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Post by Deleted on Jan 13, 2008 11:52:07 GMT
Leo is a whiz at reverse engineering ! He doesn't do too badly with "added value" engineering either !
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Post by dc on Jan 13, 2008 12:00:59 GMT
Leo is a whiz at reverse engineering ! He doesn't do too badly with "added value" engineering either ! hahah I only offer the "value added" funky angle mount to hot babes... or trannys
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Post by leo on Jan 13, 2008 13:43:37 GMT
Hi ya fella's, been a bit busy lately but thank you for sorting out the thread, not sure why it went weird like that, unfortunately sorting things like that is not one of my strong points Anyway I'll update as soon as poss, I've now all the needed boards etched for the classA, just need a few bits and pieces to get it up and running properly. The Kumisa build is also still on, just waiting for the pcb's to arrive
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Post by leo on Jan 13, 2008 13:44:45 GMT
BTW I leave the funky mounting angles to DC, that seems to be more to his area ;D
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Post by leo on Jan 14, 2008 16:30:01 GMT
JLH Reg
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Post by Deleted on Jan 14, 2008 20:21:09 GMT
Leo That's not a JLH Reg ! That's an almost completed DUAL Polarity JLH Reg. What value are the big electros, 4700uF ? If available, 4 x 1,000uF in parallel ,or 2 x 2,200uF in parallel will widen the bandwidth further past 100KHZ. Alex
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Post by leo on Jan 15, 2008 0:26:04 GMT
Thanks Alex, anything else you'd change on it? those red film caps are 3.3uf, I didn't have any 1.5uf. The lytics are 3300uf Panasonic NHG, I was going to add a 1000uf panasonic for audio in parallel (I don't have them yet)
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Post by leo on Jan 15, 2008 0:27:09 GMT
BTW ignore that track on the left, its not used at present.
Later experimentation ,Leo ? Alex
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Post by Deleted on Jan 15, 2008 0:37:23 GMT
Leo I love those 3.3uF caps, we can't readily seem to get past 1.5uF in similar. JLH originally used 2 x 2,200uF electros in parallel for reduced inductance (wider bandwidth) Ordinary 1,000uF 10V (or low ESR) are more readily available here,and nice and small physically, as are 2,200uf. You will notice no PCB holes in that area, due to varying availability/choice of electros. I have tried several combinations with no noticeable audible change. I would just put a generic 1,000uF 10/16V electro in parallel with the 3,300uF Alex
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Post by leo on Jan 15, 2008 0:49:41 GMT
Ok taa I'll fit a couple of standard 1000uf's, its a little late here but I'm going to try it in my PCM1794 dac, it'll feed the Burson discretes (for testing) as the external PSU's use pre regulation anywayway so I'll try it after those. Shouldn't take long to try it
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Post by Deleted on Jan 15, 2008 0:54:09 GMT
Leo Just make sure that the output doesn't flick between digits on the DMM, if the input reading is steady. Alex
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Post by leo on Jan 15, 2008 0:56:56 GMT
I added loading resistors with a slightly higher load than the dac to try first but will also keep an eye on it when its in the dac. take me about 15 mins to try it I guess
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Post by Deleted on Jan 15, 2008 1:01:05 GMT
Yes, then go to bed !
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Post by leo on Jan 15, 2008 1:31:11 GMT
I'm back, told you it wouldn't take long ;D Hmmm, very weird and strange results having this beastie supplying my PCM1794 dacs output stage, I've got the headphones on now
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Post by Deleted on Jan 15, 2008 1:42:06 GMT
Leo Sounds like you have a problem best dealt with after a good night's sleep. As Pagan (Allan) will verify there should be only good things happening when used with DACs too. Looks like you may have to take some DC measurements, and perhaps use the CRO. Alex
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Post by leo on Jan 15, 2008 1:49:41 GMT
No, its working fine, remember I had shunt regulation in there before which has now been removed and the JLH's are in their place, the pre regulation has been adjusted with the trimmers to match what was coming out of the shunts Sound is very smooth, bass is fatter than it was, its the instruments that now sound like they are at the back of my head which is weird though Voltages are spot on and remain constant
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Post by Deleted on Jan 15, 2008 1:55:16 GMT
Leo We have all noticed an increase in detail without sibilance, but the difference may be harder to pick when you were already using shunt regs previously. Alex
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Post by leo on Jan 15, 2008 2:11:04 GMT
Yes, main thing is they work ok they are also a damn lot cheaper than the shunts though I should have compared them to standard LM317/337's tbh. Its all good fun though and it satisfies the curiosity
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Post by Deleted on Jan 15, 2008 2:19:27 GMT
Leo Try them again with parallel electros when you get a chance The fact that you mentioned them not sounding too good initially, then improving after warm up is very reminiscent of results with Solo, Voyager etc over the first 100 hours or so. This suggests that capacitor "forming" as the main culprit. We haven't noted any similar happening with 4 x 1,000uF or 2,200uF + 2 x 1,000uF conventional electros in parallel. The ESR will be also be lower when using parallel electros. None of us have commented about a shift in instrument placing, other than more detail and better localisation. Alex
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Post by leo on Jan 15, 2008 2:54:26 GMT
Alex, I've already removed them and fitted some green 1000uf 16v ones made by SSL (never heard of them) I'll let it run in over night and try again Now really must go to bed ;D
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Post by pagan on Jan 15, 2008 8:41:34 GMT
Leo Fatter bass, should tighten up, cap breakin? "I've already removed them and fitted some green 1000uf 16v ones made by SSL" The green should help!!!!! I prefer the multiple cap lower uF approach. Been using 2 * 2200uF cheap low ESR. (jaycar) "its the instruments that now sound like they are at the back of my head which is weird though" I've noticed this on headphones, on some cd's but that were normal studio recordings. On good live recordings, different if the singer moves.
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Post by leo on Jan 15, 2008 10:29:02 GMT
Hi Pagan,
I fitted standard multiple 1000uf's, having a listen this morning it seems ok, I may get some small 2200uf low ESR too, 6.3v should be fine and a smaller fit so hopefully I can fit 2 on on the + and 2 on the-
Once the classA is up and running I'm now tempted to try ALW super regs and compare against the JLH
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Post by pagan on Jan 15, 2008 11:09:15 GMT
Hi Leo. Don't know. the 4 * 1000uF might be better.
6.3volt was what was looking for, took the cheap and easier available option, 16volt.
I use a superreg on the cd67 dac and with the tent XO.
the problem I saw with the superreg's were that they were men't for low current circuits. great for dac's, clocks etc But for higher current requirements? Thats why i like the JLH in these other areas. just my opinion
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Post by Deleted on Jan 15, 2008 11:26:22 GMT
Leo I agree with Allan.Most of mine use 4 x 1,000uF 10V low ESR, because that's what was available. I also like the idea of low impedance way past what JLH achieved (>100KHZ). The JLHs are also easily configured for current limits of several mA to >600mA ,and voltages past 55V, in BOTH polarities. Cheaper too ! BTW, Dave and I have been using JLHs in our preamps for perhaps as long as 8 years ? Alex
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Post by leo on Jan 15, 2008 13:08:57 GMT
May have to get some FM or ZA's then theres quite a range from Farnell in 6.3v, ideal for mobo repairs etc Its acually sounding quite decent now, I've tried the 3300uf NHG + 1000uf + a 10uf Polymer in parallel BTW Pagan, you tried a VBE in place of the pre reg in the ALW? it works really well. An ALW will handle a few hundred mA's no problem
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