So, I've been on the lookout for an amp/battery solution for my portable PA setup, and have struggled with finding an Alpine PDX unit used that I thought was a good value. Came up with this alternative:
PASMAG | PERFORMANCE AUTO AND SOUND - Precision Power P900.4 Amplifier
New PPI amps (Phantom & Black Ice) - DIYMA Car Audio Forum
For about $187, it's just as powerful as an alpine PDX-4.100 or PDX-F4, with a verified 4x100 4 ohms with 12v supply, and 2x350w bridged into 4 ohms. Also have on order a single 12v 35ah SLA battery (~$60), already have a charger. Will be using this with a pair of nominally 8 ohm pa mains to get about 50w or so each, and a single 4ohm sub, crossover by the amp, and passive volume knob. Might also run an analog PEQ, otherwise eq in the music player. Hoping for about 3-4 hour run time.
I thought going this route was easier and more economical than buying amp modules and dealing with a chassis, complex battery or PS setup, crossovers, etc. This does a legit 100wpc RMS off 12v, many amp modules do not.
PASMAG | PERFORMANCE AUTO AND SOUND - Precision Power P900.4 Amplifier
New PPI amps (Phantom & Black Ice) - DIYMA Car Audio Forum
For about $187, it's just as powerful as an alpine PDX-4.100 or PDX-F4, with a verified 4x100 4 ohms with 12v supply, and 2x350w bridged into 4 ohms. Also have on order a single 12v 35ah SLA battery (~$60), already have a charger. Will be using this with a pair of nominally 8 ohm pa mains to get about 50w or so each, and a single 4ohm sub, crossover by the amp, and passive volume knob. Might also run an analog PEQ, otherwise eq in the music player. Hoping for about 3-4 hour run time.
I thought going this route was easier and more economical than buying amp modules and dealing with a chassis, complex battery or PS setup, crossovers, etc. This does a legit 100wpc RMS off 12v, many amp modules do not.
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IIRC, these PPI amps (Hertz, Soundstream, and Polk all sell basically the same amp in different coverings; others too, probably) are based on a Phillips chipset.
You mean a chipamp like TDA89xx?
This amp uses discrete IRFI4212H output devices (2pcs per channel).
EDIT: Ah, ok... I found a reference in a Powerbass manual to this "chipset"...
"These amplifiers use the latest Philips/NXP Class D chipset combined with premium MOSFETSs to provide full range audio signal accuracy."
Anyone have a clue what chipset is used? I can't find any info on Philips/NXP class-d chipsets, only their chipamp stuff.
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From looking at their website, I'm guessing the TDF8591TH found here, or a newer version of it?
TDF8591TH :: NXP Semiconductors
Datasheet: https://docs.google.com/viewer?a=v&...HIEtbQxBM7cN8JtGmI3mnzo1TzMzrtwpg&safe=images
It would be great if someone had more info. PPI's rep claims that they spec the parts and the preamp in particular is their own spec, but it looks like a pretty generic amp that some chinese contractor is offering....not a bad thing really.
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No, that's one of their "chipamp" offerings.
A "chipset" would be a modulator and mosfet driver used to drive external mosfets. Only the mosfets are visible from the top of the PCB... the mystery chispet is on the other side.
Ohhh, interesting....thanks! Maybe I'll pull mine apart and see.
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Awesome! So what do you think of the implementation....good, bad or ugly? How is the smt fab, board layout, and parts quality? Anything different about it vs. other designs?
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I'm not really qualified to pass judgement on the design, although I see a couple things that don't look right.
Local supply decoupling seems inadequate. There should be something like 330uF-470uF near the output fets for each channel, but the only electrolytics are the two 3300uF bulk caps by the supply transformer. I assume they didn't include them because of space limitations.
The crosstalk is supposedly poor (30dB @ 1kHz?). I forget where I read that, it's not in the manual. There's an input filter that might be partly to blame. The L/R input signals wrap around the same ferrite toroid.
There'se also a few spots with components missing , which makes you ask "why"?
Overall build quality is decent. I guess as long as it works I have no real complaints.
Since I already have the thing apart, I might replace the 10x TL072 with OPA2132.
Local supply decoupling seems inadequate. There should be something like 330uF-470uF near the output fets for each channel, but the only electrolytics are the two 3300uF bulk caps by the supply transformer. I assume they didn't include them because of space limitations.
The crosstalk is supposedly poor (30dB @ 1kHz?). I forget where I read that, it's not in the manual. There's an input filter that might be partly to blame. The L/R input signals wrap around the same ferrite toroid.
There'se also a few spots with components missing , which makes you ask "why"?
Overall build quality is decent. I guess as long as it works I have no real complaints.
Since I already have the thing apart, I might replace the 10x TL072 with OPA2132.
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