Anyone know of a low noise boost converter?
I'm looking for low-cost units, that will give me 26V from 9-15V.
Picked up a couple different (claimed) 100-150W units from eBay, and both are putting out too much noise. Two more on the way... we'll see about those.
Setup is a 2.1 battery-powered system with active filters on an isolated 12v DC-DC converter. Sounds great from a single battery at 12V (aside from the lack of power), so I know the system is good aside from the boost converter.
I'm looking for low-cost units, that will give me 26V from 9-15V.
Picked up a couple different (claimed) 100-150W units from eBay, and both are putting out too much noise. Two more on the way... we'll see about those.
Setup is a 2.1 battery-powered system with active filters on an isolated 12v DC-DC converter. Sounds great from a single battery at 12V (aside from the lack of power), so I know the system is good aside from the boost converter.
If the converter is badly tracked inside so that high levels of noise appear between in and out, there is no way external filters will tame it
If the power source is isolated (say a lead acid battery) then common-mode noise isn't a significant issue, assuming the cables aren't long enough to radiate.
One of the first two I've received is putting out less noise.
The worst noise comes when I connect the input from the AF isolator to the output of my 11V battery pack. Again, without the boost converter also connected to the battery output (just taking the 11V battery source straight to the Amp and AF isolator), there is little noise aside from what seems to be some radio interference from using my cell phone as the input.
Presently, I'm just using 100nF bypass caps at my LM4562, going to include 1000pF & 33pF to see if that helps w interference.
The worst noise comes when I connect the input from the AF isolator to the output of my 11V battery pack. Again, without the boost converter also connected to the battery output (just taking the 11V battery source straight to the Amp and AF isolator), there is little noise aside from what seems to be some radio interference from using my cell phone as the input.
Presently, I'm just using 100nF bypass caps at my LM4562, going to include 1000pF & 33pF to see if that helps w interference.
My guess would be not, but no harm in trying. What you'll probably need is some series inductance before the opamp.
Well, folks, it's a mixture of elation and frustration for not finding out sooner...
I noticed the majority of my noise was coming through my 1000 hz low-pass channel, so I went to unplug that from the terminal block of my eBay tpa3116, and noticed the interference decreased. Decrease was most noticeable when I touched the two large caps on either side of the audio input. What previously made me suspect it could be remedied w more decoupling caps, was when I noticed a similar decrease when touching my phone, leading me to believe it was radio interference, and could be fixed with those 100pF and 33pF bypass caps (according to an article I read).
I decided to swap it out w an eBay TDA7492, and the interference has since completely disappeared.
I noticed the majority of my noise was coming through my 1000 hz low-pass channel, so I went to unplug that from the terminal block of my eBay tpa3116, and noticed the interference decreased. Decrease was most noticeable when I touched the two large caps on either side of the audio input. What previously made me suspect it could be remedied w more decoupling caps, was when I noticed a similar decrease when touching my phone, leading me to believe it was radio interference, and could be fixed with those 100pF and 33pF bypass caps (according to an article I read).
I decided to swap it out w an eBay TDA7492, and the interference has since completely disappeared.
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