Mike Hanson
Trying to understand...
Long ago I upgraded my NAP140 to use Avondale NCC200 boards and their corresponding power supply. That left me with a pair of NAP140 boards doing nothing. I've also got a spare Pesante case from Modushop. After watching @laverda play with the Mean Well switchmode power supplies, I thought I would jump into the water. This is my first time trying to use an SMPS in a build, so I'm really not sure what to expect.
First of all, I wasn't sure that the NAP140 boards would still work, as they've been bouncing around my office, standing in for NCC200, VBE, HCR200, etc. in various layout plans. Therefore, I didn't want to buy big supplies, if it turned out they would be unnecessary. Consequently, I got two inexpensive 36V 50W units (a.k.a. LRS-50-36), so I could do a proof of concept. 100W is likely insufficient for two NAP110 boards used in anger. However, if this test worked, then I could add two more and go dual-mono, so each channel would have 100W.
I dialed them up to 40V, and bridged them to create 40V-0-40V. (I believe the original NAP110 supply is closer to 42V-0-42V, but I didn't want to push the little units too far.)
Here's the current state of affairs:
[URL='https://avzine.com/images/nap140-smps/a.jpg'][/URL]
All the voltages measure fine, and the speaker output DC offset voltage is <= 20mv for each channel. I'm waiting for some banana connectors, so I can't actually try to play music through them yet.
I did notice something interesting, though. When the SMPS units are not connected to the boards, then they are dead silent. However, when I hook them up to the two boards, they both emit a piercing whine almost like a dentist's waterpick. I've got countless switchmode supplies in my house, and none of them make noise like this.
I'm wondering if this means they are struggling to power the boards. There is no input or output connected at this time, so this should be a quiescent state which I assume requires very little power.
Is my eventual plan to power them with four 50W SMPS modules misguided? I have enough room to put two larger MW units in there, but not four.
Your thoughts?
First of all, I wasn't sure that the NAP140 boards would still work, as they've been bouncing around my office, standing in for NCC200, VBE, HCR200, etc. in various layout plans. Therefore, I didn't want to buy big supplies, if it turned out they would be unnecessary. Consequently, I got two inexpensive 36V 50W units (a.k.a. LRS-50-36), so I could do a proof of concept. 100W is likely insufficient for two NAP110 boards used in anger. However, if this test worked, then I could add two more and go dual-mono, so each channel would have 100W.
I dialed them up to 40V, and bridged them to create 40V-0-40V. (I believe the original NAP110 supply is closer to 42V-0-42V, but I didn't want to push the little units too far.)
Here's the current state of affairs:
[URL='https://avzine.com/images/nap140-smps/a.jpg'][/URL]
All the voltages measure fine, and the speaker output DC offset voltage is <= 20mv for each channel. I'm waiting for some banana connectors, so I can't actually try to play music through them yet.
I did notice something interesting, though. When the SMPS units are not connected to the boards, then they are dead silent. However, when I hook them up to the two boards, they both emit a piercing whine almost like a dentist's waterpick. I've got countless switchmode supplies in my house, and none of them make noise like this.
I'm wondering if this means they are struggling to power the boards. There is no input or output connected at this time, so this should be a quiescent state which I assume requires very little power.
Is my eventual plan to power them with four 50W SMPS modules misguided? I have enough room to put two larger MW units in there, but not four.
Your thoughts?