ack's system - end of round 1
- Thread starter ack
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The Shunyata "v2" Loom: 18 cables + Denali v2
1) Cords: 14 Venom V10, V12 NR and XC
2) Power conditioning: Denali 6000/v2
3) Signal: 3 Delta v2 RCA analog interconnects for sources
4) Digital: Sigma v2 AES/EBU
Well, what a ride... it all started with a Venom V12 NR cord last August, and it quickly snowballed; I'll make it brief:
- The latest star is the Sigma v2 AES/EBU, which has elevated digital to analog levels, with phenomenal timbre, 3-dimensionality, linearity and lack of distortion; a breathtaking digital cable. The balanced connection addresses differential mode noise, this cable addresses common mode noise https://techweb.rohm.com/knowledge/emc/s-emc/01-s-emc/6899
- All equipment is connected to the Denali v2, which sits front and center... what a device! Really serious drop in noise floor all around. It can easily handle amplifiers
- The Delta v2 interconnects have proven to be extremely fast cables, increasing realism in their own way, giving a sense that they store no energy; thrilling results
- The Venom cords are everything I was hoping for: complementary to the Denali, fully shielded with no radiated magnetic fields, very fast on the amps, very effective in further reducing noise and increasing realism
... and as I was writing this, power went out for 2hrs, and now the system is again less resolving, much softer, less dynamic, less enjoyable; it sounds like before all the Shunyata power treatments. It will be interesting to see how long it takes to come back to life, maybe perhaps another 4 days?!? Two weeks?!?!? I did anticipate this would happen on power outages, thinking that these noise treatments are non-invasive and thus require time to re-activate.
I believe it's a combination of three things: the Denali primarily, which did take a few days to show results before; then, the preamp which needs 24 hours to settle, a well-known fact; and lastly, the cords, to a much lesser degree, which take a couple of hours to render full results.
This morning, things are much better, but not 100% there yet. I've learned to be patient with these power treatments, having made these changes one step at a time over a 9 month period.
Returned it, with much hesitation. Decided to stick with RCA, because the balanced input in the preamp by design reduces dynamic headroom. The all-copper Venom is much better than the Copper-Silver RCA version. Very highly recommended and an incredible bargain. I would easily buy it again if I had a need for a balanced cable.
Day 3 after the power outage and the Denali is back probably 95% - FM radio sounding so good again, along with everything else. This is basically how long it took originally to render results. Glad I jumped in before the recent price increase to $5500, and even at that price it's a bargain.
Pass XP-25 Phono shielding & mods revisited and compacted
Lately, I've been helping a few folks deal with hum and noise issues with their own XP-25s, and we decided it might be best to compact all of my experiences in a single post here. I am glad that these folks are undertaking the same or similar efforts based on my past posts on this site, and the results are rewarding.
First and foremost, noise masks issues, and therefore, removing noise can expose problems elsewhere, while improving this unit. So my mods are not without pain. Case in point, I also had to lower the arm and adjust SRA down as well as dampen the tonearm at the pivot point with VPI's own thick oil they provide. So although resolution, dynamics and timbre improve when noise is attenuated, additional changes may also need to be applied elsewhere, perhaps to cabling as well (e.g. one may have been using silver interconnects to boost the treble a bit, only to find out that the sound is bright now), and this is true irrespective of the noise attenuation approach (i.e. power conditioning may also result in changes in the system to restore balance).
The XP-25 is, as discussed years ago, particularly prone to noise - really bad; so bad, that even the reviewers point that out; here's an excerpt from the HiFi+ review, and it's an understatement:
The problem is that, only when you start removing noise from this unit will you realize how much of it is there. So let me state my original goals when I started tinkering with it, and the approach I took:
1) Reduce or eliminate hum and RF noise so that I can turn up the gain to its native 76dB (all others sound softer) and increase dynamics and dynamic headroom; ditto for the loading which should be 47K. To that extent:
- mumetal and copper shielding was applied all around the power supply and main unit, and I mean all around but the facades; the back of the main unit is especially prone to hum pick up. I used 2-inch wide copper tape with adhesive backing, and 4-inch wide mumetal with adhesive backing (sold by the linear inch) from edmo.com or opentip.com. Others have emailed me that they are experimenting with 6mm-thich mumetal under the main unit. The reality is that I have gained significant sonic results by applying mumetal to the MIT boxes, the DAC power supplies and elsewhere. The MIT boxes are particularly prone as well, to the point that MIT are now doing 5-layer shielding in some of their products.
- I replaced the silly printer-cable umbilical with the fabulous Tubulus Argentus DB-25, at the recommendation of @spiritofmusic - https://www.tubulus.net/product/tubulus-argentus-db-25-cable/
- I dumped the stock power cord in favor of Shunyata Venom V10 NR, and everything is now plugged into a Denali 6000S/v2
- I replaced the power diodes in the power supply with the sensational Vishay VS-HFA15TB60-M3, and although their power rating is overkill (15A), they just work so well because noise is so low; this was a recommendation by another fellow here at the site, who's not generally active; I placed the same diodes in my Alpha DAC and tuner. https://www.vishay.com/docs/96191/vs-hfa15tb60-m3.pdf
(One thing I would NOT do is replace the power supply caps - Pass are big on safety, and claim theirs were chosen for that primary purpose)
- Plugged the unused input with RCA plugs sporting 100ohm resistors; this is an easy A/B test: turn the volume all the way up using one input and plug the other; there is leakage
2) Be able to use the native XLR-out (it's a true balanced design), because the RCA outputs are colored as if there is a summation circuit (same situation as with the Yggy2 DAC). Noise-reduction was the ticket there as well
3) Reduce capacitance in the signal path as much as I can - so the loading 100pF capacitors - C21 and C22 - were removed from the main unit
4) Vibration control with Isodamp underneath the main unit, replacing the stock feet, also sold by the linear inch or foot, or sheets (amazon etc)
After all this work, the results are truly phenomenal; no hum even after turning the preamp to the max, about 100dB gain. In terms of order of significance of the mods, the biggest effect was the shielding of the two boxes, followed by the Shunyata Venom V10 NR cord & Shunyata Denali 6000S/v2, followed by the umbilical, followed by the diodes in the power supply, followed probably last by the transformer mumetal shield.
EDIT: Another member's reaction to the shielding:
No need to repeat pictures, but I will add references
References:
Chasing hum: Two great iPhone apps to isolate hum in your analog chain
Being OCD with all things audio, I have taken on a task to minimize or eliminate any residual hum in my Pass XP-25 (as rendered at max preamp gain) and have found a number of interesting things. For one, a lot of owners claim the XP-25 is very susceptible to magnetic fields, and place them as...
www.whatsbestforum.com
ack's system - end of round 1
Thanks Ian. Corner frequency is the -3dB point people typically quote. It's fun to watch digital do presence, timbre and articulation, separation of instruments. The technology is sound, the implementation is apparently very hard.
www.whatsbestforum.com
ack's system - end of round 1
Congratulations to your son who put in the passion and hard work, to his parents who supported him and probably suffered in the beginning, and to the Boston Latin School for providing the opportunity and context for such an achievement. He is very lucky to be able to attend such a fine school...
www.whatsbestforum.com
ack's system - end of round 1
ack What comprises Spectral's reference system, the one they use to voice their electronics? Speakers in particular. As far as I can recall, its a mystery.......
www.whatsbestforum.com
ack's system - end of round 1
I knew someone would pick up on that; you are looking at the bottom of the connector (compare with its symmetrical brother on the other side), and it's actually naked around that area, exposing the gold-plated (?) leads, and it's indeed seated just fine; my guess is that it facilitates easy...
www.whatsbestforum.com
-ack
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I was one of the pests bugging Ack. Public thanks for compiling all you have learned in one place. I have had my XP25 for about a week and just playing around confirms Acks finding about transfer induced noise being picked up. I have a sheet of 6mil Mu Metal coming, another sheet of thinner Mu Metal, and copper foil tape on the way. Plan is to shield, shield, and shield some more. Tubulus umbilical is also on the menu.
All right, one more question. Was thinking over your post last night and while the diode change and removal of the 100 pF caps makes at lot of sense I know I wouldn't trust myself to do that. However, I remembered this morning that there is someone local that does repair/rebuilds of vintage McIntosh amps as well as vintage guitar amp repairs. I am going to reach to him about the diode replace/cap removal. Just so I can give him accurate info, where you able to do both of these with the PCBs still installed in the chassis or did you have to pull the PCBs to do this correctly?
Killing the noise within - the 3M AB5100SHF
I would normally wait quite some time to post impressions of a tweak, but this is so shocking and so good that it can't wait. My friend @MadFloyd introduced me to one of his audio buddies with an impressive technical resume, to say the least. So this is not my tweak, but his, and I just implemented it.To make a long story short, this absorptive material's "Common uses include mobile phone (SAR reduction), computer, digital still camera, RF block, military equipments for radar avoidance and stealth performance" according to the spec https://multimedia.3m.com/mws/media/960653O/3mtm-emi-absorber-ab5000shf-series-halogen-free.pdf and costs some $63 for a sheet of 8x12 inches. There is another version of it, AB1500HF, which costs $1500. For us consumers, we may find it in our cell phones, to isolate the various components. I bought mine from https://www.mouser.com/ProductDetail/3M-Electronic-Specialty/AB5100SHF?qs=gMfM3zrbS4r0qTugzC4tdw== . Per spec, there are various thickness versions, this one is 1mm. They all have an acrylic adhesive.
I used it to shield the digital and analog components of my two DACs, and the results even without the requisite long warm-up are shocking. It's pliable - a resin or resins with metal parts, but NOT conductive - and can easily be cut. RF was measured around the boards before and after the application with the TriField TF2 device that I wrote about in its own thread.
The material is claimed to be effective in the 1.8-1.9GHz range according to the specs, which is GSM cell phone territory, but I can attest it works for what we need it for. This is the material digital designers must be using.
Here's Iteration 1 on the Yggy2, with the shield over every DSP, integrated circuit or transistor, on all boards:
After letting it "soak" overnight, the results were astounding; then it was time for Iteration 2, over 3 out of the 4 sides of the analog board:
There is a also divider between the analog and digital sections as well.
At the same time, the Alpha DAC was also shielded in two steps (pics do not represent the final shape, which covers all of the analog section):
Sonics
1) There is exceptional linearity in both DACs, with string tone TO DIE FOR and I don't use this term lightly, cello like never done before in here. Microdynamics and note sustain something I have never heard before from digital
2) Bass articulation unlike anything I've had in here before from digital; organ pedals really tight and deep
3) Power, presence and macrodynamics approaching direct-to-disc analog
4) An elevated truth-of-timbre, coming close to the A90
5) The Yggy sounds like a fine MC cartridge, and I can no longer detect any off-notes
6) HDCD out of the Alpha is something be reckoned with, in digital playback
7) My son commented how un-distorted and linear the sound was, with great piano and trombone body
8) With the right recordings, exquisite treble finesse
9) A convincing argument that redbook can actually sound exceptional, with no signs of digititis
I should add that the Shunyata Sigma v2 AES/EBU installed lately is mandatory in rendering the above results. This material is claimed to outclass the somewhat similar product by Stillpoints.
Finally, here's a set of CDs (one of a sensational trilogy) by a quartet that our friend @VLS introduced us to, which extols string tone - goosebump territory:
Digital has come a looooong way
-ack
Ack
I'm surprised u do not put dampening material on top of all the caps. It is the only tweak I have done on my MSB S II dac and power supplies (probably 45 caps in total) and the improvement is substantial...similar to what u describe above.
I really look forward to your posts, very thought provoking....
I'm surprised u do not put dampening material on top of all the caps. It is the only tweak I have done on my MSB S II dac and power supplies (probably 45 caps in total) and the improvement is substantial...similar to what u describe above.
I really look forward to your posts, very thought provoking....
Ack, I’ve been following your post with great interest. Thanks for the great write up and useful information.
Are the chips and boards adequately dissipating heat with all these covers and stick ones ?
have you given any thought to separating the PS section to a separate chassis?
Are the chips and boards adequately dissipating heat with all these covers and stick ones ?
have you given any thought to separating the PS section to a separate chassis?
Thanks. There are no heat issues with the chips, they never really heat up. And I am not going to bother with the power supply much, other than possibly bypass the power line input filter they have, which appears to be off the shelf. The power supply overall appears to be of very high quality, including the diode bridges that I care about.
@ack Berkeley has released their Alpha Dac Series 3
Alpha DAC Series 3 — Berkeley Audio Design
I'm not sure of pricing but, if your dealer gets one and allows an in home demo.
I'd be curious on how it compares to your YGGY 2 and Alpha.
Alpha DAC Series 3 — Berkeley Audio Design
I'm not sure of pricing but, if your dealer gets one and allows an in home demo.
I'd be curious on how it compares to your YGGY 2 and Alpha.
Yes, I am aware of that; I told my friends that I intend to try it, but if it does not sport a Class A output section then I highly doubt it will beat the Yggy2. But I am open to trying it, though I am sure it will require my usual modifications. My current modified Alpha1 with the 3.0 software upgrade sounds as lovely as the Yggy2 but not as dynamic - micro, or macro - and am only using it for HDCD
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