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Post by Deleted on Feb 26, 2010 9:53:51 GMT
fault151 Personally, I think you would be, as you would be trying to obtain an accurate and neutral sound by using them. As the audio GD modules aren't quite neutral sounding, I see little point in using extremely high quality capacitors there. On the other hand ,if you were using LME49710HA I.C. s (metal can) the sound would be very close to neutral, and as they are FET input opamps, you would most likely be able to get rid of the input capacitors. (assuming that there is no more than a few millivolts DC from the source ) SandyK
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Post by fault151 on Feb 26, 2010 10:12:58 GMT
Ok cool, i'll stick with what I have then. Its a big cost just to try them out. I have heard the LME49710HA metal can, it did sound really good, but i preferred the sun module. Which did you prefer the most?
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Post by Deleted on Feb 26, 2010 10:35:56 GMT
Ok cool, i'll stick with what I have then. Its a big cost just to try them out. I have heard the LM4562 metal can, it did sound really good, but i preferred the sun module. Which did you prefer the most? fault151 I haven't tried the AudioGD modules yet, as my son is now using the original. However, I always go for the most accurate sound, although many people like a little colouration. I am finding the single version LME49710HA even better than the dual can, at least in the new SC DAC, when compared with the LME49710 plastic version . If I had more of them, I would love to try 2 pairs of those in the Jaycar HA. I am also in the position of being able to compare with the Class A HA which is considerably higher quality again. Alex
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Post by fault151 on Feb 26, 2010 10:39:38 GMT
Yeh it was the single version that i heard. I may get hold of one myself and see what i think no i have heard it more. The first time I heard it was only for a quick 5 minute listen.
where can you get them from? Mouser, RS...?
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Post by Deleted on Feb 26, 2010 11:01:42 GMT
Yeh it was the single version that i heard. I may get hold of one myself and see what i think no i have heard it more. The first time I heard it was only for a quick 5 minute listen. where can you get them from? Mouser, RS...? fault151 Unless you used a browndog adaptor, and fitted a pair of the LME49710HA, then you haven't heard them in the Jaycar HA. You most likely heard the dual metal can version LM4562HA/LME49720HA Digikey has the single version LME49710HA for around US$11 each, but P and P could be a killer. Alex
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Post by fault151 on Feb 26, 2010 11:09:18 GMT
Right sorry i'm getting confused with all the different versions. Yes i think your right, it would have been the LM4562HA as it definitely wasn't on a browndog board.
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robertkd
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Post by robertkd on Feb 26, 2010 11:59:12 GMT
They are EXPENSIVE capacitors Mark, if you want to ditch the input electrolytic capacitors try some polyester or polypropylene capacitors and you don't have to pay mega $ for them. I know Alex says to ditch the input capacitors and for some of the philosophy sure, but doing so is fought with danger unless you are certain of the output characteristics of the equipment your using as a source
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Post by Deleted on Feb 26, 2010 12:10:47 GMT
They are EXPENSIVE capacitors Mark, if you want to ditch the input electrolytic capacitors try some polyester or polypropylene capacitors and you don't have to pay mega $ for them. I know Alex says to ditch the input capacitors and for some of the philosophy sure, but doing so is fought with danger unless you are certain of the output characteristics of the equipment your using as a source Robert I did say this "you would most likely be able to get rid of the input capacitors. (assuming that there is no more than a few millivolts DC from the source )" However, perhaps I should have been more explicit . Alex
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robertkd
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Post by robertkd on Feb 26, 2010 12:16:03 GMT
;D
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Post by punkjr on Jun 1, 2010 11:31:50 GMT
okay, my first serious attempt at a build. here is the scha with all of the sandyk mods, except the jlh. sound is unbelievable, i can't stop using it.
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Post by corky on Sept 10, 2010 13:56:21 GMT
Well i finally got around to finishing my SCHA-take 2. After sitting on this project for a good 12 months i have sort of almost finished it My first attempt is here rockgrotto.proboards.com/index.cgi?action=display&board=chitchat&thread=3729&page=6#45774 It's still working well but i felt i needed to try it all out again. This time around I mostly followed the AK suggestions. Main points are; -most electros are Panasonic FM series (FC if values were not available in FM) -matched 2SC5171/2SA1930 -all other transistors are matched in amp and JLH(All selected from bulk buys of 100 or more! ) -if you look at the output I have made it easy to swap out the output resistors -most notable inclusion is the volume controller with LCD display. I got it from DIYaudio forums ages ago, finally found a project to put it in! -10uF input caps have a switch to bypass them. I wanted to get rid of them but was still worried about possible DC from a source that i might not be 100% on. The front panel looks dodgy because you can see i scratched it twice when i was cutting out for the LCD. So i started sanding it back, with the intention of repainting it and that was taking too long, decided to do that later, most likely never:)
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Post by oohms on Sept 23, 2010 14:11:47 GMT
SCHA in a 3.5" external hard drive enclosure Minimal mods, gain to 4.7, larger low ESR caps, changed values on HF filtering caps (1.2nf for input LPF, 47pf for opamp feedback LPF) The black box attached to the PCB is a switchmode PSU, 12 to +/-15v - makes less audible noise than any linear PSU i have had
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Post by lark on May 19, 2011 13:04:32 GMT
Far from complete - electronically it's almost there. All the wiring is just a temporary bench test setup.. The caps on the JLH are a bit ...... squashed .. but not too bad.. Thanks have to go to all the help I've received on this forum, especially Alex.. Now to build the enclosure..
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Post by Deleted on May 19, 2011 14:21:41 GMT
Looking good Is that an USB input/DAC board I spy? If yes please tell where you found it, I may have use for that. Cheers Attachments:
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Post by lark on May 19, 2011 23:59:20 GMT
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Post by Deleted on May 20, 2011 0:58:17 GMT
lark I would recommend separate screened leads for the L and R inputs throughout to maximise channel separation.I realise it is more fiddly to implement though. All these little attention to detail things add up. Alex
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Post by lark on May 20, 2011 1:23:17 GMT
lark I would recommend separate screened leads for the L and R inputs throughout to maximise channel separation.I realise it is more fiddly to implement though. All these little attention to detail things add up. Alex Certainly - this is only my on bench test setup - that was the audio cable I had handy. I will have much shorter cable lengths and proper shielded runs for L and R throughout. I'm waiting until I get my enclosure built before I put too much effort into the cabling.. Thanks for the heads-up though! Cheers.
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Post by Deleted on May 20, 2011 13:32:05 GMT
Ta! I was thinking of possibly adding this and an SD card reader input to my SCHA, along with input switching. I'd have to re-case it though as I've no more room inside, just to make it more flexible without extra boxes... Maybe one of these
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Post by lark on May 20, 2011 15:40:16 GMT
I'm wanting something similar but how do you choose your music (effectively) with these.. It really needs a high res touch screen - I'm thinking of integrating (gut and fit) a cheap second hand old Android phone to drive the dac..... Hmm...
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Post by Deleted on May 20, 2011 15:54:48 GMT
Absolutely. The general idea you mention has been used by a couple of folk here, can't remember who or where though. My intended use would be far more casual, not requiring total ease of access. I'm supposed to be building a Music PC for serious and copious amounts music listening
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Post by lark on May 22, 2011 11:07:31 GMT
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Post by Deleted on May 22, 2011 11:42:24 GMT
Very innovative ! Doesn't look too bad either.
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Post by lark on May 22, 2011 12:49:56 GMT
Thanks, but don't worry, I carefully selected the shots that emphasised its ugliness factor the least..
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Post by Deleted on Jun 6, 2012 12:40:16 GMT
After huge delays, due to lack of spare time, and a final problem which was sorted with Alexs kind help, I have finally finished my SCHA re-work. The idea was to have a decent quality USB input married up to the amp, reinstate output resistance selector, other input switching and generally improve layout and quality, without getting toooooo huge. I decided to make my own case again, in the same vein as my original but much larger, to accommodate the extra gubbins and make any reworking/future ideas much easier. First chop up some steel with preplanned holes for everything in place; CHASSIS FRONT/REAR/TOP/LEGS Form the chassis Spray it all up Stack in transformers, one for the Amp, two for the usb Stack in Alans trusty PSU/JLH hybrids; 15v/cricket 3.3v for Wills PK oscillator, 3.6v for PK sabre chip 3.3v for usb->I2S board Said digital stack in situ and shielding from main power section PSU and JLH for amp mounted vertically on shield, amp to go in vertically on opposite side of same shield (also shows parts bin rescue of cable link selector switch) DONE! ...finally, courtesy of photo prog, what does what...
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elysion
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Post by elysion on Jun 6, 2012 14:18:22 GMT
Very nice case, Chris. I remember also another case from you, I don't recall exactly what is was (most likely a tube amp I guess), which was also a beauty. I like your case style. Larks temporary housing for the SCHA also doesn't look that bad. It's still a good achievement IMO. Maybe some paint spraying would enhance it in case the final case would be delayed.
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