New HQ DIY DAC

[Deleted]

May 12, 2010 14:01:06 GMT @cjarchez said:

I've now received enough parts to build the JLHs for the DAC.

Just one question before I proceed....

The single JLH for the +5v supply, does it need any component changes from the +15v version?

Thanks in advance,

Chris

Hi Chris
The JLH isn't as quite effective at 5V , but it will still give a worthwhile improvement without any component changes. Just remember to check the voltages using the Troubleshooting chart on completion.
The reading of almost 1.8V is important, as it is from 3 transistor base and emitter junctions in series.
Alex

[Deleted]

Alex,

Cheers matey.

Still moving home? I bet your pretty creamed by now!

Chris

[Deleted]

May 12, 2010 22:16:35 GMT @cjarchez said:

Alex,

Cheers matey.

Still moving home? I bet your pretty creamed by now!

Chris

Hi Chris
Still slowly moving lots of the smaller stuff. It's amazing how much junk you can accumulate so quickly. June 2nd is the final day at the existing location. I am looking forward to listening to music again, but it will take a little while to fully set up again.
Alex

[Deleted]

Just remember to check the voltages using the Troubleshooting chart on completion.

It's on my hard disk somewhere
Could anyone point me to it

Alex, I'm without louspeaker music too, sold on my old set and have new ones (to me) awaiting assembly/setup.
Need time!

[Deleted]

May 13, 2010 1:31:10 GMT @cjarchez said:

Just remember to check the voltages using the Troubleshooting chart on completion.

It's on my hard disk somewhere
Could anyone point me to it

Alex, I'm without louspeaker music too, sold on my old set and have new ones (to me) awaiting assembly/setup.
Need time!

Hi Chris
Try the attached link.
The board layout you are using is likely to be different, but you should be able to work it out.
Alex

P.S.
During the changeover, I am using the Class A HA to listen to TV with headphones. Sounds much better than the inbuilt speakers of the TV !

img149.imageshack.us/img149/9346/linsleyhoodpsutroubleshsq0.jpg

[Deleted]

Aha, I didn't look under SCHA, DOH!

Thanks again Alex.

Chris

ps TV is running through my wifes system, the kids new Wii sounds fun in through it too!

[Deleted]

The JLHs are in! One double and a single. The sound quality has taken a very pleasing leap. I have yet to compare it to the on-board DAC of my 506.24, should be interesting.

I ran out of 5mm pitch poly caps, so I had to get a little funky with the single JLH....



The DAC, though still a bit makeshift in it's temporary home is currently looking like this...



It's definitely getting there

[Deleted]

Hi Chris
It will further improve when you fit 2 single or 1 dual "Crickets", for the 3.3V rails on both PCBs. Don't forget that the SQ will cycle up and down for a few days as the JLH's big electros form.You will need at least 48 hours on them to do this. A future improvement could be replacing the 2 output I.C.s on the Analogue OUT PCB with 2 x LME49710HA.
Alex

[mrarroyo]

You guys rule! I wish I had the ability and patience to build something like this. Cheers.

[jeffc]

Another small step for man....

After revisiting the manual, I noted that the designer Nicholas Vinen mentions that cap values either side of the DAC PCB 7805 IC should be increased to negate 7805 manufacturer variations that can affect THD. As I’ve been using the 7805 IC on the Jaycar PSU to supply 5V the DAC via a JLH, and using cap values lower than he recommends (56uf Panasonic FM/10uf Oscon), and that were probably not ideal types anyway in this application, I swapped the Oscon for the 56uf cap and placed a 100uf Suntan upstream of the IC. Outcome... after overnight cap forming.. really good.. slightly insipid and etched midrange now smoothed so vocals much nicer with no real downsides.

Seeing I was in test mode, and as I recently picked up 20 disposable cameras for $20 at the local photo developing lab, various brands all with flashes to get a stash of flash caps (80uf, 100uf, 120uf x 330V, most with long leads), I thought why not test a couple. Easiest for a quick and dirty test was to stick 2 x 80uf caps in the terminal blocks of the dual JLH supplying +/-15V to the I/V and output opamp section on the DAC PCB. Wasn’t expecting much as the beaut JLH given to me by Alex simulates 1F of capacitance here, however, the differences/improvements were instant and dramatic.. I was gob-smacked TBH, dynamics and attack of instruments and particularly percussion grab you and nuances hidden before appear with gusto so that laid-back tracks come alive with vibrancy and up-tempo tracks grab you with speed and energy that compel your feet to tap....

... SC-DAC meets Flash cap Gordon

With anticipation I then decided to stick a 120uf flash cap in the terminal block of the receiver PCB being supplied 5V from the Jaycar PSU via a single JLH, and now also feeding the DAC 5V supplies. Not so dramatic changes here but again perceived better sonics, and certainly no perceived downsides.

All up I now have what I think is a much better sounding SC-DAC for the $3 investment. If impressions stay the same over the next few weeks, the caps will find more permanent homes soldered to the underside of the PCBs.

Guys you gotta try this, I don’t think you’ll be disappointed, the added aliveness is terrific.

And I can see me playing about more with these flash caps, next in my T-amp, as I now have the odd one or 17 lying about.

cheers..jeffc

[Deleted]

Hi Jeff
Don't get too carried away until you compare the beast with Phil's Buffalo. "Feral" may be exciting, but most likely not accurate, and perhaps a personal taste.When someone whose opinion you respect says it has an Analogue sound about it and is still very revealing, then you know you are getting there. I think that you will find that is the case with Phil's Buffalo too.
Alex

[jeffc]

Hi Alex,

You know me, the closer to "feral crash-bang-wallop", the closer to "real" for me as that's what I think reproduced music lacks, as well as resolution, real live transient attack.

I'm playing the SC-DAC direct into a 10K ladder attenuator to my Charlize 2020 T-amp feeding stiffened carboard NXT panels now with naked piezo tweeters, free in air, each mounted via its bimorph to a small carboard extension with double-sided tape, zero crossover parts... almost like headphones. Nonconventional but NO BOX COLOURATIONS and no compressed toneless bass. If only I could get more volume.. but plans are afoot for 190 cm x 76 cm NXT panels made of 1 cm thick VH EPS of all things ($57 for 7 sheets so no drama if they fail, and spare sheets for additional speakers if they work as planned) that hopefully will get me that vol and even wilder transient attack.

The SC-DAC vs Phil's PH regulator-decorated Buffalo II DAC comparison will be interesting no doubt.. old school vs new school ... and in price and technology the SC-DAC should have no right even being in the race, and I expect it will be bettered in most aspects.. but hop-too, there must be a few more mods we can look at to ring the neck of this thing for whatever its SQ potential is.

cheers.. jeffc

[Deleted]

Hi Jeff
No offence, but I think you may need to feed both DACs into something more conventional for the big test. I gather that some of your friend's have some pretty upmarket gear, and extra pairs of ears make for much better positive feedback.
I am counting on Phil's Buffalo revealing the remaining weaknesses of the SC DAC, so it may be a good idea to go easy on the flash caps for the moment ?
Rest assured that we ain't done yet ! Don't forget that the Buffalo has more transformers and PSUs than the SC DAC, and we can still easily squeeze in a separate toroidal purely for the JLHs feeding the digital area .
Irrespective, ours will have cost much less, and it is very rewarding to achieve such high quality from a relatively cheap unit.
Alex

[Spirit]

Jun 5, 2010 12:13:42 GMT @sandyk said:

I think you may need to feed both DACs into something more conventional for the big test. I gather that some of your friend's have some pretty upmarket gear, and extra pairs of ears make for much better positive feedback.

Don't worry Alex... said friends have been briefed and are looking forward to the audition almost as much as we are

[leo]

I'll soon be hearing how great this BuffaloII is

[Spirit]

Jun 5, 2010 23:49:17 GMT leo said:

I'll soon be hearing how great this BuffaloII is

Sahweet.

Looking forward to your thoughts Leo

(Not that I'll be able to change anything till after UK trip mind you )

[Will]

Huzzah! Another SC Dac lives (well, after you get the right chips in the right place, but enough of that )

I've built it stock first, and it sounds OK. Dark, rich and cosy springs to mind, similar to my Arcam Alpha CD player.

Trouble is, it's too dark and rich for me, needs to be clear and quick, so now looking to change the opa124's on output to lm48910HA, and change the filter setup.

Also, if anyone is interested, I'm getting some AK crickets made up (the op-amp psu), so please PM if interested (although doubtful, at this late stage)

[Deleted]

Jul 2, 2010 12:02:59 GMT Will said:

Huzzah! Another SC Dac lives (well, after you get the right chips in the right place, but enough of that )

I've built it stock first, and it sounds OK. Dark, rich and cosy springs to mind, similar to my Arcam Alpha CD player.

Trouble is, it's too dark and rich for me, needs to be clear and quick, so now looking to change the opa124's on output to lm48910HA, and change the filter setup.

Also, if anyone is interested, I'm getting some AK crickets made up (the op-amp psu), so please PM if interested (although doubtful, at this late stage)

Will
Are you using any JLHs yet ?
Just using a JLH for the +-15V supply to the DAC will open up the soundstage and improve channel separation and HF detail.
Alex

[Will]

Alex,

Yep I'm using a JLH for the 15V supply, and feeding it into my SCHA, which I'll be using with the dac.

It's probably why it sounds better than I thought it would.

[Deleted]

Jul 2, 2010 12:02:59 GMT Will said:

Huzzah! Another SC Dac lives (well, after you get the right chips in the right place, but enough of that )

I've built it stock first, and it sounds OK. Dark, rich and cosy springs to mind, similar to my Arcam Alpha CD player.

Trouble is, it's too dark and rich for me, needs to be clear and quick, so now looking to change the opa124's on output to lm49710HA, and change the filter setup.

Also, if anyone is interested, I'm getting some AK crickets made up (the op-amp psu), so please PM if interested (although doubtful, at this late stage)

Welcome to the party!
When I first put mine together in stock form it was as you say, I'd call it laid back, almost lazy!

Mine has since had most of Alexs board mods, twin and single JLHs added, and the, LM49710HAs on the outputs. Each addition has lifted it from the shadows a degree at a time. Mine is still on the warm side with a noticable vagueness in the mid range. Obviously I'm hoping a couple of tweaks left to do on the O/P board, the AK crickets and the extra psu will bring it up to where it should be.

As it stands it is way ahead of the on-board dac in my Marantz CD52II and starting to close the gap on my Meridian 506.24. So pretty satisfied with progress so far, not to mention that I've got this far with no problems! Which is completely thanks to all the great info posted here, so, er, thanks!

[Deleted]

Hi all,

I have decided to join in !! I picked up an Altronics kit today.

Don't tell Alex, he might think I was impressed with his when I heard it a couple of weeks ago.

regards

[Deleted]

Sept 16, 2010 8:50:36 GMT @gregerskine said:

Hi all,

I have decided to join in !! I picked up an Altronics kit today.

Don't tell Alex, he might think I was impressed with his when I heard it a couple of weeks ago.

regards

Greg
At least you won't have to wait for the new JLH GB !
Do yourself a favour though, and get polyprops for the DAC PCB as per the Tweaks Thread. Then forget the original draconian filtering and go directly to the simplified wide band filtering as in the Tweaks Thread . (from DSD1792 data sheet.) You will see that the other RG members prefer that too.
BTW, if you need 2 x LME49710HA for the output devices, then I owe you a couple for your much appreciated efforts with the JLH PCB.
Regards
Alex

[mrarroyo]

Stop it guys, this project fills idiots like me who have no ability to build it with envy.

[Deleted]

Sept 16, 2010 10:44:43 GMT mrarroyo said:

Stop it guys, this project fills idiots like me who have no ability to build it with envy.

Miguel,

I have recently switched back to using only a Marantz CD52II, as my system is all packed away. It sounds AWFUL after the SCHQDAC being taken out of line, plus mine is not up to full mod. spec. yet...

.....maybe you can persuade Alex to make you one

[Deleted]

Sept 16, 2010 9:56:34 GMT @sandyk said:

Sept 16, 2010 8:50:36 GMT @gregerskine said:

Hi all,

I have decided to join in !! I picked up an Altronics kit today.

Don't tell Alex, he might think I was impressed with his when I heard it a couple of weeks ago.

regards

Greg
At least you won't have to wait for the new JLH GB !
Do yourself a favour though, and get polyprops for the DAC PCB as per the Tweaks Thread. Then forget the original draconian filtering and go directly to the simplified wide band filtering as in the Tweaks Thread . (from DSD1792 data sheet.) You will see that the other RG members prefer that too.
BTW, if you need 2 x LME49710HA for the output devices, then I owe you a couple for your much appreciated efforts with the JLH PCB.
Regards
Alex

Thanks Alex. I have been reading the threads, trying to digest the info and will have some questions.

regards