Help picking a plate amp

Just above $100, but the PE 240w w/ Boost would probably would as well as can be expected with that drive and enclosure. I'm not sure where the high-pass is set, but it should give some protection against bottoming.

Another option a bit more in line with the overall budget nature of the build would be the surplus Foster WF-100K for $35 from the NHT Surplus Sale if there are any left. It's 110w at 4ohm, has a 29hz high-pass, and an adjustable 10db shelve can be modified using data available from the sale website.

Keep in mind that the Rockford Fosgate reccomendation for that driver is for car-audio (enclosed space, cabin gain) as well as music (far less subsonics and near subsonics). I'd play some modeling software and compare enclosures for the driver. You know the volume (roughly) and port size/length, so you're really just comparing the FR curve and output of sealed vs. vented. Since you're looking to replace the amp anyway, you don't have any unknown boost characteristics to deal with.

I'd say the PE amp would noticeably increase output over the Foster, which may or may not noticeably increase output over the stock amp... but with the Foster amp you have a clean slate (no unknown boost) and you're not sinking a lot of money into an unknown. A $110 amp probably isn't going to make this project $75 better than the cheaper Foster amp. Buy the cheap amp to play with what you have, and buy or build a better sub when you're ready to upgrade.

Very happy with several NOS Hafler/Rockford 100 W plates I have used. E-Bay for around a buck, something like that. Don't know if there are any left. I might grab a couple more myself.

I was late to this thread, I have 4 of Jack's amps in my garage unused.

I don't think you're going to have much luck bridging them with a 8ohm load. I really wouldn't sink much more than the cost of one of the Foster amps into this unless you plan on reusing it building an HT oriented design later on. Any more than the $35 a surplus Foster 110w costs seems like throwing good money after bad.

Now that's thinking with your dipstick, Jimmy!

Just wanted to drop in and say I picked up 4 of these to put onto some unpowered eD 12" subs I had left from the last upgrade and sell them on Craigslist (I'm keeping the EP2500 ). I'm quite happy with the performance and believe they put out a true 110W (that's not just their "rated power" it's actual).

Funny story, I had a guy come over to look at the subs. He'd just bought an Infinity sub rated at 500W from Best Buy but was unhappy with it. He demo'd the large ported eD sub using one of these plate amps and was blown away. He didn't want to spend the $175 on the sub I was selling since he already had the Infinity and didn't want to pay for return shipping (we're in the middle of nowhere!) but asked if I'd sell just the plate amp. $75 later and he was on his way with one. I wouldn't have charged him so much but I figured if I sold it at $75 he'd be back to trade up to the ported sub for another $100 for sure. I emailed him the other day and he was ecstatic with the performance of his Infinity with the new amp. He said the "500W" infinity amp wasn't half the size or weight of the Foster amp, go figure

Are you saying they are no good? Im pretty sure Jack, NHT would disagree with your opinion. You can ask jack about the Bridging, from what I have read it can be done.

Definitely not saying they're no-good... just saying that bridging them with a 4ohm load might be pushing the limits of their abilities... that would be the equivalent one amp driving a 2ohm load. If Jack says it can be done, I definitely believe it, but his site says they can be bridged for an 8ohm load.

For the $$$ they can not be beat period!!

I haven't used them for the same reason I havent used the other $2000 worth of drivers sitting in my garage

Too many projects, too little time....I couldnt pass up on them and the 10" 081s that Jack was selling many months ago. A bass bin for $70 is sick and Im happy I bought many things from him including incredible VR-3 kits! Most of the stuff now is sold out but I have great value for future projects.

Any neighbor or friend that wants speakers is going to love me

Oh, sorry I misread your post....Yeah 2 ohm wont work.

but since he has a 4 ohm driver two bridged amps giving him 200W into 4 ohms?

Not sure where I read it but Jack said he tried bridged into 4ohms and the amps went into protection so that's a no-go. I'll see if I can find it.

Edit: Found it, it's in the FAQ located on his page:

"When two WF-100k amplifiers are bridged together, the load must 8ohms or greater. I tested this setup with a 4ohm load and the amplifiers instantly went into protection. It may work with a 6ohm load. I don’t know. Into the 8ohm load, the amplifier pair delivered 220W at 1% THD at 50Hz."

Which thread? If you mean the quote from Jack I got it from the Foster WF-100k amplifier FAQ, it's the first link under the Foster amps on his page that you linked above:

http://home.comcast.net/~jhidley/

There is a thread here that Jack's been posting in regarding the items he has for sale but there's not much discussion of these amps there:

http://www.avsforum.com/avs-vb/showthread.php?t=1125860

A table saw would be best but a circular saw will do for a one-time sub build... I was thinking you were on a tight budget but now you're buying a table saw for a new sub build??? And just ordered an eD A5-350??? If you do make a run at a DIY sub what would the budget be and what kind of performance are you looking for? HT/music? Size restrictions?


You could wire it that way but it would be messy. Any gain settings or crossover settings would have to be performed on each amp separately. Usually with a DVC sub you'd wire the coils together in series or parallel depending on the load you want to present to the amp - wiring in series will double the impedance of one coil, parallel will halve it. So a sub with two 4ohm voice coils could be wired in parallel for a 2ohm load or series for an 8ohm load. Most of the amps commonly used won't drive a 2ohm load though.

Wow!!! What a thread that guy has going over there on the forum you linked too!!! My goodness!!! I wasn't about to read all 100+ pages but I read more than enough on the first couple of pages to know what was going on...I am no schill but have been calledone for being a bit too enthusiastic about certain things that I write about...

OK...Sort of hard trying to figure where I want to start based on your questions and the other excellent advice you have already received...I guess the first thing I should state is that I am only stating my opinion and you can take what you want out of it...However please be aware that my opinion(s) are ALL based on actual experiences of mine and I am not fabricating anything...

Well lets start with the sub you bought that is a POS...While I know nothing more about the sub other than what I have read I feel confident in saying that for the price I am sure it is not really a POS but rather won't do what YOU want it to do...Nothing wrong with that as it was never meant to be that kind of sub...

Most subs will benefit in a huge way by simply upgrading the driver...Now the driver you used is absolutely better than the OE driver...However it is still a car sub and while it works it is not fair to expect it to perfrm well in the environment you are using it...For $10 I would probably do the same...Now the reason the OE amp is getting so hot is because of 2 reasons...The first is because you are using an 8ohm amp to drive a 4ohm load...The added strain makes the amp work harder which causes the heat...The second is because you have the amp that is already working hard turned up I am sure to get the output you are looking for...Again there is nothing wrong with that but is the reason for the heat...The amp will certainly cease working sooner than later if you keep using it like this but I sincerely doubt any fire will occur...

Now as for what is the best amp to use...That Foster IF it is as nice as has been posted is hands down the best way to go...But be warned that you intend to use an 8ohm amp on a 4 ohm load so you will have heat issues again IF the amp does not go into self protect mode first...And according to one of the replies here it states that the amp MAY be able to run 6 ohm but certainly not 4ohm and 8ohm is ideal...But when I look at the actual specs it does state a 4ohm load will work...Regardless a 4ohm load will make the amp hotter than an 8ohm load...

Now honestly if it were me I wouldn't worry about buying a table saw and building a cabinet...How is the AA cabinet??? Is it decent??? is it the standard 5/8 to 3/4 thickness??? Is the baffle thicker than the other 5 sides??? if the answers are yes to all of the above then this is what I would do if you really want the best for as little cash as possible...The Dayton 240watt plate amp for $109 + free shipping...Pick up this driver:
http://www.parts-express.com/pe/show...number=299-106
or For even less use the Foster amp you just ordered and get rid of the Rockford driver and get this one instead:
http://www.parts-express.com/pe/show...number=295-485
You will be amazed with what these drivers can do...VERY impressive...I have the 12" DVC and it seriously rocks...Go to a hobby store and get some poly fill as it is cheaper that way...You do the 2nd way and you'll have a sub that rivals $300 subs from Best Buy and the like easily...

Also don't be concerned about having dual leads from a plate amp when using a DVC driver...You can connect only 1 coil and be fine...Won't hurt a thing...Or you can connect the coils in series or parallel...Personally i would use them in series to make it a 4 ohm load for the Foster to drive...Now don't forget as nice as the Fosters are supposed to be they aren't THAT nice...The power supply and capacitors I'm sure are no larger than absolutely necessary for cost reasons so don't expect a whole lot from them...The BEST is to use the 240watt Dayton amp and the second driver I linked to connected in 4ohm for the best 10" sub for cheap...

It's late and I may have rushed through this but I think I have made my point...Take what you will from it as little or as much along with the other suggestions and you'll be fine...All I can say is I take cheap subs with decent amps and replace the drivers all the time and the sound is incredible...As a matter of fact I am using a sub I bought off the internet with a 150watt plate amp but it has oversized capacitors and a torroidal (sp?) power supply in a curved cabinet I paid $129 shipped for and removed the POS driver that constantly bottomed out and replaced it with this:
http://www.parts-express.com/pe/show...number=295-464
Added some poly fill that I had sitting around and re-veneered the cabinet and I will put it up against any $800+ sub for sound quality...And I sold the old driver for $35 on ebay so my cost ended being $237...Pretty respectable I think...

Sorry if it wasn't clear but the statement was regarding bridging two of the plate amps together to push a 4 ohm load (so essentially the load to each amp would be 2 ohms). The amps will push 4 ohms just fine


That's true for the most part. It likely won't hurt anything but it does lower power handling and alters the T/S parameters. Using only one coil will double the QES. Here's a great page with more detailed information on options for hooking up DVC drivers:
http://www.geocities.com/f4ier/dvc.htm



I honestly think that the Foster amps will put out near the same as the Dayton 240w amp. I don't have anything to base that on other than the other Dayton amps tested didn't produce anywhere near rated wattage whereas the Foster amps were able to. Also the two amps are nearly the same size and shipping weight.

I'll bet! You've certainly moved to the next level from the Brick and Mortar subs

Thanks for the explanation of what you're trying to achieve too. It makes perfect sense when you lay it out like that, it just threw me off. Be sure to let us know how it works out.