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

Im thinking to bias the wire amp at 1Amp per FET at 25V for the fets and 35V for the LME49830. I just have a doubt regarding the stability of the bias. Does the inherent property of the lateral mosfets takes care of bias? Do I need an extrenal vbe multiplier?

Im using transformers with 4% of regulation with these some of them are planned for 2% are there any disadvantages of using high regulation transformers?
 
2% regulation for a transformer is very low.
Has it been manufactured to specifically meet this 2% regulation value?

yes 2% is very low indeed the manufacturer said lower the regulation better the transformer for transient design. He said the voltage will not drop substantially if your regulation is low enough. He has 30 of experience building trafos for heavy electrical aerospace and defence applications I had to believe him.
 
Working on a ps for this amp. Would it be acceptable to regulate the lme supplies to the fet rails or should they be regulated in reference to gnd? Attached is my sample sch that regulates 10v to the Fet rails.
This amp (with exicon Lats) doesn't need zener gate protection?
 

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opc

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Working on a ps for this amp. Would it be acceptable to regulate the lme supplies to the fet rails or should they be regulated in reference to gnd? Attached is my sample sch that regulates 10v to the Fet rails.
This amp (with exicon Lats) doesn't need zener gate protection?

If your regs can handle the additional voltage, it would be best to regulate to GND to avoid adding the unregulated supply's noise to the LME rails.

Consider just putting the additional 12V windings in series with the 45V windings and rectify / regulate from there.

As for the gate protection zeners, they are easy to add across the fet legs if you feel the need to add them. It really depends on how you plan to use the amp, but it doesn't hurt to have them there.

Regards,
Owen
 
Working on a ps for this amp. Would it be acceptable to regulate the lme supplies to the fet rails or should they be regulated in reference to gnd? Attached is my sample sch that regulates 10v to the Fet rails.
This amp (with exicon Lats) doesn't need zener gate protection?

the regulators with inverted outputs for the regulators do they work properly?
using the same positive regulator for the negative output but with inversion giving negative voltage? will that be full stable?
 
My boards came in. Same circuit (minus the DNPs) with option for a 2nd pair.

Hi!

I like how the mute circuitry is taken to the chips power side. I actually like that very much!
The chips GND pin (nr 3) is the return for the mute pin (nr 2). If I see correctly, that is now taken to the opposite direction? I would like these two tracks to closely follow each other. But that is hardly any problem on your PCB if the mute input is kept clean from injecting interference to the board (ground plane)...

Supply bypass caps could be a bit closer to the chips power pins. You use Fischers SK145 as heatsink? There is room "inside" the heatsink for the negative rail cap.
You use also SMD on the board. These supply caps could be MLCCs. With SMD you can get ridiculously close to the chips power pins.

...Just a couple of ideas if you plan to make a v.2 of your board some day...

Anyways, excellent work! Congratulations! You could sell some of those on the sites Swap meet forum...

Will be waiting for your test results and most important of all; how does it sound!!!
 
Hi!

I like how the mute circuitry is taken to the chips power side. I actually like that very much!
The chips GND pin (nr 3) is the return for the mute pin (nr 2). If I see correctly, that is now taken to the opposite direction? I would like these two tracks to closely follow each other. But that is hardly any problem on your PCB if the mute input is kept clean from injecting interference to the board (ground plane)...

Supply bypass caps could be a bit closer to the chips power pins. You use Fischers SK145 as heatsink? There is room "inside" the heatsink for the negative rail cap.
You use also SMD on the board. These supply caps could be MLCCs. With SMD you can get ridiculously close to the chips power pins.

...Just a couple of ideas if you plan to make a v.2 of your board some day...

Anyways, excellent work! Congratulations! You could sell some of those on the sites Swap meet forum...

Will be waiting for your test results and most important of all; how does it sound!!!

Thank you. This is the first board I've done so I could use all the advice for the next version. There are a few vias connecting the gnd planes around lme pin2. The heatsink is here....
heatsink

I'm surprised how cheap the boards were to have made. 11 boards $100usd shipped.
 
Well this post isn't quite 'The Wire' related it feels a lot more 'on topic' than some of the recent posts ....



I am a born procrastinator. So I decided to keep my LME49830 amps and DPS600 PSUs on a shelf until I had my speakers ready. I've now got my speakers ready to power up and time to open the box with LME49830 amps and finish off my 4ch monoblock in one chassis build (2 channels of LME49830 'the wire' and 2 channels of the wire lpuhp). These will power my 2 way active speakers via 4pole speakon outputs.

All going well up to here.


I have tested one amp on a bench PSU and ramped its voltage up slowly, all went well there too.

Then I snapped my M3 tap in the heatsink as I was making mounting holes for the second amp ... now I need to wait till a week day to get my hands on a new one locally.

So with the mechanical items at a road block for a few days, I thought lets test these DPS600 PSUs so I could maybe finish the other working and mounted amplifier.

The best I could find quickly for testing the PSU before connecting the amps was 470R 10W resistors and connected these between the each rails to gnd.

First of the DPS600 powered up quickly as expected.

Second DPS600 never finishes its power up, the LED beside the output flickers and the output fluctuates between 29 and 31V although watching the multimeter during power up does seem to indicate that maybe it gets to something higher then drops down again. The LED that indicates power up complete stays infuriatingly unlit.

This happens when using either the standby switch or just hard power on from the power point switch.

I thought I'd ask if anyone else with DPS600 for these amps had any thoughts to offer before I email audio-power support? I think Audio Power will be on summer vacation at the moment so rushing to email them tonight does not help.

I remember buildmesomething had some issues after turning it on with a high bias setting, I'll go and read through his experience shortly and see if any of the symptoms with blinking LED are matching what was discussed then.




Cheers,
Chris
 
Read a bit the First One thread and see the troubles we had with their SMPS. :yes:
Hi Lazy Cat,

I had a look through your thread, did you repair the module that you were testing or just test it with regulation broken? Sounded like something damaged in transit, like similar situation for mine also. Having seen the performance from the measurements that Owen took in this thread I'd like to repair mine, will get in touch with AP when they're back for help identifying the portion of the circuit needing attention.

Cheers,
Chris
 
will get in touch with AP when they're back for help identifying the portion of the circuit needing attention.

I ended up sending a note to audio power while I had the info fresh in mind. A support guy had popped into the office during their vacation and was able to answer my query and confirm my suspicion of the likely failed part which I've now ordered and will see how repair goes next week. Hopefully repairs go smoothly and I avoid posting it back to Italy!


Cheers,
Chris