500 Watt Op Amps from Apex Microtechnology

[jasonc]

Has anyone used the PA05 Operational Amplifier in thier designs?



This amp is amazing, .001% THD @ 200W, .01% THD @ 300W.

http://eportal.apexmicrotech.com/mai...pa05.asp?guid=


I still can not get over these specs:


ABSOLUTE MAXIMUM RATINGS SUPPLY VOLTAGE, +VS to –VS 100V

OUTPUT CURRENT, continuous within SOA 30A

POWER DISSIPATION, internal 250W

INPUT VOLTAGE, differential ±20V

OPERATING TEMPERATURE RANGE, case –55 to +125°C

COMMON MODE REJECTION, DC Full temp. range, VCM = ±20V 90 100 * * dB

INPUT NOISE 100KHz BW, RS = 1KΩ 10 * µVrms
GAIN

OPEN LOOP, @ 15Hz Full temperature range, CC = 82pF 94 102 * * dB

GAIN BANDWIDTH PRODUCT RL = 10Ω 3 * MHz

POWER BANDWIDTH RL = 4Ω, VO = 80VP-P, AV = –10 400 * kHz
CC = 82pF, RC = 120Ω

PHASE MARGIN Full temperature range, CC = 470pF 60 * °
OUTPUT

[Duo]

That is a very nice looking opamp.

I wouldn't be able to fork out the money for that price, however, the idea is definitely worth trying if you can afford it.

That sucker looks like you might need a sophisicated heatsink though.

I'd certainly be interested to see a design incorporating that chip.
One could build an especially simple amplifier with power opamps like that. It would probably be quite reliable and compact. I'm wondering what the sound quality would be like. And also what modes of amplifier operation you could achieve.

[peranders]

Originally posted by Duo
I'd certainly be interested to see a design incorporating that chip.

If you look at the pictures you will see that this is a hybrid, not a single chip.

[speaker]

APEX has been building high-power chips for at least 12 years. I believe they are mostly used for motor control. I've always been curious how they might work on a subwoofer application as they spec most impressively but have not wanted to be the gweenya-pig either.

Has anyone tried them on audio applications?

speaker

[Duo]

Peranders: Yeah, I understand that, I was thinking about that as I wrote the last post. Still, my point is that this is relatively esoteric and would be interesting to see in the audio world, even if it didn't sound good.

[sam9]

Pretty interesting what you can get into a small package. A few of observations from the data sheet:

--To get those great THD figures you can't operate it over the 200W level.

--Attention to the power supply is needed since the PSRR at 1kHz and below is OK but not super.

--Heatsinking may be critical as the power rating falls rapidly above ambient. At 76C you only have a 150W amp, at 100C only a 100W amp. If I was trying to make one go, I'd plan on a fan from the start. This pretty much makes it dubious a a plate amp for a sub.

- I would want to study the SOA a bit more; with a 4 ohm speaker or a nominal 8 ohm that has big dips you may have less power than available than first appears. The 30A current figure doesn't mean much when you match it against the voltages you are more likely to require.

-- There is no info on clipping characteristics: clean, soft, ugly. . .?

I'm not nocking it. It would be fun to mess with if they were giving them away for free. It has the both the principal pluses and minuses of any IC amp: it lets you build an amp with few parts but you are limited to what it is. In passing, I wonder if it can be bridged.

[BStrum]

Crown started out building power amps used for servo motor and shake table control application in the seventies. Thier products where "discovered" for audio applications. Apex may be another case.

It doesnt look like the economics make much sense, since you could use multiple LM 3886s (etc) to achieve the same power levels.

We need to find someone who has heard them in action.

[jasonc]

The PA05 can be bridged in a parallel, series or series - parallel configuration:



The have stated in the application notes that the amplifiers will operate well under these configurations and offer sample designs.

http://eportal.apexmicrotech.com/mai...otes.asp?guid=

Could you imagine getting 6 KiloWatts from a dozen of these amps in series / parallel configuration?

[BStrum]

Besides building an amp that doubles as a spot welder, what would you do with 6Kw?

[speaker]

Originally posted by BStrum
Besides building an amp that doubles as a spot welder, what would you do with 6Kw?

Drive a sonar array and troll for N. Korean submarines?



speaker