For this one I used LM780CT. According to spec the Pi 3b draws 1 amp. The datasheet of the regulator says it can go up to 1.5. When I fed both the Pi and the Isolator hat (200 mA max) from the same PSU, I heard the odd stutter, indicating power shortage. But when feeding only the Pi, it works fine and sounds great. So with this reg, the little PSU seems just fit for a Pi. 🙂
I also mean to build one with LM340AT, which is a slightly narrower spec’d version of 780.
So both of then finished with the Ebay LT1963 set at 5v.
Both are 5.00v. Maybe I could have done with 5.2v for some headroom, I may look at altering the R values but they are tiny.
I made an error on the first build and had 1000uf instead of 2200, so that is remedied. Only had 1 220uf Pana FC for some reason so one has an Elna Silmic 2 in there.
Look forward to rigging them up to some gear!
Both are 5.00v. Maybe I could have done with 5.2v for some headroom, I may look at altering the R values but they are tiny.
I made an error on the first build and had 1000uf instead of 2200, so that is remedied. Only had 1 220uf Pana FC for some reason so one has an Elna Silmic 2 in there.
Look forward to rigging them up to some gear!
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Was wondering if I could wire up two boards for a bipolar supply by using a dual-secondary transformer plus two bridges to feed the two boards and finally joining the 0V output of one board with +ve output of the other,to get the common 0V.
This would be for a dual-supply preamp.
Will it work this way?
thanks.
This would be for a dual-supply preamp.
Will it work this way?
thanks.
Yes, as long as it is fed by floating dual secondaries and bridges. You can then think of it as a battery that is put in series.
Also, you cannot connect the chassis GND on the “negative” supply to GND as that would short.
But if you wanted to do this, it might be best to get hold of one of Prasi’s dual rail cap multiplier boards. Then add the voltage regs after it, if needed.
Also, you cannot connect the chassis GND on the “negative” supply to GND as that would short.
But if you wanted to do this, it might be best to get hold of one of Prasi’s dual rail cap multiplier boards. Then add the voltage regs after it, if needed.
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Just go to eBay and do a search for "TPS7A regulator"
TPS7A4701 Ultralow Noise RF LDO Regulator Positive Power Supply Board 1.4-34V 1A 699912549723 | eBay
TPS7A4701 Ultralow Noise RF Linear Regulator Power DC-DC 3-36V to 1.4-34V 12V 1A 699936833310 | eBay
TPS7A4701 Ultralow Noise RF LDO Regulator Positive Power Supply Board 1.4-34V 1A 699912549723 | eBay
TPS7A4701 Ultralow Noise RF Linear Regulator Power DC-DC 3-36V to 1.4-34V 12V 1A 699936833310 | eBay
X, I was just looking for that particular one with the 'Ultralow-Noise text/logo. on it. I realize there are others. Seems I had seen that one before in another DAC thread I follow and been recommended. Thanks for the links though.
As a follow up.
I'd like to use this board to supply both the o/p mosfet in a MOFO at 2A and use a regulated output for the front end gain stage. So, could I use something like a IRF630 in place of the IRF610 and pull a 2A output from across C121 and then take ~200mA of regulated output from the board's DC output?
cheers
Beardy
I'd like to use this board to supply both the o/p mosfet in a MOFO at 2A and use a regulated output for the front end gain stage. So, could I use something like a IRF630 in place of the IRF610 and pull a 2A output from across C121 and then take ~200mA of regulated output from the board's DC output?
cheers
Beardy
The single rail SLB psu is a much better solution for a MoFo power supply.
The SLB (Smooth Like Butter) Active Rect/CRC/Cap Mx Class A Power Supply GB
The SLB (Smooth Like Butter) Active Rect/CRC/Cap Mx Class A Power Supply GB
Hi Beardywan,
Vunce is correct. This particular PSU is really meant for smaller devices under 1A like headphone amps and preamps. For the MOFO, you want the SLB single rail. It has superb low ripple and will give you some nice silent black background.
The SLB (Smooth Like Butter) Active Rect/CRC/Cap Mx Class A Power Supply GB
Here is a scope shot showing upstream ripple vs downstream after the cap Mx for 3.75A (30v into 8ohm dummy load) showing 0.71mV rms ripple:
On the drop down choose “Single Rail”
Smooth Like Buttah SLB Class A PSU | Etsy
Vunce is correct. This particular PSU is really meant for smaller devices under 1A like headphone amps and preamps. For the MOFO, you want the SLB single rail. It has superb low ripple and will give you some nice silent black background.
The SLB (Smooth Like Butter) Active Rect/CRC/Cap Mx Class A Power Supply GB
Here is a scope shot showing upstream ripple vs downstream after the cap Mx for 3.75A (30v into 8ohm dummy load) showing 0.71mV rms ripple:
On the drop down choose “Single Rail”
Smooth Like Buttah SLB Class A PSU | Etsy
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Hi Both,
Many thanks for your speedy responses. Yes, I looked at both but I am using a SMPS, so the low pass filter and capX is ideal for my needs. The regulated output is perfect for the gain stage. So switch out the inductor and resistor resistor for something more appropriate, put a bigger mosfet in as the CapX and pull a couple of amps out prior to a second output from the regulated output...
Many thanks for your speedy responses. Yes, I looked at both but I am using a SMPS, so the low pass filter and capX is ideal for my needs. The regulated output is perfect for the gain stage. So switch out the inductor and resistor resistor for something more appropriate, put a bigger mosfet in as the CapX and pull a couple of amps out prior to a second output from the regulated output...
IRF610 can actually handle several amps easily. If you need say 2.5A for MOFO, then that is about 3.5v drop x 2.5A = 8.8w which means the MOSFET needs to use flying leads and be mounted to a substantial heatsink.
Do you happen to have an LTspice model for the 78xx voltage regulator?
I mentioned the IRF630 as it came up in the Juma's easy peasy thread as offering lower voltage drop...
I mentioned the IRF630 as it came up in the Juma's easy peasy thread as offering lower voltage drop...
No, sorry I never bother to sim a regulator. There are many newer ultra low noise regulator choices that are higher performing than 78xx. Many from LT so they would have models for it.
We did simulate the SLB though. That was crucial for setting the size (and ripple current rating) of the big bulk caps, the big R, and the network for the CFP cap multiplier.
We did simulate the SLB though. That was crucial for setting the size (and ripple current rating) of the big bulk caps, the big R, and the network for the CFP cap multiplier.
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