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Post by Dickybottle on Jun 15, 2010 8:34:39 GMT
Hello, I have just ordered from Jaycar the SC headphone amp kit and PSU. Been watching the (many) threads relating to tweaking the SCHA and have finally decided to give it a go. However, just a few questions if you don't mind... Could someone please point me to a summary of recommended mods so I can prepare for the kits arrival? Also, is the JLH ripple gobbla PCB still available, and if so how can I obtain one with a list if parts? Are all the modded bits available in the UK? I'm sure I will have other issues as time goes on, but many thanks in anticipation... Ken
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Post by Deleted on Jun 15, 2010 10:09:19 GMT
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Post by Dickybottle on Jun 15, 2010 15:59:08 GMT
OK, many thanks Alex.
Ken
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Post by Deleted on Jun 15, 2010 22:09:17 GMT
Ken If you or anybody else is interested in obtaining the LME49720HA (LM4562HA) metal can version for the SC HA, send a PM to "traf". Simon has these available at a much lower price than you could get them for in small quantities , and P and P is also a fraction of that charged by the big suppliers like Digikey.He also has them available via ebay, where I was lucky enough to get a couple of the LME49710HA (single version) These are however now almost gone, but he will be attempting to get more in stock. The LME49710HA is recommended for the SC DAC. Alex
P.S. If anybody checks the LME49710HA on ebay, do NOT be fooled by the much lower price from "sisitronics" Their listing is misleading, and it is actually for the normal DIP8 version. Also, their price for that version is damn high, as I purchased some of those via a DIYAudio GB for <AU$2 each !!!
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Post by Dickybottle on Jun 16, 2010 7:54:59 GMT
Alex, The LME49710HA seems to be available for about 10.50 GBP at the moment - Is this a fair price? I already have a couple of LM4562NA's (plastic) - Is there really that much difference - I seem to have read somewhere that the HA version is a bit TOO revealing.
Also, just a quick question - I have a spare 30VA toroidal 0-12 0-12 transformer - Will the regulator drop out with only 12V inputs?
Thanks - Ken
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Post by Deleted on Jun 16, 2010 10:01:16 GMT
Alex, The LME49710HA seems to be available for about 10.50 GBP at the moment - Is this a fair price? I already have a couple of LM4562NA's (plastic) - Is there really that much difference - I seem to have read somewhere that the HA version is a bit TOO revealing. Also, just a quick question - I have a spare 30VA toroidal 0-12 0-12 transformer - Will the regulator drop out with only 12V inputs? Thanks - Ken Ken Below is from Simon on ebay. LME49720HA DUAL OPAMP 8PIN LME49860 LM4562 LME49720 Location: United Kingdom Feedback: 726 | 100%Watch this item AU $17.19 +AU $3.44 I checked Digikey and a single LM4562HA is > US$19. A single LME49720HA is US$20.90 P and P from Digikey is not cheap either. I am unaware of anybody who has built the SC HA with JLH, regretting changing from the plastic to the metal can version. There have also been many reports of an improved low end with the metal can version. The LM4562 , especially the plastic version is very unforgiving of mediocre power supplies. With poorer power supplies it can sound fatigueing.I do not believe that this is the case with the SC HA when the JLH is fitted. A 12-0-12VAC toroidal is not suitable for use with a +-15V supply. The LM317/LM337 ideally need at least 3V headroom to ensure proper regulation with normal mains voltage fluctuations. That means that it is best to have at least +-18V into them for +-15V out.. The 12-0-12 toroidal will give around 16.8V after rectification. You could of course reduce the adjustable regulators output to +-12V, but there is likely to be a reduction in performance. Robert from Rockhampton even prefers +-18V for the output stage of the amplifier. Alex
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