where to buy sc947-02

JoshK · « **Reply #80 on:** 22 Jun 2007, 03:29 am »

That might be it....I found a thread with some discussion, and it looks a bit like that. I'll need to confirm.

F-100 · « **Reply #81 on:** 22 Jun 2007, 03:42 am »

That circuit diagram was from this link below. Some good stuff there from Professor Jocko.

http://www.diyhifi.org/forums/viewtopic.php?f=2&t=284&st=0&sk=t&sd=a&start=60

randytsuch · « **Reply #82 on:** 22 Jun 2007, 05:22 am »

Here is a diyaudio thread I like, on this subject

http://www.diyaudio.com/forums/showthread.php?s=&threadid=67247

It shows the evolution and education of someone, designing a spdif output circuit, using a transformer. There was a lot of advice from Jocko and others, to help the guy. You can go to page 5 if you want the answer, but it worth going the first 5 pages, to see how he got to the answer.

Randy

JoshK · « **Reply #83 on:** 23 Jun 2007, 01:22 am »

That was the thread I found, along with one about a balanced receiver circuit.

art · « **Reply #84 on:** 25 Jun 2007, 04:05 pm »

I'm still waiting on those samples to arrive........

Pat

art · « **Reply #85 on:** 29 Jun 2007, 10:44 pm »

Quote from: JoshK on 13 Jun 2007, 03:37 am

If you want one of the SC's that we all bought in the group buy to test out, pm me and I'll send one out to you.

Ahem............I'm still waiting.........

Pat

JoshK · « **Reply #86 on:** 29 Jun 2007, 11:33 pm »

Sorry Pat...I know you are...didn't mean to keep you hanging. I had a bit of a busy week and didn't find my way to the Post Office (we have no mail boxes in our town, believe it or not, so you must to to the PO to ship).

art · « **Reply #87 on:** 30 Jun 2007, 03:14 pm »

Not the Post Office.......!

Things have gotten so bad there that I am no longer sending parts to friends overseas. I can't stand in line 1/2 hour to send out a handful of parts.

That explains everything.

"Never mind."

Pat

art · « **Reply #88 on:** 3 Jul 2007, 04:01 am »

Here are some comparisons between "tweaked" 22083 and what I am sure is a Newava 22160. As I said.....that one is not my fave, but I tried to make it better. So, here it is, both tweaked:

Sorry......but I did not realise that the camera was tilted until after I took the test jig apart. Deal with it. Anyway.........I was able to get the rho down to 0.1, or a return loss of -20 dB. Not bad, but better can be had.

For comparison, the tweaked 22083:

Ah....a bit better. Rho drops in half, so RL drops by 6 dB. Should work good.

Now.....some have asked what if I limit the BW, instead of using a TDR that is working at 1 GHz or so. Good question, and here is what it looks like in the frequency domain. IOW, I used a Vector Network Analyser to make these RL plots.

Well, not too bad. The RL at the data rate is around -32 dB, and drops to around -40 dB at 70-80 MHz.

But.......the 22083, down with the same tweak:

Hmmm......quite a bit better. -40 dB at the data rate, and drops to around -50 dB at 100 MHz.

So, which one would you guys want to stick in your doo-hickey?

Until next time.......

Pat

art · « **Reply #89 on:** 5 Jul 2007, 11:00 pm »

Ok, everybody, let's hear it for Gordy who was brave enough to sacrifice his transformer to the evil clutches of the madman in Texas.

So......here is what you guys plunked down your money for, hooked up just the way Crystal tells you to:

And one the Vector Network Analyser:

Lovely, isn't it?

I know, some (if not all) of you are going "Hey, big nose, we were happy until you came along and stirred up trouble. We were happy with the way things sounded without your butting in."

Well, I suppose so. But then there was also a time when you were probably happy drinking malt liquor. So what does that prove?

Pat

art · « **Reply #90 on:** 5 Jul 2007, 11:10 pm »

Those of you who have been paying close attention to my rantings might recall that I pointed out that you can play games with the way you hook these things up?

"Yeah, so?

And that I said SC may have done something like that in their tests.....and not done it to Brand X.......

"Maybe."

Well, I have to be honest. Looks like this transformer, when tweaked, isn't really all that wretched.

Proof:

And

Not bad, I have to admit.

Still the Newava is better both in the stock and tweaked version.

But it just goes to show...........you can fudge the data anyway you like if you know how to.

I will stick with Newava in all my designs. My work here shows that you can get decent results with a SC transformer, if you have access to all sorts of test gear.

Either that, or you find a schematic of a tweaked one somewhere on the 'Net.

Good luck finding it! It is probably out there somewhere, but don't ask me to look for it.

Over and out....

Pat

Gordy · « **Reply #91 on:** 6 Jul 2007, 01:24 pm »

Not that I understand it but, either a Z pad...

or a zobel network to cancel out leakage inductance, 10 pg. thread is here... Jocko Homo

art · « **Reply #92 on:** 6 Jul 2007, 03:23 pm »

You can use those in addition to the other tricks. Helps even more. No pads used for any of the tests.

Pat

art · « **Reply #93 on:** 10 Jul 2007, 03:30 am »

Well, sort of......

http://www.diyhifi.org/forums/viewtopic.php?p=8978#p8978

Jim uses a circuit almost identical to the one I designed into our D/A box. Around '92, I think.

Anyway, if you look on his site, there is a usable schematic for an input stage. It does not have any of the tricks, but hey, it is a free schematic.

It will work on only +5 V DC, but not for noobs to try. I have needed to make that circuit work on a single supply. (Not in my product, obviously!) But it is a good starting point to learn something about SPDIF.

And not look like I am the only guy preaching it.

(BTW, Jim has a good paper on snubbers somewhere on the 'Net. I bet if you ask him, he will point you to it. A very good read.)

Pat

gitarretyp · « **Reply #94 on:** 10 Jul 2007, 03:40 am »

Quote from: art on 10 Jul 2007, 03:30 am

(BTW, Jim has a good paper on snubbers somewhere on the 'Net. I bet if you ask him, he will point you to it. A very good read.)

Pat

I think this is the article to which you are referring.

art · « **Reply #95 on:** 10 Jul 2007, 04:01 pm »

The file you point to is a 1.3 Mb file. I don't have the time (or patience) to d/l that one. The one I have is only 117 kb.

Pat

art · « **Reply #96 on:** 10 Jul 2007, 09:58 pm »

Well, it appears that I have finally managed to get most everyone here mad at me. So, this will be my last post on this subject.

Many of you here bought a component that the manufacturer claimed was the best around, based on their marketing claims. That is nothing to be ashamed of, as a great deal of the manufacturers in this business also fell prey to that approach. I have expended a great deal of effort the last 15+ years educating high-end companies about this. And yes, I was paid for my work.

SC claims that not only do they make the lowest interwinding capacitance transformers (a fact that I have shown by the large leakage inductance that their products have), but that they also perform better than any other brands.

Well, some of you wanted measurements, and I provided them. I have shown how high amounts of leakage inductance has a poor reflection coefficient. In addition, there is reasonable assumption that this also has poor high-frequency performance, which limits BW, and therefore rise time. Other manufacturers who post on AC have products and/or "white papers" explaining how BW and rise time are important to SPDIF. So, I am not alone in my beliefs.

I have also shown that there are tricks that can be employed to make a transformer measure better (or worse!) than it is all by itself.

And that is the crux.

SC proudly points to an AES paper which they claim proves their product is better. But do they show the actual test set-up? No! They point to a bunch of test results, but no real clue as to how they were performed.

Go ahead, call me a skeptic (or even a horse's butt), but I have been around this business long enough to know when something is fishy. At least to my nose. (And anyone who knows me will attest to its size and "gas chromatograph" abilities.) I have a strong suspicion that the test set-up may have used the trick configuration for the SC and the "non-trick" one for the other guys. Of course, I can not prove that.

But SC has not given any proof to the contrary. In fact, they provide nothing at all. Hell, if you look at their website, you will find no specs, just a lot of marketing gibberish. They do not even provide a pin-out diagram! Oh, sure, you can call or e-mail them, and ask all the questions that you want. But you won't get solid answers. (I have tried........many times.........trust me..........)

What kind of outfit does business that way?

Well, to me.....a company that does not give the answers probably does not know the answer. I can't believe they have a bunch of trained monkeys that answer the phone and go "We have the lowest interwinding capacitance in the industry." "Yes, but how low is it exactly?" "The lowest in the industry." "I need an actual number!" "We don't provide that."

But, that is what they do. I wonder if they even know. For all that any of us know, they could just be some marketing company that pays some hotshot designer to do all the technical stuff, and they just build 'em and sell 'em.

Not that it really matters..........

What does matter is that they need to be more forthcoming. It would seem prudent to me (as a user of that type of product) that the more info that is provided, the more likely I am to use it.

So, where is this leading?

I have alluded to ways of hooking up transformers to make them work better. But is it my job to do their job for them? No! If they want to sell transformers and make sure that they really work as well as they claim, then why don't they tell you? They are the ones who should provide all that information.

But, for whatever reason, they don't. So, now we have a bunch of hobbyists, upset because some goofball in Texas has pointed out that the Emperor may not have any clothes on.

(Gee, when has that ever happened before in high-end audio, he asks under his breath?)

Go ahead, get mad as hell at me if it makes you feel better. The people you should be mad at are the guys who make the parts. They should tell you all that they know if they expect you to buy their products. It is in their best interest to do whatever it takes to get the best performance, and therefore maximum usage, of their parts.

If they don't want to, then maybe next time you should consider buying from someone else.

If they can't (because they don't know), then how the hell did they design them in the first place?

It has to be one or the other. Maybe both. But I am not in the business of selling pulse transformers and pulse transformer accessories. Therefore, I could be wrong. So, I would depend on the manufacturer to set me straight. One of them won't or can't, so I see no reason to do business with them.

I have given you an alternate supplier. Hold their feet to fire as well. If they can't (or won't), supply that information, well...........we all may be up a creek without a paddle.

Go ahead.........put my theory to the test. Ask SC (and Newava as well!) all about how to use them. See if they cooperate. They know stuff they are holding back on. Their products (not mine), so it is incumbent on them (not me!) to educate you. I'll just sit back and chuck stones when they don't, and give them an "Atta boy!" when they do.

You know where to find me...........

Pat

JoshK · « **Reply #97 on:** 10 Jul 2007, 11:01 pm »

FWIW, I for one beleive you. I read quite a number of threads on that other forum and you and Jocko look to be saying much that same thing and I have long thought that Jocko seems to know what he is talking about. At least I don't know enough to know otherwise. So two smart people confirming eachother makes me think its probably true.

In fact he actually says many of the same things you do like 1) tx's other than 1:1 are junk, 2) SC's are junk, 3) Newava/the other are decent, etc. He is also from TX. At first I thought you might be the same person.

tanchiro58 · « **Reply #98 on:** 11 Jul 2007, 12:13 pm »

Besides my thought is people at Newana just nicely talked but did not do what they promised to do. Sorry to say that but customer services are very important for the first impression. I talked to Kathy and ordered SC' s products they have a superb customer support.

tanchiro58 · « **Reply #99 on:** 5 Sep 2007, 07:10 pm »

Hi Everyone,

I am just done the modification of Newava S22083 to my SB2 and compared to modded SB3 with SC947-02 pulse transformers.
First when the modded SB3 with SC947-02 was done it is very impressive sounding and I like a lot. Then I was done modifying my SB2 (wired version) with a Newava S22083 two days ago. First day the modded SB2 was sounding with more smooth high and mid with details but the mid and low bass was not so impressive. But I have to admit the modded SB2's sound is sweeter (maybe low noise) than modded SB3. In the second day the modded SB2 was not so impressive like the first day everything was dull and flat the details disappeared. Why? I still do not know maybe because modded SB2 has not totally past the break-in time. I will listen today again and will let you know.