CurtPalme.com Home Theater Forum

beun · Joined: 28 Jun 2006 Posts: 676

I am seeing that people are using essentially pro-amps to power sub-woofers or other home theater speakers and to keep the rest of the Crown thread clean (after polluting it in the first place) I was wondering if it would be possible to develop a replacement for these amplifiers and what the requirements would be.

Mono or Stereo
Power
Filter or any other options
Cost
Looks (High end or utilitarian)

Please throw in your ideas, I am always looking for new products to design to keep me busy.

macgyver655 · Joined: 22 Aug 2007 Posts: 8508

What class amp would you be thinking of experimenting with?

beun · Joined: 28 Jun 2006 Posts: 676

A class-D is the easiest way to get lot of power out of a small and cool package. My DPA-5 uses Hypex modules and I am currently designing and building my own modules as well.

dturco · Posted: Tue Mar 29, 2011 6:24 pm Post subject:

Cool, Here is what I am looking for. A power amp 2 channel 150W @8ohms with XLR inputs and rca. I want to use it for the surround channels More specifically to add into a system which is currently using Bryston 4bSST and 6B SST amps in 5.1 configuration.

I realize that the Bryston's are pro and high end audiofool gear, but I just can't justify 2500 for an amp to do just 2 more speakers.

Emotiva has something UPA 2 [$350] close but no XLR input and the Toroidal power [a must for me} at 300va seems small, but I have no idea what size is really needed to do 150w anyway. I would like it to be 600va just ..well because, it seems powerful but not crazy.

Emotiva XPA2 over shoots and gives me what I am looking for and way more than I need at 300w 1500va toroidal power and jumps to $800.

I want a small 125-150 wats class A A/B or A/b type amp under 350 Bucks XLR inputs. Can't find it anywhere except used and 20 years old. [No thank you on that]

Class D amps have zero appeal for my wants.

Edit: 12 volt trigger no fans and rack mountable.

Hope that helps.

Still looking

Dave

greg_mitch · Joined: 03 May 2006 Posts: 5320

Here were my requirements when looking for pro-amps.

~200W x 2 @ 8 ohms
Unbalanced and balanced inputs
Bridgeable
Rack mountable
No fans
~$200

I ended up with 3xBehringer A500 amps. They have served me fine for over 2 years.

The dancing lights look kind of neat as well. Wink

But I would have liked a more finished "high-end" look...without the plasticy feel.

dturco · Posted: Tue Mar 29, 2011 6:52 pm Post subject:

Oh and as far as looks go HEATSINKS that can be seen either at the rear or sides, front not my first choice, but acceptable. Hell just make a Bryston 4 Bsst clone downsize it, and 350 bucks. Or a 2B LP clone again 350 bucks.

That's my real answer.

macgyver655 · Joined: 22 Aug 2007 Posts: 8508

I would do everything in my power to never buy an amp that has software or electronic control. More stuff to fail and make the amp worthless.

I would also never buy an amp with more then 2 channels. Again, higher loss with a failure.

I also dont get the response of no fans. Unless you guys have only heard pro amps with loud fans. My QSC's are so quite I occasionally have to put my hand back there just to be sure they are running.

Bridgeable would be a must along with multiple style ins and outs. 2 ohm capable also a must.

Other wise, high quality parts.

**Curt Palme** · Posted: Tue Mar 29, 2011 8:54 pm Post subject:

My question would be, why make a product in a market that's flooded already? Heck, even people here buy on price alone (see the other Crown thread), and at something that I'm assuming you won't get made in China, do you really want to compete with a $200 retail amplifier?

The only thing I'll disagree on with Mac is a MUST for a 2 ohm load. Why? THe amp runs red hot at 2 ohms, draws current that most outlets can't supply, which is why I personally never run under 4 ohms.

macgyver655 · Joined: 22 Aug 2007 Posts: 8508

beun · Joined: 28 Jun 2006 Posts: 676

Curt,

I can agree with your question, the amplifier market seems to be full and yet more new ones seem to be popping up all the time. I can also understand buying on price alone although the quality of far east manufacturing isn't always there.

This thread was just intended to see how much interest there would be for a more utilitarian amplifier since the high end ones do not seem to sell. A price point of $200 is very hard to meet while manufacturing in the US although a price of $300-$350 like mentioned before seems a whole lot more doable. Ultimately I may or may not do it but I thought it worthwhile to at least test the waters.

I am a bit surprised with the objection to class-D amp's though, the new modules sound very good and they make the heatsink requirements so much easier.

dturco · Posted: Tue Mar 29, 2011 9:19 pm Post subject:

**Curt Palme** · Posted: Tue Mar 29, 2011 9:30 pm Post subject:

Sorry, I wasn't trying to rain on your parade, but yes, the 'economical' market seems really saturated, unless you can come up with something super unique, or alternatively go balls out and make something so insanely esoteric to appeal to few, but with enough profit margin that you could afford to hand make the screws holding the chassis together. Smile

macgyver655 · Joined: 22 Aug 2007 Posts: 8508

I dont know. What would it cost to build a plain and simple 2 channel, class D amp?

No software or electronic controls.

Plain little box with various ins and outs.

dturco · Posted: Tue Mar 29, 2011 9:49 pm Post subject:

On that class "D" issue. I have no experience with them at all. Never heard one. Never had the desire to, and I would never buy one just to try it out.

With all that said if I could listen to one for free I would not be against doing that. The old dinosaur amps are what I know and would have a hard time trying to except the new class "D.

Maybe one day I would be willing to think in some new terms, but I am stubborn, as suspect many who have spent multi thousands on big old amps are too.

It's a philosophical drive to hold onto what I have can't be replaced so easily or cheaply....Hey kinda like CRT HUH?

beun · Joined: 28 Jun 2006 Posts: 676

A plain and simple Class-D 2x120W in 4Ohm or 1x240W BTL in 8Ohm could be made for around $300 resale. I am already working on the module, the size of the case would be mostly determined by the connectors on the back.

beun · Joined: 28 Jun 2006 Posts: 676

If you don't care that the case looks a bit hacked up I can send you a 150W mono block to try out

dturco · Posted: Tue Mar 29, 2011 10:38 pm Post subject:

macgyver655 · Joined: 22 Aug 2007 Posts: 8508

Is your design comparable to this?

macgyver655 · Joined: 22 Aug 2007 Posts: 8508

beun · Joined: 28 Jun 2006 Posts: 676

I need to check if I have enough parts left for another mono version. I also have a 5channel amp but I would need to check on the shipping cost, that puppy is heavy. Shipping the 5 channel amp would also have to wait till after the Lone Star Audio Fest show at the end of May.

With respect to the schematics, the 5 channel amp and high end mono blocks are very different, they use Hypex modules which use direct feedback from the output after the filter in order to remove the filter influence.

The modules I am working on now is a hybrid of the Hypex modules and the schematic you showed, it has feedback from both before the filter and after the filter.