Breakthrough mod to reduce jitter for OR5 and SM

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audioengr

Re: Breakthrough mod to reduce jitter for OR5 and SM
« Reply #20 on: 16 Mar 2013, 08:30 pm »
Very impressive work, Steve. For what it's worth, Stereophile measured about 70psec from the Simaudio Moon 650D, an $8K CD player/DAC, so that's good company to be in. Most of the average USB > S/Pdif converters are in the 300+ range.

The SM is actually much better than that.  The transformer and galvanic isolation is the impediment.  I'm getting 20psec or less once I remove the transformer.  I'm thinking about winding my own version now. :scratch:

I will post more plots soon.

Steve N.

audioengr

Re: Breakthrough mod to reduce jitter for OR5 and SM
« Reply #21 on: 17 Mar 2013, 12:38 am »
Here is a plot using a new transformer (these may take time to procure):




And just for grins, I did basically the same circuit, but no transformer:




Even though the new transformer jitter is on the order of 40psec, I can hear the difference with no transformer at <20psec.  It's particularly noticable in vocalists.  More solid and 3-D.

Now, what to do????

I am thinking because the edge-rates are so fast with the no-transformer output that I need to sell a cable to go with that mod if I do it.  Lesser cables will puke with it I think :o  Even my own Bitmeister is not good enough.  The user must also use the same AC outlet for the SM and DAC.

The good thing about the transformerless solution is that I can do it right away, no waiting for parts.

In the meantime, I'm enjoying it :thumb:

Steve N.

paul79

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Re: Breakthrough mod to reduce jitter for OR5 and SM
« Reply #22 on: 17 Mar 2013, 02:18 am »
LOL! Well Steve, hang on to my SMR till you get all the bugs worked out. No hurry at all.

I am using an API Power Wedge Ultra 116 that features Balanced A/C, and some trick filtering. It has individual isolation transformers for each outlet. Would the no transformer solution for the SMR be a problem here? I power the entire system off this thing... It works very well btw... Even for the amps.

audioengr

Re: Breakthrough mod to reduce jitter for OR5 and SM
« Reply #23 on: 17 Mar 2013, 03:02 am »
LOL! Well Steve, hang on to my SMR till you get all the bugs worked out. No hurry at all.

I am using an API Power Wedge Ultra 116 that features Balanced A/C, and some trick filtering. It has individual isolation transformers for each outlet. Would the no transformer solution for the SMR be a problem here? I power the entire system off this thing... It works very well btw... Even for the amps.

Well if the two things are not grounded together or they are on the same ground, it should be good.  It's only a problem if the grounds are different.

Steve N.
« Last Edit: 17 Mar 2013, 04:55 am by audioengr »

audioengr

Re: Breakthrough mod to reduce jitter for OR5 and SM
« Reply #24 on: 17 Mar 2013, 06:49 pm »
Here is my current thinking:

Two upgrade options, OTL and OT (Output TransformerLess and Output Transformer):

OTL option:
If you have a DAC like the Overdrive SE with galvanically isolated S/PDIF coax input, remove the transformer from the SM or OR5 and make the other circuit changes.  Only one transformer is needed for galvanic isolation.  This also removes the RCA output jack on the SM, so includes a BNC-RCA adapter.  Include a 4-foot BNC-BNC 75 ohm cable of high quality with the mod.  This achieves less than half the jitter of the OT option.

OT option:
If you have a typical DAC, replace the transformer in the SM or OR5 and make the other circuit changes.  This may require hand-tuning with the scope to optimize jitter performance.

Pricing for OT will be around $150.00 plus shipping.

Pricing for OTL depends on the cable cost.  I expect it to be in the $200-$250 range for mod and cable.  For those with the right DAC, this could save you hundreds on the cable.

Steve N.

paul79

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Re: Breakthrough mod to reduce jitter for OR5 and SM
« Reply #25 on: 17 Mar 2013, 07:21 pm »
Sweet! My Bel Canto has galvanic isolation on all the S/PDIF inputs... So, if you think going without the transformer is the best option, then make mine that way please.

audioengr

Re: Breakthrough mod to reduce jitter for OR5 and SM
« Reply #26 on: 17 Mar 2013, 07:23 pm »
Sweet! My Bel Canto has galvanic isolation on all the S/PDIF inputs... So, if you think going without the transformer is the best option, then make mine that way please.

Okay, will do.

Steve N.

tpaxadpom

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Re: Breakthrough mod to reduce jitter for OR5 and SM
« Reply #27 on: 18 Mar 2013, 04:09 am »
Steve, ship me one of the modded units and I will measure it on Audio Precision 2722, then you can compare numbers with the old one John Atkinson measured in Stereophile. You can ship it with the cable of your choice (bnc will eliminate the need for adapter on AP2722).

path73

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Re: Breakthrough mod to reduce jitter for OR5 and SM
« Reply #28 on: 18 Mar 2013, 09:11 am »
Steve, a few questions below:

1) If my DAC only has RCA input, does this mean that I would not be able to use the OTL version?

2) Would the usage of a BNC-RCA adapter plug be an option on the DAC side right after your BNC-BNC cable or would it degrade sound more than just getting the OT version?

3) Would you offer a BNC-RCA version of your custom coax cable as well (for us non-BNC DAC owners)?

4) Do you remember if the Northstar m192 DAC you modded for me a few years ago already has isolated coax inputs, as required for the OTL version?

5) Just out of curiosity, when listening to your Overdrive (still on my wishlist) how does the sound compare (jitter-wise) between
   a) coax input from a modded OTL OR5/SM
   b) I2S connection from OR5
   c) internal direct USB connection (is this still best since no external digital cable is needed?)

Best, /patrick

audioengr

Re: Breakthrough mod to reduce jitter for OR5 and SM
« Reply #29 on: 18 Mar 2013, 04:25 pm »
Steve, ship me one of the modded units and I will measure it on Audio Precision 2722, then you can compare numbers with the old one John Atkinson measured in Stereophile. You can ship it with the cable of your choice (bnc will eliminate the need for adapter on AP2722).

I have an OR5 that I can use for this.  I need to modify it first, probably to the transformerless version (OTL).

Send me an email about this.

Steve N.

audioengr

Re: Breakthrough mod to reduce jitter for OR5 and SM
« Reply #30 on: 18 Mar 2013, 04:32 pm »
Steve, a few questions below:

1) If my DAC only has RCA input, does this mean that I would not be able to use the OTL version?

No, I may offer it with RCA also.  I just need to find a suitable RCA plug or us a BNC to RCA adapter.  I may make the cable optional.

2) Would the usage of a BNC-RCA adapter plug be an option on the DAC side right after your BNC-BNC cable or would it degrade sound more than just getting the OT version?

IT will probably degrade a bit.

3) Would you offer a BNC-RCA version of your custom coax cable as well (for us non-BNC DAC owners)?

Possible.

4) Do you remember if the Northstar m192 DAC you modded for me a few years ago already has isolated coax inputs, as required for the OTL version?

IT does not have transformers, so you need the OT version.

5) Just out of curiosity, when listening to your Overdrive (still on my wishlist) how does the sound compare (jitter-wise) between

   a) coax input from a modded OTL OR5/SM
   b) I2S connection from OR5

I think the OTL S/PDIF coax might be better.

   c) internal direct USB connection (is this still best since no external digital cable is needed?)

The OR5 with OTL has overtaken everything because of the external Hynes supply.

Steve N.

KBK

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Re: Breakthrough mod to reduce jitter for OR5 and SM
« Reply #31 on: 18 Mar 2013, 05:07 pm »
Hey Steve,

I used to, in my CRT projection days..I used to transmit the HD video in analog. Hardwired inside the Projector, and hardwired into the video card.

video card modded, entire CRT projector modded, and so on.


I used mini RG-62 as cables.

I custom tweaked the impedance of each, by hand, using my eye, with variable caps and variable resistors.

I did this at each end of each cable, painstakingly, and slowly wound it down to the best pairing of end terminations for each cable. Took a month or more. Brutal work.

People thought I was nuts, but the system was so tweaked, that this effort, the effect of it...was readily visible. It made it get that much closer to perfection. I took quite the beatings for all those experiments and results, over at AVSforum.

It just goes to show that a thing can be very real, and it's reality can simply be in the observing  and noting of it. That it does not need to be verified via measurement before it is allowed to exist.

That the ears are the most complex system of sensory input in the human body. More neural horsepower is dedicated to hearing than nay other sense. That the senses do not need to be of a visual nature in order for the given sense to verify. Hearing can be believing too, as it is a case of even more neural input than any other sense.

I trust my ears  to about as much as I trust my capacity for rumination and deduction. That some of us self trust, hear better and ruminate a bit more objectively than others might. Even though it may be delegated as being entirely subjective due to no measurements being applied.  Many of us are like this. And many are not. Thus the arguments are born.

It is good that you have measured it, and please whack a few linear-minded moles for me, they need it.

kzhtoo

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Re: Breakthrough mod to reduce jitter for OR5 and SM
« Reply #32 on: 18 Mar 2013, 06:38 pm »
Hi Steve,
(1) I'm thinking to upgrade my digital RCA cable, possibly Cabledyne Silver or Nordost Heimdall 2 (I'm currently using Grover digital RCA cable with a RCA to BNC adapter on SM side). After I read this thread, I'm thinking OTL option for my SM. It seems to be more user-friendly to those who aren't tech savvy like myself. Will I still be able to use "other cables" mentioned above or it must be used with yours? My dac is Metrum Octave that only has RCA inputs.

By the way, I'm also on your waiting list for your modded version of Paul Hynes 12v power supply for my SM.

(2) One other separate question. Is there a specific reason you recommend digital cable to be 1.5m (not 1m or 2m)?

Best,

audioengr

Re: Breakthrough mod to reduce jitter for OR5 and SM
« Reply #33 on: 18 Mar 2013, 07:27 pm »
Hi Steve,
(1) I'm thinking to upgrade my digital RCA cable, possibly Cabledyne Silver or Nordost Heimdall 2 (I'm currently using Grover digital RCA cable with a RCA to BNC adapter on SM side). After I read this thread, I'm thinking OTL option for my SM. It seems to be more user-friendly to those who aren't tech savvy like myself. Will I still be able to use "other cables" mentioned above or it must be used with yours? My dac is Metrum Octave that only has RCA inputs.

You can certainly use any cable you want.  I was just surprised that even my Bitmeister was outclassed by the silver coax 75 ohms with BNC's that I built.  It is a 4-footer.  That's why I want to make an inexpensive cable that delivers.

Quote
(2) One other separate question. Is there a specific reason you recommend digital cable to be 1.5m (not 1m or 2m)?

Yes, 1.5m is a good middle-ground that works with all interfaces.  I think certainly with OTL you could go to a 1m length, but never 0.5m.   The reflections come too soon and effect the jitter.  Longer is okay, but starts to affect performance if too long.

Steve N.

Best,
[/quote]

path73

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Re: Breakthrough mod to reduce jitter for OR5 and SM
« Reply #34 on: 19 Mar 2013, 06:55 pm »
Steve,

1) Are you now actually able to measure the performance degradation in terms of jitter which occurs when signal goes through a digital coax cable (e.g. using the SM output and comparing jitter with to without cable inserted)?

2) Do you think about offering your newly designed/assembled digital coax cable as a stand alone product as well? (the price / performance ratio seems rather astonishing)

/patH

audioengr

Re: Breakthrough mod to reduce jitter for OR5 and SM
« Reply #35 on: 19 Mar 2013, 07:00 pm »
Steve,

1) Are you now actually able to measure the performance degradation in terms of jitter which occurs when signal goes through a digital coax cable (e.g. using the SM output and comparing jitter with to without cable inserted)?

I have not specifically looked at this yet.  All I know is the 75 ohm coax I made sounds better than my expensive Bitmeister for the first time ever.

Quote
2) Do you think about offering your newly designed/assembled digital coax cable as a stand alone product as well? (the price / performance ratio seems rather astonishing)
/patH

I am thinking about this.  They are not too difficult to build, but I still have to buy an expensive crimper and make the optimum size crimps from scratch, probably brass tubing.

Steve N.

path73

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Re: Breakthrough mod to reduce jitter for OR5 and SM
« Reply #36 on: 19 Mar 2013, 07:01 pm »
Steve,

Are your latest plots of jitter measurements on modded SM in OT and OTL version done with standard wall-wart power supply or with your modded Paul Hynes SR3-12 power supply?
(on the first measurement plots you indicated "standard wall-wart")

/patH

audioengr

Re: Breakthrough mod to reduce jitter for OR5 and SM
« Reply #37 on: 19 Mar 2013, 07:52 pm »
Steve,

Are your latest plots of jitter measurements on modded SM in OT and OTL version done with standard wall-wart power supply or with your modded Paul Hynes SR3-12 power supply?
(on the first measurement plots you indicated "standard wall-wart")

/patH

These are all with the wall-wart.  The Hynes is in the system and I'm listening to it so I don't want to take it out :nono:

Steve N.

audioengr

Re: Breakthrough mod to reduce jitter for OR5 and SM
« Reply #38 on: 22 Mar 2013, 09:23 pm »
I have been getting some ORs and SM back for this mod already, so here is a result for an OR5 with OT mod:




Here is a loaded OR4 before the OTL mod - not shabby  :thumb::





Here is the same loaded OR4 after the OTL mod - more than cuts it in half:




All of these used the wall-wart that I am currently shipping with OR5 and SM.

BTW, I did a shootout between the SM with OTL and the OR4 with OTL above.  The OR4 beats the SM.  I used Jimi Hendrix "all along the watch tower" with both 96 and 44.1 SM with OTL.  Its not detail that is different.  There just seems to be more HF energy and jump factor with the OR4.  I think this is one artifact of upsampling.  If you like a slightly more mellow laid-back sound, but all of the detail and same imaging, the SM does this.  Vocalists were virtually identical as well as soundstaging.  Its the percussion where the OR wins.  If you are using PM rather than my favorite version of Amarra, they would probably be identical.

Steve N.

andrewd01

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Re: Breakthrough mod to reduce jitter for OR5 and SM
« Reply #39 on: 22 Mar 2013, 11:04 pm »
Thanks Steve, I think that is my OR4!  Just clarifying that the standard deviation of the jitter is the stat that matters, they all seem to have the same mean.  I guess the mean is some function of the sample rate, and the  scatter around that mean is related to the timing errors.

looking forward to hearing the modded OR4!

I was interested to read your comments that a modded OR5 with hynes power supply beats the inboard USB of overdrive. What are your thoughts for the future development of the overdrive? I can see it going two ways: a) try to implement the same power supply improvements to the inboard USB interface through upgraded substation or b) conclude that perhaps external USB interface has technical benefits and consider the option of a trimmed down overdrive which does not have an internal USB interface. 

Thanks for doing the mod on my OR4 so quickly and posting the jitter analysis.  Great to see you are really pushing the boundaries of what is possible in digital audio.

Cheers,
Andrew