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KGSSHV Carbon Build Thread

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Finally, well, I have fixed the "KG Carbon - more carbon" ......,in beginning I wanna make a "more carbon and lots cheaper version",but see what I got:

DN2540 and IXCP10m90s I have bought from taobao.com......are fake, now show you guys photo:

Fake DN2540(yes, I have bought all of them for testing):

11.jpg.332606aa22fe1bb87e21c912ac76b482.jpg

22.jpg.68ba2fbb1ac4832b58b22bcf7c468d25.jpg

simply them didn't work ,that's all , I can read 455V from multimeter though probe touch the headsink,but....nothing happened, until I replaced the replica silicon:

Mouser version:

333.jpg.e7670953b6cee9c454f132cc1548341f.jpg

 

Taobao -  Save your broken heart also bit expensive version:

444.jpg.5ed70d6ed75603eb7e406083ae950911.jpg

 

Now the IXCP10M90S time:

Left: mouser

Right:You don't know who I am version

555.jpg.6b71a999366ba0c57f589847328275f2.jpg

 

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On 8/15/2019 at 6:12 PM, Hirsch2k said:

Ok that is understadable... The fat C2M, Caps and Heatsinks are probably not very enjoyable with lead-free. 

I am collecting more components for my second mouser order and thinking about the on/off switch on the front. What do you think, is it critical or will transients and spikes be completely filtered in the PSU and one can workwith an ordinary push button switch?

I thought about ordering the Amb epsilon 24 with transformer but that will set me back  ~40 dollars in shipping alone ?

To be honest, I don't have much EXP on this, but 40 USD is enough to afford the alumium amplifier case with heatsink......few weeks ago I took a relay pcb from garbage bin,it's working on Carbon(or more carbon) now, don't you want to make your own one?

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21 minutes ago, hyperma said:

Finally, well, I have fixed the "KG Carbon - more carbon" ......,in beginning I wanna make a "more carbon and lots cheaper version",but see what I got:

DN2540 and IXCP10m90s I have bought from taobao.com......are fake, now show you guys photo:

Fake DN2540(yes, I have bought all of them for testing):

simply them didn't work ,that's all , I can read 455V from multimeter though probe touch the headsink,but....nothing happened, until I replaced the replica silicon:

Mouser version:

Taobao -  Save your broken heart also bit expensive version:

Now the IXCP10M90S time:

Left: mouser

Right:You don't know who I am version

 

I had the same issue a couple years ago with my first amplifier build.  I bought some 10m90s and DN2540 from ebay, with the result that my power supplies kept blowing up.  I had no idea that there was enough money to be made selling fake parts.  But I guess there is.  Now everything is from Mouser or DigiKey.  

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I'm not sure what advantage have when buying components in places like ebay, tobao ...   when It´s a current production component so it´s easy to obtain in official distributors.

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33 minutes ago, jose said:

I'm not sure what advantage have when buying components in places like ebay, tobao ...   when It´s a current production component so it´s easy to obtain in official distributors.

The price ..... worth that risk, AK4497  $35per/100pcs  and $5 a package of TIP122(500 pcs).

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12 minutes ago, hyperma said:

The price ..... worth that risk, AK4497  $35per/100pcs  and $5 a package of TIP122(500 pcs).

I understand but precisely the price difference is what should make you suspect and now you have to spend twice as much to replace the defective components. Then this will be more expensive.


On the other hand, we are handling voltages and amperages that are highly dangerous. IMO trying to save money here is not recommended.

Pay attention to Blueman (SRX-P thead), his experience is quite instructive.

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Proper funding is mandatory for those DIY projects.

Not mentioning killing yourselves with fake sand, along with troubleshooting made impossible not knowing who's who.

Saving a few ten or hundred bucks is bullsh*t, common, you are going to play those with top dollar headphones, and they are designed to last decades.

Quality remains, prices forgets. And some savings are costly.

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On 2019/8/21 at PM3点42分, jose said:

I understand but precisely the price difference is what should make you suspect and now you have to spend twice as much to replace the defective components. Then this will be more expensive.

 
On the other hand, we are handling voltages and amperages that are highly dangerous. IMO trying to save money here is not recommended.

Pay attention to Blueman (SRX-P thead), his experience is quite instructive.

It's true, for diyer, Mouser, RS , Element14 or TME etc are best choice.

Few month ago,I have bought some FAKE PCM1704s, of course they didn't work. The best way to find out who they are , is disassembling.....by fire, on microscope , I saw HC574 and TI mark on the die.......What a joke.

Another example was my personal favorite op LM4562, I got some on same way, and matched their dies with AD744, remarked for sure. Also funny is in China AD744 is more expensive than LM4562 now.

8 hours ago, Blueman2 said:

HERE is what happens when you buy parts from eBay.  Never, never, never again.  

Hell......but seems Kevin already known everything about fake parts.?

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So I have finished the PSU and I am getting the expected voltages on all rails except Bias, which reads +380V to ground. But I guess this is expected behavior for Bias voltage without the proper ballast?

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54 minutes ago, Hirsch2k said:

So I have finished the PSU and I am getting the expected voltages on all rails except Bias, which reads +380V to ground. But I guess this is expected behavior for Bias voltage without the proper ballast?

most likely you are measuring at BIAS output, having an output impedance of 5Meg ... and the DMM most likely 10Meg, so the +380V is actually 570V

Use the test point (TP) rather to get the right voltage

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So I have finished the boards and adjusted Current, Offset and Bias but Oh Boy is this a fiery beast. I have mounted 3mm thick aluminium under the SiCs and it is at 100 C after a minute. Just to make sure that I do not have a short somewhere, this is expected behaviour right?

I thus don´t feel comfortable giving it a real test run without the proper heat sinking.

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Output current?  Depending on this, the amplifier heats up to a greater or lesser extent.

Mine needed a good heatsink

 

 

 

 

 

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I was a bit involved "in real life" in the last couple of weeks, so only now got back to the Carbon. Both channels are working but I have a nasty ground hum. It is present with the Carbon turned off and no input device so it´s not the transformer and probably not a loop. I suspect the crappy electric panel in my workshop. I will finish everything up and take the Carbon to my listening spot, I hope it is better there.

Also, my torridial is very audibly humming. It has a metal plate on the top and a screw in the middle which I screwed into the metal baseplate of the housing at the bottom. I hope I didn´t short it with the two metal plates.

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7 hours ago, Hirsch2k said:

I was a bit involved "in real life" in the last couple of weeks, so only now got back to the Carbon. Both channels are working but I have a nasty ground hum. It is present with the Carbon turned off and no input device so it´s not the transformer and probably not a loop. I suspect the crappy electric panel in my workshop. I will finish everything up and take the Carbon to my listening spot, I hope it is better there.

Also, my torridial is very audibly humming. It has a metal plate on the top and a screw in the middle which I screwed into the metal baseplate of the housing at the bottom. I hope I didn´t short it with the two metal plates.

The hum is present with the Carbon amp OFF?

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On 12/13/2019 at 11:18 PM, mwl168 said:

The hum is present with the Carbon amp OFF?

Positive. I suspect ground wiring issues outside of the amp but not sure yet.

On 12/14/2019 at 7:41 PM, UFN said:

A toroid transformer that's audibly humming is normally either badly made, overloaded or miswired. Does it hum without load as well? Also, you do know about shorted turns on toroids, right? https://www.bicronusa.com/resources/tech-guide-toroidal-power-transformers

Will test the no-load hum as well as the efficiency and the power consumption. Maybe I have a short somewhere?

 I can sort out the shorted turn since nothing is connected to the top metal plate.

 

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Starting on building a Carbon for a French friend here on the forum (DrizztDo). I built one of the SS Mini Dynalos for him a year or so ago, and he asked if I would be willing to build some other shit for him (including a UGS Muse preamp ?), and I said yes, since he was very pleasant to deal with.

At any rate, using the latest BOM I could find, I wound up with some 182R resistors that I find no markings for. Searching the thread, I find some references stating that these should go to 120R, and the boards have one 120R marking on them... go figure.

Questions:

  1. has anyone used Vishay/BC MRS25 resistors in a Carbon? They are rated at the same voltage as the KOA Speer MF1/2 are (which is what I am using elsewhere)? Just asking since I have a pair of 120R MRS25s.
  2. He sent along some of the left/right GRHV boards (which I asked about earlier). I would prefer to use one of the dual GRHV boards in order to do a mwl168-style universal PSU, which could accommodate a GG or other tube stat amp for him in the future. Anyone have a spare they would be willing to sell? I would like to do a 2 transformer build, with GRLV for the +/-15V supply, so 2 PSU boards and 2 transformers.
  3. What size of aluminum angle do most of you use for the heatsinking? 1 x 1 x 1/8"? Or?
  4. Do I need to use PEEK screws for the HV transistors, or are steel screws with the appropriate insulators around both the screws and the transistor/bracket OK?

Thanks!

 

Edited by Pars

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4 hours ago, Pars said:

Do I need to use PEEK screws for the HV transistors, or are steel screws with the appropriate insulators around both the screws and the transistor/bracket OK? 

IMO you need steel screws to apply adequate torque – what now that might be? I apply 81 Ncm – but PEEK is certainly OK.

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7 hours ago, Pars said:

 

  1. He sent along some of the left/right GRHV boards (which I asked about earlier). I would prefer to use one of the dual GRHV boards in order to do a mwl168-style universal PSU, which could accommodate a GG or other tube stat amp for him in the future. Anyone have a spare they would be willing to sell? I would like to do a 2 transformer build, with GRLV for the +/-15V supply, so 2 PSU boards and 2 transformers.

pars,

If you are interested I have up to 3 spare dual LV (goldenreference6d) boards from my blue hawaii build they are I believe the latest release colour Blue, hot air leveled for leaded solder. Im in the UK. I dont have any spare Dual HV boards but I could get some more made....

 

Edited by jamesmking

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5 hours ago, JoaMat said:

IMO you need steel screws to apply adequate torque – what now that might be? I apply 81 Ncm – but PEEK is certainly OK. 

I have used steel screws with this insulating washer  Ref. Mouser  Edit: I add a drop of Nural 50 to the screws too

About r182 replaced with 120 ohm to get 20mA output current

Edited by jose

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1 hour ago, jose said:

I have used steel screws with this insulating washer  Ref. Mouser  Edit: I add a drop of Nural 50 to the screws too

About r182 replaced with 120 ohm to get 20mA output current

Using the proper washer with the tube long enough to extend through the tab of the sand into the ceramic insulator is mandatory when you use the steel screw as Jose stated. Craig had a great post where he explained and illustrate the reason why somewhere in the forum.   

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17 hours ago, jamesmking said:

pars,

If you are interested I have up to 3 spare dual LV (goldenreference6d) boards from my blue hawaii build they are I believe the latest release colour Blue, hot air leveled for leaded solder. Im in the UK. I dont have any spare Dual HV boards but I could get some more made....

 

Thanks James. I have plenty of GRLV PCBs. I was thinking about looking for a dual GRHV board. Not sure yet.

On the BOM I was using (which supposedly was the latest, with the 182R resistors), there were some Nichicon 0.47uf/50V caps (647-QYX1H474KTP) which don't even come close to fitting the board. These are 7.5mm LS and should be 5mm LS. The body on these things is huge, and would require bending resistors to fit them in. Who the fuck did this BOM anyhow?

Any recommendation for a suitable cap here?

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EDIT: from a 2015 post by Laowei, he recommended a Wima MKS2C034701C00JSSD. Mouser of course has these and anything close on order for February. Looking on Digikey, I see a Kemet R82EC3470DQ70J, which didn't come up on my Mouser search, but they of course do have (and in stock). I'll probably just wait for the Wimas.

 

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