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Post by Deleted on Feb 1, 2010 9:26:26 GMT
The JLH will improve it right across the range, as well as improving channel separation.
Let's see what Jeff has to say, now that his is working in that state.
Alex
P.S. I am using LME49710 for the 2 output opamps, and OPA134 for the other 4. Did you also fit a 4n7 MKP to pin 22 of the DIR9001 ?
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Post by jeffc on Feb 1, 2010 12:00:53 GMT
Better still I'm let Spirit comment.... He's just listened to a dozen tracks or so with my SC-DAC fed s/pdif from my old Rotel RCD965BX, and it supplying a Charlize T-amp via a 10K ladder attenuator, playing through my DIY NXT panel prototypes.  I got excited and played a few tracks a little louder than I should have...  I hope his young hearing wasn't damaged....  cheers.. jeffc |
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Spirit
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Post by Spirit on Feb 1, 2010 12:43:33 GMT
Well... the trouble with commenting on the sc dac in Jeff's setup, is that I don't know what any of the other components sound like. Case in point would be the DIY NXT panels... anything I describe will mostly be the effects of the nxt panels  Having said that, the sound was incredibly dynamic, diffuse (nxt panels at work), and instrument separation was good (even if you couldn't pinpoint where each one was), . I enjoyed the sound a lot, but as I said... my 'review' is very biased by the panels. They're have amazing VFM - they're the speaker equivalent of the hd681s Sorry I couldn't be more helpful. Next time I go round, I'm hoping it'll be with a Buffalo2, and my soundcard to compare to. |
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Post by bpgoa on Feb 1, 2010 16:56:50 GMT
The JLH will improve it right across the range, as well as improving channel separation. Let's see what Jeff has to say, now that his is working in that state. Alex P.S. I am using LME49710 for the 2 output opamps, and OPA134 for the other 4. Did you also fit a 4n7 MKP to pin 22 of the DIR9001 ? Hi Alex, yes i did fit the other MKP Cap.... and it is sounding a bit better today... can't wait to fit the JLH's... meant to say ... Amp is a Krell KAV 300I interconnects are Transparent Music link plus Speaker cables are Transparent Musicwave biwire speakers are B&W Nautilus 804s Adrian. |
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Post by bpgoa on Feb 1, 2010 20:49:34 GMT
No bloody wonder I had trouble initially getting my blue LEDs to work.  I used the magazine article itself from October 2009 page 39 , where there was no mention of bending the Blue LED leads. I must admit that I did see some reference to this in the amended copy included with the Jaycar kit, but I knew better, didn't I ?  I cheated... I covered the pad and LED leads with rework flux and flooded the solder in off the iron... not in the text book but worked for me  |
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Will
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Post by Will on Feb 2, 2010 21:14:10 GMT
Hi Gents, Here is the pcb for the op-amp based PSU. I've created two versions, one for those that have easy access to 5mm pitch 10uF film caps, and another that allows a variety of different types at the same position, depending on what can be sourced locally. More info and etch files, and a version that allows C3 with 3mm - 15mm lead pitch, etc, here.If you make any of these boards, I'd appreciate your thoughts and feedback, so that I can correct any shortcomings. |
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Post by Deleted on Feb 2, 2010 21:40:18 GMT
Will On reflection, it may have been better to make the lead pitch for C3 , 5mm or 15mm. It's easy enough to form the leads of an electro to fit a 5mm spacing, and this could then make this PCB a universal PCB. Regards Alex. P.S. I like the possibility of using 5mm spaced input and output terminal blocks to avoid the need for soldering connections. The next thing we know, is that some enterprising gent may end up supplying the PCBs already assembled, and people could connect them together like Lego blocks,as in a Twisted Pear concoction. Perhaps even supply precut and tinned connecting leads too ? |
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Will
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Post by Will on Feb 2, 2010 21:58:33 GMT
Nice idea, but as soon as You, Alfred, Jeff, Adrian, Chris and Andy have bought them, the market will have dried up!
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Post by Deleted on Feb 2, 2010 22:09:54 GMT
Nice idea, but as soon as You, Alfred, Jeff, Adrian, Chris and Andy have bought them, the market will have dried up! Will I was just being mischievous !  Alex |
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Post by Deleted on Feb 3, 2010 1:26:18 GMT
Nice idea, but as soon as You, Alfred, Jeff, Adrian, Chris and Andy have bought them, the market will have dried up! Only 7 members on board so far Come on guys, there must be plenty of peeps who need this. For your own sanity and for your musical future. Your forum, your music, NEEDS YOU. You know in your heart it's all going this way. (Not sure Will needs any more pressure on his leisure time though ) |
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Will
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Post by Will on Feb 3, 2010 20:23:34 GMT
Definitely a case of the more the merrier, Chris  |
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Post by jeffc on Feb 6, 2010 6:00:17 GMT
Guys.
As I've got a stash of small vero boards, I'm building some AK-crickets P-to-P to supply the DSD1796 DAC chip Vdd and a VCXO. Alex sent me build parts including a couple of 3.3V zener diodes and I 've since got a couple more 1N746s of another brand. With the R1 = 2.2K and +15.11V from the PSU, this gave 2.79V. Worked my way down through lower values I had and a 560R was needed before I could get close to 3.3V (3.29V). Same with either zener.
cheers.. jeffc
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Post by Deleted on Feb 6, 2010 6:45:56 GMT
Jeff
It's a shame that we have been unable to readily obtain the BZX55C3V3 as used in the Class A. The test current with them is only 5mA as per the schematic.
Alex
BZX55C3V3 VZ =3.1 to 3.5V ZZ @ IZ =85 ohms Test Current IZ =5mA
Farnell AU
368921
FAIRCHILD SEMICONDUCTOR
BZX55-C3V3. DIODE, ZENER 500MW 3.3V
Voltage Vz:3.3V; Alternate Case Style:SOD-27; Case Style:DO-35; Diode Type:Zener; External Diameter:2mm; External Length / Height:4.8mm; Available until stocks are exhausted Alternative available;
AU 1478
UK 0
1 Each 5+ $0.05
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Post by jeffc on Feb 6, 2010 7:51:25 GMT
Bugger Alex, And I just got an order delivered from Farnell last week. Are the 2 x AK-crickets I've just built, with the 3.3V zeners I've used, and the 560R R1 to get ~3.3V, OK for supplying the DAC and CVXO? ;D Thanks.. jeffc |
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Post by Deleted on Feb 6, 2010 8:02:40 GMT
Jeff
Have you checked the output voltage with a suitable opamp plugged in ?
If the voltage out checks O.K. I would initially try at the link which feeds 3.3V to the DAC PCB via the cable.
Alex
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Post by jeffc on Feb 6, 2010 11:25:49 GMT
no change in voltage (3.29V) measured on the output of an LME49710 so ....... time to test ....... as soon as I muster the courage.... |
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Post by Deleted on Feb 6, 2010 11:38:37 GMT
no change in voltage (3.29V) measured on the output of an LME49710 so ....... time to test ....... as soon as I muster the courage.... Jeff You could always try it first with the oscillator module,but not connected to the input PCB, and keep tabs on the temperature of the opamp. If you are really worried, you could fit a 4.3V or 4.7V 1W Zener across the output. Ask Alfred what to expect, and which opamp he used. Alex |
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Will
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Post by Will on Feb 6, 2010 12:41:05 GMT
Guys. As I've got a stash of small vero boards, I'm building some AK-crickets P-to-P to supply the DSD1796 DAC chip Vdd and a VCXO. Alex sent me build parts including a couple of 3.3V zener diodes and I 've since got a couple more 1N746s of another brand. With the R1 = 2.2K and +15.11V from the PSU, this gave 2.79V. Worked my way down through lower values I had and a 560R was needed before I could get close to 3.3V (3.29V). Same with either zener. cheers.. jeffc Thanks for the info Jeff. Did you get your courage up to try it? I did feel a slight disturbance in the the force If you guys want some of those BZX55 C3V3 zeners sending over, just let me know, I have plenty left over from the Class A build, and I'll get some to you, it's the least I can do |
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Post by Deleted on Feb 6, 2010 20:26:52 GMT
Will It would be much easier for us downunder to get some from Farnell at 5c each with free postage, althoughpersonally, I would make a reasonable sized order to be fair to Farnell. I find it amazing that Zener diodes of the same wattage can have such a huge gap between reference currents. We are talking 4 times higher with the 1N746 ! Alex |
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Post by Deleted on Feb 10, 2010 16:03:36 GMT
still waiting for mine! Will, did you get stung for import duty? turned up today... £5.19 duty and £13.00 to collect the duty (thieves) Adrian Mine has just rolled up in the UK. Those sweet guys at customs have stung me £18.81. Still, I saved more than three times that by ordering via the UK, so can't moan.....too much |
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Will
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Post by Will on Feb 10, 2010 16:57:31 GMT
The cheek of it! You don't even live in the UK, and they're taxing you |
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Post by bpgoa on Feb 11, 2010 23:58:24 GMT
between farnels and cricklewoods, i parted with a lot of dinero late last night to buy enough components for 4 JLH's , two crikets and one new clock source. done my usual trick of forgetting one / two components!!!
in the words of the great yellow prophet.... "doh!"
now to place that remedial order for the screw terminals and ferite beads!!!
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Post by alchemy on Feb 14, 2010 11:06:40 GMT
Now I am certain that the reqiurement of old age is lists, the other quality of old age is you can't remember where you put them ;D  |
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Post by jeffc on Feb 16, 2010 11:41:06 GMT
Small update, 4 x I/V stage LME49710s I'd soldered in have just been swapped out for the kit OPA134s. I'd thought ths SC-DAC was sounding pretty good .... but a quick listen and its immediately obvious these provide much nicer overall SQ. Hopefully further improvements after some burn in. AK-crickets next. ;D cheers..jeffc |
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Post by Deleted on Feb 19, 2010 6:29:28 GMT
Another small update.
This morning I replaced the 2 x LME49710 output I.C.s with the LME49710HA metal can types.( the other 4 are OPA134)
I soldered them in as they will definitely be keepers.
I was immediately surprised at how much better they sounded than the plastic versions. Even when listening to DTV, the sound was much more 3D sounding. Hopefully, there will be even further improvements up to 48 hours of use, as in the SC HA when LME49720HA/LM4562HA were fitted.
Being single devices, they run cooler than the LME49720/LM4562HA , and no heatsink needs to be fitted.
Alex
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