ColdAmp modules

[SnakeFingers]

Anyone familiar with these ColdAmp modules?

Amp: http://www.coldamp.com/opencms/opencms/ ... es/BP4078/ (.4 lbs each and bridgeable)

Switching power supply: http://www.coldamp.com/opencms/opencms/ ... index.html (1.4 lbs, will power multiple amp modules)

The modules are very light, and can be configured in various ways. For example, 1 PS + 2 amp modules yields 800W into 8 ohms with a weight of approx 2.5 lbs. Make it 5 lbs with the addition of a plate/heatsink.

Rod Elliott's site has an article discussing them-
http://sound.westhost.com/articles/pwm.htm

There's also a couple projects on his site featuring the amp module-
http://sound.westhost.com/project114.htm
http://sound.westhost.com/project116.htm

A tad pricey at $512 for the above mentioned configuration, but if they work as described, they could be paired with a couple of Jacks in a very light weight system.

Mark

[Bill Fitzmaurice]

Since they're (oddly) not distributed in the US they remain a mostly unknown quantity.

[AntonZ]

I think forum user Thijs666 has built himself a four channel amp with Coldamp modules. Don't know the details. You can PM him if he does not respond in this thread.

[Dazombiewoof]

There are some class D amps available here in United States. Peavey's IPR series ought to bring class D to the masses. $299 street price for 800 per channel into 2 ohms plus built in 100Hz corner frequency high pass or low pass built in is the smallest. Lot of times you see power amps of this class not being rated into 2 ohm loads. Quoting from announcement.

In addition to the standard IPR 1600, IPR 3000, IPR 4400 and IPR 6000 models, Peavey has announced four models that feature built-in 32-bit, floating-point digital signal processing. The IPR DSP models ship with program-specific EQ presets that make common sound-reinforcement EQ treatments easy to perform, as well as delays, crossover and stereo/mono operation with lockable security settings. A front-panel LCD screen allows users to quickly identify and assign presets.

The smallest one in complete 19 inch 2 space rack format is all of 7 pounds. Peavey has a tendency to build reliable stuff and one hopes this is such a case. They own Crest amplification and have done both switching power amps and power supplies for some time. The most fascinating being producing a 300 watt vacuum tube bass amp weighing in at something like 37 pounds courtesy of a switch mode power supply.

[jswingchun]

There are some class D amps available here in United States. Peavey's IPR series ought to bring class D to the masses. $299 street price for 800 per channel into 2 ohms plus built in 100Hz corner frequency high pass or low pass built in is the smallest. Lot of times you see power amps of this class not being rated into 2 ohm loads. Quoting from announcement.

In addition to the standard IPR 1600, IPR 3000, IPR 4400 and IPR 6000 models, Peavey has announced four models that feature built-in 32-bit, floating-point digital signal processing. The IPR DSP models ship with program-specific EQ presets that make common sound-reinforcement EQ treatments easy to perform, as well as delays, crossover and stereo/mono operation with lockable security settings. A front-panel LCD screen allows users to quickly identify and assign presets.

The smallest one in complete 19 inch 2 space rack format is all of 7 pounds. Peavey has a tendency to build reliable stuff and one hopes this is such a case. They own Crest amplification and have done both switching power amps and power supplies for some time. The most fascinating being producing a 300 watt vacuum tube bass amp weighing in at something like 37 pounds courtesy of a switch mode power supply.

That $299 is for the model without the dsp. $449 for the same model with DSP. The $299 one would make a nice monitor amp.

[Dazombiewoof]

The DSP version has all sorts of features which would be nice. If one has the appropriate highpass to protect your subs already and crossing over at 100 Hz is not objectionable it might be a bit of inexpensive power. I have heard real heated debate regarding class D amps for low end, bass rigs in particular. I suppose it might do well for some Tuba or Titan subs, tops, or full range.

Cedar Rapids I remember well. I recall a country bar called the Czech Inn, probably long gone. The old Sokol halls were wonderful venues.

[jswingchun]

The DSP version has all sorts of features which would be nice. If one has the appropriate highpass to protect your subs already and crossing over at 100 Hz is not objectionable it might be a bit of inexpensive power. I have heard real heated debate regarding class D amps for low end, bass rigs in particular. I suppose it might do well for some Tuba or Titan subs, tops, or full range.

Cedar Rapids I remember well. I recall a country bar called the Czech Inn, probably long gone. The old Sokol halls were wonderful venues.

The DSP version is pretty similar to the Crown XTI but costs a bit more. The XTI weighs twice as much, but 7 pounds versus 18 pounds I don't know if it would be worth the extra cash.

The Czech Inn did all kinds of music. I played there a lot in the late 1980's in a zep/aerosmith/van halen cover band. The place changed hands a bunch of times. It was the Czech Headquarters when the floods came thru last year and filled it with 8 feet of water. Looks like it's getting ready to reopen as the Red Baron or something. The Sokol halls don't do local music anymore, though one of them is open as an arts center and occasionally has touring "artsy" music.

[Dazombiewoof]

I think Brave Combo played one of the Sokol halls in Cedar Rapids.
Crown XTi I presume does crossover for subs or whatever and will do an adjustable highpass to keep your subs safe? There is appeal in going with something that has been in production a while like the Crown. Interesting Peavey price point for their DSP model is beat by Crown. One must assume the DSP offered must be more extensive or they don't understand the market.

[AntonZ]

The DSP in the Crown XTi amps is quite extensive as is. The DSP section in the Peavey has got to be quite something if they want to beat Crown with that while charging a higher price. Curious to learn what their DSP is like, and how it is operated (frontpanel only, PC link, store/upload/download presets, ...)

[thijs666]

I think forum user Thijs666 has built himself a four channel amp with Coldamp modules. Don't know the details. You can PM him if he does not respond in this thread.

I built a 2 channel amp and was planning on a 4-ch one using the Coldamp modules

(Sorry for my late reaction; I'm moving and don't have internet available yet in my new place )

I used 2 BP4078's and two 400W SPS's, which in total equal about 1.5 kg . That comes close to the metal housing they're in. I really should look into some aluminum housings . I'm using this (stereo) amp to power up to 4 DR200's. It's 400W@4 ohms and 240W@8 ohms, so almost perfect for my beta8 loaded DR's.

They NEVER run hot, but just to be sure, I installed 2 8 cm fans, which I ripped out of some faulty computer powersupplies.

I wish I had the funds to replace my PV2600 which I use to power my T48's with class d modules, because I really can do without that lump weight (although it never let me down). And I still need a monitor amp, for which I was planning to use the Coldamp modules too. But this is also looking tempting...

One other thing to consider: due to their high efficiency (both the amp and the power supply), the 'overhead' normally needed for AC power can be much smaller. I run my complete system (2 T48's and 4 DR200's + mixer and processing) from one outlet (admitted a standard outlet in Europe is 230V@ 16 amps, thus 3680W) with room to spare. I can even hook up 2 more T48's and DR's if I wanted to (and I would, but I don't have them (yet ).

[sbe]

Instead of the T-amp I think you'll be beter off with an Alto D2 or D4.
They have powersoft modules inside.
Cheapest I've have seen them is at www.prosl.com

[AntonZ]

Yeah, I also noticed these amps - 4ch in a single rackspace is something special, the price makes me wonder if it can be any good. You cannot buy class D modules (coldamp, hypex) and powersupplies for that kind of money. QSC GX5 is light and affordable, but only 2 channels in 2 units. And Peavey recently got some new class D amps, too. Looks like switch mode is going affordable mainstream now.

How do you find the coldamp modules on the piezo's of your DR's Thijs? It has been mentioned that many class D amps don't go well with piezo's. Something to do with sensitivity of piezo's for high freq distortion iirc.

[thijs666]

How do you find the coldamp modules on the piezo's of your DR's Thijs? It has been mentioned that many class D amps don't go well with piezo's. Something to do with sensitivity of piezo's for high freq distortion iirc.

I used a 4 Ohms resistor in series with the piezos and I don't ever had any problems, other than that the DR's are so effecient, they make every little whine or noise audible. As soon as you play some music, this is of no concern. I never had problems with high freq distortion from the amps. The piezos WILL however painfully point out ANY flaws in your rig. The clearness of the DR200's equals that of a true hifi system (subjectively of course). Playing 128k or 160kbps MP3 is NOT a good idea! Use AT LEAST 192kbps from a good source (320kbps or uncompressed is highly recommanded). Even clipping in an overly produced (read 'compressed') commercial record can cause trouble ...