sc947-02 group buy

rajacat · « **Reply #60 on:** 17 Apr 2007, 07:08 pm »

Hi Josh,

2 for me please.

Thanks for organizing this group buy.

Raj

jhm731 · « **Reply #61 on:** 17 Apr 2007, 08:02 pm »

tanchiro58 -

I agree with you about value of mods.

I've had SC947-02 pulse transformers in my digital gear since they were introduced.

They make a lot more $ense than sticking a silver or gold Bybee on the SB's digital output.

Have you or Gary tried using the transformer without connecting the shield to the SB's ground plane,
if so can you hear any difference?

PS- have you try this SB tip:
To optimize the CPU and memory for streaming: Select Control
Panel/System/Advanced/Performance Settings/Advanced/Background
services and System cache.

JoshK · « **Reply #62 on:** 17 Apr 2007, 08:13 pm »

by the way, is anyone here in the GB outside the US? if not, should we opt for the leaded version? Europeans should order the lead free, so if we are mixed company maybe we all go lead free.

LMK

tanchiro58 · « **Reply #63 on:** 17 Apr 2007, 08:25 pm »

Quote from: JoshK on 17 Apr 2007, 08:13 pm

by the way, is anyone here in the GB outside the US? if not, should we opt for the leaded version? Europeans should order the lead free, so if we are mixed company maybe we all go lead free.

LMK

Josh,

You should double check with Kathy or Jon. Kathy told me the price of $16.50 (I guess they discount for the lead free $11.50 if you got the list to 50 pieces- now you got 54? Wow, I could not believe this!!) is for lead free but I do not know what Jon told you.

tanchiro58 · « **Reply #64 on:** 17 Apr 2007, 08:35 pm »

Quote from: jhm731 on 17 Apr 2007, 08:02 pm

tanchiro58 -

I agree with you about value of mods.

I've had SC947-02 pulse transformers in my digital gear since they were introduced.

They make a lot more $ense than sticking a silver or gold Bybee on the SB's digital output.

Have you or Gary tried using the transformer without connecting the shield to the SB's ground plane,
if so can you hear any difference?

PS- have you try this SB tip:
To optimize the CPU and memory for streaming: Select Control
Panel/System/Advanced/Performance Settings/Advanced/Background
services and System cache.

jhm731,

I do believe your suggestion about the ground which is usually very noisy. But last time I built my PS and forgot to connect to the ground my SB3 did not work (I had to use myself as ground). Then I realize I could not stand there day long to be grounded.

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

F-100 · « **Reply #65 on:** 17 Apr 2007, 08:39 pm »

Quote from: jhm731 on 17 Apr 2007, 08:02 pm

PS- have you try this SB tip:
To optimize the CPU and memory for streaming: Select Control
Panel/System/Advanced/Performance Settings/Advanced/Background
services and System cache.

This is an excellent tip if you're running SlimServer on Windows XP. Tanchiro58 & I are using dedicated music server with Linux based system (ClarkConnect).

Builder Brad · « **Reply #66 on:** 17 Apr 2007, 08:58 pm »

Hi Josh,

I am in the UK and happy to have pb or no pb - makes no difference to me!, and as the transformers will be sent via post as a "gift" I would hope that our customs will not be too concerned with the contents meeting the ROHS directives.

Brad

posternutbag2000 · « **Reply #67 on:** 17 Apr 2007, 09:40 pm »

Include me for one as well...I ordered one prior to this group buy and am going to install it tonight in my SB3...I guess I'll get another to try and install on my Paridisea DAC...Josh thanks for organizing this....I received mine about 5 days after ordering it...Shipped in a small padded envelope with 3 stamps for postage...Just an FYI for everyone...

anyway 1 for me, please.

Thanks,
Scott

jhm731 · « **Reply #68 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 · « **Reply #69 on:** 18 Apr 2007, 01:44 am »

I just spoke to mauimods.com.

Anthony is offering the audiocircle group SC947-02s for $10.@.(plus shipping) for a 50+ order.

He has them in stock.

JoshK · « **Reply #70 on:** 18 Apr 2007, 03:34 am »

thanks, i'll get in touch with Anthony tomorrow.

brj · « **Reply #71 on:** 18 Apr 2007, 04:28 pm »

For those of us just tuning in that may have missed the answer while skimming the thread at high speed... what are you using this transformer for on the SB?

(My first guess based on references to "digital" was that people were using it on the digital out to guarantee a true 75R connection and minimize ground issues, but that would only matter if you were actually using the digital output...)

Thanks!

P.S. Josh, did you ever get my PM a while back asking about Neutrik Speakons? No problems - just curious.

JoshK · « **Reply #72 on:** 18 Apr 2007, 05:17 pm »

Brian,

Yes, this is used on the SP/DIF digital output stream. I am not sure about the whole rationale for tx's in the digita transmission, but the idea is not new and you can reference the AES papers on SC's website for their explanation of things. However, I could see how it might have some benefits with ground loop breaking, and maybe even some noise rejection as well as what you said about it providing a more consistent 75R load. I fully intend to replace the RCA's with true 75 ohm BNCs while I am at the hacking.

I did get your PM about neutrix but I completely forgot to respond. I read it when I didn't have a chance to reply and then forgot about it later. It happens from time to time when I don't respond to someone. What about Speakon's were you asking?

brj · « **Reply #73 on:** 18 Apr 2007, 05:43 pm »

Thanks, Josh! Sounds like it would make for a nice simple project for a new DIY guy, but that a whole new housing for the SB would be needed... things to ponder...

I'll dig up the Neutrik PM, as I don't want to derail this thread.

tanchiro58 · « **Reply #74 on:** 18 Apr 2007, 05:46 pm »

Quote from: JoshK on 18 Apr 2007, 05:17 pm

Brian,

Yes, this is used on the SP/DIF digital output stream. I am not sure about the whole rationale for tx's in the digita transmission, but the idea is not new and you can reference the AES papers on SC's website for their explanation of things. However, I could see how it might have some benefits with ground loop breaking, and maybe even some noise rejection as well as what you said about it providing a more consistent 75R load. I fully intend to replace the RCA's with true 75 ohm BNCs while I am at the hacking.

I did get your PM about neutrix but I completely forgot to respond. I read it when I didn't have a chance to reply and then forgot about it later. It happens from time to time when I don't respond to someone. What about Speakon's were you asking?

Josh,

Correct me if I am wrong. I have tried to swap the RCA with BNC to my ear I do not hear a bit change except with transformer and think every digital connector even though 75 Ohm or 110 Ohm it should have a transformer to be a true 75 or 110 Ohm. I did follow Jon Paul research and see (also like you said) a lot of reducing noise at the high frequency level. I usually listen to the CDs that had recorded with too much high frequency (maybe they use equalizer). Therefore, I believe digital output and input transformers are good reference for modifying.

Brian T. · « **Reply #75 on:** 18 Apr 2007, 06:52 pm »

Quote from: JoshK on 18 Apr 2007, 05:17 pm

...providing a more consistent 75R load. I fully intend to replace the RCA's with true 75 ohm BNCs while I am at the hacking.

Hi Josh,

Rather than using BNC’s, (making up the cables is a PITA), I think that a fully balanced approach might be better. Figure 34 of the ‘reference’ applies. Any mismatch of impendance created by the XLRs and balanced cable should be offset by the improvement in Common-Mode Rejection. Of course, mounting the XLR on the SB case might be a problem. I am putting mine into a 19” rack so space is not a problem for me.

Adding the ferrites and choke ‘a la Fig 38’ could be fun!

Cheers!

krikor · « **Reply #76 on:** 18 Apr 2007, 08:44 pm »

Looking at scientific conversions website, I notice that the SC961-04 transformer can be used to convert 75ohm unbalance output to a 110ohm balanced output. Given that my DAC has a 110ohm AES/EBU balanced input, would there be any benefit to using one of these transformers instead so that I can run balanced cable? Is this even possible?

crooner · « **Reply #77 on:** 18 Apr 2007, 10:00 pm »

I also plan to use BNCs in my upcoming "Super Squeezebox" project.
The digital cables from Stereovox have BNC terminations with snap-in RCA adapters. I got a used HDXV model for around $70. These were designed by the same fellow who developed the famed Kimber Illuminati.

JoshK · « **Reply #78 on:** 18 Apr 2007, 11:20 pm »

Quote from: crooner on 18 Apr 2007, 10:00 pm

I also plan to use BNCs in my upcoming "Super Squeezebox" project.
The digital cables from Stereovox have BNC terminations with snap-in RCA adapters. I got a used HDXV model for around $70. These were designed by the same fellow who developed the famed Kimber Illuminati.

That is the digital cable I am using too. But anyway, making bnc terminated cables is a snap with the right crimper.

JoshK · « **Reply #79 on:** 18 Apr 2007, 11:24 pm »

Brian,

Correct me if I am wrong, but I understood the AES/EBU standard to be more than just SP/DIF over an XLR and that it really does need a different Tx/Rx, and they are different standards, not just an XLR cable. True, using an XLR cable with a center tapped tx at each end will provide CMR.

My DEQX provides an RCA and an XLR input, not sure if the XLR is real AES3.

P.S. BNC's come in 50 ohm and 75 ohm characteristic impedances, with 50 ohm being the common one. However, if you specifically search for them 75 ohm ones can be had. RCA's provide typically greater than 110 ohm Z from my understanding. This has to do with their diameter and geometry, so even Canare's "true 75 ohm RCA" is not 75 ohms. Whether one can hear this or not is a different story altogether. But if audiophiles are going to worry about difference in coaxial cables, one is led to believe that getting the basics right first should be the first course of action.