Subwoofer plate amps downunder?

[Stu]

It's the old Shiva Mk I, got it second hand on eBay.

12", dual 8R voice coils, 600 W, xmax of about 15 mm.

Was either going to go ported or use Rod Elliot's ELF circuit in a sealed box... either way, it should reach 20 Hz pretty easily if the amp lets me.

[Moondog55]

Wife wouldn't let me bid on that one, not allowed until the house is fixed.
Would work which ever way you go, old stereo amps are more available and cheaper.
I have one of Rods boards here waiting to be populated, but our new house is so much smaller than the old I don't know if I need it.

[col]

I highly recommend Rod's ELF circuit (P48A)

I'm using it with a pair of slimline pioneer 10" car subs in 19ltr boxes tuned to an FS fo 43hz. Sounds awesome, I have bass down to 25hz.

don't bother with plate amps

col.

[Moondog55]

I have 6 of those cheap Redback 12 inch woofers to use, ELF would be the only way I could use them.
Wired series /parallel for the nominal 12R load.
I need a new cabinet for the TV I want to buy don't I?? Trouble is the room is only 4.5M wide

Rod did tell me of another cheap and easy way to use any amp in bridged mode but I have lost that email, that would give me 800 watts from the cheap Inkel power amp that is currently dieing a slow death, I was told to replace the bypass capacitors and the smoothing caps.

[Eddie Wolve]

If you want to mod the Jaycar, or 'Digitech' 600W unit, my guess is that is has a cut=off of 32 Hz, because if DC blocking capictors inline with the signal. I recon it wouldn't be too hard to replace these with a different value to give you a lower f3.??

[Ian Millar]

Originally posted by Moondog55
Rod did tell me of another cheap and easy way to use any amp in bridged mode

That could be his Project 14 at http://sound.westhost.com/project14.htm

The project article comes with a few important warnings regarding speaker impedance, which I guess means you might be limited to a nominal 8 Ohm driver for a cheaper stereo amp.

I use a bridged Class-D subwoofer plate amp of 800W into a nominal 4 Ohm load (two 8 Ohm drivers in parallel) with ESP P48 in front and it is OK, but runs out of spit earlier than with the an old 365W 8 Ohm A/B stereo amp with each channel connected to respective drivers of the same subwoofer.

[Moondog55]

No while I did ask about that project there is apparently another way to do it, old computer with dead hard drive holds all of my older emails; from memory tho it was a permanent switching of input direction.
Not something I'm going to attempt without a diagram and explicit instructions

[Ian Millar]

Probably just using a balanced line driver with hot to one power amp channel +ve input and cold to the other power amp channel +ve input and ground to ground. He sells a stereo balanced line driver PCB but you only need mono. Here is a mono one that I built around a single dual opamp:



Output resistors (not shown in the photo) are off-board to an XLR socket. Since the photo I substituted 0.1% resistors and it works OK.

[Stu]

Originally posted by Eddie Wolve
If you want to mod the Jaycar, or 'Digitech' 600W unit, my guess is that is has a cut=off of 32 Hz, because if DC blocking capictors inline with the signal. I recon it wouldn't be too hard to replace these with a different value to give you a lower f3.??

I'm hoping it's something as simple as that. Shouldn't be too difficult, really, just have to find the cap and shunt it out. Might try and borrow a CRO for it, though...

[robywan]

Hi Every one, I know this is an old thread but just some advice to anybody that researches these Jaycar Plate amps (Class D 150 and 600 models) Please do not purchase them, I have had two fail on me in a row (6 or so months usage fo each - 150 model) First one I had had a sound problem (distortion/humming variable with volume) and auto on function was a bit funny, second one failed from bad electrolytic caps on the power supply and amp board (common hydrogen build up with cheap caps), Resistors in SMPS where under rated and burn't out (before blowing any fuse) and heat-sinks missing off two voltage regulators.

BTW I actually work at a Jaycar Authorised Stockist.