If that may help, a french test of such "top" opamp.
https://jipihorn.wordpress.com/2009/12/20/modules-burson-les-bonus/
https://jipihorn.wordpress.com/2009/12/20/modules-burson-les-bonus/
A fav of mine is the AD825 really dynamic and really punchy, can be a bit forward in the wrong system.
Cheers George
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Folks:
This is like wine; so many choices, so dependent upon personal taste and impossible to find the "best" at a price point unless all are sampled.
Not a bad way to spend your time if you have the money to invest in testing the options. Maybe I'll take the money I was going to invest in the Burson op-amp and spend it on pairs of possible NE5534 replacements. In truth, that'd be a bit uncharacteristic of me, but I do like the idea.
Thanks to everyone for the recommendations!
Regards,
Scott
This is like wine; so many choices, so dependent upon personal taste and impossible to find the "best" at a price point unless all are sampled.
Not a bad way to spend your time if you have the money to invest in testing the options. Maybe I'll take the money I was going to invest in the Burson op-amp and spend it on pairs of possible NE5534 replacements. In truth, that'd be a bit uncharacteristic of me, but I do like the idea.
Thanks to everyone for the recommendations!
Regards,
Scott
It seems to me that the main advantage of a discrete opamp over an IC is that usually the output stage has a much 'richer' bias. However an external current source can be added to an IC opamp to enrich its output stage, a tweak that has already been mentioned on this thread. That's a much cheaper option than swapping out the opamp for a discrete one.
Latest generation mods update...
I posted back in Sept about my plans to use TDA1545A - I've shelved those for now because I couldn't get good enough sound from those DACs. Perhaps its because I have substandard parts, or maybe I'm missing something vital in the implementation but the 1545As I tried exhibited a weird noisiness which changed with signal. So I'm back once again on the TDA1387 trail, after a month or so working on headphone amps
Here's a pic of my most compact DAC to date - on the 5*7cm board is a pair of TDA1387s (differentially driven), discrete CFB I/V stages and a 6th order anti-imaging filter with built-in droop correction. I had a first listen yesterday and its promising enough to build a second 5*7cm board with two more channels of I/V and filtering so I can run fully balanced with transformer outputs. The transformers I'm planning to wind are based on EP17 cores because those are the smallest I figure I can get the full bandwidth through - still experimenting with smaller wire gauges on those.
I posted back in Sept about my plans to use TDA1545A - I've shelved those for now because I couldn't get good enough sound from those DACs. Perhaps its because I have substandard parts, or maybe I'm missing something vital in the implementation but the 1545As I tried exhibited a weird noisiness which changed with signal. So I'm back once again on the TDA1387 trail, after a month or so working on headphone amps
Here's a pic of my most compact DAC to date - on the 5*7cm board is a pair of TDA1387s (differentially driven), discrete CFB I/V stages and a 6th order anti-imaging filter with built-in droop correction. I had a first listen yesterday and its promising enough to build a second 5*7cm board with two more channels of I/V and filtering so I can run fully balanced with transformer outputs. The transformers I'm planning to wind are based on EP17 cores because those are the smallest I figure I can get the full bandwidth through - still experimenting with smaller wire gauges on those.
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Two issues with my modded x8: one I've mentioned before, a hum or mild buzzing sound when the amp is turned up all the way. This is either getting worse or I'm getting more sensitive to it.
The other is that sometimes when I touch the chassis of the DAC, the music cuts out completely for a second.
I know Abraxalito gave some thoughts on the first item, now I'm wondering if the two are related? I'm guessing the second is a grounding issue, maybe easily fixed by running a wire from the case to the ground terminal of the IEC?
There is already a connection from IEC ground to the PCB (with a 9R). And the PCB itself has that exposed strip on the bottom which is presumably for grounding... But with the chassis anodizing, I wonder if that's actually a reliable connection? I think this may have been discussed earlier...
Any thoughts?
The other is that sometimes when I touch the chassis of the DAC, the music cuts out completely for a second.
I know Abraxalito gave some thoughts on the first item, now I'm wondering if the two are related? I'm guessing the second is a grounding issue, maybe easily fixed by running a wire from the case to the ground terminal of the IEC?
There is already a connection from IEC ground to the PCB (with a 9R). And the PCB itself has that exposed strip on the bottom which is presumably for grounding... But with the chassis anodizing, I wonder if that's actually a reliable connection? I think this may have been discussed earlier...
Any thoughts?
It does indeed sound like a lack of grounding issue the drop-out of music when you touch the chassis. I'd imagine you're getting some mild static discharge which upsets the lock of the S/PDIF receiver for a time. Having the chassis earthed via a low impedance route most likely will fix this. Yes the anodization will prevent a good contact, you'll want a nut with a star washer methinks.
I have some smaller transformers on order for implementing my latest set of mods, 1VA. The ones fitted are 5VA which seem to me to be overkill. I'm hoping the smaller the trafo, the better the mains isolation but want also lower leaked field which touches on your hum problem. As I think I mentioned before I don't have any kind of hum problem with the DAC in my system at present coz the trafos are in a box some distance from the PCB.
I have some smaller transformers on order for implementing my latest set of mods, 1VA. The ones fitted are 5VA which seem to me to be overkill. I'm hoping the smaller the trafo, the better the mains isolation but want also lower leaked field which touches on your hum problem. As I think I mentioned before I don't have any kind of hum problem with the DAC in my system at present coz the trafos are in a box some distance from the PCB.
Schematic?
Can't really comment based on a "pretty picture".
A schematic, even hand-drawn, would be useful.
Can't really comment based on a "pretty picture".
Folks:
Okay, it is highly probable that I'm going to soon regret asking this question, but here goes: what is the likelihood that LT1028 chips found on ebay are counterfeit? I'd like to buy two and, not surprisingly, Chinese sellers are offering them at attractive prices (for example, 2pcs IC Linear DIP 8pin LT1028CN8 LT1028 New J36 | eBay).
The alternatives, from reputable sellers, are more than double the ebay price. It isn't a lot of money to risk, so I can always take the chance, but I am curious whether there are some products that are sufficiently common that there is little reason for counterfeiters to bother.
Your thoughts?
Regards,
Scott
Okay, it is highly probable that I'm going to soon regret asking this question, but here goes: what is the likelihood that LT1028 chips found on ebay are counterfeit? I'd like to buy two and, not surprisingly, Chinese sellers are offering them at attractive prices (for example, 2pcs IC Linear DIP 8pin LT1028CN8 LT1028 New J36 | eBay).
The alternatives, from reputable sellers, are more than double the ebay price. It isn't a lot of money to risk, so I can always take the chance, but I am curious whether there are some products that are sufficiently common that there is little reason for counterfeiters to bother.
Your thoughts?
Regards,
Scott
Hey guys,
I've been enjoying my modded DAC for a while now. I'd like to try a tube output stage (for no better reason that I like tubes and making stuff.)
I've googled tube i/v stages, and not really come up with a consensus on a good circuit to use. Has anybody here tried this, or know of a suitable circuit?
Cheers,
Jon
I've been enjoying my modded DAC for a while now. I'd like to try a tube output stage (for no better reason that I like tubes and making stuff.)
I've googled tube i/v stages, and not really come up with a consensus on a good circuit to use. Has anybody here tried this, or know of a suitable circuit?
Cheers,
Jon
The wiki for this dac seems to be down: http://www.diyaudio.com/wiki/TDA1387_X8_NOS_DAC
I have ordered one via a taobao agent. It should be here in a few weeks. Douk on ebay no longer have it.
Just a heads up that I found the 4x tda1387/tda1543 dacs on aliexpress for a very attractive price:
4x l1387dac vier tda1387 koorts en decoder usb producten, tda1543 buiten in Vijf circuit kenmerken:usb direct aangedreven door de clc netwerk dat aanbod schoonVier tda1387 decoder chip in parallel van versterker op AliExpress.com | Alibaba Groep
Aliexpress.com: Koop Hifi l'1543 dac vier tda1543 usb decoder van betrouwbare decoderen wma leveranciers op jack Electronic
I have ordered one via a taobao agent. It should be here in a few weeks. Douk on ebay no longer have it.
Just a heads up that I found the 4x tda1387/tda1543 dacs on aliexpress for a very attractive price:
4x l1387dac vier tda1387 koorts en decoder usb producten, tda1543 buiten in Vijf circuit kenmerken:usb direct aangedreven door de clc netwerk dat aanbod schoonVier tda1387 decoder chip in parallel van versterker op AliExpress.com | Alibaba Groep
Aliexpress.com: Koop Hifi l'1543 dac vier tda1543 usb decoder van betrouwbare decoderen wma leveranciers op jack Electronic
What USB receiver chip (manuf/model)?
What USB receiver chip (manuf/model) is being used in these D/A's?
E.g., Tenor, SAVITECH, TI, etc. I doubt that --at the prices on Ali or eBay-- it's XMOS).
Ref:
USB Receiver Chips: Do they really matter?
https://www.reddit.com/r/headphones/comments/35m6nf/jds_labs_releasing_odac_revb/
What USB receiver chip (manuf/model) is being used in these D/A's?
E.g., Tenor, SAVITECH, TI, etc. I doubt that --at the prices on Ali or eBay-- it's XMOS).
Ref:
USB Receiver Chips: Do they really matter?
https://www.reddit.com/r/headphones/comments/35m6nf/jds_labs_releasing_odac_revb/
i bought a few of these dacs. One had a slight hum with volume turned up with a digital pause. The other DAC didnt have the issue. Bad component perhaps. But I noticed when I went with the optical connection it was cleanest no buzz or humm relative to the digital connection.
That's weird. I have a local copy of the raw text so I can quickly and easily re-create it... I went to do just that, but when I go to edit it, it actually shows up in its entirety. But if I try to "preview" it, then I get the "not found" error. So I think the forum software is hosed. I'll go post in the other section about this. Hopefully they can get it resolved soon!
Still enjoying mine very much by the way. Some day I'll get around to doing Abraxalito's "next gen" mods, but work, kids, holidays, etc etc, plus the fact that I'm really happy with it as-is... means I've spent what little free time I have actually listening to music lately!
Edit: looks like all or most diyAudio wikis are down now, see the Wiki down? thread over in the "Forum Problems" sub-forum. Site admin says hopefully in a week it will be back.
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