I do have a question for the group, would you want a cheap PSU that is good and does the job well or balls to the wall T2 type PSU? The difference in cost will be substantial so it is something Kevin and I are discussing.

RN60 will derate to values suitable for this

The CMF70 would work but isn't that way too big?

Edit: which resistors are you worried about getting even close to this limit?

The output resistors (the reason why they aren't normal metal films in the T2, ditto for the Stax amps) but stuff like the feedback line is split up.

If lurkers are eligible, I'd love a boardset and whatever stuff gets offered as a package with it.

If 2SA1968 are sourced and available for anything close to $.70 ea, I will commit to buying couple hundred extra to bump up the volume discount.

Back under my rock now ....

The boards will be open to everyone and nothing has been decided wrt a group buy of parts. Given the huge logistical nightmare of getting things to me it might not even happen.

put me down for one boardset + parts, possibly two sets!

on another note: Kevin, why doesn't someone order the boards for you, everybody could save the 9% sales tax, not much on such a project, but always helps!

First time posting here, but I'd love to be apart of 2 sets of everything that you're selling for this. It'll probably take me a year or 3 to get it done, but it'll keep me occupied and learning.

I'm interested too, I'd like a set of boards required to build the amp. Thanks!

Why are you worried about the output resistors? In a failure condition you want them to go due to overvoltage and in the normal case they don't drop anywhere near that voltage???

Birgir,

I think that a nice well built power supply is a must in such a design and would personally go for the best possible design, however if such a power supply means off board custom heat sinks and what not it might be a turn off for many people, myself included.

I think the price no object one is the way to go, but using easily sourced parts and on board heatsinks.

There is also an alternative power supply board, cheaper than the T2 style, its pretty

much identical to the BH power supply board, at 450 or 500 volts.

No reference, opamp or 2sc3675 needed, and 2 less heatsinks.

http://gilmore.chem.northwestern.edu/kgsshvps2.jpg

option for 2nd pass fet and heatsink for better heat spreading.

amp schematic updated.

I've tried having someone else order the boards. But if i pay for them even

if they ship out of state, they still charge me tax. For boards i buy for nwu

with the tax exempt number, i still have to go over it with them every single

time. A real pain. But they are the best boards i have ever seen.

Edited September 5, 201015 yr by kevin gilmore

So that one would be some sort of compromise between the cheap well built one and the T2 one?

ps: welcome back Kevin!

KG any chance the all out assualt KGSS originally mentioned in the first page of this thread will be seeing a board set? The version with higher biased output stage and chassis mounted heatsinks.

I'm for the compromise route as (unfortunately) my budget doesn't allow for a price no object option. My opinion is that if a 20% increase in build costs brings about a 5% gain in SQ then I'd rather go for the cheaper option but I'm in whatever the decision.

Birgir,

I think that a nice well built power supply is a must in such a design and would personally go for the best possible design, however if such a power supply means off board custom heat sinks and what not it might be a turn off for many people, myself included.

I think the price no object one is the way to go, but using easily sourced parts and on board heatsinks.

I'm for the compromise route as (unfortunately) my budget doesn't allow for a price no object option. My opinion is that if a 20% increase in build costs brings about a 5% gain in SQ then I'd rather go for the cheaper option but I'm in whatever the decision.

It doesn't make much sense to go for such a project with a short budget. And how can you measure 5% increase in SQ? lol

Original design can run on +/-600 volts and absolutely requires T2 style heatsinking.

Which puts the chassis at about triple the cost of the rest of the parts combined. Maybe more.

I don't think that is what people want. This is supposed to be an everyman kind of thing.

If you want nuts, go and build a T2. Or you have to be someone like luvdunhill or n_maher with

the equipment at home to do the chassis. Or even kerry which manages to do that kind of stuff

on a balcony overlooking central park. Even i don't do chassis like that at home and i have

all the right machine tools. Getting the heatsink interface right pretty much requires a NC machine.

Or a whole bunch of patience.

I'm working on yet a third power supply design. Shunt regulator. Sure, why not. Except my

version does not blow up without a load, it uses the ixys parts as the current source, and i measure

the current thru the shunt, and if its too much, i shut down the amount the current source supplies.

Sort of the best of both worlds.

Edited September 6, 201015 yr by kevin gilmore

Definitely want in on this. One board set and a handful or so of the 2SA1968.

i'd take at least 500 of the 2SA1968LS at that price

Original design can run on +/-600 volts and absolutely requires T2 style heatsinking.

Which puts the chassis at about triple the cost of the rest of the parts combined. Maybe more.

I don't think that is what people want. This is supposed to be an everyman kind of thing.

If you want nuts, go and build a T2. Or you have to be someone like luvdunhill or n_maher with

the equipment at home to do the chassis. Or even kerry which manages to do that kind of stuff

on a balcony overlooking central park. Even i don't do chassis like that at home and i have

all the right machine tools. Getting the heatsink interface right pretty much requires a NC machine.

Or a whole bunch of patience.

I'm working on yet a third power supply design. Shunt regulator. Sure, why not. Except my

version does not blow up without a load, it uses the ixys parts as the current source, and i measure

the current thru the shunt, and if its too much, i shut down the amount the current source supplies.

Sort of the best of both worlds.

Totally understandable. I'm in for the regular board set everyone else will be getting.

Count me in for a board set.

Ok, time to stop lurking and start lining up a project for when I finish my PhD - I'm also interested in a board set. Kevin, looking at the artwork for the power supply options with and without the reference, opamp and 2sc3675, it seems that the two designs could be combined into one PCB without too much difficulty or increase in board space. The final decision is then up to the user.

So that one would be some sort of compromise between the cheap well built one and the T2 one?

ps: welcome back Kevin!

I think this would be a good spot to aim for. If someone wants to go no holds barred, that would be the T2, IMO. I was expecting the kgsshv to require off-board heatsinks, but having all on-board heatsinks makes the casing a much easier job. I like that.

if deemed trustworthy enough, i wouldnt mind volunteering the time to split up a big box of parts into individual kits (assuming none of that parts matching stuff is required). my schedule prohibits any of sort extracurricular activity on days besides friday, saturday and sunday but i figured its better than nothing. so if a big shipment of parts were to land on my desk, i could split it up to kits but obviously it might take me a lot longer than someone who had more time to devote to it. i dont have anything to add to the project intellectually, perhaps time could count for something.

i dont know if this is far too tedious a task or far too difficult but who doesn't like a good dragon to slay every now and then.

Definitely want in on this. One board set and a handful or so of the 2SA1968.

Kerry, now that I know you're in for sure, you know I will be harassing you since you're close

Crappyjones123:-

Originally Posted by Sherwood

CJ, I nominate you for team "source absolutely dead fucking last".

Originally Posted by HighLife

AND STOP BEING LIKE A ASIAN GOLD FARMER IN WORLD OF WARCRAFT....they dont play, all they do is buy-sell-buy-sell-buy-sell....

Never mind the detractors, there are two principles in life to keep in mind...............

1/ Nothing (nobody) is ever a complete failure - they can always serve as a bad example.

2/ It may well be that your sole purpose in life is to serve as a warning to others.

I'm in for a board set and kit set.

lookin good Kevin!

Count me in for a board and kit set, Kevin.

Would be great if the Stax jack and maybe the 2.5" heatsinks are also options for the kit.

Kevin does the layout for the lsk170s allow the use of those nice little to-92 heatsinks that were group ordered sometime ago? I don't have any, but I'm sure some one has some laying around or that another group order would easily be organized!

I don't think that the stax should be part of the kit, since some might want two, some might want just one and that would require a lot more trouble for the distributor of the boards. The heatsinks would be nice though.

Edited September 6, 201015 yr by MASantos
add info

Kevin does the layout for the lsk170s allow the use of those nice little to-92 heatsinks that were group ordered sometime ago?

Had not thought about that. Will have to look into it.