Yes, the 15v Talema will work fine as a headphone amp.
15v ac is 21vdc and about 3v drop in cap multiplier so 18vdc supply.
Both Melbourne and WB18 boards are dual rail and +/-18v will work great for lower voltage preamp or headphone use.
PCA, Hakuin, Pass ACP+, and Pass H2 will also work on 18v.
You can’t get 40Vpp though for some preamp needs like driving 0dB gain amps to 25W.
15v ac is 21vdc and about 3v drop in cap multiplier so 18vdc supply.
Both Melbourne and WB18 boards are dual rail and +/-18v will work great for lower voltage preamp or headphone use.
PCA, Hakuin, Pass ACP+, and Pass H2 will also work on 18v.
You can’t get 40Vpp though for some preamp needs like driving 0dB gain amps to 25W.
Hello Vunce, X, other ALP builders,
I am ready to start building the PS for the ALP. I have 2 possible supplies and a DC-DC boost converter in the pic attached. One is a D-Link router wall wart with 12V/2A output, and the other is an HP laptop brick with 18.5V/3.5 amp output. I am thinking that the HP brick is probably a better choice. Any comments on choice of PS are welcome.
I was looking at post#446 (some AL TLC), and I see that the boost converter shown uses a barrel connection on the input, I think. I don't have any of these laying around, and I am thinking of cutting the connector off the cable and using the supplied screw connectors on the boost, along with the fancy ferrule tips that X is fond of. Any problem with this reasoning, and how do I determine which wire is +/- in the cable ?
Would like to know how other folks managed this?
Thanks for the help, slowly inching forward to power up.
I am ready to start building the PS for the ALP. I have 2 possible supplies and a DC-DC boost converter in the pic attached. One is a D-Link router wall wart with 12V/2A output, and the other is an HP laptop brick with 18.5V/3.5 amp output. I am thinking that the HP brick is probably a better choice. Any comments on choice of PS are welcome.
I was looking at post#446 (some AL TLC), and I see that the boost converter shown uses a barrel connection on the input, I think. I don't have any of these laying around, and I am thinking of cutting the connector off the cable and using the supplied screw connectors on the boost, along with the fancy ferrule tips that X is fond of. Any problem with this reasoning, and how do I determine which wire is +/- in the cable ?
Would like to know how other folks managed this?
Thanks for the help, slowly inching forward to power up.
Thanks X, I will try the HP brick and the boost DCDC board I have. You missed a question:
I was looking at your post#446 (some AL TLC), and I see that the boost DCDC board uses a barrel connection on the input, I think. I don't have any of these laying around. I am thinking of cutting the male round connector off the cable and using the supplied screw connectors on the boost DCDC board.
Any problem with this reasoning, and how do I determine which wire is +/- in the cable ?
Thanks again
I was looking at your post#446 (some AL TLC), and I see that the boost DCDC board uses a barrel connection on the input, I think. I don't have any of these laying around. I am thinking of cutting the male round connector off the cable and using the supplied screw connectors on the boost DCDC board.
Any problem with this reasoning, and how do I determine which wire is +/- in the cable ?
Thanks again
Hi X and other builders,
I cut the barrel off the laptop brick and found 3 wires inside, a green wire for ground, a black wire, and a white wire.
I hooked up the DMM and with green wire to ground, com lead on DMM to the black supply wire, and red lead on DMM to white supply wire. I measured 19.5V. If I reverse the white and black wires I get -19.5V.
When I attach to the DCDC boost converter, I assume that based on above, the white wire connects to +in and the black wire to -in. Is my analysis correct ? Would like to make sure so I can continue to build and test my ALP.
Thanks for the help.
MM
I cut the barrel off the laptop brick and found 3 wires inside, a green wire for ground, a black wire, and a white wire.
I hooked up the DMM and with green wire to ground, com lead on DMM to the black supply wire, and red lead on DMM to white supply wire. I measured 19.5V. If I reverse the white and black wires I get -19.5V.
When I attach to the DCDC boost converter, I assume that based on above, the white wire connects to +in and the black wire to -in. Is my analysis correct ? Would like to make sure so I can continue to build and test my ALP.
Thanks for the help.
MM
Hi X,
I hooked up the variac, dbt, and attached the 19V laptop supply to the DC-DC boost. I attached 2 test wires to the DC-DC boost output, attached the DMM test leads, and adjusted to 53V by adjusting the pot on the + side. Wasn't sure if I had to do anything with the - side pot, so I tried decreasing the V by adjusting the pot on the - side. The voltage immediately dropped to 19.2 V, so I adjusted the pot the other direction and it immediately went back to 53V. I left it there. Solid at 53V.
As I am not familiar with the DC-DC boost operation I just want to ask if this is normal operation and am I operating it correctly?.
Thanks
I hooked up the variac, dbt, and attached the 19V laptop supply to the DC-DC boost. I attached 2 test wires to the DC-DC boost output, attached the DMM test leads, and adjusted to 53V by adjusting the pot on the + side. Wasn't sure if I had to do anything with the - side pot, so I tried decreasing the V by adjusting the pot on the - side. The voltage immediately dropped to 19.2 V, so I adjusted the pot the other direction and it immediately went back to 53V. I left it there. Solid at 53V.
As I am not familiar with the DC-DC boost operation I just want to ask if this is normal operation and am I operating it correctly?.
Thanks
Hi X, other builders,
So today i wanted to watch some YT video's on these boost units before I started working with them. I found 3 video's that were good, but they used different techniques to set the output voltage and current. 2 of the video's used an output load to draw some amps to set the output current, while 1 video showed that it was possible to set the output current without a load.
I tried the one with no output load and had no problem setting the voltage, but was unable to adjust the current. The current would cycle between 0A and 4A in about 10 sec intervals. Thought the meter may be faulty, so tried another, with same result.
Shut everything down and when hooked up again I received a consisted beeping sound (when on the 10A DC setting), so I tried for about 5 sec to make some adjustments, with no luck. Output current stayed at 0 A. Shut it down, and when I went back to check the output voltage, it would not change throughout the range of the pot, stayed at input voltage of 19 V. Sounds like I might have over stressed some components or maybe the pot's are no good from all the adjusting.
So I am going to try a new unit in the next couple of days, being very careful of what I do. I think I will pick up a small led array to use for a load if needed. If you or others that have used these DC-DC boost converters have any tips or hints, please let me know.
Thanks,
MM
So today i wanted to watch some YT video's on these boost units before I started working with them. I found 3 video's that were good, but they used different techniques to set the output voltage and current. 2 of the video's used an output load to draw some amps to set the output current, while 1 video showed that it was possible to set the output current without a load.
I tried the one with no output load and had no problem setting the voltage, but was unable to adjust the current. The current would cycle between 0A and 4A in about 10 sec intervals. Thought the meter may be faulty, so tried another, with same result.
Shut everything down and when hooked up again I received a consisted beeping sound (when on the 10A DC setting), so I tried for about 5 sec to make some adjustments, with no luck. Output current stayed at 0 A. Shut it down, and when I went back to check the output voltage, it would not change throughout the range of the pot, stayed at input voltage of 19 V. Sounds like I might have over stressed some components or maybe the pot's are no good from all the adjusting.
So I am going to try a new unit in the next couple of days, being very careful of what I do. I think I will pick up a small led array to use for a load if needed. If you or others that have used these DC-DC boost converters have any tips or hints, please let me know.
Thanks,
MM
Try to find some circa 270ohm 10W resistors and connect that as a load to your DCDC booster. Set the voltage first with a 2k resistor load. Then connect to the 270ohm dummy load (should draw about 200mA at 53v). Now slowly increase the current pot until it maintains 53v into 270ohms. With this set you can try powering the amp since the amp has a slow ramp cap multiplier and if that is not working right you may be getting funny results.
Hi X,
I ordered in some 270 ohm/10W resistors and proceeded to test the DCDC boost.
If my above procedure is OK, then I conclude that I may have a faulty DCDC boost. Suggestions please and thank you.
I ordered in some 270 ohm/10W resistors and proceeded to test the DCDC boost.
- connected a 2k resistor across the outputs, connected the DMM, and dialed in 53V using the pot on the + side of the DCDC boost.
- removed 2k resistor and connected 270k resistor across the outputs
- connected DMM and had a reading of 0.0 mA or A. Tried to adjust the amps reading with no change throughout the range of the pot. Tried with another DMM with same result, reads 0.0 amps or mA. I did notice that the 270 ohm resistors are very toasty. I tried it with dialing in 26 V and had same results with the resistors not as toasty.
If my above procedure is OK, then I conclude that I may have a faulty DCDC boost. Suggestions please and thank you.