i'm on a roll... the kgsshv

[Lil Knight]

not sure where the 5pf at 200 volts came from, but that is clearly

wrong.

needs to be 1kv cap.

My fault Opened 2 tabs and copied the wrong one.

[cobra_kai]

Has anyone besides Livewire had trouble with the 100 mA rating for the 485 volt secondaries? I am wondering if the recommended transformer is beefy enough

Also anyone have an alternative source to bdent for the 2SC4686A? They are nil stock until october

[Horio]

I think Mouser may stock these parts. Are these the same ones?

Has anyone besides Livewire had trouble with the 100 mA rating for the 485 volt secondaries? I am wondering if the recommended transformer is beefy enough

Also anyone have an alternative source to bdent for the 2SC4686A? They are nil stock until october

[cobra_kai]

I think Mouser may stock these parts. Are these the same ones?

Looks like it, thanks.

Found a mistake in Lil Knights BOM I bleieve. Line 7 under the PSU is listed at 3k but the mouser part is 9.53k. I think mouser p/n 660-MF1/2CC3011F should work.

[blubliss]

So are most people going to build the off-board heatsink model in the pesante dissipante 3U 400mm depth case? Has anyone found anything else?

[Horio]

I'm planning on using the 3U x 40mm dissipante case for the KGSSHV's I am building. Looks like a nice case and it fits the bill.

FYI, I've been talking to SumR about a custom transformer for the KGSSHV 500V version. I think I've got it pretty well sorted out with Richard, and I'll post the part number and specs once its finalized.

[wink]

Sounds good..

[manaox2]

I'm planning on using the 3U x 40mm dissipante case for the KGSSHV's I am building. Looks like a nice case and it fits the bill.

FYI, I've been talking to SumR about a custom transformer for the KGSSHV 500V version. I think I've got it pretty well sorted out with Richard, and I'll post the part number and specs once its finalized.

Awesome, thank you.

[Horio]

For those of you who are planning to build the 500V output version of the KGSSHV, here is the transformer I worked out with SumR.

Part #: RC0100 049 1

Specifications:

• 100VA / 117V primary
  
• 2 x 450V (@100mA output ea) secondaries
  
• 1 x 30VCT (15V-0-15V) 10VA secondary
  
• Core band
  
• Static shields
  

I believe you should be able to email SumR with this part number, and he'll know exactly what you are after. Either way, I'd still confirm the specifications with SumR just to be safe. Cost came out to $91/ea for my order. I purchased (4) transformers, so I am not sure if I got a bit of a discount. They said it would take about 2 weeks to fabricate, and probably a week or so to ship.

If you are planning to do the standard 450V build, you'll probably want to modify/lower the HV secondaries a bit so the PS will run a bit cooler. Maybe KG or someone else chime in, and give you the target secondary voltage under 100mA load.

[livewire]

@ Horio, does your trafo spec take into consideration the required 580V output bias branch of the psu?

[Horio]

@ Horio, does your trafo spec take into consideration the required 580V output bias branch of the psu?

I sure hope it does. =)

The rectified unreg voltage should be somewhere around 630V. Correct me if I am wrong but this should give roughly 10% headroom for the 580V bias branch. I originally was going to spec 475V secondaries. I ran it by KG and he recommended 450V instead. He said 475V would work, but the PS would definitely put out more heat.

Edited August 15, 2011 by Horio

[spritzer]

The bias is run off the B+ so there is no separate winding for that. Also that transformer is for the US only given the single 117V primary. 230V requires two primaries or a single 230v winding.

[kevin gilmore]

the new power supply board also has a voltage multiplier so you can build it with

lower voltage primaries for less heat.

http://gilmore.chem.northwestern.edu/kgsshvps8e.pdf

[ujamerstand]

What's the lowest recommended input voltage we can use to generate the bias voltage without using the voltage multiplier circuit?

[kevin gilmore]

600 volts DC unregulated under load.

Which translates to 430 VRMS under load.

Turning that into a transformer that works can be more problematic than

you might think.

[Kerry]

Turning that into a transformer that works can be more problematic than

you might think.

I've tried to cut things too tight on my first couple of transformers and ended up under voltage when the full load was applied. You also have to consider that there could be as much as a 10% variance in what's coming out of the wall.

If you're looking to save on heat, then you're better off using the doubler circuit for the bias. Because of the current regulator and two RC filters, it is incredibly clean.

If you want simpler, then don't use use the doubler, but make sure you've got enough volts under load.

Richard at SumR is pretty good if you tell him what the load is (I usually multiply by 2.5 of the actual required current) and what your required AC voltage is under load.

Edited August 16, 2011 by Kerry

[Horio]

Richard at SumR is pretty good if you tell him what the load is (I usually multiply by 2.5 of the actual required current) and what your required AC voltage is under load.

Out of curiosity, do you roughly know what the actual transformer secondary current requirement is for the new PS?

[luvdunhill]

Doesn't the KGSSHV have a variable output stage bias design?

[Kerry]

I just looked at the circuit and it looks like it will draw around 52mA or so (Kevin - please chime in if I'm wrong here) for both channels. Doubling is not a bad rule of thumb, so 100mA should be OK, but 150mA would give a bit more headroom.

The power supply is pretty efficient. It consumes about 5mA for the pre-reg stuff, about 1.2mA for the bleed-off resistors around the caps, and an additional 3mA on the positve rail for the bias.

Edit:

Doesn't the KGSSHV have a variable output stage bias design?

I was looking at the current sinks on the output stage to guess the current draw.

Edited August 16, 2011 by Kerry

[livewire]

Doesn't the KGSSHV have a variable output stage bias design?

Nope. The new design is pro bias only.

The older one that I built had one pro and one regular output like the older Stax energizers do.

[luvdunhill]

I was looking at the current sinks on the output stage to guess the current draw.

ah well-played. 52mA looks good to me as well, but it's tracking this value back to RMS current before the diode that might be tricky to nail down exactly.

[spritzer]

Nope. The new design is pro bias only.

The older one that I built had one pro and one regular output like the older Stax energizers do.

Easy enough to install a voltage divider off the B+ to generate the required secondary bias voltage.

[livewire]

Indubitably.

[wink]

"Indubitably."

And no doubt undoubtedly........

[luvdunhill]

Easy enough to install a voltage divider off the B+ to generate the required secondary bias voltage.

Yeah, that's much easier than understanding my original question and offering an appropriate answer