NEVER goes too high.
35-0-35Vac will give around ±50Vdc when powering typical ClassAB amplifiers and can rise as high as ±53Vdc, when mains is high and current load is low.
Save the 174VA transformer for another project.
Buy the correct transformer to power the chipamps.
The BOM states:
"MT2114 25 +25V 160VA toroid"
It is my view that using ±2200uF for a chipamp will impact adversely on performance.
I recommend at least ±10mF per channel and I use ±20mF for my own 8ohms channels.
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The PSU sch is misleading. The use of GND symbols will lead you into wiring it up incorrectly, resulting in the charging pulses contaminating the audio.
And you can't have TWO audio grounds from a single PSU. You will create a loop and that will induce HUM into your audio.
The slow blow 3A fuse is too big.
You are on a 240Vac supply.
A 160VA transformer fed from a 240Vac supply has a maximum operating current of 667mAac.
If you use a soft start you should use a T800mA mains fuse. Use a 120ohms to 150ohms soft start resistance for a 160VA transformer.
If you start the transformer direct on line, then use a T2A mains fuse.
Do not fuse the Neutral. Only fuse the Live line and place the fuse BEFORE the switch, not after.
Looks like you need to read up on wiring Mains safely.
Try ESP and decibel dungeon.
And you can't have TWO audio grounds from a single PSU. You will create a loop and that will induce HUM into your audio.
The slow blow 3A fuse is too big.
You are on a 240Vac supply.
A 160VA transformer fed from a 240Vac supply has a maximum operating current of 667mAac.
If you use a soft start you should use a T800mA mains fuse. Use a 120ohms to 150ohms soft start resistance for a 160VA transformer.
If you start the transformer direct on line, then use a T2A mains fuse.
Do not fuse the Neutral. Only fuse the Live line and place the fuse BEFORE the switch, not after.
Looks like you need to read up on wiring Mains safely.
Try ESP and decibel dungeon.
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You can connect both chipamps to the one PSU.
The One PSU will have two sets of three output wires.
One set to each chip amp.
The two chipamps will have/share a common Main Audio Ground.
Because they share that MAG, be especially careful you don't create a hum loop with the signal ground/return. Read D.Joffe.
The One PSU will have two sets of three output wires.
One set to each chip amp.
The two chipamps will have/share a common Main Audio Ground.
Because they share that MAG, be especially careful you don't create a hum loop with the signal ground/return. Read D.Joffe.
As mentioned before, the direct current voltage AFTER the bridge rectifier will be approximately sqrt(2) larger than the transformers secondary alternating current voltage (35V) - 50VDC in total.
A single bridge rectifier will provide both a positive, negative and ground rail which you will connect to your board.
A single bridge rectifier will provide both a positive, negative and ground rail which you will connect to your board.
A voltage divider will waste a ton of power, and the output voltage will sag when the bass hits. Not a good idea.
If I was forced at gunpoint to use that transformer, the best choice would be to unwind some turns off the secondary windings. Next choice would be to use appropriate linear regulators to reduce the supply voltages.
If I was forced at gunpoint to use that transformer, the best choice would be to unwind some turns off the secondary windings. Next choice would be to use appropriate linear regulators to reduce the supply voltages.
Should there be fuses at the transformer secondaries, many of our diy power supply of lower volatge, 12v doesnt have a fuse before the bridge rectifiers.
I have hear that diode and regulators can develop a short in which the fuse will blow after the secondary.
Assuming no fuse is presents unless both rectifier and regulator shorts, without a fuse, all chips powered by the PSu will be dead, what are the chances of this happening.
Should we leave out the fuse, is damage likely limited to the rectifiers and possibly regulator alone. I was thinking if the rectifier develops a short, ac will be passed to the regulator and blow and act as a fuse?
I use these three pieces for fused power inlet with switch: (and I only have a fuse on the mains coming in)
0034.3781 Schurter | Mouser
DD12.4111.111 Schurter | Mouser
4301.1405 Schurter | Mouser
And here's a powersupply, 25+25v, but it's 200vac, but it should work for you. You could use 24+24v if you can't find a 25+25. For Vac, 160, 200, or 300Vac can work. (maybe even 100vac would be okay, certainly for a single channel, but for stereo 160vac or more will be stronger during those times that the amp is demanding power).
Here's an example;
AN-2225 - 200VA 25V Transformer - AnTek Products Corp
Sorry I don't know any Australian distributors, someone with that answer may chime in.
0034.3781 Schurter | Mouser
DD12.4111.111 Schurter | Mouser
4301.1405 Schurter | Mouser
And here's a powersupply, 25+25v, but it's 200vac, but it should work for you. You could use 24+24v if you can't find a 25+25. For Vac, 160, 200, or 300Vac can work. (maybe even 100vac would be okay, certainly for a single channel, but for stereo 160vac or more will be stronger during those times that the amp is demanding power).
Here's an example;
AN-2225 - 200VA 25V Transformer - AnTek Products Corp
Sorry I don't know any Australian distributors, someone with that answer may chime in.
Don't mix up Vac, the AC voltage
and VA the power specification in Volt Amperes.
You need a 230:0-25, 0-25Vac 160VA transformer.
The 230 specifies the mains voltage
the 0-25, 0-25Vac specifies the DUAL secondary voltage. You can use 20+20, or 22+22, or 24+24, or 25+25
160VA specifies the minimum power. You can use any size from 100VA to 300VA
Post6 shows the DC voltage to be supplied.
-35Vdc, 0Vdc, +35Vdc This is a dual polarity DC supply.
You need a transformer and PSU that starts with 230Vac, transforms this to ~25Vac and then rectifies this to ~35Vdc
If your boss could not understand this, then sack him and get a new advisor.
and VA the power specification in Volt Amperes.
You need a 230:0-25, 0-25Vac 160VA transformer.
The 230 specifies the mains voltage
the 0-25, 0-25Vac specifies the DUAL secondary voltage. You can use 20+20, or 22+22, or 24+24, or 25+25
160VA specifies the minimum power. You can use any size from 100VA to 300VA
Post6 shows the DC voltage to be supplied.
-35Vdc, 0Vdc, +35Vdc This is a dual polarity DC supply.
You need a transformer and PSU that starts with 230Vac, transforms this to ~25Vac and then rectifies this to ~35Vdc
If your boss could not understand this, then sack him and get a new advisor.
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Yes RS do operate here, here are 2 photos of the toroids I was thinking about, my workplace does have an account with them so I can get them through work, much cheaper than fleabay, would one of these do the right job? I know I have to put bridge rectifier between these and amps and caps etc,
or
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