leo
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Post by leo on Mar 7, 2010 8:51:22 GMT
Better see what single op-amps I have ;D P.S. We are using 2 ferrite beads. One on each side of the small loop is easy to do. The X-DAC V3 uses several special encapsulated devices, which appear to be 2 FBs done this way. I would suggest 2 beads for the oscillator module, but the normal PSU is unlikely to be critical. Ok ta, thats easy enough to do, regarding the caps in the X-dac I presume the ones you mean are ceramic T-networks?
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Post by leo on Mar 7, 2010 8:47:08 GMT
Alex,
Ok ta, The zener values was wrong anyway, I just fitted one I had to allow easy testing (to make sure it works) into a light load. May call in maplins today later on to see if they have any 3v3's
Leo
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Post by leo on Mar 7, 2010 0:46:29 GMT
Better see what single op-amps I have ;D
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Post by leo on Mar 6, 2010 23:25:41 GMT
Ok dokey thanks, should be fun, you know me always honest
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Post by leo on Mar 6, 2010 22:50:21 GMT
More manufacturers should be doing this, it works out better both ends
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Post by leo on Mar 6, 2010 22:46:56 GMT
I knew from the start far less would be trying the Sabre dacs and especially the PH regulation, I simply posted a few impressions and pics, if I felt more would be interested or had requests like on another forum I'd have done a full list of mods on here. I'd have thought far more would be interested in this cheaper kit. Leo Unfortunately, it is still early days with the SC DAC, with Will,and Chris yet to start, and Adrian not even up to the point of a JLH yet. With the Sabre DACs, I think that Will may have posted many experiments with shunt regulators, and the Salas was judged to be the best of the cheaper shunt regs.Are any of these other shunt regs still in use ? Alex Alex, Probably why I'm trying to hold off getting the SC kit for now because I'd probably have it built in a day and be fiddling later that evening A good shunt reg is hard to diy and keep stable imo so I didn't personally experiment with many types, the Burson ones was pretty decent but they are ready built. I think Will still does use the Salas in some locations. Leo
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Post by leo on Mar 6, 2010 22:25:01 GMT
A good thought Leo... - the SCHA mods thread was very useful indeed when building mine. Do we have something like that in the RG "ESS Saber DAC" thread ? I knew from the start far less would be trying the Sabre dacs and especially the PH regulation, I simply posted a few impressions and pics, if I felt more would be interested or had requests like on another forum I'd have done a full list of mods on here. I'd have thought far more would be interested in this cheaper kit. Infact in all honesty I wish I'd never posted about the Buffalo or PH regs over on here
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Post by leo on Mar 6, 2010 17:40:06 GMT
Happy Birthday
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Post by leo on Mar 6, 2010 17:39:36 GMT
Many Happy Returns
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Post by leo on Mar 6, 2010 11:43:19 GMT
Just an observation is all, as we know some are quicker than others at trying things, some may take weeks longer even months, by then you've had a lot more emails , posts added etc Anyway it was just a thought
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Post by leo on Mar 6, 2010 11:38:08 GMT
Just had a look at the top view pic, I can't see any extra mosfets so I presume they are just used as added heatsinks to the standard ones? using that metal spacer to transfer the heat to the extra pair isn't going to be very effective, for those good with metal work ;D it maybe worth cutting a piece of flat aluminum to wedge between the heatsinks with a hole drilled in the middle, bit of heatsink compound added each end and a longer M3 bolt through clamping it all together
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Post by leo on Mar 6, 2010 11:20:52 GMT
, they were a MAJOR dissapointment compared to the Senn HD-250 I had just been listening to. Most things are mate IMO anyway, I do read all these threads with interest and hoping one day one of you will post I've found something as good or better than the HD250's. I love these cans and find it hard going to anything less tbh which is a PIA because the 250's are like hens teath
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Post by leo on Mar 6, 2010 11:13:53 GMT
Obviously little etched pcbs look far nicer but at least they are easy to build p2p on vero
Regarding the 10uf, I'll dig the datasheets out but I'm wondering if the larger 10uf is rolled film and the lower 4.7uf is stacked? if so I'd prefer the stacked for decoupling, should be lower inductance
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Post by leo on Mar 6, 2010 11:08:48 GMT
Even cheap op-amps could be used for the error amp in the crickets so it wouldn't be expensive to make quite a few of them Leo So when are you going to make some ? ;D The big 10uF could also be scaled down to 4.7uF if hard to obtain. The main thing slowing me down from making more is that I am having trouble getting more DP50 +VE Developer sachets. Alex If I get one of these dacs I'd build a few crickets on vero at the same time, one would be used for comparing error amps mainly to see how cheap it can go before performance takes a hit. The problem with threads like these is that they tend to get big, very big and often any updates for mods etc usually get lost, I'd personally start a new thread for the mods and edit the first post adding any extra worthwhile things on there so its easy to find especially for us lazy buggers who can't be bothered reading through all the posts
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Post by leo on Mar 6, 2010 11:00:11 GMT
Well it looks nice but the way the extra heatsinks have been implemented LOOK odd, I just hope its the picture being misleading , only other guess is that theres another pair of Mosfets on the other side of the back heatsinks? maybe they are doubling those up too?
Only other thing is how close those blue capacitors are to the heatsinks , I presume those are the coupling caps? hopefully the caps used are high temp types, remember how hot those heatsinks get (especially the LM317's ) and heat is no good at all for caps, having those electrically leaky would be bad for your cans if they are coupling caps, also noise issues
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Post by leo on Mar 6, 2010 10:46:32 GMT
The regulation quality for CS8412/4 and 6 used to have a noticeable effect on performance especially on its analogue supply so I'd imagine the DIR9001 would be the same Looks like the reg for the DIR9001 also supplies the DSD1796's vDD supply, I'd isolate the dacs 5v vCC and 3v3 vDD supply keeping the DIR9001 on its own line Leo We have already fixed the 3.3V supply to the DAC (VDD) with the 1st Cricket. 5Vcc is derived from +15V via a JLH ,then the DAC PCBs own 5V regulator, (7805) Alex Ok, obviously wrong jumping in this far of the thread, I'll bow out and let you carry on
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Post by leo on Mar 6, 2010 10:44:08 GMT
Even cheap op-amps could be used for the error amp in the crickets so it wouldn't be expensive to make quite a few of them
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Post by leo on Mar 6, 2010 10:40:51 GMT
I'd be very surprised if not tbh Leo I was thinking especially of more accurate timing from the 74HCU04, as well as less noise from the Toslink and SPDIF areas. Alex Just looking at the schematic, talk about skimping on the regs at least its not too hard to improve
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Post by leo on Mar 6, 2010 10:13:05 GMT
Jeff Seeing that the 5V from the Cricket will be derived from +15V via the JLH, perhaps you should try relocating your 5V JLH, to in line with the +5V that supplies the Optical and SPDIF inputs on the Input PCB.This MAY be beneficial with respect to derived data feeding the DIR9001 ? Alex I'd be very surprised if not tbh
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Post by leo on Mar 6, 2010 10:06:19 GMT
The regulation quality for CS8412/4 and 6 used to have a noticeable effect on performance especially on its analogue supply so I'd imagine the DIR9001 would be the same
Looks like the reg for the DIR9001 also supplies the DSD1796's vDD supply, I'd isolate the dacs 5v vCC and 3v3 vDD supply keeping the DIR9001 on its own line
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Post by leo on Mar 5, 2010 23:24:37 GMT
Yes, Leo, but they tied together some PS so it made it difficult to experiment with different & separate supplies to all the PS pins on this DAC. Still don't know if they have achieved this with the current incarnation? Such a shame they are so secretive, also don't seem to like advice even from those with lots of experience in psu and regulation design. To illustrate - I'm just re-reading a really interesting thread on Diyhifi.org that I read a number of times before & in it Gordon Rankin states that different oscillators work better with different supplies - some clocks work better with feedback regulators & others not, some perform better at 3.2V rather than 3.3V I do know the shunt reg was noticeably better than the stock LT1763 for the XO, I remember comparing in each of these positions, I may try converting a PF flea to 3v3 and give that a go here , the XO is certainly one part I want to add a separate raw supply to its reg
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Post by leo on Mar 5, 2010 23:02:44 GMT
I agree Alex - it took a lot of extra expense to get a good performance out of the Buffalo but maybe this could be also be achieved at a reasonable cost? By arrogantly insisting on the un-impeachable sound quality of their implementation, the TP guys held back the experimentation necessary to push this DAC & realise if it is capable of a stellar performance for a reasonable price. Pioneers like Leo & others did this despite the poo-pooing of the Twisted Pair (Russ mainly) & I suspect arrogant commercialism was at the heart of this & still is at the heart of the new Buffalo implementation. This experimentation is becoming more feasible now with others offering modular ESS DAC boards/implementations which should help in teasing out what are the critical elements to achieving best sound out of this ESS DAC. I know all about the poo-pooing mate, I do try my best to be nice although sometimes it can be bloody hard work at the end of the day if I think something isn't as good as it could be I'll be honest about it and will fiddle until I'm happy, of course this tends to annoy a certain few
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Post by leo on Mar 5, 2010 22:42:14 GMT
Any comparisons would be made fair, its Lego blocks remember jus a simple case of swapping things about , the regs would be no problem to change around
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Post by leo on Mar 5, 2010 19:57:09 GMT
Thats weird, I had it in my head you was younger than me for some reason BTW this is getting crazy, I have three more dacs to try yet ;D
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Post by leo on Mar 5, 2010 19:33:45 GMT
I think more people prefer lego block type build especially when the components used are 90% SMD BTW Will, I noticed even the raw supply for the AVCC before the regs has an influence on the SQ mainly the big cap after the rectifiers.Its honestly worth comparing a few types here. I currently have one traffo supplying AVCC,XO , digital supply and dac core, even though each now has shunts I want to run each on a separate secondary so I'm on the hunt for a suitable traffo. When are you guys going to try Lithium Nano Phosphate batteries instead of phaffing around with regulators ;D do I have to do all the hard work around here & buy a PH myself to do the comparison Ok, if you're going to stick with mains fed PS here's an idea that might be of interest - a stepped rectifier supply (see attached pic). This is from the fevered brow of -ecdesigns- over on DIYA. Here's his explanation: Interesting, can't say I've tried this tbh
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