Hello, Kerry. Did you receive my message?

I’ve finished my KGSShv and have at last been able to listen to my SR-507. The amp has run for 10 hours so far and I have listened to it for the latter couple of those. It’s certainly working well. I have heard some beautiful music already. Thanks to members who so kindly helped with advice and offers to supply parts, and to those who've joined in my "mini group buy". It's been a pleasure hooking up with you.

I am really looking forward to getting to know this set-up and am already thinking of another version.

Congratulations!

Looking good!!!  Now where are the internal pics... 

OK if you insist!

I basically a retiring guy -this feels like dropping my pants in public.

Incidentally, I didn't buy the 3900pF used in the power supply - it wasn't in the circuit diag. I used. Is it for stability or noise control?

Cheers

That's a nice build.  Congratulations!

 

Wachara C.

That is a neat build, well done.

Edited January 26, 201313 yr by padam

Thank you guys.

I expect I'll be asking a number of questions as I get used to this system. Apart from what do those capacitors do?

What is good practice with the amps and Stax "earwhatsits". Is it OK to plug in or unplug the phones from a live amp,for example?

Any advice on that?

The cap is there for stability so I'd recommend adding it. 

 

How hot do those sinks get? 

 

Edit:  No issues with plugging/unplugging headphones when the amp is on and playing. 

Edited January 26, 201313 yr by spritzer

I want to build a headamp with HV's input state and T2's output stae, but I am not really sure how to do.

 

Here's what I had posted a while back...

 

This version uses the KGSS front end and the output servo from the T2 - pretty much a blue Hawaii otherwise.  I built a version on bread board using the T2 style batteries and a modified input stage as well.  I'll look around for that too.

Here's the version with the active batteries to translate down to the bottom rail...

 

 

Here's my build of one channel to test it out...

 

 

 

 

EDIT:  I built this using 425V rails instead of 500V.  It simplified a number of things

Edited January 27, 201313 yr by Kerry

Awsome Kerry. What level of performance did you built it to achieve?

Just got my PSU for my off board working. Took me 3 attempts to get it going. In the first attempt, negative channel saw flying silicon due to fake Mosfet. Ixys10m90s and FPQF8n80c spouted silicon and also killed the 2n3904, 24v zener.

After repair, blew it again when I inserted the LT1021 the other way round melting the whole zener string taking out the 2n3904s and 24v zener.

Reapir done and its been on for the last hour and no explosions so far. Thanks to Kerry for pointng out that the 2n3904 also had to be changed.

Positive rail is +ve502v and negative at -ve500v.

Edited January 27, 201313 yr by Victor Chew

Me like that one Kerry.   

 

In other news I have on my desk now a much smaller and simplified version of the HV supply.  It's roughly half the size but with only one input cap it is more voltage limited. 

The cap is there for stability so I'd recommend adding it. 

 

How hot do those sinks get? 

 

Edit:  No issues with plugging/unplugging headphones when the amp is on and playing. 

Thanks for that spritzer.

As for temp - I have not done accurate heatsink checks yet, other than to note that they are not too hot to touch! The room temp is 20C, the temp in the case next to the heatsinks with the lid on is about 40C. it's running about as warm as I expected, but I will do more checks and report back.

Great to see you're back on track, Kerry

 

I've just managed to picked up this monster 'sink, 10 kgs, 565mm x 204mm.

Any idea on how I should cut to make the best use of it? Been trying to find another one for a second T2 but no luck so far.

 

Now that's what I'd call a heatsink!

I'd be thinking of slicing it into 4 or 5 at around 100mm each. It would go on the sides of a case nicely.

I agree. Get the fins oriented vertically and it should work well. 100mm seems like a nice size as well.

Nice job.Kerry

 

But I just wonder if I replace the 2sc2240 to 2sc3381 in active battery would be better?

That's fine.  That was a print from LTSpice.

 

I've used the 2SC2240 in the active battery component of the power supply (KGSSHV) and wasn't able to measure the noise unless I shield my apartment.

 

Low noise and matched are both good things.

My KGSSHV is done. 

 

The chassis and the heatsinks aren't very good match, but since I have them sitting around, I might as well just use them.

 

 

 

 

 

 

 

It sounds really nice with all my DIY headphones.  Thanks Kevin for your wonderful amp design.

 

Wachara C.

Congratulations on the project completion Wachara! Nice neat and compact.

 

My off board is near completion. It has been a hard build. Lining up the sand to the head sinks has been difficult and not to mention the earlier psu problems.

 

DC offset and balance are ok. Still need to wire and doll it up.

 

Edited February 1, 201313 yr by Victor Chew

That's a nice build, Victor. Looking forward to seeing your finished amp.

Wachara C.

My KGSSHV is done. 

 

The chassis and the heatsinks aren't very good match, but since I have them sitting around, I might as well just use them.

 

 

 

 

 

 

 

It sounds really nice with all my DIY headphones.  Thanks Kevin for your wonderful amp design.

 

Wachara C.

That is very nice. Well done. I have been toying with that sort of layout for a few days and it is great to see you have it going.

I would be interested in how warm your room is and how hot your amp gets. Also what resistor /current have you set in the output stage?

Very best wishes

And I too echo your thanks to Kevin for the circuit and pcb design

Well done to both of you!

I just tested and found that I have a ventilation issue with this layout. As soon as I put the top cover on, the offset and balance shift up. They go up as much as 20+v. No good.

I might try to put the PS on the upper part and the amp boards to go below.