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

[qusp]

hey Cristi, just reaffirming my interest, if all goes well i will take 2-4 (assuming one powers one balanced channel? or 2?) you could also look at a website called zero, who do really nice deep drawn enclosures, they fully anneal them and even have mumetal options. they have like 30000 already tooled shapes so the likelihood of needing a custom design is slim.

on that note would it be possible to get without your enclosure as an option if you don't go for the above? because i will probably go for one from there and would rather not pay for an enclosure i won't use. they will do further tooling as needed too and i expect bulk pricing.

i would be looking at 60-70 and 45-55vdc voltages. with fully regulated preferred

the enclosure does look good though, i guess i'll see how it pans out

[opc]

Looks great Cristi!

I see a nice PFC and a pretty hefty looking transformer (ETD35 or ETD39?). The PFC will be nice to have, especially for those looking at multi-channel setups where you can quickly max out a 15A circuit without a good PFC. With the PFC you should be able to draw a full 1800W from the wall all day long on a NA 120V/15A circuit.

I can't see where you're taking the feedback for regulation, but I'm guessing it's off the high current rails to maintain regulation under load? If so, then the low current supply will probably wander upwards under heavy load, so it might be advisable to post-regulate those supplies. The current draw is so low that even an LM317/337 would easily be up for the task as long as the outputs don't get shorted. I don't see any post regulation on board, but nothing is stopping people from adding their own in between.

I really like that style of case as well. Cheap and functional. I've use that style of supply before for 36VDC motor drivers, and they worked admirably. You can mount them pretty much anywhere, and the shielding should help keep radiated noise to a minimum providing the outputs are well filtered before they leave the chassis.

If you need some assistance in testing these, I'd be happy to give it a go on one of my prototypes here. If you ship it here, then I'll cover return shipping or I'll just buy it if it works. Let me know what would work best for you!

Regards,
Owen

[qusp]

where does one put star with a supply like this? at the outputs?

[opc]

At the high current output GND I would think. It might be a benefit to have a few extra solder points for speaker GND and input GND so everything can be cleanly returned to the supply. I have all of these points on the board, but it's usually better to return everything to the supply.

Cheers,
Owen

[IanAS]

Originally Posted by DIGORA

Do you have the schematic with 2SK1058 2SJ162 ?

Thanks

Where to put the protection diodes is my question. They are sometimes before a driver, protected from over current in the case of over voltage.

[IanAS]

Originally Posted by opc

I've updated the list and added all those who used to be on the waiting list.

Hi Owen, did you miss me out or is it still kits only?

If I can have boards only then:

2 boards please.

Thanks.

[qusp]

cool, as i thought, yeah i agree it would be nice to have multiple copies of the high current output ground, or just 2 of a heavier duty screw term so that heavy duty ring terminals could be stacked on top of each other and bolted down.

or was the picture of the enclosure just illustrative of the type of enclosure and there isn't going to be any high current screw terms on the output? i would prefer that at least for this purpose as it would make for much easier connection of more outputs, or more channels, as desoldering a 12awg wire from a star ground of this scale would not be fun.

either that, or i have seen some very neat board mount amphenol ground buss bar connectors that would do nicely.

[IanAS]

Owen,

If this LME chip is heat sinked to the same main sink as the output devices, do you think there will be any high frequency coupling or oscillation?

[IanAS]

Originally Posted by HYPERTUNE

custom toroidal transformer

Is that for audio or general purpose?

Are you having:
a 30% over wind to reduce magnetostriction noise,
an inter winding screen,
GOSS wrapping,
potting,
insulative over wrapping,
M0 core (or at least M3),
silicone core impregnation.

Instead of 55 volt windings you can have a pair of 12, or so, volt windings and join them to the main windings to get the extra 12 volts.

[opc]

Hi Ian,

Sorry, I did forget to add you again! I'll put you on the next update, and you can definitely order just PCBs. I'll add you to the list for two more.

As for mounting the LME directly on the same heatsink as the transistors, National specifically recommends againstdoing this, but I think it's more for thermal reasons than HF coupling. Either way, if the manufacturer tells you not to implement it a certain way, then I'm sure they have a good reason for it.

If you want to add external protection diodes for use with the Toshiba parts, I would suggest soldering them directly to the pins of the transistor before you mount it.

As for the transformer, your list is more of a "nice to have" than "absolutely necessary". It will likely drive the cost up to $250 and depending on how and where you mount it, it might not provide much benefit overall. I think if you want something that extreme, you might need to organize it yourself. In terms of winding arrangement, you are correct, it would probably be better to just add a few turns to the existing high current windings to get the extra voltage.

Cheers,
Owen