Using consumer-grade power amp as Power opamp

The high-power amps I mentioned are clearly consumer grade; they're not studio amps, SFAIK, although the specs may be good enough. As for automotive systems, I imagine they've pretty much all moved to class D. Using parts like TI's tpa3116 family of dual 15 to 50-watt BTL amps. These are "filter free", have "AM Avoidance" with PLL-based multiple switching frequencies (to 1.2MHz), and with SpeakerGuard. 50W part, $2 qty 10k.

Four channel and up are available, like the TAS5414C.

Class D provides OK sound quality, is cheap and doesn't get hot - these issues are important to designers, no?

--
 Thanks, 
    - Win

------------------

** A low impedance between the + and - inputs does the trick.

Say 100hms plus a 22nF cap in series.

Leaves the DC condiitons in place.

.... Phil

The Zobel is only needed when driving an inductive load.

NT

On a sunny day (16 May 2017 05:53:25 -0700) it happened Winfield Hill wrote in :

Looks like an interesting chip, but all those switch mode wall warts already kill the shortwave band here. Seems a bad idea on say a boat that also needs SSB short wave say for sendmail or whatever. Are we just sacrificing parts of a useful spectrum just for power sake?

Actually I had some sort of switching power amp from ebay, not that chip, it died in a very short time, don't even remember why, used the inductors for something else.

It all depends...

Current limit and thermal shutdown not least among them. What else?

--
www.wescottdesign.com

Nope. The classics are still class-AB from ST, NXP, and Toshiba. There are some class-Ds used but it's not the norm. They're too expensive and not needed.

Power is limited by speaker impedance and Vcc. In a car, for practical purposes that's 2-ohms and 14V, which gets close to 50W. It doesn't matter what the class.

Cheap matters. Class-D is not. Heat doesn't matter much. You're not really pumping 600W into a car cabin.

Yep, sorry for the typos... I had a visit to my opthalmologist that day and looking at anything that emitted light was like staring into the sun, so please forgive.

Right about the gain... that caution is mentioned on the first page of the LM1875. DC offset coltage & current are only specified at 25C, and isn't great, for sure.

Dave M

That's mostly it. C-load stability is good, too. And cost.

I tried every imaginable way to destroy an LM1117 by abusing the Vadj pin, and it survived.

--

John Larkin         Highland Technology, Inc 
picosecond timing   precision measurement  

jlarkin att highlandtechnology dott com 
http://www.highlandtechnology.com

Student's managed to blow up an LM395, you are probably just not 'creative' enough. :^) (It involved mistakenly putting a big ass coil on the output.)

George H.

This, of course, depends on the colour of your ears, and their reflectability...

-- Kevin Aylward

- SuperSpice

I remember that one--it hit the thermal limit, tried to turn off, and the inductive kick blew it up. Creative, as you say. ;)

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs 
Principal Consultant 
ElectroOptical Innovations LLC 
Optics, Electro-optics, Photonics, Analog Electronics 

160 North State Road #203 
Briarcliff Manor NY 10510 

hobbs at electrooptical dot net 
http://electrooptical.net

Try listening to class-D crap via hearing aids that are class-D :-(

Class-D is for audiophools. ...Jim Thompson

--
| James E.Thompson                                 |    mens     | 
| Analog Innovations                               |     et      | 
| Analog/Mixed-Signal ASIC's and Discrete Systems  |    manus    | 
| STV, Queen Creek, AZ 85142    Skype: skypeanalog |             | 
| Voice:(480)460-2350  Fax: Available upon request |  Brass Rat  | 
| E-mail Icon at http://www.analog-innovations.com |    1962     | 

     Thinking outside the box... producing elegant solutions. 

"It is not in doing what you like, but in liking what you do that 
is the secret of happiness."  -James Barrie

I can make a fortune selling golden ear makeup.

--

John Larkin         Highland Technology, Inc 
picosecond timing   precision measurement  

jlarkin att highlandtechnology dott com 
http://www.highlandtechnology.com

It just lost the will to live.

--

John Larkin         Highland Technology, Inc 

lunatic fringe electronics

I have 5 kW of pro audio power amps, none of them are class D.

The weigh a bit, but its just an addition to my few times a week weight training at the gym. I am only 60kg, so I need the practice.

-- Kevin Aylward

- SuperSpice

I fondly remember my first UltraLinear... with power and output transformers it took two people to carry it ;-) ...Jim Thompson

--
| James E.Thompson                                 |    mens     | 
| Analog Innovations                               |     et      | 
| Analog/Mixed-Signal ASIC's and Discrete Systems  |    manus    | 
| STV, Queen Creek, AZ 85142    Skype: skypeanalog |             | 
| Voice:(480)460-2350  Fax: Available upon request |  Brass Rat  | 
| E-mail Icon at http://www.analog-innovations.com |    1962     | 

     Thinking outside the box... producing elegant solutions. 

"It is not in doing what you like, but in liking what you do that 
is the secret of happiness."  -James Barrie

---------------------

** Have you come across the Behringer iNUKE amps yet ??

SMPSs plus class D output stages.

I tested an iNUKE 6000 recently and found it pretty much meets all its specs - with the switching transformer and output FETs running reasonably cool.

I found it puts out 2500wpc with low THD - about 0.3%.

Weighs under 12 pounds and sells for around $US350.

A real game changer.

..... Phil

As long as you configure it as a inverting opamp with a gain of 20 or more, LM3886 is one big op-amp that works down to DC. We have them in some mech anical servo systems that need a DC to 2500 Hz response and +/- 12V of driv e. . I'm driving 3 ohm and 7 ohm coils with them, no problems. Must use a split rail, we use +/- 24 volt rails.

Steve

On a sunny day (Tue, 16 May 2017 16:03:40 -0700) it happened Jim Thompson wrote in :

Class D means interference.

I have this, nice fan at the back, 19 inch rack:

mixed languages. Good enough for the living room and street level. Was only 70 Euro at the time...

It now seems there is a force in the EU, now that UK leaves EU, to move back towards French or German as the main language. I remember getting French lessons in kindergarten... History repeats itself. What the consequences are for 'the world' I don't know, and about units, we use a comma where the US uses a dot.

12,5 means 12 1/2 that gets tricky if one needs 12,997 gram.

Will it ever be fixed?

1,999 percent distortion ;-)? Could be useful in marketing...