Ive just finished building a system with two tpa3255 evm boards in 2.1 mode, driving two dayton 600w subs, and a pair of dual alpair fullrange cabinets.
Whole thing is driven by a minidsp hd, and the volume control is provided by that.
I gave it some welly for the first time today, and it definitely gets louder than i need.. however, i stopped turning it up further, as the clip lights started blinking on the amps.
This surprised me somewhat, as the simulations of my subs said they would hit xmax at around 200 - 250w in my vented boxes. They were definitely nowhere near xmax, and with the sub channels capable of circa 300w each, and an 800w smps, id have expected the subs to complain before the amp. The other amp channels are rated much higher than the alpairs, so again, id have expected the speakers to complain first.
Any thoughts?
Whole thing is driven by a minidsp hd, and the volume control is provided by that.
I gave it some welly for the first time today, and it definitely gets louder than i need.. however, i stopped turning it up further, as the clip lights started blinking on the amps.
This surprised me somewhat, as the simulations of my subs said they would hit xmax at around 200 - 250w in my vented boxes. They were definitely nowhere near xmax, and with the sub channels capable of circa 300w each, and an 800w smps, id have expected the subs to complain before the amp. The other amp channels are rated much higher than the alpairs, so again, id have expected the speakers to complain first.
Any thoughts?
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Hi, thanks for the reply!
There are a number of threads where i discuss amp and speakers, ill dig them out later.
Speakers are dayton high output reference 10" rated for 600w for the subs, and a pair of alpair 7 gen3 for each fullrange cabinet. Each of the 4 alpairs has a seperate single ended amp channel, and the two subs run from btl channels of the amps. , the psu is the connex smps 800w (1kw peak) set for 52v, so the max the amp is rated for.
Obviously the subs are rated higher than the amp, but as i said, in my sims, xmax should be reached around 250w in my vented boxes.. Maybe this estimate by winisd does not correlate with a real world music load?
There are a number of threads where i discuss amp and speakers, ill dig them out later.
Speakers are dayton high output reference 10" rated for 600w for the subs, and a pair of alpair 7 gen3 for each fullrange cabinet. Each of the 4 alpairs has a seperate single ended amp channel, and the two subs run from btl channels of the amps. , the psu is the connex smps 800w (1kw peak) set for 52v, so the max the amp is rated for.
Obviously the subs are rated higher than the amp, but as i said, in my sims, xmax should be reached around 250w in my vented boxes.. Maybe this estimate by winisd does not correlate with a real world music load?
Hi Khron, here is the datasheet for the EVM:
http://www.ti.com/lit/df/slar129a/slar129a.pdf
my suspicion is that under a music load, the subs are not bottoming out before the amps run out of steam and start clipping, despite the sims suggesting they should bottom out before the amps.
i guess this is why people say to get an amp rated higher than your speakers rated power (600w in this case)
i deemed it unnecessary as
a) the sims suggested 250w was all they could handle in my cabinets
b) im not running a nightclub and generally listen at modest volumes.
possibly i missed something in my design process.
http://www.ti.com/lit/df/slar129a/slar129a.pdf
my suspicion is that under a music load, the subs are not bottoming out before the amps run out of steam and start clipping, despite the sims suggesting they should bottom out before the amps.
i guess this is why people say to get an amp rated higher than your speakers rated power (600w in this case)
i deemed it unnecessary as
a) the sims suggested 250w was all they could handle in my cabinets
b) im not running a nightclub and generally listen at modest volumes.
possibly i missed something in my design process.
as mentioned in the previous post, i have two amps in 2.1, so in total, 2 btl channels driving subs, and 4 single ended channels driving fullrangers.
-ah i see you edited your reply.. so ignore this post
regarding the peaks they react to, i didnt push it past the first flickers of the clip lights.. no reason to push it, i was just testing..
-ah i see you edited your reply.. so ignore this post
regarding the peaks they react to, i didnt push it past the first flickers of the clip lights.. no reason to push it, i was just testing..
as mentioned in the previous post, i have two amps in 2.1, so in total, 2 btl channels driving subs, and 4 single ended channels driving fullrangers.
-ah i see you edited your reply.. so ignore this post
regarding the peaks they react to, i didnt push it past the first flickers of the clip lights.. no reason to push it, i was just testing..
Yes, I noticed the two amplifiers were for 2.1 use so it matched.
So the clip LED(s) are on the daughterboard that plugs into that 28-pin header?
I don't suppose a schematic for that is available anywhere, is it?
The datasheet says that, when the "/FAULT" output (active low) is high (i.e inactive), the "/CLIP_OTW" active indicates "Overload (OLP) or undervoltage (UVP). Junction temperature lower than 125°C"
Also:
"Signal clipping is signalled on the CLIP_OTW pin and is self clearing when signal level reduces and the device reverts to normal operation. The CLIP_OTW pulses start at the onset to output clipping, typically at a THD level around 0.01%, resulting in narrow CLIP_OTW pulses starting with a pulse width of ~500ns."
So... Let's just say that indication might be a bit "trigger happy" - THD 0.01% is hardly what you might call "running out of steam" (imho)
That is, unless you're indeed tripping the overcurrent protection; i'd be shocked if the undervoltage protection would be the one kicking in.
I don't suppose a schematic for that is available anywhere, is it?
The datasheet says that, when the "/FAULT" output (active low) is high (i.e inactive), the "/CLIP_OTW" active indicates "Overload (OLP) or undervoltage (UVP). Junction temperature lower than 125°C"
Also:
"Signal clipping is signalled on the CLIP_OTW pin and is self clearing when signal level reduces and the device reverts to normal operation. The CLIP_OTW pulses start at the onset to output clipping, typically at a THD level around 0.01%, resulting in narrow CLIP_OTW pulses starting with a pulse width of ~500ns."
So... Let's just say that indication might be a bit "trigger happy" - THD 0.01% is hardly what you might call "running out of steam" (imho)
That is, unless you're indeed tripping the overcurrent protection; i'd be shocked if the undervoltage protection would be the one kicking in.
I dont have a daughterboard plugged in, i just bypassed the on-board clip led, and ran extension wiresfrom there to a case mounted one.
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