Which IC amp for +/- 42 Vdc?

[gunny1]

I was given a Peavey mixer amp (mono) with a totally smoked power amp section. It's model 200H rated 100 Watts into 4 Ohms. I don't wish to restore the power amp section, I'd rather just build or buy a new chip amp.

Here's the question: the DC power supplies are both A-OK. +/-42 Vdc and +/-16 Vdc (to operate the mixer/pre-amp). The mixer is working fine.

I realize that 84 Vdc is the max rated applied voltage on spec sheets for 3875, 3886 chip amps.

Any suggestions on which amp circuit I could build or buy and still be able to use the power supply I have?

It's not imperative that I get 100 Watts out of it; just something over 30 Watts would be fine.

[planet10]

I have a 3875 chipamp running on just a bit over the maximum. It sounds very good when driving high impedance loads (16 ohms, not as good when the impedance starts dropping)

dave

[infinia]

you could get a ready made kit on ebay $10-20 along with a new $10 transformer and rewire the old powersupply;

[Minion]

Try a TDA7293/94 , it will put out close to 100w into 8 ohms , A Pretty good sounding chip , I"m useing one in a Guitar amp at +/42Vdc and it sounds nice , it won"t drive 4 ohms at +/-42v , you would need a lower Voltage to drive 4 ohms like +/-30Vdc .....

[geraldfryjr]

if you parallel 3 or 4(one leg of a bpa 300) of them you shouldn't have any problems when driving 4 ohm loads common in pa speakers.jer

[geraldfryjr]

i forgot to specify lm3886

[gunny1]

Thanks for all the replies. I've struggled with the decision on whether to use 3886 or the 7293/4 but decided to use the TDA2050 powered from the +/-18 Vdc that's also available on the parent circuit.

The main reason I didn't use the typical 'clone' variety amp chip was that I didnt' want to risk operating at the maximum Vs for 7293 and wanted to use the existing power transformer.
The kits for clone circuits were attractive but since I'm not using this in a stereo application, I'd be wasting half of the board.

Let's consider this thread closed. Thanks again to all.

[pacificblue]

If the power supply has ±18 and ±42 V the TDA7293/94 is the right choice in class H configuration. The datasheet calls it High Efficiency Application Circuit (Figure 6, Page 9).

[infinia]

Originally Posted by gunny1

Thanks for all the replies. I've struggled with the decision on whether to use 3886 or the 7293/4 but decided to use the TDA2050 powered from the +/-18 Vdc that's also available on the parent circuit.

Its doubtful that the added demands placed on the existing +/-18 Vdc can support a Power Amp driving a 8 ohm or perhaps 4 ohm speaker. Before your decision can be finalized you must verify that the XFMR windings and rectifier can tolerate this without blowing. Be very careful when testing as it very easy to pop these lighter windings. Me I wouldnt even go there.

[gunny1]

Infinia: absolutely correct. I will use one half of the PT's main secondary winding instead +42 Vdc to CT and operate the TDA2050 in single rail mode. The PT won't be overloaded - I'll be using the half winding at ~80% of what it can deliver current-wise.

I know 7293/4 would work using the full transformer output but my speaker's aren't rated that high.