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

[particleman14]

can you add 1 rework se-se board for me. thanks!

 

[qusp]

if possible just one extra pair of fets for spares in case of early death =) because being so fringe they may not be all that easy to attain

 

[vitalica]

Hi Owen,

Can you add 4 extra sets of FETS?

Thanks!!

Vitaly

 

[Ferrari]

Same as the 2 posters a bove, can you add 3 extra sets of FETS (if possible)?
Thanks!

 

[rileywc]

Owen,

Would you please add the following to my current order?
2 amp PCBs,
2 sets of FETs.

Thanks!

 

[opc]

Hi Guys,

I've been working away on the power amp trying to get the circuit dialed in, and I think I've got the SE input setup for power outputs up to 150W pretty much dialed in.

I'm still tweaking a few things on the BAL input setup, and I still need to adjust the CCOMP filter for higher output power levels (between 150W and 300W)

I do have some measurements to post though for the SE input version under the following conditions:

- +/-42VDC on output stage - linear supply - 600VA toroid with 40,000uF
- +/-50VDC on input stage - regulated using PSU PCB.
- All 8 ohm load
- Gain = 29dB
- Input = SE
- Bias = 400mA

Here they are:

1. FFT with input grounded, measured across 8 ohm load
2. FFT with input connected to AP, measured across 8 ohm load
3. FFT @ 1W, measured across 8 ohm load
4. FFT @ 50W, measured across 8 ohm load
5. FFT @ 1W, Class B (not quite true class B about 5mA bias)

The FFT plots show that the amplifier has an amazingly low noise floor, and the regulated front end essentially eliminates all line noise from the system. The noise floor sits at an amazing -130dBV above 500Hz, and creeps up to a little over -120dBV down at 20Hz. This is one reason why good class AB will always be better than class D. You won't find a class D that can touch this level of quietness. The FFT for the 1W output shows the 2nd harmonic about 116dB down, and the 3rd harmonic about 110dB down. All other harmonics are more than 130dB down.

The FFT with the amplifier biased in class B is kind of a neat one. The odd order harmonics don't really get any lower and there are only a few dB between the 3rd and 19th harmonic! This is why you shouldn't use class B amplifiers for audio! To put this into perspective though, the horrible distortion show here is still lower than the noise floor on many class D amplifiers.

6. Frequency Response
7. SNR at 50W
8. THD Ratio at 1W 8R
9. THD Ratio at 50W 8R
10. Distortion Product Ratio - 1W 8R

The above graphs are pretty self explanatory. More to follow!

 

[opc]

Next up we have all the distortion product ratios at 1W

 

[opc]

And at 50W

 

[opc]

Lastly we have all the intermod goodies for those still interested:

 

[npdot]

Owen,

Wow! Thanks for doing all these measurements. This represents a lot of work. It will take a while for us to absorb it all. Can't wait to see the BAL report as well.

Neel
PS: Does your wife know what you are doing?

 

[opc]

She does indeed! She's extremely supportive to boot...

Tonight we spent an hour folding these fifty boxes for shipping while watching "Top Chef" on the computer.

There are fifty more yet to be folded which helps put the task of packing and shipping into perspective.

Cheers,
Owen

 

[Francec]

Hi Owen,
I'm not participating in this BG but I would like to say that the DIY community relies on the actions of people like you. You conceptualise, plan, create, test, offer and share and you are to be applauded. Thank you.

Frank

 

[AP2]

Hi Owen,
I agree that you did a great job, especially from an organization.
Your amp seems to have a good behavior.
I take this opportunity to invite you to test SMPS. this independently from the sale. (If You agree, i send one from laboratory MDI).
My interest is in fact to show how important is psu in the realism of the sound.
I think you're the right person to try.

Regards

Roberto P.

 

[AKSA]

Frank,

You really should have participated in the FetZilla group buy!

Hugh

 

[amaco]

Dear OPC
Can you provide me with all equipment and techniques so that we can trade. Thanks

 

[qusp]

I hope Owen knows what that means

 

[opc]

I have no idea?????? Maybe he wants to send me a million dollars in exchange for my design files? If so, I'm in! 🙂

Francec:

Thanks for the very kind words! My efforts here pale in comparison to some of the others, but I do appreciate all the support I've gotten from people here. diyAudio is truly a diamond in the rough when it comes to online forums.

AP2:

I sent you a PM with my shipping address and other details. I'm looking forward to testing your supply! If it works well, it really will provide people with a great option for a completed supply.

Amaco:

I think we've hit a bit of a language barrier as I have no idea what you're trying to say. Please be more specific as to what it is you'd like.

Regards,
Owen

 

[qusp]

hehe indeed,

me thinks he is the victim of a bad google translation

kinda ironic dont you think?

 

[wirewiggler]

And my thanks as well for one of the most thoroughly documented projects. I purchased a pretty decent sound card for testing and being able to compare results to your baseline will be quite insightful. Also a real bonus will be having a first class amp and headphone amp to show for it. Thanks for all the effort you put in this, the way the requests were coming in I would surly pulled all my hair out in your place. I ran a group buy a year back and understand the challenges, and it was minuscule by comparison.

Bill

 

[Soulwind]

I would like two kits please.

Hello,

If still available, I would like two kits please.

Thank You