where to buy sc947-02

F-100 · « **Reply #60 on:** 20 Jun 2007, 06:23 pm »

Quote from: Builder Brad on 20 Jun 2007, 05:16 pm

has there been any more developments with this?

anyone tried comparing the sound of the SC transformers with the suggested alternative?

I would do this, as its an easy swap out, however those transformers seem more readily available over in the US.

Brad

I received my Newava S22133 transformer from digikey yesterday and not quite sure how to install it yet.

Is it a straight swap between the S222133 and SC947-02 as far as the pin configuration goes?

Master Pat,
Please help this young grasshopper ...

art · « **Reply #61 on:** 20 Jun 2007, 06:59 pm »

I dunno......I do not have a spec sheet for the SC parts. All I know is that they claim to have the lowest interwinding capacitance around (and I do not dispute that, despite the fact that they do not spec it anywhere. And yes, I went as far as to call them once to get an exact number. Which they would not or could not supply. Just rattle off more sales hype.)

But as for the Newava part that you somehow managed to get hold of.........

I only have data for the 22083 and 22160.

Usually, most companies put the primary pins on one side.....the secondary pins on the other side. Sometimes, they put a "dot" on the start winding. Usually indicates the "cold" side of the circuit.

Any other questions that I can supply vague answers to? (it is a joke........don't have a cow, man.)

Pat

tanchiro58 · « **Reply #62 on:** 20 Jun 2007, 07:07 pm »

Quote

I only have data for the 22083 and 22160.

Pat,

I just got both from digikey and want to give me any hints how to install them to a transmitter (SB3) and to a receiver (DAC). I also see the dot one side of the Newava S22083 (entcapsulated). Is this primay or secondary? Which side is going to S/PDIF connector? Thanks in advance.

Regards,
Tan

F-100 · « **Reply #63 on:** 20 Jun 2007, 08:01 pm »

Quote from: art on 20 Jun 2007, 06:59 pm

But as for the Newava part that you somehow managed to get hold of.........

I only have data for the 22083 and 22160.

Pat

From the spec (see link below), I thought they both are the same except 22133 have shield grounded. Am I right or wrong??

http://rocky.digikey.com/WebLib/Newava/Web%20Data/S22160.pdf
http://rocky.digikey.com/WebLib/Newava/Web%20Data/S22133.pdf

Builder Brad · « **Reply #64 on:** 20 Jun 2007, 08:02 pm »

Tan, F100,

I also have fitted one of the Sc transformers into my Paridisea DAC, and heard an improvement that pleased my ear. I remember that you had differing experiences when you tried the same SC transformers in your Squeezeboxes. I tried the transformers in my Squeezebox and was not completely happy with the performance which forced me to do a little bit more digging, as I really thought I was missing something.........and I found this thread

http://www.diyaudio.com/forums/showthread.php?s=74980590b96ba4203c923b745ece1e17&threadid=67247&perpage=10&highlight=&pagenumber=1

which kind of covers some of the reasons why the second trandformer sounded crap in the Squeezebox. I built the additinal circuity, based on the final Scematic from Kapatum on page 5, using standard .6w resistors, and have heard an improvement that is definately getting there.

I plan to make up a small pcb and add SMD components for this circuit and include the BNC connector terminals which I will solder to the pcb - ideally I will also include the transformer on the pcb, I am just waiting on the outcome of this discussion.

Brad

art · « **Reply #65 on:** 20 Jun 2007, 08:31 pm »

Didn't I tell you guys not to use any that have a shield...........?

I give up.

Pat

F-100 · « **Reply #66 on:** 20 Jun 2007, 08:52 pm »

Quote from: art on 9 Jun 2007, 03:54 pm

Transformers with shields are not worth diddly. Besides lower capacitance, it adds a big chunk of capacitance to ground. (What did they think that a big hunk of capacitance to ground was going to do?)

Sorry, Master Pat. I screwed up... I should had paid more attention to your post...

Brad,
My experience was the other way around. I had the SC tranformer in the SB3 at first and really like the sound. Then I added another SC transformer into my Paradisea DAC using your diagram

, and wasn't happy with the performance either so I removed it from the DAC.

art · « **Reply #67 on:** 20 Jun 2007, 09:11 pm »

They break up ground loops, which is good.

They are hard to make a constant output impedance, which is bad. Most driver circuits are horrible, so there is no way to know how they will react.

BTW.....most of the circuits I see on the 'Net are horrible. Some place called ePanorama, or something like that, comes to mind as the worst collection imaginable.

Using lots of gates in parallel leads to more jitter. Yeah, I made that mistake, more than once.

On the RX end........Crystal receivers need a linear stage in front of them. Yes, "they" will say that is BS, but they are not RF guys.

Wherein lies the problem.........

It would seem, to the average guy, that this is just audio stuff. The fact that "bits are bits" gives a false sense of nothing can go wrong. You have to look at these things as quirky RF circuits. Just because it uses RCA jacks and it will somehow work with mic cable does not mean that it is worth diddly.

Telling you guys how to do it is one thing. it will get you in the ball park. But, you really need to consider making special PCBs, done by someone with knowledge of the subject, to really make full use of what you are working with.

No....I am not in the business of selling mod kits. I know a few guys here who are. A few seem to know their stuff. Some of you may want consider approaching them, and seeing if they are interested in making TX/RX PCBs.

I would offer to test them, but not design them.

Pat

Builder Brad · « **Reply #68 on:** 21 Jun 2007, 05:38 pm »

F100,

I found that the transformer sounded best in the Paridisea, not the squeezebox and even worse in both.

It seems that the TX part of this is more complicated than the RX when using transformers - if you are inclined I wwould try the transformer in the DAC and not the SB.

Brad

Builder Brad · « **Reply #69 on:** 21 Jun 2007, 05:39 pm »

Pat,

I would be interested in working with those custom TX and RX pcbs.

Brad

art · « **Reply #70 on:** 21 Jun 2007, 05:58 pm »

You have to take into account the intrinsic impedance of whatever chip drives the output. Most don't. Whether they know the difference or not.........your guess is as good as mine.

Brad,
Get your favourite mod guys to make some PCBs. As I said, I will measure them, but not do their design work for them. I suspect most would be wary to let me measure their stuff, as I bet most will get a "thumbs down".

Remind them that I am not their competition.......

Pat

F-100 · « **Reply #71 on:** 21 Jun 2007, 06:05 pm »

Quote from: art on 20 Jun 2007, 09:11 pm

I know a few guys here who are. A few seem to know their stuff. Some of you may want consider approaching them, and seeing if they are interested in making TX/RX PCBs.

Pat

Most of them charge around $200/hour for their labor which is too rich for my budget. That is why some of us are going the DIY route in order to save some doughs and hopefully learn a few tricks from the experts like you.

F-100 · « **Reply #72 on:** 21 Jun 2007, 06:20 pm »

Quote from: Builder Brad on 21 Jun 2007, 05:38 pm

F100,

I found that the transformer sounded best in the Paridisea, not the squeezebox and even worse in both.

It seems that the TX part of this is more complicated than the RX when using transformers - if you are inclined I wwould try the transformer in the DAC and not the SB.

Brad

Brad,
Thanks for the suggestion.

I'll give it a shot next time when I have some free time.

art · « **Reply #73 on:** 21 Jun 2007, 06:25 pm »

You mean to tell me that:

1.) None of them have something like this already built to sell to you guys.

2.) None of them see this as way to make $$ by spending 1/2 hour laying out a PCB, and......

3.) They charge 3 times what I do? With minimum qualifications? Good grief......

BTW.....when did this become a DIY site? I heard that the emphasis was to go away from that.

Pat

F-100 · « **Reply #74 on:** 21 Jun 2007, 06:42 pm »

Quote from: art on 21 Jun 2007, 06:25 pm

You mean to tell me that:

1.) None of them have something like this already built to sell to you guys.

Not that I know of.

Quote

2.) None of them see this as way to make $$ by spending 1/2 hour laying out a PCB, and......

3.) They charge 3 times what I do? With minimum qualifications? Good grief......

You mean you only charge $70/hour. Damn, you're cheap comparing to most of the modders out there.

Maybe you should think about building these PCB and sell them to us at reasonable price.

Quote

BTW.....when did this become a DIY site? I heard that the emphasis was to go away from that.

FYI, here is a brief description of
"The Lab Circle": The technical side of audio. How and why our equipment works, construction, and DIY.

JoshK · « **Reply #75 on:** 21 Jun 2007, 08:35 pm »

I'm ok with the figuring out the rest of the circuit to get the proper impedance terminations, using the chip's Z, if I can figure out what the chip's Z is. Its the driver circuit that I don't have a clue about. Would a simple follower circuit using a transistor work? I am assuming probably not given your previous comments.

art · « **Reply #76 on:** 21 Jun 2007, 11:19 pm »

Depends on both family and manufacturer. I would use a number between 25 and 35 ohms as the Z of a typical digital IC.

I assume that is where the output comes from.

Make sure that no DC flows through the transformer. Tiny cores, saturate very easily.

Forget the follower. If it is a BJT follower, it will not be able to swing the full output on the chip driving it. Assuming the chip puts out a CMOS level.

(This is where having a 'scope is needed. You can figure out the Z without much problem, and what the voltage swing is. The output should be 0.5 V _p-p, when terminated in 75 ohms.)

But........you are probably going to stick a resistor in series with the transformer (and probably a shunt across it to ground) to get the level down. If the resistor is in the few hundred ohm range, being off a few ohms won't be the complete kiss of death.

Granted, the whole point is to get around a 32 dB return loss. Not a task easily done without test equipment.

As for DIY....

I was referring to the entire site. Guys that I know who are in the business of selling kits and such have told me that this site has been moving away from DIY stuff. So they claim.

Pat

JoshK · « **Reply #77 on:** 22 Jun 2007, 12:25 am »

From my own perspective, we have more DIY'ers now than we have ever had. As a %, no idea...

Thanks for the feedback. I have a scope, actually two.

My knowledge of active circuits is heavily, if not entirely, tube biased. But I don't think I want to use tubes here, not even subminis.

JoshK · « **Reply #78 on:** 22 Jun 2007, 12:37 am »

bonus points to the guy who can find Jocko Homo's driver circuit. It is probably a concept schematic and not a full one so source of the thread would be needed. He requires that you do your own homework, which is fine by me.

F-100 · « **Reply #79 on:** 22 Jun 2007, 03:01 am »

Joshk,
Are you referring to this one?