• WANTED: Happy members who like to discuss audio and other topics related to our interest. Desire to learn and share knowledge of science required as is 20 years of participation in forums (not all true). There are daily reviews of audio hardware and expert members to help answer your questions. Click here to have your audio equipment measured for free!

Starkrimson® Ultra Amplifier Modules -- 250/500W into 8/4ohm

OP
orchardaudio

orchardaudio

Addicted to Fun and Learning
Manufacturer
Joined
Aug 24, 2018
Messages
761
Likes
1,117
Location
Succasunna, NJ
Nice ... do you have efficiency data for rev 2.0 modules and compare both on the same graph?
No, power stage efficiency for Rev 2.0 should be very close or the same as that has not changed.
With Rev 2 modules it is much harder to measure efficiency as they require 5 supplies.

Also, are power/distortion specs still the same?
Yes. No change.

What did you do to increase module efficiency, if it's not a trade secret? Optimize the PWM switching speed?
I did not do anything. I am saying that power stage efficiency is higher that what is shown in the graph if you subtract the power taken by all the op-amps and safety circuits and so on.
 
OP
orchardaudio

orchardaudio

Addicted to Fun and Learning
Manufacturer
Joined
Aug 24, 2018
Messages
761
Likes
1,117
Location
Succasunna, NJ
Rev 3.0 Multitone, identical to previous rev here:

1654819427246.png
 

tomchris

Active Member
Joined
May 14, 2021
Messages
131
Likes
252
Location
Denmark
Hi,

I am looking into building high current monoblocks capable of driving low impedance ribbon speakers possibly down to 1 ohm.

I know that the Starkrimson modules are 2-ohm stable and capable of 20A peak current, however have you done any test of what is achievable of the GaN FETs when is come to current delivery at lower impedances such as 1-ohm?
 
OP
orchardaudio

orchardaudio

Addicted to Fun and Learning
Manufacturer
Joined
Aug 24, 2018
Messages
761
Likes
1,117
Location
Succasunna, NJ
Hi,

I am looking into building high current monoblocks capable of driving low impedance ribbon speakers possibly down to 1 ohm.

I know that the Starkrimson modules are 2-ohm stable and capable of 20A peak current, however have you done any test of what is achievable of the GaN FETs when is come to current delivery at lower impedances such as 1-ohm?

They will drive 1ohm load you will be limited by the 20A peak current still, also efficiency drops with 1 ohm load, so you will probably want additional heatsinking.
 

David_M

Active Member
Joined
Sep 10, 2019
Messages
177
Likes
103
No, power stage efficiency for Rev 2.0 should be very close or the same as that has not changed.
With Rev 2 modules it is much harder to measure efficiency as they require 5 supplies.


Yes. No change.


I did not do anything. I am saying that power stage efficiency is higher that what is shown in the graph if you subtract the power taken by all the op-amps and safety circuits and so on.
But to an end customer, all we see are the effects of drawn AC mains and heat dissipated by the amplifier as a black box. So, in that regard, Rev 2.0 is identical to Rev 3.0? If not, what's the difference between the two PCB revisions?

BTW, your plot should be efficiency vs power not Efficiency vs efficiency :)!

Slightly off-topic... but what are the channel separation specs of your stereo ultra system ? It'd determine if the layout/wiring of the modules within the box is optimal.
 

restorer-john

Grand Contributor
Forum Donor
Joined
Mar 1, 2018
Messages
10,385
Likes
29,965
Location
Gold Coast, Queensland, Australia
Rev 3.0 Module Images

IMG_1727_1920px.jpg.webp


IMG_1728_1920px.jpg.webp

Incredible images. Has to be the best nude PCB shot I've seen :)

So, the temp sensor on only one pair of GaN OPTs? What does the other side of the PCB look like?

Three LEDs? Overcurrent, thermal and DC?
 
OP
orchardaudio

orchardaudio

Addicted to Fun and Learning
Manufacturer
Joined
Aug 24, 2018
Messages
761
Likes
1,117
Location
Succasunna, NJ
BTW, your plot should be efficiency vs power not Efficiency vs efficiency :)!
It is efficiency vs output power.

But to an end customer, all we see are the effects of drawn AC mains and heat dissipated by the amplifier as a black box. So, in that regard, Rev 2.0 is identical to Rev 3.0? If not, what's the difference between the two PCB revisions?
The difference between the PCBs is that Rev 3 only needs +/- 40V supplies, where as Rev 2 required +/-40, driver and op-amp supplies a total of 5. Also rev 3 has a 12V trigger input.

What does the other side of the PCB look like?
Its just a heatsink on the back, ill post picture later.
 

Sel53

Member
Joined
Nov 5, 2021
Messages
6
Likes
0
Hi folks,

I haven't seen this anywhere ... do we know what the Ultra output power will be into loads less than 4 ohms? For instance, speakers that dip to 2 - 2.5 ohms at lower frequencies?

Thanks
 
Last edited:
OP
orchardaudio

orchardaudio

Addicted to Fun and Learning
Manufacturer
Joined
Aug 24, 2018
Messages
761
Likes
1,117
Location
Succasunna, NJ
Hu folks,

I haven't seen this anywhere ... do we know what the Ultra output power will be into loads less than 4 ohm? For instance, speakers that dip to 2 - 2.5 ohms at lower frequencies?

Thanks

The amplifier is limited to an output current of 20A peak or 14.14A RMS. Hence the maximum RMS power into 2 ohms is 400W.
 

schubert

Member
Joined
Oct 3, 2022
Messages
5
Likes
1
OP
orchardaudio

orchardaudio

Addicted to Fun and Learning
Manufacturer
Joined
Aug 24, 2018
Messages
761
Likes
1,117
Location
Succasunna, NJ
Yes, they are all 4700uF, if you have a single power supply for both modules then you can only use 4 caps per board instead of 6.
 
Top Bottom