I plan on building a solid state power amp, but don't know which one yet. In the meantime, I figure I can go ahead and start making the PSU for my future amplifier.
I tried iTead Mall to place my order for (5) PSU boards. So far, I'm pleased with iTead's quality, though there was some miscommunication with them. They didn't update my order status for 2 weeks, it still says "Processing" on their website, when in reality, they've already shipped my order but didn't email me a tracking #. Anyway, once I submitted a ticket, they've been very responsive and apologetic. Then by coincidence, I got my PCB in the mail the day after I complained. I will be using them again in the future.
So basically, I want the PSU to be able to cater to higher voltages, like +/-80 or 90VDC... so I made sure there's enough room on the board to allow the use of bigger capacitor, 100+V rated or more.
The PSU board can accept either spade connectors, or terminal blocks.
I'm using Ultra Fast Recovery Rectifiers, bypassed with Panasonic Safety Class X2 polyester film caps (250V rated). I have heatsinks on the rectifiers but they don't need it. They're cool to the touch.
There are green LED indicators under the fuse on the DC output, so if the fuse blows, the LED also goes out and you can quickly see the problem. There's also a couple of AC fuses.
It's basically just a simple power supply, albeit using high current/high voltage parts.
Step 1: Bare PCB … ready for population and build.
STEP 2: Insert 0.1uf / 100V ceramic caps. These are bypass capacitors for the DC output. If you need to add more bypass caps, you can solder them underneath the board across the capacitor terminals.
STEP 3: These are the current-limiting resistors for the LED power indicator. The 3mm LEDs are located under the fuse on the DC output. Only 1/2 watt, they're sized correctly. Doesn't even get warm.
STEP 4: Fuse holder clips…. 2 fuses for the AC primary side, and 2 fuses for the DC side. Depending on the VA size of your power transformer, pick the appropriate/correct fuse rating.
STEP 5: These are the 4x Ultra Fast Recovery Rectifiers, rated 600V Reverse Voltage, 10Amps. Added TO-220 heatsinks just to be sure. Yes, I know… it’s overkill.
STEP 6: I made a mistake of trusting the datasheet… the component size is correct but the lead spacing is wider than I expected. So here’s a temporary fix to make it work with the PCB.
STEP 7: These are the (4x) Safety Polyester Film Capacitors, rated 250Volts, Class X2. Each capacitor is connected across each Rectifier Diode. Slight mistake here too... I didn't have enough clearance between the capacitors and the terminal block for the AC input. Good thing, I have extra holes on the board (to accomodate spade terminals), and I just simply move the terminal block a bit forward. So a few mm of the terminal block is hanging off the board. See photo for STEP 8.
STEP 8: Terminal Blocks with screws. Heavy-duty, rated up to 32Amp, and can handle up to AWG#10 gauge wire. AC side accepts dual secondaries from power transformer. DC side outputs split voltage, V+, V- and GND.
STEP 9: 10,000uf capacitors for DC Filtering. Since this is a split power supply, there’s 20,000uf for each V+ or V- voltage rail. Use the appropriate voltage rated capacitor matched to the power transformer, and DC output you need. The higher the capacitor voltage rating, the more expensive it gets. There’s enough room on the board to accept bigger diameter/higher voltage capacitors up to 100Volts DC rated or more.
Another view of the finished High Voltage Power Supply.
Size comparison of finished High Voltage, High Current Power Supply compared to an iPad Air. PSU weighs in at 11.1 ounces.
Power Supply Testing. The biggest transformer I have on hand is a 230VAC, 25+25AC transformer. Not big enough for use in a power amp, but good enough for testing my PSU board.... just to see if it works.
Ripple voltage is 11.5mVolts peak-to-peak, 25V+25 AC input, 35.4VDC + 35.4VDC output. Would be interesting to test this fully loaded, but I don't have an electronic load equipment in my "lab." I'll update this thread once I've tested this with full load.
So that's it. Just a basic power supply. I have (4) leftover boards, I think I'll build another one using 100VDC or plus rated caps. This prototype is just using 63V caps. So I'll have (3) extra boards, if anyone is interested in buying them, let me know... so I can have the funds to buy parts for a second PSU build 🙂
I tried iTead Mall to place my order for (5) PSU boards. So far, I'm pleased with iTead's quality, though there was some miscommunication with them. They didn't update my order status for 2 weeks, it still says "Processing" on their website, when in reality, they've already shipped my order but didn't email me a tracking #. Anyway, once I submitted a ticket, they've been very responsive and apologetic. Then by coincidence, I got my PCB in the mail the day after I complained. I will be using them again in the future.
So basically, I want the PSU to be able to cater to higher voltages, like +/-80 or 90VDC... so I made sure there's enough room on the board to allow the use of bigger capacitor, 100+V rated or more.
The PSU board can accept either spade connectors, or terminal blocks.
I'm using Ultra Fast Recovery Rectifiers, bypassed with Panasonic Safety Class X2 polyester film caps (250V rated). I have heatsinks on the rectifiers but they don't need it. They're cool to the touch.
There are green LED indicators under the fuse on the DC output, so if the fuse blows, the LED also goes out and you can quickly see the problem. There's also a couple of AC fuses.
It's basically just a simple power supply, albeit using high current/high voltage parts.
Step 1: Bare PCB … ready for population and build.
STEP 2: Insert 0.1uf / 100V ceramic caps. These are bypass capacitors for the DC output. If you need to add more bypass caps, you can solder them underneath the board across the capacitor terminals.
STEP 3: These are the current-limiting resistors for the LED power indicator. The 3mm LEDs are located under the fuse on the DC output. Only 1/2 watt, they're sized correctly. Doesn't even get warm.
STEP 4: Fuse holder clips…. 2 fuses for the AC primary side, and 2 fuses for the DC side. Depending on the VA size of your power transformer, pick the appropriate/correct fuse rating.
STEP 5: These are the 4x Ultra Fast Recovery Rectifiers, rated 600V Reverse Voltage, 10Amps. Added TO-220 heatsinks just to be sure. Yes, I know… it’s overkill.
STEP 6: I made a mistake of trusting the datasheet… the component size is correct but the lead spacing is wider than I expected. So here’s a temporary fix to make it work with the PCB.
STEP 7: These are the (4x) Safety Polyester Film Capacitors, rated 250Volts, Class X2. Each capacitor is connected across each Rectifier Diode. Slight mistake here too... I didn't have enough clearance between the capacitors and the terminal block for the AC input. Good thing, I have extra holes on the board (to accomodate spade terminals), and I just simply move the terminal block a bit forward. So a few mm of the terminal block is hanging off the board. See photo for STEP 8.
STEP 8: Terminal Blocks with screws. Heavy-duty, rated up to 32Amp, and can handle up to AWG#10 gauge wire. AC side accepts dual secondaries from power transformer. DC side outputs split voltage, V+, V- and GND.
STEP 9: 10,000uf capacitors for DC Filtering. Since this is a split power supply, there’s 20,000uf for each V+ or V- voltage rail. Use the appropriate voltage rated capacitor matched to the power transformer, and DC output you need. The higher the capacitor voltage rating, the more expensive it gets. There’s enough room on the board to accept bigger diameter/higher voltage capacitors up to 100Volts DC rated or more.
Another view of the finished High Voltage Power Supply.
Size comparison of finished High Voltage, High Current Power Supply compared to an iPad Air. PSU weighs in at 11.1 ounces.
Power Supply Testing. The biggest transformer I have on hand is a 230VAC, 25+25AC transformer. Not big enough for use in a power amp, but good enough for testing my PSU board.... just to see if it works.
Ripple voltage is 11.5mVolts peak-to-peak, 25V+25 AC input, 35.4VDC + 35.4VDC output. Would be interesting to test this fully loaded, but I don't have an electronic load equipment in my "lab." I'll update this thread once I've tested this with full load.
So that's it. Just a basic power supply. I have (4) leftover boards, I think I'll build another one using 100VDC or plus rated caps. This prototype is just using 63V caps. So I'll have (3) extra boards, if anyone is interested in buying them, let me know... so I can have the funds to buy parts for a second PSU build 🙂
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My ripple scope measurement above may be bogus.
I disconnected the power supply and my scope still shows a 9.4mV ripple measuring nothing. Just with the scope probe connected, picking up noise in the surroundings.
I disconnected the power supply and my scope still shows a 9.4mV ripple measuring nothing. Just with the scope probe connected, picking up noise in the surroundings.
Thanks to Dave of EEVBlog, picked up some techniques on measuring PSU noise.
Here's an updated screenshot. 2.5mV peak-to-peak ripple!
You can see the caps charging and discharging on each cycle.
And just to make sure it's really the caps we're watching here, the frequency is exactomundo around 120Hz, give or take. Of course, since it's a full wave rectifier.
Here's an updated screenshot. 2.5mV peak-to-peak ripple!
You can see the caps charging and discharging on each cycle.
And just to make sure it's really the caps we're watching here, the frequency is exactomundo around 120Hz, give or take. Of course, since it's a full wave rectifier.
For your second PSU build:
http://sound.westhost.com/power-supplies.htm
Great read, especially the part explaining why multiple smaller capacitors are better than the biggest ones you can find.
http://sound.westhost.com/power-supplies.htm
Great read, especially the part explaining why multiple smaller capacitors are better than the biggest ones you can find.
@Jsix, thanks
@ivan, thanks for the link. Yes, great read!
I hope to keep parts costs down. A big jump in price for capacitors going from 63V to 100V.
10,000uf 63V = $4.62 each <--- currently installed
10,000uf 80V = $5.92 each <--- I think a good buy
but 10,000uf 100V = $15.94 each <----- yikes
then 4,700uf 100V, only $5.23 each
I'm leaning towards a LM49830 amplifier build, and according to TI datasheet, they recommend +/-55 to +/-60V supply for it.
Maybe I can get away using 80V rated caps?
@ivan, thanks for the link. Yes, great read!
I hope to keep parts costs down. A big jump in price for capacitors going from 63V to 100V.
10,000uf 63V = $4.62 each <--- currently installed
10,000uf 80V = $5.92 each <--- I think a good buy
but 10,000uf 100V = $15.94 each <----- yikes
then 4,700uf 100V, only $5.23 each
I'm leaning towards a LM49830 amplifier build, and according to TI datasheet, they recommend +/-55 to +/-60V supply for it.
Maybe I can get away using 80V rated caps?
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