John Curl's Blowtorch preamplifier part II

Status
Not open for further replies.
There are DAC's and DAC kits with full isolation if needed. E.G. Isolated XMOS 768kHz DXD DSD512(DSD1024) high-quality USB to I2S/DSD PCB - DIYINHK While its possible to make small improvements on these kits I don't think its worth the time to try.

No one has been able to explain to me how you're supposed to galvanically isolate a USB interface from inside the box when you have a metal chassis and you must make a connection from the USB shell / shield to that chassis. If you have a plastic enclosure or you plan to not make that USB shield connection then maybe you can, but is that really good practice?
 
Administrator
Joined 2004
Paid Member
Hi Richard,
I agree completely. I've actually seen this in practice and have improved the sound of CD players (and FM tuners) on the bench. The THD numbers are often inconclusive, but the distortion spectra does tell the story. It's just that the differences are smaller than you might expect on the instruments.

Some OP Amps are better than others among the newer crop. Excluding obvious examples like the 741 and 1458. The TL07x family that sounded so good in the 70's really doesn't cut it against the current contenders.

-Chris
 
Administrator
Joined 2004
Paid Member
Hi Chris,
Transformers for the data, or the newer charge coupling devices. Let's not forget opto-isolators.

Remember, you don't need the power connection, or the protective ground connection. You only need data transfer. This is how isolated USB 'scopes work as well.

-Chris
 
Robert,
I didn't say that vinyl can't sound good, even great for enough money as John keeps bringing up, but generally those systems are rather rare. As I said I still have my turntables and have kept my vinyl when most of the people I know have long ago gotten rid of some major record collections. I even still have a vacuum tube McIntosh receiver, MR71, that I wouldn't get rid of. But it is time to move on, it is no different than the fact I still have my 1967 first year Pontiac Firebird, a lot of fun but it sure is a lot easier to make massive power with a new fuel injected engine from a new Corvette than an older small block Chevrolet engine. Yes I have a Chevy engine in my Pontiac! I also have a pile of Alesis amplifier modules I pick up years ago that were from some self powered Alesis speakers with 3886 chips on them. I can't say I have been a major fan of their speakers but they did move the needle for small studio speakers many years before others.
 
Administrator
Joined 2004
Paid Member
I mean the easy to hear ESS DAC may have been just fine, and the rest of the associated equipment may have lacked "bite" as you might say.
Ah, I see what you mean. It was not the case in this instance, a wide range of speakers in the room, including at least one pair of coax drivers that were too rough for my taste. And I noticed the same thing at home with my system which was smooth. I liked the gentle sound of the ESS, but it wasn't really exciting. More realistic? I can't say. At audio shows, exciting sells. I've gotten that out of other DAC chips.

I don't know what other people are saying about the ESS chips and the OPPO, but I did not pursue the ESS, it would not have sold. Too tame.
 
Robert,
I didn't say that vinyl can't sound good, even great for enough money as John keeps bringing up, but generally those systems are rather rare. As I said I still have my turntables and have kept my vinyl when most of the people I know have long ago gotten rid of some major record collections. I even still have a vacuum tube McIntosh receiver, MR71, that I wouldn't get rid of. But it is time to move on, it is no different than the fact I still have my 1967 first year Pontiac Firebird, a lot of fun but it sure is a lot easier to make massive power with a new fuel injected engine from a new Corvette than an older small block Chevrolet engine. Yes I have a Chevy engine in my Pontiac! I also have a pile of Alesis amplifier modules I pick up years ago that were from some self powered Alesis speakers with 3886 chips on them. I can't say I have been a major fan of their speakers but they did move the needle for small studio speakers many years before others.
Just because you are tired of vinyl technology doesn't invalidate the end result of digital not quite cutting it like vinyl can. Heck, I don't even have expensive vinyl gear and and I get playback that is way better than any digital I have heard. Good thing Chad Kassem and the like don't think like you.

Those Alesis amp boards are from the Alesis M1 Active speakers designed by Greg Stock. He does guitar pedals now for his own company. I had a pair of them but since the bass had a steep roll off purposely designed into them at like 50hz or something I sold them to a guy at Harman for cheap. He used them for patio music. Those speaker boards are not a serious Alesis product. They were just to fill out the product line. Most of the real innovative gear was designed by Keith Barr.
 
A few years back when everyone was all gaga over the ESS chips, I was commissioned to build one for a production unit (not the current model chip). Another forum member here designed the controller.

It didn't do well at RMAF. People found it pleasant, but not dynamic enough, a little soft. One visitor listened to some Nick Cave cuts he knew well and found it didn't have enough bite and dynamics. That was the general consensus. Personally I found it "polite and gentle."

I agree with this description of the ESS DAC sound.
 
Abraxalito, I have to agree with you I think Demian was commenting on the name Oppo and not Alesis. I can't think of a much worse name that just seems silly.

Robert, sorry you haven't heard any nice digital systems, there is no question in my mind with a great recording that digital has it over vinyl reproduction. As I said I don't dislike it, just that it has many limitation which many others much smarter than I am have elucidated so many times. Now if we are talking about some of the earliest CD's I agree some were horridly mastered and today with the loudness wars we are again getting lots of junk music but that doesn't mean the media or the medium of digital is the real problem here. There is still a place for analog, I have no problems with that. Of course we don't actually listen to digital and I always laughed when I heard people describe some speakers as being digital speakers, such nonsense.

I was just talking to a friend tonight about mixing consoles and he was saying how much he loved older analog mixing desks, he was talking about how horrid some of the newer all digital mixing consoles were with computer screens and having to go through screens to use a particular function and how disconcerting that was doing live mixing at a show, not doing recording but PA. There is a time and place for everything.
 
AX tech editor
Joined 2002
Paid Member
That was NOT my experience with the ESS DAC. Rather the opposite. It was smooth and not aggressive, not fatiguing. It's not a sound that may people are used to, at least with digital.

Could that have been the case, Pano? That it was more transparent, less aggresive and fatiguing than other DACS and therefore rejected as not fitting the expected pattern? Happens a lot.

Jan
 
Member
Joined 2016
Paid Member
I was just talking to a friend tonight about mixing consoles and he was saying how much he loved older analog mixing desks, he was talking about how horrid some of the newer all digital mixing consoles were with computer screens and having to go through screens to use a particular function and how disconcerting that was doing live mixing at a show, not doing recording but PA. There is a time and place for everything.

Tat sort of poor ergonomics is a plague these days, equipment of all sorts where you used to have a separate control for all the important functions, now you get a multifunction control and have to punt through interminable menus to get the parameter you need, or poke at a bad touch screen. Bad design - you couldn't do it that way with analogue kit even if you wanted to...
 
Administrator
Joined 2004
Paid Member
That it was more transparent, less aggresive and fatiguing than other DACS and therefore rejected as not fitting the expected pattern?
Certainly possible. To my ear the ESS did not have a lot of the usual artifacts of D/A. Artifacts you may not realize are there, until there aren't. But I still wonder about its current output, maybe a little lean? Hard to say. Subtleties.

Thanks Pavel, good to know someone else was hearing the same thing.
 
Status
Not open for further replies.