Hello,
I built a battery powered subwoofer using the AA-AB31395 board from Sure Electronics. Two pcs Beyma 8 Ohm drivers are connected in parallel. Supply voltage is 60V. I use the Sure DSP for xover+eq.
Even with shorted input the amplifiers noise floor is horrible.
I should have read the datasheet better before ordering, noise floor is stated with 450uV.
DATASHEET
My expirience with amplifiers of this kind is very limited. So the only solution that i have for this problem is a passive low pass filter, an inductor in series with the speakers. the subwoofer crossover point is set to 110hz (DSP). i could use an inductor which cut's off everything above 150 hz, that would probably solve the problem, but introduce another one: inductors for 300-400W continous into 4R are very expensive.
maybe someone with more knowledge have another idea to solve this problem. any input appreciated.
thank you,
georg
I built a battery powered subwoofer using the AA-AB31395 board from Sure Electronics. Two pcs Beyma 8 Ohm drivers are connected in parallel. Supply voltage is 60V. I use the Sure DSP for xover+eq.
Even with shorted input the amplifiers noise floor is horrible.
I should have read the datasheet better before ordering, noise floor is stated with 450uV.
DATASHEET
My expirience with amplifiers of this kind is very limited. So the only solution that i have for this problem is a passive low pass filter, an inductor in series with the speakers. the subwoofer crossover point is set to 110hz (DSP). i could use an inductor which cut's off everything above 150 hz, that would probably solve the problem, but introduce another one: inductors for 300-400W continous into 4R are very expensive.
maybe someone with more knowledge have another idea to solve this problem. any input appreciated.
thank you,
georg
Hi I am about to build two of these into a PA system what exactly is the manifestation of that noise floor can you be more specific?
cheers
cheers
Is the power supply quiet? Are you taking 60V direct from the batteries, or from a boost converter? I don't see any numbers for PSRR on the Sure page. A data sheet for the Tripath TA0103A says PSRR is just 67 dB, for what that's worth.
I would NOT recommend it. Its broadband noise.
Outside, in a city, for subwoofer application only, combined with hi-mid units one can tolerate the noise. when playing music the himid will cover the noise.
For all other applications i wouldn't use this model. I use another sure amp for the hi mid units, this amp is less noisy and with a passive attenuator (L-pad) before the tweeter it is okay. not for studio use, but for PA.
i definitely will use hypex units the next time. it's a pain in the *** cause of the symetric supply, but regarding sound quality i am sure (haha) that it is a better choice. more expensive, of course.
yes, directly from the battery. only component in between is a Mosfet which acts as on/off switch.
