That sounds like it would be excellent with halibut!

Got my new power supply ready for my KG amp collection

 

What is it for?

I have seen a similar but smaller stup a while ago, it was a local power backup for wired home telephone.

totally 100% safe.  looks like about 100kva.  proper personal protective equipment required.  typically 600v if its to generate 3 phase.  makes the stuff birgir is doing to e-cars look tame.

I've seen a similar setup in the dungeon of a leather bar back in the early 80s. Most likely for a different purpose though.

X-altra MM/MC phono stage.

A project published on audioexpress a few years ago and a different design approach compared to my Simplistic phono designed by Salas over at diyaudio.com

 

Will be fun to compare both. 

 

Edited September 18, 20241 yr by MASantos

Aerial picture of a balanced amplifier for dynamic headphones. Only light from LEDs and tubes. ISO-25600, F4, 1/13 sek.

And in day light. 4 x 2A3, 4 x 12BH7, 8 x switch mode filament supplies, 2 x GRHV and 4 x transformers.

DIY is still fun. 

 

5 minutes ago, JoaMat said:

Aerial picture of a balanced amplifier for dynamic headphones. Only light from LEDs and tubes. ISO-25600, F4, 1/13 sek.

And in day light. 4 x 2A3, 4 x 12BH7, 8 x switch mode filament supplies, 2 x GRHV and 4 x transformers.

DIY is still fun. 

 

All it needs is an Unobtanium case...😁

10 hours ago, JoaMat said:

Aerial picture of a balanced amplifier for dynamic headphones. Only light from LEDs and tubes. ISO-25600, F4, 1/13 sek.

And in day light. 4 x 2A3, 4 x 12BH7, 8 x switch mode filament supplies, 2 x GRHV and 4 x transformers.

DIY is still fun. 

 

Very cool! How do you couple output stage to headphones, doesn't look like output transformers are used?

No output transformer. There are output electrolytics to headphone.

Schematically it looks something like this.

Reason for three KSC2690A in CCS is to distribute the heat, so no heat sink needed. At the moment I only use two transistors in CCS due to insufficient transformers.

I don’t know how to optimize the circuit, but I’m happy with the result.

A few words regarding filament supplies I’m using with 2A3 and 300B tubes.

9 VAC => unregulated 11 VDC => XL4015 DCtoDC step down converter...

... with trimmers for output voltage and current limiter. It’s easy to set voltage to correct voltage depending of tube and also to trim current to achieve a sort of soft start. So far it works ok.

It's been approximately eleventybillion years since I actually built something and I'm not sure that this qualifies but at a minimum, i finally assembled and wired something that I've been procrastinating/avoiding for like two years.  I present, the IcePower 1200AS2 in a Ghent Audio case.

I'll post a completed picture at some point but it looks like a black box.  Not entirely sure what I'll do with it.  Maybe I'll build a set of bookshelf speakers to overpower?

Long live Mr DIYer!

Making a soft starter module with switchable voltage function.

No screws required if attached to the AC socket directly.

The distance from earth to AC and other components is scary small there.  I'd at least put in isolation slots as the voltage can creep over the PCB. 

In an effort to try and finish up some of the gigantic pile of projects, here is a fully DC/DC powered KGSSHV. 

The unit is close to 10 years old but not really used at all as it ended up at Kevin's with some transformer trouble.  A couple of years ago I made an effort to bring all those amps home so I stripped it down for transport and the transformer went in the trash to save on weight.  

Then I found those lovely 400V DC/DC bricks, added one for 600V bias (with a bit of a trim and filtering) and one for +/-15V, all driven off a 90W 24VDC Meanwell brick. 

I had to lower the output stage current a bit from stock and there is a tiny bit of coil whine coming from those HV supplies but it works well.  The B+ supply is the hottest part in there at 60°C.  

Edited July 24, 20251 yr by spritzer

Nice work!

After around 7 years away from DIY, I got back into it a few weeks ago and finished this KGST. It’s been nice reconnecting with the bench.

 

I still have a Carbon and a BH waiting to be finished (PCBs are populated, just need to design proper enclosures). Hopefully it won’t take me another 7 years this time...

Edited July 29, 20251 yr by PICaudio
Rearrange the pictures

I like that riser for the power switch and the tubes visible through the front.    

I’m looking for a way to produce 125 VDC low current.

One idea is to use a switching voltage regulator, LT8365 maybe …

board size 2.0in x .73in (51mm x 18mm)

On 7/24/2025 at 6:50 PM, spritzer said:

In an effort to try and finish up some of the gigantic pile of projects, here is a fully DC/DC powered KGSSHV. 

The unit is close to 10 years old but not really used at all as it ended up at Kevin's with some transformer trouble.  A couple of years ago I made an effort to bring all those amps home so I stripped it down for transport and the transformer went in the trash to save on weight.  

Then I found those lovely 400V DC/DC bricks, added one for 600V bias (with a bit of a trim and filtering) and one for +/-15V, all driven off a 90W 24VDC Meanwell brick. 

I had to lower the output stage current a bit from stock and there is a tiny bit of coil whine coming from those HV supplies but it works well.  The B+ supply is the hottest part in there at 60°C.  

still looking for a reputable source of that lovely DC bricks.... Taobao doesn't work (or I am not able to) for me...

I bought some DC bricks from LCSC Electronics. Seems to be an all-right supplier.

https://www.lcsc.com/product-detail/C2999063.html

Edited September 15, 2025Sep 15 by JoaMat

I was recommended LCSC by someone on diyaudio so used them for some LDOs which were on extended backorder everywhere else. I received what I believe to be genuine parts (they work like they should).

Nothing wrong with LCSC, I use them all the time for some hard to find parts.  

I can second this