March 19, 201313 yr comment_566634 Tube input makes no sense as it gives us no benefits. That's the whole issue with most hybrid amps, most of them were designed with a SS front end but then tubes were added after the fact by somebody else. Report
March 19, 201313 yr comment_566646 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 Report
March 19, 201313 yr comment_566647 You may find some overlap in hFE when you test them between grades. Or not. If matching, I you can see what matches up and use those. No difference in the parts, just graded during testing by the manufacturer. Report
March 20, 201313 yr comment_566917 well I had nothing to do for an hour today http://gilmore.chem.northwestern.edu/dynahipower6.jpg Report
March 21, 201313 yr comment_566921 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 March 21, 201313 yr by livewire Report
March 21, 201313 yr comment_566929 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 March 21, 201313 yr by Victor Chew Report
March 21, 201313 yr comment_566941 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. Report
March 21, 201313 yr comment_566951 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 March 21, 201313 yr by jwzhan Report
March 21, 201313 yr comment_566991 black out is to prevent arcing via the cap metal casing.. more relevant to HV... Thanks for the reply. Is this an extra coating on the pcb? Or maybe an applied kapton tape or other insulator? Please educate me. Report
March 21, 201313 yr comment_566994 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 March 21, 201313 yr by Victor Chew Report
March 21, 201313 yr comment_566999 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 March 21, 201313 yr by kevin gilmore Report
March 21, 201313 yr comment_567073 Kevin, is it possible for you enlarge the holes for 2pF and 0.47uF (on the amp board) a little? made the holes .040 inch, they were .030 inch enough? Report
March 22, 201313 yr comment_567153 Very nice on the PS Kevin. I was just looking at this and was wonder if the voltage reference was floating. I thought it should tie to ground but didn't see it. Report
March 22, 201313 yr comment_567162 both are tied to ground at the bottom of the 6k resistor. thermal hard to see. Report
March 25, 201313 yr comment_567554 Things are looking up for me being able to actually build something here without family chaos interfering so I want to ask, given the issue with the sand, should I simply wait for the new boards first? Report
March 25, 201313 yr comment_567565 if you already have the old boards and a way to do the off board heatsinks, then you should do it, you should have very little trouble getting the parts there. Otherwise the new boards are going to be a fair amount easier to build. Report
March 26, 201313 yr comment_567690 Now that I got my hands on a GS-X mk2 . What will be the major differences between the GS-X mk2 and the on board SuSy Dynahi? Report
March 26, 201313 yr comment_567714 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 Report
March 26, 201313 yr comment_567725 Wait a minute. ^^This fucking guy isn't blubliss so what is he doing with this avatar?! Report
March 26, 201313 yr comment_567730 He has been using it at the other place for quite sometime. BB has a dog's head o'er there. Report
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