Helium
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Posts posted by Helium
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i will be testing the new amp boards when i get them
will order the power supply board soon
i'm sure i can do a completely off board version of the
power supply board
Yes, please call Goldreference stable and final, and I will order PCBs.
Interested in on board version.
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looking forward to this one
With big output transistors? But why would you need it if Susy dynahi exists? What's the major difference? I guess none.
AFAIK, it has always been like this: dynalo = w/o big output TO-220 transistors, dynahi = with big output TO-220 transistors.
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Minimum quantity from Mouser is 1 pcs (2SA1930). Same from BDent (2SC5171).
Ah yes, 2SA1930 is in stock in Digikey. Minimum quantity is 1 pcs. too.
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Try Toshiba 2SC5171/2SA1930.
They are available at Bdet (2SC5171/2SA1930) and Mouser (2SA1930). Grab them!
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Aaa want!
Seems that I will add 1 more PS case with goldenreference.
It will be 5 case setup: balanced beta22, Susy dynahi, Krell clone, Sigma22 PS, Goldenreference PS.
All amps will include full setup of AMB delta1/delta2 with screen and motorized pot. PS cases will include Sigma11 for 5VDC as well, 2 transformers and Crydom/Tyco SSR.
I've buit maybe 15 Betas already, this one will be most complicated and for myself.
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When things are changing so fast, it's hard to follow the story.
So, Goldreference is the updated and improved KSA5 PS board, right? This one:
http://gilmore.chem.northwestern.edu/boards/ksa5psg.zip
And it also must be compatible with KSA5 clone, Susy dynahi.
Seems complicated (no no, not a drawback). Curious how is it compared with Sigma22? Maybe worth to try it with Beta.
On silkscreen, 2000 Ohm resistors marking near DC output are upside down...
What should be changed to push it to +-24V? +-30V?
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I have D punches and the IEC punch.
yep they deform the metal but only on one side, so
you make sure the other side is the outside.
wrapping the die in some electrical tape along the
surface helps making no marks.
Wow IEC punch. Can you give punch maker/model (greenlee, ruko, qmax...) and corresponding IEC maker/model? I'll look into it.
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It deforms inside (punch side), not outside (die side).
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Power is still necessary
Looks like I need to save the attenuator boards for this and not the T2
what's wrong with SMD in this case, the packages are large enough to do by hand, not to mention still available at mouser
Harder to match them.
Anyway, there are just 4 of them per board. It's OK.
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Thanks, I see now. Offtopic: any plans to update dynahibal8, dynahibal9, ssdynahibalsmt and the like as well?
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what I could do now is add some ground plane on the back of that board like I have done for the
others. lower impedance ground means even less noise
Like what board? Can you give a link please? I far as I have seen from repository, all KG dynamic amps have only top copper ground plane at best. Which one already enjoys bottom ground plane?
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by the way fully balanced version coming.
lots of parts!
100% differential
100% complementary
http://gilmore.chem.northwestern.edu/cfa3production.pdf
not sure why it took me years to come up with this
NO FEEDBACK of any kind
thd <.005% and absolutely flat over the 10hz to 200khz
frequency response +0, -3db .017hz to 4.43 MHz
So, is it end of the game SS dynamic amp??? What's your opinion?
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Hmm you switched to SMD? Pity. Any chance to design them simultaneously please - SMD and all TH?
I've got plenty of MPSW.
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speaking of holes I'm really tempted to buy a square hole punch, a hole saw produces good results but it's really time consuming... especially when you want to use inlets with built-in switches
IMO square hole punch is useless for me. I've got one, 1inch x 1inch, and never used it. Not to mention they are very expensive.
However, round hole punches are used very frequently. I've got the whole set from 10 to 31mm to fit all Neutrik connectors, pots etc.
Avoid D-holes and square holes as much as possible. Round holes are much easier to cut. And more accurate.
I even chose to install separate Neutrik powercon+switch+fuse holder combo instead of single AC inlet module. Just for the fact that the latter requires square hole.
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I'm after some help with my latest chassis design.
It's an off board KGSSHV, in which Camexpert will be fabing all the panels and drilling the heatsinks.
Which leaves me to create all the brackets, I've bought 16mm equal angle x 3mm x 1 metre lengths.
Cutting is a no brainier, I've bought a little metal mitre box for this.
It's the accurately positioning of the drill holes is where I may struggle, with my limited knowledge and tools, this is my plan...
I have 100% accurate paper print outs of the drawings, which I'll use spray adhesive to stick on the brackets, the quick test I did last week proved to be a good technique for accurate hole location.
I plan use a Stanley knife to cut a cross for the centre of the holes in the aluminum.
Then using a automatic centre punch as starting point in the middle of the cut cross, which I'm hoping to find the exact centre by feel.
This is where I start to get nervous, I bought several #2 centre drill bits to make a pilot hole using a drill press.
From what I've read and watched, it's best not to clamp down the aluminum, instead it's best to let it float on the drill press and let the centre drill bit grab the metal and find the punch hole. Bearing in mind the spinning bit would be very close to punch proximity to enable this, doing an alignment beforehand.
Then finally a pass through with the final drill bit size, an M3 or M4, again with the piece of aluminum floating on the drill press.
That's the plan, sorry it's so long winded, am I on the right path?
I've experimented a lot on drilling precisely located holes. This is a technique I've developed for myself and it's working for me. Drilled >20 cases already.
1. First make drawing in FPE software to the size of your panel/case. In the drawing use as narrow lines as possible for increased accuracy.
2. Print it with scale set to 100% (A4, A3, A2 or whatever your panel size is). This is very important to ensure that printer/plotter prints precise size according to drawing. Sometimes the printer outcome is different by fraction of mm/inch to what you expect. It will ruin accuracy. Measure the paper drawing with ruler ot caliper. If not perfect, either calibrate the printer or search for another one. It may take time to find a printer/plotter which prints precisely. Also, make sure you use the following settings as on screnshot attached (this is all about FPE software, other software setting may be different). Print in B/W mode, not color so that only one printer cartridge will be engaged for maximum accuracy).
3. Cut the outer shape (=panel shape) of the drawing with Xacto knife guided by metal ruler.
4. Stick it precisely to the panel by using glue (you will remove it later with solvent). Don't apply too thick layer of glue. As thin as possible. Wait for the glue to harden.
5. Now you proceed to drilling itself. Slightly punch reference points to be drilled on paper with carbide scriber. The scriber must protrude the pater and reach the metal to leave mark on it. This is very important to put the scriber exactly in the center of reference point (funny enough, it's harder than you can imagine). That's why I recommend to apply thin layer of glue and use thin paper for printing. Use good lighting and magnifying glass if necessary.
I use this carbide scriber:
http://www.amazon.com/gp/product/B00004T7S1?psc=1&redirect=true&ref_=od_aui_detailpages00
6. Punch paper (and panel underneath it) with automatic center punch. After you mark the center of the hole with carbide scriber (step #5), it's easy to punch it with center punch, it doesn't wander. I use this center punch:
http://www.amazon.com/gp/product/B000HTAH70?psc=1&redirect=true&ref_=oh_aui_detailpage_o02_s00
Try to punch once only. Only if you see that it is offset, make second ot third strike to remedy.
7. Take good screw-driver drill, preferably cordless. Chuck must be good (tricky to find drill with chuck that doesn't stagger on the shaft).
8. Make starting cavity with drill bit for ceramic tile. It has totally different shape from usual drill, but it doesn't wander. I use this one:
Mine has 4 cutting blades. 2 cutting blades (more common) will do the trick as well, I guess.
Just make small cavity with it. Don't try to drill through, of course. Always apply oil at drilling. I use WD40.
The cavity made by ceramic drill bit will ensure that the final drill bit will not wander.
As you can notice, the whole process is about minimizing wandering of the bit.
8. Now you are prepared to drill the final hole. Don't try to use generic drill bit. Instead, use spotting drill. I use this one made by Europa Tool (if talking about 3mm hole, there are different sizes):
What's so special about spotting drill? First, it has very short fluted part. It means that it's sturdy and doesn't bend when you press the drill against the material. Believe me, drill bits under size of 5mm with large fluted part do bend when you press it down.
Then, it has no side cutters. It means that it cuts material only with its tip. Side cutters tend to bite the material which make the bit wander sideways.
Use oil at drilling and VERY low RPM (~1 revolution per second). For that screw-driver drill must be used, not usual drill. Screw-driver drill will maintain torque at low RPM.
Spotting drill is not designed to drill trough thick material, but it's good enough to drill through 3-4mm.
And yes, when drill panel up to 1.5mm thick, don't use drill bench. Better by hand (just control it that you hold the drill vertically).
9. You are done. Remove the paper and clean the panel. Deburring may be needed (I use Noga tools).
This method is about drilling small holes (e.g. for screws, standoffs etc). For large holes (e.g. for Neutrik connectors), knock-out punch must be used (that is another story, and there are also some trick to share).
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Is it published here? I mean balanced differential cfa3
http://gilmore.chem....ern.edu/boards/
I think not. Any progress please?
Part Sourcing Assistance/Advice Thread
in Do It Yourself
Posted
Checked rectangular knockout punches of many makers, couldn't find one that cuts hole for IEC at once (punch size and IEC size must match).
So will stick to RS 545-345 which is 28.2 x 22.5mm for my favourite Qualtek 764-00/002. Will have to cut 4 overlapping holes.
OEM is Manuform MA9730140.
BTW, they have MA9740040 which is 31.4 x 28.3 with radius corners, but that is 2 times more expensive.