insomniac
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Post by insomniac on Jul 29, 2009 1:18:01 GMT
Had myself similar idea with Audio-GD "Lego" headphone amp. Kingwa (the Audio-GD guy) can also provide the "space shuttle" attenuator and R-core transformers for cheap. The main problem is getting proper enclosure and defining the layout of modules inside of it. Hmm, no... the biggest problem with this project is that for a couple of bucks more you can buy their properly built headphone amp (C-2C)... and I suppose their build would beat the "Lego". Still... looking forward to Insomniac's impressions. True... the cost of a full dual mono SA-3 build could exceed that of the C-2C, especially considering the prices of decent aluminium cases these days. The C2-C certainly looks technically much better as a dedicated headphone amp IMO, operating in full current transmission mode and fitted with the V2 BPM modules based on the expensive Japanese Satri modules. The SA-3 appears geared more towards easy DIY build and flexibility with the option of experimenting with different PSU setups and rolling the different buffer modules. I will upload some photos of the C2C, before and after the space shuttle attenuator mod and a review will follow soon The present wiring is both audio boards power inputs to the same PSU board outputs (V+ to V+, V- to V-, Gnd to Gnd. The PSU (08edition) is configured for 18V and supplied by a single 30VA toroid. Hope to finish this one at the weekend ;D
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leo
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Post by leo on Jul 29, 2009 18:33:30 GMT
Which expenses are incurred for? You do the decent thing and pay postage costs both ways you greedy motherfcker' Glad it wasn't just me thinking that
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Deleted
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Post by Deleted on Aug 3, 2009 23:52:53 GMT
Chris, sorry but yes, so no drive to power amp i.e. speakers not being driven and distortion in the driver stage ok why? are you getting output from the monitor out, i.e. there isn't a short on that signal line? Also is there distortion on the monitor out(s) Robert Robert, finally got around to this. Yes, I do get signal from the monitor and yes it has the same distortion. Cheers. EDIT the amp is now in more capable hands...TBC...
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Deleted
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Post by Deleted on Oct 20, 2009 14:28:30 GMT
UPDATE; more out of politeness/gratitude to those who tried to help before The amp is back from intensive care, problem, unknown Two electronic engineers ( 1x telecoms & 1x radar ) have checked it over using their combined knowledge and proper equipment. By experiment the 10kohm in-line attenution resistors ( between the rca plugs and selector switch) were swapped out to 100k. This removed the distortion but left the gain still high and a bloated bass. An increase to 330k brought minimal improvement. I pointed out Alex's/Roberts? suggestion of a problem with the gain resistors/earthing around the opamps as I was unable to check this properly. Answer, now't wrong there. So although working after a fashion it still ain't right.
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robertkd
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Electronics Engineer from sunny Queensland
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Post by robertkd on Oct 20, 2009 15:03:20 GMT
So how do we fix it Chris?
Rob
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Deleted
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Post by Deleted on Oct 20, 2009 15:44:43 GMT
Rob,
I have no idea mate. As you may have picked up from my previous post, I've almost given up on it.
After 2 engineers (granted not audio specific) gave up on it I'm a tad despondent.
That's why I worded it almost in closing.
Chris
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Deleted
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Post by Deleted on Nov 29, 2009 16:33:04 GMT
UPDATE. The amplifier was repaired by its designer, thanks Colin! I continued with efforts to get the Suns working properly in this design. To cut a long story short I currently have a cobbled outboard psu running the Suns, with success! I have also swapped out the LEDs for zeners and think they are better for it, sweeter and more information in the highs. Altogether sounding rather nice, definitely better than standard or any drop-in opamps I tried. So my remaining work is to create a proper case for the outboard psu which may just get a JLH too. In Mr. Bodgit mode... I will thank all those who helped me along again, greatly appreciated and I've learned more along the way. Cheers guys, Chris EDIT = slightly better photo with JLH in line/on test.
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Deleted
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Post by Deleted on Nov 30, 2009 0:21:14 GMT
MORE... I stole the JLH out of my SCHA to give a whirl. OMFG, quite a revalation, this combo LOVES the JLH! Effortless power when required, very clear tuneful bass that digs deep. Voices and acoustics are yet more natural. On the strength of findings with the SCHA I thought I would give the LM4562HAs a try. NOT in here folks, real bruiser attack but no finesse, reminded me of an old Cyrus amp>>> boom,boom, tiss,tiss>>>where's the rest? Bedfellows they are not. Suns straight back in, I'm loving this, next album please
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insomniac
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Post by insomniac on Dec 1, 2009 15:14:04 GMT
Chris, Glad to know that the Claymore is back in action and the Suns are finally getting to assist in a bit of musical action. A Bit of an uphill struggle but worth it for the end result I'm sure. It should sound even better when cased up and the external PSU cables shortened etc... Enjoy Dave
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Deleted
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Post by Deleted on Jan 6, 2010 2:11:49 GMT
Just to confirm... All changes have now been made (except a JLH, still have not ordered the parts ), suns soldered in, psu properly built & boxed, wires shortened and all other changes soldered in properly for permanent duty. Sounding great
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FauDrei
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Post by FauDrei on Jan 6, 2010 21:02:12 GMT
Nice Chris, I'm sure you'll enjoy it.
Dave, how about your dual SA-3 "lego"? Can you give us any SQ impression/comparison?
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insomniac
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Post by insomniac on Jan 7, 2010 11:37:54 GMT
Dave, how about your dual SA-3 "lego"? Can you give us any SQ impression/comparison? I haven't finished this one yet Valter. Somebody nicked the toroid for something else and never replaced it ;D Gonna move this up my "to do" list and get it completed very soon though.
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insomniac
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Post by insomniac on Jan 7, 2010 11:51:20 GMT
Just to confirm... All changes have now been made (except a JLH, still have not ordered the parts ), suns soldered in, psu properly built & boxed, wires shortened and all other changes soldered in properly for permanent duty. Sounding great Good job Chris! Time to feed that mofo some tunes and enjoy
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Post by Colin Wonfor on Feb 23, 2010 7:35:29 GMT
???Hi Chaps just seen your writings and wondered if I could help. I have all the orignal circuits if you need them.
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Post by Colin Wonfor on Feb 23, 2010 7:41:10 GMT
Hi Chris, after sending it to me , and me fixing it you went and did it again, bad man, I would have fitted it for you if asked, nevermind enjoy, did you see my new cable? www.telluriumq.com getting reviews, I am still working in London I hate trains. Take care
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Deleted
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Post by Deleted on Feb 23, 2010 18:48:54 GMT
Hi Chris, after sending it to me , and me fixing it you went and did it again, bad man, I would have fitted it for you if asked, nevermind enjoy, did you see my new cable? www.telluriumq.com getting reviews, I am still working in London I hate trains. Take care Colin, I thought it too thick skinned to ask you to bastardise your own design! I noticed the cable reviews, good luck with that. You mentioned some phono stages in an email, any more info. on those? You could cheer up your commuting with some 'phones and maybe create your own portable amp. design! Of course, do share ;D Chris
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robertkd
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Electronics Engineer from sunny Queensland
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Post by robertkd on Feb 25, 2010 13:29:12 GMT
So Chris how has this ended up,... ?
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Deleted
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Post by Deleted on Feb 25, 2010 23:36:39 GMT
Robert,
You have pm.
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