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KG Balanced Dynahi build discussion thread


Vortex

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So I just got some old 1982-made Toshiba 2SA1145Y and 2SC2705Y. And now I'm looking at my Mouser-ordered 2SA1145-O.

nd I was thinking. Wait, what's the difference except being 25 years newer. Well that O and Y.

 

hFE classification O: 80 to 160, Y: 120 to 240

 

And after reading that in the data sheet. I still can't fathom, which is "best"? Neither? Or should Y's be used with Y's and O's with O's etc?

orry, very new to the whole transistors-thingie.

 

Cheers,

V

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Ok, I'll bite, Tho i'ma not building a dynahi.

 

What is with the superimposed LT1021 and the LM4040 ? One on each side of the pcb?

 

Also the "blacked-out" psu 'lytics.

Are they placed on opposite sides of the pcb, or just use extra insulation over the solder-resist, or ??? ?

 

Please excuse the seriously stupid questions, just curious...

Edited by livewire
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Slightly more parts than the original (ie. addition of 24v zener, ik resistors etc). I assume better current regulation. The 40 kdt has also been corrected to 20kdt. Previously missing 1k resistor has also been added. I believe this makes checking, for those of us that have built the older version, easier with comparison against this updated version. Thanks Kevin. ::)

Edited by Victor Chew
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Ok, I'll bite, Tho i'ma not building a dynahi.

 

What is with the superimposed LT1021 and the LM4040 ? One on each side of the pcb?

 

Also the "blacked-out" psu 'lytics.

Are they placed on opposite sides of the pcb, or just use extra insulation over the solder-resist, or ??? ?

 

Please excuse the seriously stupid questions, just curious...

1. Use either of them.

2. Take a look at the revised KGSSHV psu.

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black out is to prevent arcing via the cap metal casing.. more relevant to HV...

 

 

Kevin, is it possible for you enlarge the holes for 2pF and 0.47uF (on the amp board) a little?

I just got some 0.47uF wima caps, and again the leads don't fit... I didn't want to look for replacement, so I'm just shaving the leads to make them fit...

Lead diameter for the wima is 0.8mm

Edited by jwzhan
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As far as I understand, this is to avoid the possibility of ground plane shorting the cap. For some reason arcing occured between the two in jwzhan KGSShv build blowing a hole in the circuit board. Could have been caused by cracked cap covering which cut through the solder resist resulting in arcing. Its rare but did happen to jwzhan.

Edited by Victor Chew
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The black area is where there is no groundplane.

So if there is going to be an arc, it has to go thru the board

to the other side. The thickness of the board is good for

a few kilovolts. I'm sure its not necessary at 30v, but

its trivial to do.

 

I will increase the size of the cap holes on the amp board.

 

As far as the voltage references, the linear tech part is a fair

amount more expensive than the ti part. You use one or

the other, not both.

Edited by kevin gilmore
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gsx-mk2 will do 80 volts peak to peak balanced with a balanced input only

dynahi will do 120 volts peak to peak balanced

 

gsx is about 8 watts class A per balanced channel

dynahi is about 30 watts class A per balanced channel

 

dynahi drives speakers if you want it to.

 

gsx-mk2 will NOT drive HE6 to ear bleeding levels

dynahi WILL

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