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KGSSHV Carbon Build Thread


mwl168

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A picture from my kitchen.

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My dear is away for a few days and will be back on Friday evening so I have time to fix this mess. Anyhow, a second board of three layer Carbon is done. This one’s offset is as good as the first board after fixing an error. Mixed up the feed backs so first offset was +440V and -440V.  First board was free from errors but this one have some serious errors. Glad I didn’t sent it to a board house for manufacturing.

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I’ve a bad habit. I want my boards to be symmetrical. Take the first board turn it 180 degrees and flip it. Next I’ve to tidy it up to get it working. This time I missed a couple of things. Kevin once told me this method – maybe there was something I didn’t understood.:huh:

Edited by JoaMat
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On ‎2017‎-‎03‎-‎09 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).

Trimming the output stage tail resistor to get the amp in balance and DC balance requires all voltages

I’ve used the method described by Soren for a quite a while. Found it reliable and easy to use and it’s an advantage not to do the measurements on a live amplifier.

While I did this on my latest board I got some funny readings on one current source. Increasing the voltage (I use lab power supplies) the current increased to a much higher value then expected. It turned out that when increasing voltage above some 15 volts the other current source start to provide current. At about 70 V it provided full current. Didn’t understand how this could happen unless I did something wrong. Checked my board layout for more errors, changing components etc.etc., but I didn’t found anything explaining this issue. Finally, after two days of investigations, I decided to just power it up and hoping for the best. OK flipped feedbacks. When corrected the board worked all right.

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Today I’ve shorten in the front and back panels. Makes the three layer Carbon looking neater. Dual power connectors on the back. Using the T2 power supply, too lazy to build a new one.

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Still more work to. But it works as it is and it sound all right.

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Thanks everyone for all the kind words and encouragement along the building of the Carbon. I think it turned out very well. In previous post I said it sounded all right – that’s an understatement, it sounds fantastic. But of course everything you just built is the best sounding ever built :D never trust a DIYer.

George, I wish you hadn’t asked me about the 500 V. Yep, I run it at 500 V. I’ve read the datasheets but I haven’t told the amplifier.

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On 3/28/2017 at 3:13 PM, Pars said:

Is it one of the Bulgin MP0045 switches? Latching?
I need to get one, or something like it. I know Birgir was using switches from one of the PC modding places, frozenCPU.


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I started out with those but mine are now custom made for me.  Not cheap but who cares.... ;)  

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On 11/15/2016 at 2:46 PM, sorenb said:

 

 

 

stkMbkX.jpg

 

fogzb1E.jpg

 

Went back and looked at this again; a lot to like here!

Neat power inlet... some kind of Schaffner inlet?

EDIT: nope, Schurter (found it).

Edited by Pars
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6 hours ago, Pars said:
6 hours ago, Pars said:

fogzb1E.jpg

Went back and looked at this again; a lot to like here!

Agree. I like the small boards close to power inlet.

@sorenb  I guess the power switch on front panel is a toggle type? Is the switch just an elegant black one or is there light in it? 

Edited by JoaMat
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3 hours ago, JoaMat said:

@sorenb  I guess the power switch on front panel is a toggle type? Is the switch just an elegant black one or is there light in it? 

I used this one ....it has a red ring lighting up when power is on. I used something like 3-3.5V for the light ...it gets way too bright to my taste at 12V.
Small boards close to the inlet is voltage selector 120/240VAC with main relay, and another 12VPSU + latching circuit. When main switch on the back is turned on only the latching circuit is on until the power switch at the front is pushed momentary. The power switch at the front only carries <12V voltages.

Edited by sorenb
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49 minutes ago, johnwmclean said:

Really nice Soren.

I've been using AMBs driver switch board as I prefer the feel of momentary switches and without the chance of false triggering from latching types.

Used wrong word here ... the switch is in fact a toggle switch, though it needs to be pushed rather deep to act as a toggle ...if only push'ed lightly it acts as a momentary ... so rather similar to the AMB setup

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Thanks for all the discussion! I'm getting ready to case the DynaFet up and am trying to determine how I want to switch the power. A 2 switch approach (one on the inlet, and a ring LED vandal type switch on the front) appeals to me. A plus would be not having to run line AC to the front.

I'm using a 2U Pesante Dissipante 300mm (from the age old group buy), so have plenty of room. Voltage selection would be a plus, though not required.

Are many of you still using SS relay to switch the AC? I'm looking at the Amb board, and I guess might need a 2nd xfrmr, turned on by the back panel switch, to then switch the main xfrmr AC?

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Interesting topic this inlet AC controlling.

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Found this board in my closet. Small power supply with a PIC 10F202. Input IR and toggle  momentary switch. Out to SS relay and two color LED for on/off indication. This board has served in a T2 power supply. For some reason it didn’t work when I used it for BH and Megatron. Those amplifiers draw more current than the T2 and the control powered up just to fall back to off within a second. So I took it out. I’ve a similar board with SS relay onboard in a KGSShv power supply and that works OK.

Mean Well has small power modules that might be used to power the control unit. Like this.

Correction:  not toggle switch - it is a momentary switch.

Edited by JoaMat
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HiFi2000 question(s):

  1. For those who have used the pesante dissapante, any of you have experience with both the aluminum and steel rear and top and bottom panels? If so, which do you like the best?
  2. If aluminum, is it worth it to get them from hifi2000/modushop, or could FPE do them? If so, any drawings available for the panels? 2U 300mm case.
  3. Cam Expert: do they still accept FPE designer files, or do you have to supply cad files? I don't have any cad software on my Mac, and no experience with it.
  4. For Mac, any cad software recommendations? I do have Fusion360 but haven't used it. Not even sure what all it is capable of.

The case I bought back in the group buy was with the steel panels, and I can't say I'm feelin' them :)

It would be around $70 ordering them thru modushop or diyaudio store. I suppose if I went thru modushop, I could have them do the machining on them for the IEC, etc. Might be worthwhile to just get another 10mm faceplate from them and have them machine that as well, and re-anodize.

 

Edited by Pars
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1. Their steel panels are not nice IMO, definitely prefer 3mm aluminium.

2. FPE could do them. Modushop should advise dimensions. I’ve done this with several of my builds (Modushop heatsinks and brackets and Cam Expert have milled the panels.)

3. Cam Expert accept FPE files, that’s what I’ve been suppling them with for years.

4. No experience with CAD software on a mac sorry, what I do initially is draw up files in Adobe Illustrator CC, then manually export x and y coordinates into Front Design, works well and is a great double check.

Soren has had some nice machining done by Modushop, I’ve used them for some heatsink drilling/tapping which was very nice as well, they were always good to deal with.

 

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I use Fusion360. and PhotoShop CS5. In my experience Fusion is capable of much more than needed to plan/design a chassie.
Turned out that the dxf-file export from Fusion doesn't work for ModuShop.
Now I provide FPE files for ModuShop which seems to work fine.

If you do you own machining, be aware that the aluminium provided by ModuShop is very soft. Even with sharp tools it can be a bit of a challenge.
Also, if you'll have ModuShop do the customization (or some of it) they charge a premium to do customizations from both sides.

Edited by sorenb
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Thanks John and Soren,

I wasn't going to do my own front panel machining nor the rear panel. I had drilled and tapped blind holes in the heatsinks for the L brackets some time ago. I seem to recall the aluminum being somewhat "gummy", but they turned out fine. This was a few years ago after the DynaFET GB.

 

 

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