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KGSSHV Carbon Build Thread


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7 hours ago, johnwmclean said:

There are 2 different gerber files for the carbon version .6G 




I see clear differences with the traces, does anyone know why?

I am having the same question as well as the PCBs I have for my next build are made as per the "kgsshvcarbon6ground2" file.

From what I could see, comparing the 2 gerber files, the main change from kgsshvcarbonv6ground to kgsshvcarbonv6ground2 consists of moving the low level feedback signal trace for the servo from passing next to the output and high voltage supply Phoenix connector to passing much further away across the top of the PCB.

Any feedback on this will be much appreciated.

Edited by hhobeika
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  • 2 weeks later...

I use momentary switches, they have a nice tactile feel, something like this works well:


I really dislike the the tarty, latching and overused illuminated switches. So then you can use a a solo LED for the power indicator, I find it helps your amp from not looking like a door bell.

You’ll need a driver switch circuit of some sorts with a relay, but well worth the effort.

Edited by johnwmclean
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12 hours ago, johnwmclean said:

I really dislike the the tarty, latching and overused illuminated switches.

Oi! I resemble that remark! I recently went even bigger than the usual 19mm with these 22 mm jobbies for a couple of builds. It sits alongside one of the enormous 39 mm polished silver knobs from Hifi2000. It's gaudy, it's pretentious, by any reasonable standard it's awful, but I f'en love it.

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I'm sorry, but I still like the blue ring illuminated vandal switches... banish me to the corner :)

Perhaps it is because I have rarely gotten around to casing any of my shit (yet), so I haven't gotten tired of living with them...

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8 minutes ago, Pars said:

banish me to the corner :)

I think I’m the minority here, maybe I should have some time in the corner.
Just don’t get me started on the dot illuminated variety... 🤮

... to add fuel to the fire and to further rant aimlessly, I’ve rarely seen any commercial audio companies using these switches, I just can’t see the likes of Accuphase or Audio Note banging one of these bad boys on the front of their products.

But hey this tots my personal pref, just throwing it out there :P

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5 hours ago, muskyhuntr said:

"Always wanted to find that elusive black anodized + orange LED latching, but they're always out of stock."

Try.. performance-pcs.com

They have them in 16 and 22 mm. 


Only problem with those is the low power rating on the switch, 24 V @ 50 mA. Should be plenty to drive a relay, but you can't use it directly for power switching. That's why I liked the e-switch model I linked above, rated for 3A at 250V, good enough for direct power control of anything but a big power amp. Unfortunately, the selection of stocked colors at Mouser, Digikey and Newark are pretty limited.


(I also notice the switch Rudewolf linked is good for 250 V @ 10 A resistive loads. Proper, genuine power switch that one!)

Edited by Beefy
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  • 2 weeks later...

A look at Sebdti's finished Carbon boards - Seb wanted to mount these flat against the heatsink so the L-brackets in the pic are just to help position the transistors precisely and protect during transport.



Here is one of my own Carbon boards set for horizontal mounting (Joachim, the DN2540's are mounted underneath the PCB ) Also the completed PSU.



For anyone who is interested - I'm using the 1200V Wolfspeed SiC's - https://www.digikey.co.uk/products/en?keywords=1697-C3M0350120D-ND‎

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  • 4 weeks later...

Hello folks

Mostly finished the Carbon this week, powers up fine, no smoke!

Can someone please help with instructions to adjust the 4 trim pots - assuming 2 are for offset and balance and correct measurements.  Could not find a thread on this easily




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Nice work, Sebtdi!

Here is a schematic for the amplifier boards Sebtdi and sweetleaf are using.

Main difference to above schematic (kgsscarbonproduction.pdf) is the offset servo.

The adjusting procedure for this is like any other Carbon. Balance is set by the trimmer close to the LED and offset balance is set by the trimmer close to output connector.

For setting the output current use the two most outward trimmers. It might be bit tricky to measure the voltage cross the resistor (R21 and R22 in your case) on a live amplifier. Myself, I always check the current with help of a low voltage supply and a multimeter in mA DC mode cross the constant current source. Below sorenb  tells how to do. I guess a 9V battery for low voltage will work just fine.

On 3/9/2017 at 1:17 PM, sorenb said:

You can trim the CSS's using only LV and a DMM in mA mode (assuming AMP board is not connected to anything):

Connect LV+ -> AMP HV+
Connect LV- -> DMM (Common)
Connect DMM.(+) -> the probe
put the probe to the tail of the CSS (the Drain of the Sics (middle leg))
Now you'll have the CSS current reading directly on the meter, and the CSS can be trimmed to what ever current < 27mA you have sinks for
(one might shoot a mA lower as the current grows a bit at higher voltage and heat).


Edited by JoaMat
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If your Carbon board has the offset servo, you need to deactivate the servo before making the offset adjustment. Then activate the servo afterwards. 
I don’t remember the detail steps but that information is in this thread somewhere.

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