Jump to content
kevin gilmore

i'm on a roll... the kgsshv

Recommended Posts

Apologies since I obviously missed this earlier: what is the advantage of the Carbon relative to the original ("classic"?) KGSSHV?

Edited by gepardcv

Share this post


Link to post
Share on other sites

of course, thats the point, i'm working on adding connector blocks now.

 

joamat did 2 boards, left side and right side, similar to the t2, that way

everything is symmetrical. but it also means that there are twice as many boards.

Share this post


Link to post
Share on other sites

Great! I am looking forward to one day getting a pair made.

 

Please take your time, I did not intend to pressure you. 

 

I appreciate all that you have already given so much to us DIYers as a gift..

 

And thank you too for getting me involved with Stax.

Share this post


Link to post
Share on other sites

it's a KGST with silicon carbide output devices in place of the triode 

Actually, it looks like a KGST with a solid-state equivalent of the BH output stage (grounded grid/gate) and cascode current sources, if I'm not mistaken.

  • Like 1

Share this post


Link to post
Share on other sites

yep, grounded grid.  There is much more gain in the output stage, so all the extra parts in the BH are not needed.

 

So the amp is faster because of less parts in the signal path. 3 stages instead of 5.

 

board is 6.3 x 2.75 so it fits on a 3 inch high heatsink.

 

(do I want to do 1500 lbs of aluminum again... highly unlikely)

Share this post


Link to post
Share on other sites

2SC3324 is NPN.   2SA1312?

 

 

Upside down...  Pars number is correct.  sorry..

Edited by Inu

Share this post


Link to post
Share on other sites

With those colors, I bet if you stared at one side of the board for 30 seconds, then shifted down to the other side, you'd see the whole board layout at once.  :laugh:

 

More seriously, one concern I have is that while the 10M90S/DN2540 makes for a very high impedance CCS (good) there is a fair amount of variability between DN2540 samples in the amount of current that is produced for a fixed source resistance (bad).  That's why I put a trimpot in the source to adjust the current.  This is unlike the 10M90s which is designed as a current source so is reasonably tightly controlled for current vs source resistor.

Share this post


Link to post
Share on other sites

I believe JimL have an important point and a trimmer is needed and it will make the setup considerable easier.

Edited by JoaMat

Share this post


Link to post
Share on other sites

First time I got 2 pieces of DN2540 from a local store. Same resistance gave same current with 0.1 deviation between them. Second time I bought 20 pieces of DN2540 from Mouser. From that population I found 17 or 18 individuals that gave a current of 10mA within +/- 0,2 mA with 150 ohms resistor. I don’t remember resistance for the first 2 DN2540 but it was different, not 150 ohms. If you randomly pick a group of 10m90s you will have a variation not less than what I found among the 17 or 18 DN2540. My guess is, if you get DN2540 which are produced at the same time (batch or whatever you call it) they are close but else there are deviations and you need to adjust resistance accordingly.

 

I built a small test board with the actual current source and with an uTracer I tested the dn2540 relatively easy.

 

I didn’t feel any needed for a trimmer and that’s why there are no trimmers on the board (at this moment).

 

Either you were lucky or I was unlucky or both.  I found 5-10% deviations in current with the same source resistor was fairly common, but I also ordered various DN2540 over a period of time.  Also, I was trying to get within 1% of designed current so my OCD is probably showing. ::)

Share this post


Link to post
Share on other sites

I have found very close matching of DN2540, as I have a project that uses a dozen or so of them. I did add trimmers though, but didn't really end up using them much. I am considering using the SMD with the TH part to try and reduce some board space and not sure if that will net the same consistency.

Share this post


Link to post
Share on other sites

I just received a batch of KGSSHV mini stereo boards. Looking good. :) I've been thinking about the build, and it looks like my original plan to use a KGSSHV mini power supply with the stereo board in a Galaxy 388 chassis won't work, it's about 10mm too narrow, unfortunately. A larger chassis would certainly work, but the 388 fits really well on my desk.

 

The question now becomes: do I have any alternatives for a smaller power supply board? The mini BH power supply is just the right size, but it's 350V, and I'd like 400V (though I'm also wondering if it would make significant audible difference if I tried running the KGSSHV mini stereo circuit at the lower voltage). I remember reading that the kgbhultraminipsv4 can be cranked to 400V — will I have heat issues? What are the drawbacks to using this power supply with the KGSSHV?

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

×