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500W (4ohm) GaN Class D Modules - Starkrimson Ultra

JohnYang1997

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So should be just a bit higher than 0.001% with Amir's test condition.
 

DonH56

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Ah right. 8ohm vs 4ohm is 6db. 5W vs 10W is 3dB. Then noise can contribute 1db or so, can be higher due to spikes or rising high frequency noise but not present here.

Thanks, had me wondering! I would not expect significant rise in noise (compared to any other amplifier class) until much higher in frequency and much closer to the switching frequency.
 

JohnYang1997

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Thanks, had me wondering! I would not expect significant rise in noise (compared to any other amplifier class) until much higher in frequency and much closer to the switching frequency.
With limited negative feedback and decreasing when frequency rises, this can happen.
 
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Will it be possible to bridge the amps? Since I implemented Dirac Live my Purifi amp is struggling.
 
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orchardaudio

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Very impressive. I would like to ask some question.

1. Can your amplifier drive the 2-Ohm load safely? If yes, how much power it can produce within distortion of 0.1% at 2-Ohm load?
2. Even if the efficiency of your class-D is very high, I would like to ask if there is an easy way to mount your amplifier module to a large heatsink to keep the amplifier cool when driving a high load long time.
3. What is the CMRR of your amplifier module at 100 Hz, 1000 Hz & 10000 Hz?

Yes, it can drive 2-ohms.

I will have to do some testing and get you answers to all your other questions.
 

Veri

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Will there also be a Starkrimson-Ultra with PecanPi DAC built-in ..? :)
 
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orchardaudio

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Due to supply and schedule issues exacerbated by COVID, I unfortunately will need to delay the release of this product. Quality and customer satisfaction are my primary concerns, and I refuse to release a product that does not meet the highest quality standards. I am actively updating the existing design and - as always - will fully test and verify that everything not only meets but exceeds industry standards. I anticipate at this time a June/July delivery and will try my best to get it done earlier.

Those who have already placed a preorder received an email.

For this reason, I have also extended discounted preorder pricing until further notice.
https://orchardaudio.com/shop/ols/products/strk-ltr-mdl
 
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orchardaudio

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1. Can your amplifier drive the 2-Ohm load safely? If yes, how much power it can produce within distortion of 0.1% at 2-Ohm load?
2. Even if the efficiency of your class-D is very high, I would like to ask if there is an easy way to mount your amplifier module to a large heatsink to keep the amplifier cool when driving high load long time.
3. What is the CMRR of your amplifier module at 100 Hz, 1000 Hz & 10000 Hz?

1. Yes it can drive 2-ohms safely, full test results will have to wait (see my previous post)

2. The GaN devices are bottom cooled, which means they dissipate heat into the circuit board, putting a heatsink on top will help but this will provide minimal improvement. I will do a set of efficiency tests for you, once I have the final boards.

3.
CMRR at 100Hz: 87dB
CMRR at 1kHz: 87dB
CMMR at 10kHz: 87dB
 

Lord Victor

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If this keep up with other top contenders in performance, I will be very interested - its a step in the right direction, as I've been looking for something with Purifi performance, but more power... A real shame about the delays though.
 

Lord Victor

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@orchardaudio I'm considering ordering a pair, but would any of Hypex' other power supplies work? The A100 appears to be discontinued here in Europe for some reason, and it would be much more affordable for me to purchase what I can here in EU. A180 and up are available, but those are higher voltage. Though if the board operates best with that specific supply, I'll just have to figure something out - I want the best performance at the end of the day.
 

Harry

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I wonder if this product works well with the MC phono stage. Sometimes I suffer from noise using some class D amps with it, presumably from the effect of EMC or RFI.
 
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orchardaudio

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@orchardaudio I'm considering ordering a pair, but would any of Hypex' other power supplies work? The A100 appears to be discontinued here in Europe for some reason, and it would be much more affordable for me to purchase what I can here in EU. A180 and up are available, but those are higher voltage. Though if the board operates best with that specific supply, I'll just have to figure something out - I want the best performance at the end of the day.
It will not work with any supplies in that series other than the A100, this is because the voltage would be too high and damage the amp.
 
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orchardaudio

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Should have an update within the next two weeks. My manufacturer is finishing up the latest revision board assembly.

70869B1-T.jpg
 
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orchardaudio

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Very impressive. I would like to ask some question.

1. Can your amplifier drive the 2-Ohm load safely? If yes, how much power it can produce within distortion of 0.1% at 2-Ohm load?
2. Even if the efficiency of your class-D is very high, I would like to ask if there is an easy way to mount your amplifier module to a large heatsink to keep the amplifier cool when driving high load long time.
3. What is the CMRR of your amplifier module at 100 Hz, 1000 Hz & 10000 Hz?

1. Yes it can drive 2-ohms safely, full test results will have to wait (see my previous post)

2. The GaN devices are bottom cooled, which means they dissipate heat into the circuit board, putting a heatsink on top will help but this will provide minimal improvement. I will do a set of efficiency tests for you, once I have the final boards.

3.
CMRR at 100Hz: 87dB
CMRR at 1kHz: 87dB
CMMR at 10kHz: 87dB

I am now able to answer your question # 1. So the amplifier cannot get to a point where it can drive 0.1% THD into a 2-ohm load because it will overcurrent and shutdown before ever reaching this condition.

I just ran some efficiency tests on the new modules, here are the results. The efficiency is mainly driven by conductive losses. As an example at 160W into 8-ohms, the efficiency is much better than 160W into 2-ohm because the current is much lower. I cannot go higher than 160W due to limitations in the equipment that I have for accurately measuring input voltage and current.
1621301477605.png


The new modules also have silk-screen removed on the back of the boards to allow for heatsinking the bottom-cooled GaN devices. Ill post pictures of this tomorrow its getting very late here.
 
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orchardaudio

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I have started to test the new modules and the results are looking very promising. Ill be posting more later.

For now here is wideband FFT with -40dB otuput. 0dB = 44.72V (250W into 8 ohm)
You can see the switching frequency of 770kHz. The noise floor in the audio band is very low.

Switching frequency of Hypex power supply is around 90kHz, can also be seen in the graph.

1621302089968.png
 

restorer-john

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I have started to test the new modules and the results are looking very promising. Ill be posting more later.

For now here is wideband FFT with -40dB otuput. 0dB = 44.72V (250W into 8 ohm)
You can see the switching frequency of 770kHz. The noise floor in the audio band is very low.

Switching frequency of Hypex power supply is around 90kHz, can also be seen in the graph.

View attachment 130343

So, 2.5W. Can you show the same plot at full power?
 
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