sc947-02 group buy

GBB · « **Reply #80 on:** 19 Apr 2007, 02:43 am »

Quote from: Brian T. on 18 Apr 2007, 06:52 pm

I think that a fully balanced approach might be better.

I agree with Josh K here - there is no benefit to using XLR and balanced cables. Once you've gone to transformers on the output of the SB3 and the input of the DAC then things are already balanced. The BNC connector is better than the XLR so you'll be moving in the wrong direction.

--- Gary

viperrabbit · « **Reply #81 on:** 19 Apr 2007, 06:39 am »

Hi Josh

3 for me, please. Thanks.

Regards
Edmund

tanchiro58 · « **Reply #82 on:** 19 Apr 2007, 07:21 am »

Quote from: jhm731 on 17 Apr 2007, 09:47 pm

How and where would you connect the ground 5,6,7 to?

If you followed Gary's plan, try disconnecting the wire you have connected to the shield pins 6 &7 and
see if it makes any difference. If you have an earth ground connection in your PSU, you could use a shielded two wire cable (connect the shield to ground) for the power connection from the PSU to the SB, and connect pins 6 &7 to the shield or run a separate ground wire from the PSU to the SB.

jhm731,

You are absolutely right about the true ground for SB3 and DAC when we install SC947-02 Tx and Rx. I just rewired the ground from Rx in DAC to Tx in SB3 then to PS. The noise had reduced to almost I could not hear them. Music has more black ground. Thanks.

JoshK · « **Reply #83 on:** 19 Apr 2007, 01:56 pm »

Well the GB is officially closed...a day early I know, but Anthony being the nice guy he is has already shipped out the units. He was sending 60, since he knew I would have a couple more stragglers, but with Viperrabbit's request, that makes 60.

I am going to send Anthony a check and Anthony is overnighting them to me, gratis, so that I will have them by the weekend to sort them out.

So if you are planning to pay me by check, you might PM me for my address, to get that out. Otherwise, I will take paypal, if you add 3%. I wouldn't normally bother with the fee, but with so many adding up to $600, it would make my units quite expensive.

Anthony is giving them to us for $10/ea. I figure it will cost ~$1-$1.2 to ship & $.50 for a padded envelope, so that makes them $11.50 via check, $11.85 via paypal shipped to you. With multiple units, the math is a bit similar.

It would make my life simply if you guys PM me with your email addresses and if you are sending check send me your address as well. I will communicate details via a mass email. Including a firmer total for each person.

JoshK · « **Reply #84 on:** 19 Apr 2007, 01:58 pm »

Here are some tips Anthony shared with us to get us thinking...

Quote

Here is a few tips with the SB3…..

A) Tie the ground plane of the SB3 to Earth ground. It will drop the noise floor dramatically. (back to the turntable days..)

B) If you do not like the idea above, then use a ferrite bead (I send you a few) to use between the ground plane and the pulse transformer shield.

Keep in mind not to use A and B at the same time…

“A” tip without the “B” is the best, IMO..

What happens is the noisy ground place will be introduced in to the P-formers shield… creating a “noise injector” out of the shield.

Another thing to do is to “increase the “speed” of the transmitter.

You can do this by removing the performance robbing RC filter and /or L (inductor) that is used after the transmitter. These filters are used to make the component to be able to pass EMI/RFI compliance. Leaving these filters in place give an open doorway to jitter…. So it is best to remove them for max performance.

GBB · « **Reply #85 on:** 19 Apr 2007, 02:12 pm »

Quote from: tanchiro58 on 19 Apr 2007, 07:21 am

You are absolutely right about the true ground for SB3 and DAC when we install SC947-02 Tx and Rx. I just rewired the ground from Rx in DAC to Tx in SB3 then to PS.

Tan,
Did you also try floating the shields?

Also, I was a bit unclear about the experiment you did. Did you just change the ground in the SB3 or did you change both the SB3 and the DAC?

Thanks,
---Gary

krikor · « **Reply #86 on:** 19 Apr 2007, 02:22 pm »

I sure hope a couple of you guys can post some pictures of how to do this mod when we get these transformers. I'm sure the less adept of us would appreciate a little step-by-step guidance.

Thanks again to everyone for making this happen!

JoshK · « **Reply #87 on:** 19 Apr 2007, 02:28 pm »

Anthony said, there is a picture floating around the net with a picture of the SB3 with the SC installed. Why don't one of you guys find that picture and post it here?

krikor · « **Reply #88 on:** 19 Apr 2007, 03:17 pm »

Wow ... that search function actually works.

http://www.audiocircle.com/index.php?topic=24353

Thanks to Gary for the pics.

tanchiro58 · « **Reply #89 on:** 19 Apr 2007, 04:21 pm »

Quote from: GBB on 19 Apr 2007, 02:12 pm

Quote from: tanchiro58 on 19 Apr 2007, 07:21 am
You are absolutely right about the true ground for SB3 and DAC when we install SC947-02 Tx and Rx. I just rewired the ground from Rx in DAC to Tx in SB3 then to PS.
Tan,
Did you also try floating the shields?

Also, I was a bit unclear about the experiment you did. Did you just change the ground in the SB3 or did you change both the SB3 and the DAC?

Thanks,
---Gary

Gary,

I am not sure what you mean by floating the shields.

Yes I did wire the ground for SB3 and DAC, which right out from pins 5,6,7 SC947-02 Rx, to PS ground ( I am sure this is a true ground). I found out the MHDT Renaissance II does not have ground at its IEC. Now I can hear a tremendous details from my system that I have never listened before. I do not need my subwoofer since I got bunch of deep defined bass.

Tan

F-100 · « **Reply #90 on:** 19 Apr 2007, 04:26 pm »

Quote from: krikor on 19 Apr 2007, 03:17 pm

Wow ... that search function actually works.

http://www.audiocircle.com/index.php?topic=24353

Thanks to Gary for the pics.

I just want to point out that since Gary didn't have the unit in front of him when he posted the instruction, R55 is not the corrected resistor. The resistor that you need to tap pin #8 of the SC947-02 into is R66.

As for removing L8 and L9 inductors, I don't know if this have any effect if you're using a 75 ohm BNC connector therefore you already bypass these inductors. Maybe Gary can chime in on this one.

One more suggestion...If anyone is planning to replace the stock output RCA with a 75 ohm BNC connector , I highly recommend to use this rear mount BNC connector since there isn't much room inside the SB3. I was using another rear mount BNC and the center pin connection was too long and it was in the way with the wireless card.

http://catalog.tycoelectronics.com/TE/bin/TE.Connect?C=1&M=BYPN&PN=227426-1&I=13

You can buy them here:
http://www.mouser.com/search/ProductDetail.aspx?R=227426-1virtualkey57100000virtualkey571-2274261

I'll try to post some pictures this weekend when I start the mod on my other SB3.

tanchiro58 · « **Reply #91 on:** 19 Apr 2007, 04:37 pm »

Quote from: JoshK on 19 Apr 2007, 01:58 pm

Here are some tips Anthony shared with us to get us thinking...

Quote
Here is a few tips with the SB3…..

A) Tie the ground plane of the SB3 to Earth ground. It will drop the noise floor dramatically. (back to the turntable days..)

B) If you do not like the idea above, then use a ferrite bead (I send you a few) to use between the ground plane and the pulse transformer shield.

Keep in mind not to use A and B at the same time…

“A” tip without the “B” is the best, IMO..

What happens is the noisy ground place will be introduced in to the P-formers shield… creating a “noise injector” out of the shield.

Another thing to do is to “increase the “speed” of the transmitter.

You can do this by removing the performance robbing RC filter and /or L (inductor) that is used after the transmitter. These filters are used to make the component to be able to pass EMI/RFI compliance. Leaving these filters in place give an open doorway to jitter…. So it is best to remove them for max performance.

JoshK,

I did the part A of Anthony' s suggestion and it works.

For the part of removing L8 and L9 inductors. I would not mind to do it but if I bypass them by using BNC mounted on the back cover of SB3 to replace the stock RCA and connected directly to ground and tap to R66 before downstream to L8 and L9. Thanks for the tips.

Tan

tanchiro58 · « **Reply #92 on:** 19 Apr 2007, 04:48 pm »

Hi Everyone,

Tip for anybody who want to mod both SB3 and DAC that has BNC connector like MHDT models.

If you would like to bring your music to a level higher than you have just done the mod of SC947-02 you should use both sides with BNC and digital cable with BNC as F100 did suggest me to do. Your music has a tremendous amount of musical and articulate details (but not making you fatigue) in 3D soundstage.

jhm731 · « **Reply #93 on:** 19 Apr 2007, 06:56 pm »

Quote from: tanchiro58 on 19 Apr 2007, 07:21 am

Quote from: jhm731 on 17 Apr 2007, 09:47 pm
How and where would you connect the ground 5,6,7 to?

If you followed Gary's plan, try disconnecting the wire you have connected to the shield pins 6 &7 and
see if it makes any difference. If you have an earth ground connection in your PSU, you could use a shielded two wire cable (connect the shield to ground) for the power connection from the PSU to the SB, and connect pins 6 &7 to the shield or run a separate ground wire from the PSU to the SB.

jhm731,

You are absolutely right about the true ground for SB3 and DAC when we install SC947-02 Tx and Rx. I just rewired the ground from Rx in DAC to Tx in SB3 then to PS. The noise had reduced to almost I could not hear them. Music has more black ground. Thanks.

Glad to hear this worked for you.

Anthony(Mauimods.com) told me about noise problem on the SB's ground plane, so I guess you can call this the mauimods SB upgrade.

tanchiro58 · « **Reply #94 on:** 19 Apr 2007, 07:16 pm »

jhm731,

I wonder if Anthony at Mauimods knows about grounding the DAC especially MHDT models that most of the AC members have owned. I did the ground for my Renaissance II's pulse transformer last night and the system sounds more dynamic with much less noise, don't you think so? Thanks for the tips anyways.

Tan

rajacat · « **Reply #95 on:** 19 Apr 2007, 07:24 pm »

Has anybody compared the sc947-02 mod (both Mhdt dac and SB as a unit) to the sound quality of the analog output Bolder mod SB3/Platinum upgrade?

Raj

GBB · « **Reply #96 on:** 19 Apr 2007, 09:41 pm »

Quote from: tanchiro58 on 19 Apr 2007, 04:21 pm

Gary,

I am not sure what you mean by floating the shields.

Floating the shields means leaving pins 6 and 7 unconnected.

---Gary

tanchiro58 · « **Reply #97 on:** 19 Apr 2007, 11:34 pm »

Quote from: GBB on 19 Apr 2007, 09:41 pm

Quote from: tanchiro58 on 19 Apr 2007, 04:21 pm
Gary,

I am not sure what you mean by floating the shields.

Floating the shields means leaving pins 6 and 7 unconnected.

---Gary

Gary,

Right now I did connect pins 5,6,7 to ground on PS from SB3 as well as DAC. The sound is totally different than before (no ground) which is more dynamic, defined and spacious. No ground makes the sound dry and bright (easy to get fatigue).

I will try floating the shields tonight. So you mean only pin 5 is connected to ground?

I will let you know. Thanks for the tips.

Tan

GBB · « **Reply #98 on:** 20 Apr 2007, 02:17 am »

Quote from: tanchiro58 on 19 Apr 2007, 11:34 pm

So you mean only pin 5 is connected to ground? I will let you know. Thanks for the tips.

Yes - that's right.

Regarding grounding transformer in the SB3 - I want to be sure I understand how you grounded things. It sounds as if you kept pins 5, 6, and 7 wired together and all of them were connected to the input ground from your new power supply. Is that right?

Thanks,
---Gary

tanchiro58 · « **Reply #99 on:** 20 Apr 2007, 03:47 am »

Quote from: GBB on 20 Apr 2007, 02:17 am

Quote from: tanchiro58 on 19 Apr 2007, 11:34 pm
So you mean only pin 5 is connected to ground? I will let you know. Thanks for the tips.
Yes - that's right.

Regarding grounding transformer in the SB3 - I want to be sure I understand how you grounded things. It sounds as if you kept pins 5, 6, and 7 wired together and all of them were connected to the input ground from your new power supply. Is that right?

Thanks,
---Gary

Gary,

That is what I did for now. I will try to do differently in my other SB3 when I get other SC947-02 as you told floating shields by leaving pins 6 and 7 out of ground, is that right? Thanks again.

Tan