"The Wire AMP" Class A/AB Power Amplifier based on the LME49830 with Lateral Mosfets

[opc]

There already is one! Check the headphone amp GB and sign yourself up for a PCB board. You'll need HV caps for the input and output.

Cheers,
Owen

[Boscoe]

I'll go for 6 x PCB depending on the price of postage to the uk.

[454Casull]

A heatsink of what C/W rise is required for each board (of course dependent on power)?

[HYPERTUNE]

Originally Posted by opc

There already is one! Check the headphone amp GB and sign yourself up for a PCB board. You'll need HV caps for the input and output.

Cheers,
Owen

OK, found it!!!

For those interested, Owens PS boards are also $12 and can be found here:

"The Wire" Ultra-High Performance Headphone Amplifier - PCB's

Owen:

Do you recommend one separate front end PS for each amp channel? Would 1 be OK for 4 channels?

[opc]

454Casull:

That question is far to vague to answer correctly.

I'm putting together a spreadsheet that will help to calculate the C/W of the heatsink you'll need based on a few factors that the user can pick.

You need to know the load, the rails, the idle bias current, the room temp, and the usage expectations. That last one is critical in the sense that if you expect to output full power indefinitely, you'll need a much bigger sink than you would if you use a 1/8th crest-factor (for music).

As an example, if you want to output 400W continuously to the load, then the output transistors will dump about 400W continuously into the sink. If you want to dissipate that much power while keeping the heatsink temp below 100C then you're looking at about 0.2 C/W which is essentially impossible to attain with passive cooling. If you're listening to real music though, with 400W transients, then you could get away with a much smaller heatsink and passive cooling becomes a viable option.

I'll post the spreadsheet tomorrow sometime and people can have a look.

Cheers,
Owen

[opc]

HYPERTUNE:

You could run all 8 channels off a single board as long as you don't push the voltage drop across the regs too high. Each channel draws roughly 15mA per rail, so all 8 channels together would draw about 120mA through each reg. As long as the input to output voltage differential is 10V or less, you'll be good to go.

In other words, if you have 50V on the mosfets, plan for 60V on the LME, and plan for about 65 to 70V before the regulators. That would be a transformer with dual 48V secondaries.

Cheers,
Owen

[Arius]

Very nice design, thank you for sharing and organizing the GBs.

Schematic Comments:

1) Datasheet says Cmute should be no less than 47uF. I see a 10uF cap.
2) Datasheet recommends a decoupling cap across Vcc and Vee. This is shown in the demo board design as Cs13. It seems to be missing.

Thanks!

[greyrab]

I would like:

2 - Full kits

Thanks.

[L-Train]

Hi Owen,

Just to confirm my request, I'd like:

2 - PCB's without part kits.
2 - Full kits which include the PCB.

Thanks!

[HYPERTUNE]

Originally Posted by opc

HYPERTUNE:

In other words, if you have 50V on the mosfets, plan for 60V on the LME, and plan for about 65 to 70V before the regulators. That would be a transformer with dual 48V secondaries.

Cheers,
Owen

OK I'll be running 60V to the mosfets, 70V for LME so I expect 55V transformer secondaries would be ideal.

Will there be any issues finding suitable caps that will fit the board? Any recommendation? Space won't be an issue so I could mount on the bottom if necessary.