Xono Double take

awsmone

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Apr 6, 2014
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Anyone try doubling up on the Xono so one unit per channel :)

I had heard of people doubling up on XP 25 with apparent improvement

Even saw video of Pass engineer with doubled up XP25's in background

Anyone with any experience of this

Thx

A
 

ack

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I've heard of this XP-25 doubling up from PeterA here... can you share the video?
 

awsmone

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will see power supplies stacked off to the left
 

PeterA

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I would think it is all about lowering noise. That may well be the goal for the new XS Phono, along with more functions. As Ack is discovering, lowering noise can have huge dividends. Two XONOs are certainly more affordable than two XP25s. Perhaps one day I will bring my XP25 over to Ack's place to try this out. I could even try to persuade him to do his noise lowering mods to my unit. That would be fun.
 

XV-1

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May 24, 2010
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Anyone try doubling up on the Xono so one unit per channel :)

I had heard of people doubling up on XP 25 with apparent improvement

Even saw video of Pass engineer with doubled up XP25's in background

Anyone with any experience of this

Thx

A

Pass labs have done that with the Xono in previous shows. before the XP-25 was released they were thinking of releasing the XONO with dual power supplies.
Wally of Wallytractor fame has/had an XONO with dual power supplies. he said an excellent upgrade.

have you upgraded the umbilical cords? users have repported nice upgrades in SQ with the cords from Revelation audio.

http://www.revelationaudiolabs.com/cables-power/

PassageDB-25.jpg
 

ack

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I would think it is all about lowering noise. That may well be the goal for the new XS Phono, along with more functions. As Ack is discovering, lowering noise can have huge dividends. Two XONOs are certainly more affordable than two XP25s. Perhaps one day I will bring my XP25 over to Ack's place to try this out. I could even try to persuade him to do his noise lowering mods to my unit. That would be fun.

Let me talk to him; he may be amenable. :D The latest mod I saw him do this week was to use a separate outlet for the XP-25 and that shaved off another 3dB of hum (as always, testing and adjusting at max preamp again, about 100dB total gain; he places the SPL meter on a mini tripod and points it right at the woofer); apparently, there is hum seeping through the XP-25 power supply from other components (digital, he says), hence this improvement. He now claims that at 66dB gain on the XP-25 - the level he uses for his A90 - he can barely hear any hum at max preamp gain, and he has, thus, switched to experimenting at 76dB gain on the 25 in order to lower it even further. Apparently, he has a lot of time in his hands, and claims that with all mods, he's been able to attenuate hum by 30dB (again, at max preamp again) - not bad and really what a bad boy the XP-25 is OOTB. With respect to hiss, he claims major success there too, and compares the used input versus the unused one on his XP-25 in this video he uploaded the other day http://www.youtube.com/watch?v=eqTcdHdEefo - it looks like the results are quite evident even through computer speakers, and really stunning in person...
 
Last edited:

ack

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Pass labs have done that with the Xono in previous shows. before the XP-25 was released they were thinking of releasing the XONO with dual power supplies.
Wally of Wallytractor fame has/had an XONO with dual power supplies. he said an excellent upgrade.

have you upgraded the umbilical cords? users have repported nice upgrades in SQ with the cords from Revelation audio.

http://www.revelationaudiolabs.com/cables-power/

View attachment 17805


Yes, I also suspect that the power supply is what might be at play here - the XP-25's doesn't look beefy enough and I was looking to use larger capacitors. PeterA also mentioned this umbilical a while ago, but I refuse to use anything with Amphenol connectors, such as this and, oh, Transparent interconnects :D
 

PeterA

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Let me talk to him; he may be amenable. :D The latest mod I saw him do this week was to use a separate outlet for the XP-25 and that shaved off another 3dB of hum (as always, testing and adjusting at max preamp again, about 100dB total gain; he places the SPL meter on a mini tripod and points it right at the woofer); apparently, there is hum seeping through the XP-25 power supply from other components (digital, he says), hence this improvement. He now claims that at 66dB gain on the XP-25 - the level he uses for his A90 - he can barely hear any hum at max preamp gain, and he has, thus, switched to experimenting at 76dB gain on the 25 in order to lower it even further. Apparently, he has a lot of time in his hands, and claims that with all mods, he's been able to attenuate hum by 30dB (again, at max preamp again) - not bad and really what a bad boy the XP-25 is OOTB. With respect to hiss, he claims major success there too, and compares the used input versus the unused one on his XP-25 in this video he uploaded the other day http://www.youtube.com/watch?v=eqTcdHdEefo - it looks like the results are quite evident even through computer speakers, and really stunning in person...

That video is quite impresssive, Ack. Congratulations on your efforts.
 

Barry

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I can't speak to the XP-25, but there are a number of mods possible to the Xono to produce substantially better SQ as described on diyAudio which would be far cheaper than going the dual mono path and probably more effective. They involve parts substitution, as there are electrolytics in the signal path (ugh), better parts choices for the RIAA network, and zeroing out the DC offset with a variable resistor so that there is no need for the 10uF output coupling cap. The overall result is a substantial improvement in transparency and especially tonal color that does not exist in the stock unit. There are downsides of course. It takes temerity to even suggest modifying a Pass Labs product, let alone do it....
 

ack

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That video is quite impresssive, Ack. Congratulations on your efforts.

Thanks. I should also point out that noise from the unused input does leak into the used one, therefore I have "plugged" the unused input... but not with those RCA caps sold out there, but Vishay resistors within an RCA plug as seen here http://www.whatsbestforum.com/showthread.php?8786-Custom-cartidge-loading-resistors (didn't I show you these last year?!?). That quiets down the unused input significantly, almost to the point of being indistinguishable from the used one; but that's only testament to the used input's noise reduction, considering that those resistors are probably the shortest signal path you can simulate, though still slightly more noisy than the entire used-input apparatus going all the way to the cartridge and back. For the video, I took out those RCA plugs to demonstrate a point.
 

PeterA

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Thanks. I should also point out that noise from the unused input does leak into the used one, therefore I have "plugged" the unused input... but not with those RCA caps sold out there, but Vishay resistors within an RCA plug as seen here http://www.whatsbestforum.com/showthread.php?8786-Custom-cartidge-loading-resistors (didn't I show you these last year?!?). That quiets down the unused input significantly, almost to the point of being indistinguishable from the used one; but that's only testament to the used input's noise reduction, considering that those resistors are probably the shortest signal path you can simulate, though still slightly more noisy than the entire used-input apparatus going all the way to the cartridge and back. For the video, I took out those RCA plugs to demonstrate a point.

Ack, I just looked at your link and don't recall seeing these before. Do you insert them in all of your unused RCA inputs? Have you tried them on your pre amp also? Sounds like its time for another visit.
 

ack

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I only use them on the XP-25; we'll arrange for a visit...
 

thekong

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May 10, 2012
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Yes, I have tried Dual Xono setup, and got considerable improvements in every area, especially in the effortless presentation!

The first thing that comes to people’s mind is probably “double up power supplies”. However, I think there is something more than that going on!

I was using a 1 module, 1 ps, Pass Lab active Xover for 2 ways Xover. Since I planned to go 3 ways, I got another module with no extra ps. While I didn’t see any reason in doing so, one of my friends insisted that I tried the dual mono set up, using only half of each module, and sharing 1 single ps. To my surprise, there was considerable improvement! Actually, that was what prompted us to try the Dual Xono setup!

So, I think, other than the beefed up ps, the 2 channels’ amplification stages actually have some interference with each other when sharing a single chassis!

Here is a photo of a recent phono shootout among our group

http://i238.photobucket.com/albums/ff64/evp1312/P1040150sunset_zps6b3d6ca7.jpg
 

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