kevin gilmore Posted May 7, 2011 Author Report Share Posted May 7, 2011 this is closer now, assumes the on board heatsinks http://gilmore.chem.northwestern.edu/kgsshv.xlsx Quote Link to comment Share on other sites More sharing options...
rille Posted May 7, 2011 Report Share Posted May 7, 2011 I already ordered a hifi2000 case with external heatsink, but it was an horror, impossible to drill it. In addition, if you want to attach a component, you must completely cross (if you succeed) the heatsink and put a nut on the outside. What did you do? It's possible This was done with a cordless electric screwdriver and a hand thread cutter. It's a Pesante Dissipante 2U: Quote Link to comment Share on other sites More sharing options...
Pars Posted May 7, 2011 Report Share Posted May 7, 2011 (edited) This is why GOD invented centering drills. Even with my NC machines good for .0005 inch positioning, without using the centering drills first, the wander is horrible even when clamped to within about .5 inch of the end of the drill bit. The problem with manual methods is first you have to use the centering drill on all the holes, then go back and actually drill them. Without a DRO, this takes a lot more time because you have to change the centering drill and the real drill bit for every hole unless you are confident enough in your positioning. By centering drill, do you mean something like this? My link Edited May 7, 2011 by Pars Quote Link to comment Share on other sites More sharing options...
kevin gilmore Posted May 8, 2011 Author Report Share Posted May 8, 2011 Thats the things. Even better in carbide. Just about impossible to get those things to walk. Quote Link to comment Share on other sites More sharing options...
Craig Sawyers Posted May 8, 2011 Report Share Posted May 8, 2011 Thats the things. Even better in carbide. Just about impossible to get those things to walk. I used those back in the dim and distant when using a metal turning lathe, either to make a feature for a tailstock centre, or prior to drilling a centre hole. I'd forgotten about them until now, and must get a few sizes for my drill press. To use such a lathe now I'd have to take a remedial course - too many decades have passed. Quote Link to comment Share on other sites More sharing options...
charlo89 Posted May 8, 2011 Report Share Posted May 8, 2011 @livewire what stax plug do you use for your kgsshv ? On the picture, this is not the plug that I usually see in DIY. Quote Link to comment Share on other sites More sharing options...
livewire Posted May 8, 2011 Report Share Posted May 8, 2011 (edited) Hi charlo89, nice to see you are taking on KG's build, love your case design. The connectors I used are a discontinued 6 pin female mil-spec microphone connector made by Amphenol. The part number is 91-PC6F. The number when encountered, may be prefixed with "WPI" or "CNA". These are available through some electrical surplus resellers. Kevin Gilmore used this connector in his first prototype KGSS amplifier. You can see it on his HeadWize website which also has much useful information about the KGSS amp. Allied Electronics also carries a plastic version of this connector without the chrome outer shell. It is a WPI design now distributed by Cooper Interconnect. EDIT: Hmmmm, just did a search. It seems that Cooper still makes them. Newark or Element 14 part number: 38F1544 ~$26 each Come and get em! Only 11 pieces in stock. Surplus houses sell them cheaper. Just sayin. + 2 pieces on ebay @ $20 each plus shipping. Auction # 350113117987 Edited May 9, 2011 by livewire Quote Link to comment Share on other sites More sharing options...
wink Posted May 8, 2011 Report Share Posted May 8, 2011 To use such a lathe now I'd have to take a remedial course - too many decades have passed I know the feeling. Haven't used a lathe since the late 60's. Quote Link to comment Share on other sites More sharing options...
livewire Posted May 9, 2011 Report Share Posted May 9, 2011 Yeah? But can you drill or mill? Quote Link to comment Share on other sites More sharing options...
wink Posted May 9, 2011 Report Share Posted May 9, 2011 (edited) In my days as an apprentice electrical fitter/mechanic in the NSWGR, we had to learn how to use drilling machines, lathes, shapers, linishers, etc. Milling machines were just out of reach. We used to drill and tap blind holes in all sorts of material. For aluminium we used kerosene. For most other metals it was machine oil or soluble oil. CNC's didn't exist as small hobby machines. Edited May 9, 2011 by wink Quote Link to comment Share on other sites More sharing options...
kevin gilmore Posted May 9, 2011 Author Report Share Posted May 9, 2011 The chrome jacks have to be machined down a bit otherwise the plug won't fit in all the way. Pictures were posted many moons ago. They are still slightly off size. My jacks are the exact right size, i will have to make more in the future. here is the print should someone want to make a bunch of them http://gilmore.chem.northwestern.edu/staxout3.pdf Quote Link to comment Share on other sites More sharing options...
charlo89 Posted May 9, 2011 Report Share Posted May 9, 2011 I bought his plug for 11 USD + 19 USD for the shipping to France http://cgi.ebay.fr/6-PIN-FEMALE-Amphenol-MICROPHONE-CONNECTOR-91-PC6F-/350113117987?pt=LH_DefaultDomain_0&hash=item51845e3723#ht_1666wt_1139 Thanks livewire If the plug is not perfect, I will machined it. Quote Link to comment Share on other sites More sharing options...
livewire Posted May 9, 2011 Report Share Posted May 9, 2011 That is the one! If you notice in the ebay pic, plastic part is recessed in front. KG was referring to machining the threaded chrome shell down until it is even with the plastic. This will insure that the Stax plug will enter completely. Quote Link to comment Share on other sites More sharing options...
wink Posted May 9, 2011 Report Share Posted May 9, 2011 They're US$20 now with US$18.95 shipping... Quote Link to comment Share on other sites More sharing options...
Driftwood Posted May 10, 2011 Report Share Posted May 10, 2011 My jacks are the exact right size, i will have to make more in the future. here is the print should someone want to make a bunch of them http://gilmore.chem.northwestern.edu/staxout3.pdf If you (or anyone) decides they want to make a bunch, I'd take about dozen Quote Link to comment Share on other sites More sharing options...
charlo89 Posted May 11, 2011 Report Share Posted May 11, 2011 There is a question I did not think. The Kgss is better than the kgsshv? Quote Link to comment Share on other sites More sharing options...
livewire Posted May 11, 2011 Report Share Posted May 11, 2011 I've never heard the KGSS, so Doctor G would have to answer that after listening to both. I've heard that the KGSS has plenty of power for driving electrostatic headphones, I would guess that the extra headroom afforded by the KGSSHV's higher voltage rating is a good thing to have for the harder to drive models. On paper, the KGSSHV is the higher power modernized version of the (12 year old?) KGSS design. 450 volt vs 350 volt rails, it also has a newly designed very low noise, current limited power supply. The design of the KGSSHV amp boards is very similar to the KGSS. Compared to the original design the KGSSHV has higher voltage withstanding output transistors and the option to use high voltage mosfets for the current source. The dual input fet (lsk389) is also a newer, very low drift design. Quote Link to comment Share on other sites More sharing options...
kevin gilmore Posted May 11, 2011 Author Report Share Posted May 11, 2011 That is a pretty accurate description of the differences. Quote Link to comment Share on other sites More sharing options...
charlo89 Posted May 11, 2011 Report Share Posted May 11, 2011 I was not expecting to have such a good response. Big thank you Quote Link to comment Share on other sites More sharing options...
spritzer Posted May 11, 2011 Report Share Posted May 11, 2011 The other big change is also how the third stage is handled as it has a CCS now and not resistors as the original used. This is also what Stax did with their newer amps (323/727). Quote Link to comment Share on other sites More sharing options...
livewire Posted May 17, 2011 Report Share Posted May 17, 2011 Been kind of quiet around here. Anybody else finish their kgsshv yet? Welp, last night I was immersed in a four hour listening session with my kgsshv. Did I ever mention how good this thing sounds? Had the bass a-thumpin on the ESP-950's. Was listening to a lot of vintage Allen Parsons Project. Heavenly! This morning I turned on the kgsshv, and nothing. Blew a fuse. Put in another fuse and it fired right up.......with a faint buzzing coming from the transformer. Then the smell of magic smoke accompanied with substantial heat rising from the toroid. Seems like my SumR piece of shit has a short. Oh well, I have yet to tear into it and form a plan of action. I'll just fire up my itty-bitty Stax amp and experience bliss without the bass. FWIW, Previously I did order from SumR, the beefier (100ma?) trafo spec that Spritzer mentioned. I think that I may head to ebay and pick up a cheap Hammond dual 500 volt job and be done with it. I have a 15VDC Sola brick (ala the original kgss) that I will be using in addition for the low-v stuff. Quote Link to comment Share on other sites More sharing options...
wink Posted May 18, 2011 Report Share Posted May 18, 2011 This morning I turned on the kgsshv, and nothing. Blew a fuse. Put in another fuse and it fired right up.......with a faint buzzing coming from the transformer. Then the smell of magic smoke accompanied with substantial heat rising from the toroid. Almost brings tears to the optical orbs................ Quote Link to comment Share on other sites More sharing options...
Horio Posted May 18, 2011 Report Share Posted May 18, 2011 I'm hoping to get going on a KGSSHV build soon. Just waiting for a board run to get going. Would be cool to give the case mounted heatsink build a shot. Sorry to hear about the transformer problems. I have ordered several transformers from Sumr and I haven't had any issues (knock on wood). People posting problems with the Sumr units on this thread and the T2 thread have me a bit weary... Quote Link to comment Share on other sites More sharing options...
ujamerstand Posted May 18, 2011 Report Share Posted May 18, 2011 Sorry to hear about the transformer woes jim. I guess some sort of soft start circuit would help here? Quote Link to comment Share on other sites More sharing options...
livewire Posted May 18, 2011 Report Share Posted May 18, 2011 (edited) Sorry to hear about the transformer woes jim. I guess some sort of soft start circuit would help here? That and a bigger trafo? I dunno. The start-up surge on this thing is quite intense. A loud buzz/thump can be heard, while the livingroom lights go dim for a second. I mentioned this earlier during the build, another more experienced board member dismissed it saying that he wouldnt worry about it, or something to that effect. So I figured why bother and didnt implement a soft start. I will now. BTW, the trafo never ran really hot, it was just warm to the touch with the amp turned on for an extended period. I couldnt find any cheap Hammond trafos on ebay, usually they have them for about $50. New, they are $105 on up, so I'm not going that route for an older, noisier design. This fried SumR toroid only cost ~$100 with the core band insulation added. Craig Sawyers talked of some super-duper trafo that has every turn layer insulated which he sourced for his T2 build, I might look into that as well as a fully encapsulated unit. So it's back to SumR? Makes me cringe, although I will spec something a bit more substantial this time around. I have room for it in this chassis. EDIT: Another thing. I'm not actually blaming SumR here due to the fact that I had previously shorted the power supply twice in the past, possibly weakening the trafo insulation in the process. I am aware that they are getting a rep for "donut fail". Since I dont have a failure analysis lab at my disposal, nor want to pay to have that done, I can only guess. Edited May 18, 2011 by livewire Quote Link to comment Share on other sites More sharing options...
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