@dlcockrum , sorry, I missed your post. I'm not married to I2S, it's the best way to transfer data in a PSA setup.
Looking for Better Jitter Reduction in a DAC
I'm looking to improve the jitter control in my digital setup, which hopefully will create a more analogue presentation. I own a PS Audio PW Memory Transport, which sports a FPGA, and a Nuwave DSD DAC with a scaled-down version of the gate array.
I have owned a Chord which uses this technology and it was like listening to analogue recordings. I sold it only because it's soundstage was very forward, like sitting in the front row of a concert hall. My current PS Audio setup has wide and deep imaging, as does my Atma-Sphere preamp.
I have auditioned the Schiit Grundir and it was a bit too fast in the attack and transients, but had the dynamics and deep imaging that I like. So, I guess what I'm looking for is a unit with a laid-back, realistic musical presentation.
The Mytek Digital Stereo192 DSD and Blue Circle DAC are in my price range, but there is no way to audition them.
So any recommendation and advice is appreciated. DSD preferred, budget is about $1200 used.
I have owned a Chord which uses this technology and it was like listening to analogue recordings. I sold it only because it's soundstage was very forward, like sitting in the front row of a concert hall. My current PS Audio setup has wide and deep imaging, as does my Atma-Sphere preamp.
I have auditioned the Schiit Grundir and it was a bit too fast in the attack and transients, but had the dynamics and deep imaging that I like. So, I guess what I'm looking for is a unit with a laid-back, realistic musical presentation.
The Mytek Digital Stereo192 DSD and Blue Circle DAC are in my price range, but there is no way to audition them.
So any recommendation and advice is appreciated. DSD preferred, budget is about $1200 used.
Showing 47 responses by lowrider57
Sorry guys, I forgot to include some details in my post. My primary need is for Redbook playback thru the PSA transport, computer audio via USB is secondary. With a PS Audio setup, I am able to use the HDMI interface (I2S) which transfers the clocked signal and data on separate conductors, versus SPDIF which combines all data. The transport stores the data from the CD into a buffer, then clocks it, and sends a jitter-free signal to the DAC where it is reclocked. There is a major difference in performance between my budget PSA DAC and the higher-end DAC's using FPGA. Yes, I'm very familiar with the Synchromesh. I spoke to Steve and almost bought one, but since I'm not using SPDIF, the I2S technology is already reclocking the data. I have tried different coax cables (1.5 meter), but the HDMI always sounds best. I believe the Nuwave DAC is the weak link. |
Benchmark DACs have a smooth but detailed top end. They all have a forward presentation in the mid range. I think this works great for far field listening but might be too forward if you sit close to the speakers. Imaging is excellent if you like a tight precise sound field. The bass is extremely detailed and tangible (but not over emphasized) and this is probably the most noticeable difference versus other DACs.@shadorne , thank you for the very detailed description. Much more informative than any of the reviews. It doesn't seem like this is the DAC I'm looking for. |
@rodge827 That sounds like the way to go when using coax. Didn't know that iFi made a reclocker, looks good. I almost bought the Synchromesh when I was using an ARC as my transport, but I discovered the great deal on the discontinued PWT. As I stated earlier, I'm not married to I2S. I have Oyaide and Audience A24 SPDIF cables. The reason I've been thinking it's a jitter issue is due the fact that music still sounds "digital" from my all tube system. I've read many positive results on the PS Audio Forum when using I2S, but this was when using Directstream or Perfectwave DAC's. The PWT outputs a bit-perfect stream thru HDMI, but I'm using a budget DAC. However, I do like the timbre and dynamics my system presents. |
I had a thought and before I make a purchase on a new DAC, I'm going to upgrade the power source to my PSA. I'm currently using all Audience PC's, which I've learned are unshielded. I'm sure a shielded PC is recommended for digital devices. I've checked the archives and the JPS Digital AC-X is highly recommended, so I'm going to give it a try. It's possible the DAC is contaminating the AC, since my Blue Circle conditioner is passive and not a regenerator. @dlcockrum , which two dac's are you referring to? thanks. |
@dlcockrum , the UltraCap LPS-1 looks like a great device. But what is the advantage of the LPS-1 over a traditional LPS with a toroidal transformer, e.g.; Teddy Pardo? According to the Uptone website, it has superior isolation to prevent AC leakage via the UltraCap™. The Teddy also claims to have isolation thru its proprietary low pass filter and series of capacitors. Also, what is the LPS-1 using as a transformer? If I can get a better understanding of this new LPS, I'd like to make a purchase. |
A couple updates for all you kind gentlemen regarding my quest for better SQ from my digital. I’m now using shielded cables from the DAC and PWT into my Brickwall (which uses ferrite filtering), plus some PS Audio Noise Harvesters and the results are positive. With the HDMI (Cardas cable), sound is closer to "analogue." With SPDIF (Oyaide coax), the music explodes thru my speakers with increased dynamics, detail, and a huge soundstage, not to mention a lower noise floor. But, the sonics are still clearly from a digital source. I still believe my DAC lacks a high quality clock, so before I upgrade the DAC, I might give the Uptone SPDIF ISO Regen a try. @dlcockrum , I saw your negative review of the ISO Regen as used in your system. It could be that the clock in your Exogal Comet is so good, you don’t need an external timing device. Also using a Purist Audio USB from the Aurender may already have excellent synergy. As a side note, if anybody knows about the PSA Noise Harvester, the LED's are constantly flashing indicating that they are detecting and filtering noise entering the power conditioner. |
Dave, I believe the clocking performed by the FGPA in the Exogal makes a reclocker unnecessary. But, everyone of us would have still tried for that extra bit of perfection. I'll bet the Purist cable also is excellent. I have all Purist analogue cables and they are an integral part of my modest system. |
Thanks for the info, Chris. I'm sure an external LPS makes all the difference. Dave, I've read user reviews of the Gustard X20 Pro and it seems the way to go is with the modded unit. Ric Schultz is charging about $400, which still makes it very affordable. But I don't want to be a Guinea Pig; I wonder who would service it after modding. That Comet SE looks positively "dreamy." But I don't have enough cash on hand, I'm still in the $1200 range. That's why I'm interested in the iFi. I'm thinking that if I go cheap right now with the reclocker, I could save for a major upgrade down the road. Thanks, Jim |
Dave, it looks like that LPS is one of a kind. Using Google, I haven't seen any others. I contacted Steve Nugent about a Synchromesh purchase and he recommended trying a few things first. He believes that so called "digital" power cables using filters can increase jitter. So I sent the JPS digital cable back and now I'm using quality shielded cables on my digital. I also bought a new 1.5m S/PDIF cable and a Lifatec Toslink. I had a financial setback due to some medical bills which makes it impossible to buy a new DAC at this time. I could afford the Mytek Stereo 192-DSD-DAC, which gets great reviews, but is 5 years old and does not have a Femto clock like the Brooklyn. So my next move is to give the iFi iPurifier a try and see if my preamp is causing problems. |
Great idea, @dskinner. I went direct from DAC to amp and the sound is very pleasant. Still sounds like music is from a digital source, but nothing offensive at all. In fact, the amp is warm with nice tube bloom but is lacking the deep imaging that the preamp provides. Could the output of the DAC be overdriving the preamp? I have a single-ended system with a push-pull tube amp and an Atma-Sphere UV-1 pre. The DAC outputs 2.8V RMS (unbalanced). I will tube-roll the 6SN7's in the preamp and see if that is the cause of the harshness. My gut says no because I'm using 1950's RCA Blackplates. |
Dave and Chris, many thanks for the good wishes. My review of the JPS AC-X... Extremely effective and affordable as an all in one filter/conditioner power cord. In my case, I did not need such powerful filtering since I have dedicated lines and 2 upstream power conditioners. Even with the AC-X plugged directly into the wall from the DAC, the soundstage was compressed compared to my other PC’s. Using a shielded cable into a Brickwall provided the best results. The issue may be that my DAC doesn’t bleed any noticable noise back to the mains, plus I already have a very a very low noise-floor. Anyway, my digital harshness doesn't seem to be power related. I would recommend trying this cable in a system w/o clean power. BTW, the cable was burned-in by running an air conditioner thru it via an adapter for one week. |
I appreciate your comments, @audioengr . I contacted you recently regarding a Synchromesh purchase and appreciate your no-pressure-to-buy attitude. I'm following your advice and focusing on each element one at a time. First, I addressed the power delivery and chose a good quality shielded cable as suggested, rather than the cable which uses ferrite filters. As for my source, I'm concentrating on Redbook playback first and am using a PSA Perfectwave Memory transport. This unit outputs a signal which has been reclocked from a buffer and not from the spinning CD. I actually don't hear much difference in sound quality between the HDMI (I2I) signal and the optical or 75 ohm coax. I'm now using a 1.5m BNC coax which presents deeper imaging and more low-end extension than the other formats. I took the advice to remove the preamp from the chain, and the result is a much smoother presentation without harshness. I believe the DAC's output of 2.8V RMS is overdriving the unbalanced inputs of the preamp. In any event, the sonics from a DAC-direct hookup is still not what I would call "analogue-like." |
@audioengr , thanks for your interest and advice, Steve. The PS Audio transport gets high marks for jitter control from users online. My PSA DAC is their budget model which uses ESS Sabre chips (no detailed info available), and does not use a FPGA device like their other DAC’s. So, I think there may still be some value to trying a reclocking unit. It does use passive filtering and casts a 3D soundstage with excellent dynamics. The superb sonic characteristics is why I’m trying to make it work in my system. As for as computer audio, I do have a Mac with CD rips and downloads, but currently it is not running certain apps like music players. There are some system extension errors and I need to get it serviced. FYI, I still enjoy collecting CD’s and vinyl, especially imports. And I am an obsessive collector :-) I will attempt to treat some CD’s; it’s interesting that you believe a disk can hold a magnetic charge. I think that the plastic coating may be capable of holding a static charge. Many thanks, Jim |
Steve, interesting stuff about some DAC designs. This problem I'm having makes me keep thinking about grounding issues due to the harsh sound. As far as outside the components, there are no grounding issues; I've tried different IC's (single-ended system), changed PC's, and checked for broken grounds and ground potential with a meter. What is very curious about all this is that the I2I signal doesn't sound any better than the other connections; the ground and data travel separately in I2I. The reason I purchased an optical cable was to test it against grounded connections. Now I'm wondering about the quality of the output from the transport. It is a refurbished unit with warranty and I did send it back to PS Audio for a transport upgrade and I have tried 2 different versions of firmware. Maybe borrowing a DAC is the only way for me to perform a proper test. |
Bruce, the 1.2 looks like a great unit and it's affordable. The reason I said USB is not a priority is due to the fact that my Mac has some bugs in it and is not running any music player software. It will go into the shop soon. Plus, I would like to get CD running smoothly since I just bought the PSA Perfectwave. |
I find it very odd that SPDIF coax, i2i, and optical from transport to DAC all sound the same. I’m using the highly rated Lifatec glass optical cable and an Empirical Design 1.5m coax. I’m starting to wonder if the problem is the output of the DAC. I'm using the unbalanced output from a fully-balanced DAC. Preamp and amp are both SE. DAC output is 2.8V RMS (unbalanced). |
@shadorne , I'm now wondering about the SQ of the output stage. I don't think it's a matter of taste, it's more that the DAC produces the typical digital artifacts we expect to be corrected. There are so many positive reviews, both pro and user, that state how smooth this DAC can sound when fed a quality stream such as from another PS Audio device. I've even been on the PSA forum regarding my issue. There is a passive analogue output filter in the design, but as Steve N. has pointed out... There are a lot of variables, even when using a transport, including jitter, digital filtering in the DAC and DAC output stage and power system. Any of these can make it sound "digital". I have taken the advice from the PS Audio forum and installed a PSA power cord and am using a Blue Circle passive conditioner. Noise floor is so quiet and soundstage is wide and deep. As per Steve's advice, I stopped using ferrite filtering in my power conditioning. For analogue output, I have changed IC's and PC's, checked for open grounds with a meter, and now I'm going direct from DAC into Amp. But I still wonder if the high output voltage could be the cause (specific to my system). I have reached out to The Cable Company regarding a DAC from their lending library. They only have a PS Audio and a Chord Hugo available. |
Here I am again asking for help to troubleshoot the "hard edge" produced by my DAC. Here's an update... I haven’t tried the iFi spdif ipurifier yet since I’m not convinced the problem is due to poor jitter control. I’m really sold on the HDMI (I2S) interface from PWT to DAC, it presents a realistic holographic image. Music sounds wonderful thru tubes, but there’s the damn harshness in the highs, same as with 75 ohm coax. I tried an experiment, taking all digital and analogue components and running them thru a power strip on the same dedicated AC line. The result was a very offensive harshness in the top-end. Even though all PC’s are shielded, it’s possible there is backflow from the digital devices into the mains. Normal setup is a separate line for analogue and digital wired from a subpanel. Low noise-floor, excellent imaging, but music has that digital edge to it. Tried it with and w/o power conditioning, I prefer it without. Also tried different AC receptacles around the house, cheater-plugs and a Jensen Iso-max. Now I’m wondering if the DAC output of 2.8V (unbalanced) is too high and what I’m hearing is distortion thru the speakers, since it is noticeable on peaks; e.g., massed strings sound fine, but brass and solo violin will sound harsh (can sound like distortion). My computer is still kaput, so I haven't been able to try CD rips or USB. Anybody know where I can get an inexpensive DAC for a trial or loan? The Cable Company has DAC's in the $2K to 4K range, so the trial would be very costly. |
It is entirely possible that the harshness could be from the speakers. Tuner and TT sound fine, but are of course lower than 2.8V output gain. I'm using Gallo floorstanders; 88dB, 8 ohms, a benign impedance curve between 4 and 8 ohms. Gallo uses a very revealing 180 degree radiating tweeter, piezoelectric, no crossover. I have also tried some soft dome bookshelves; 88dB, 8 ohms, and they presented the same harshness or distortion in the highs from digital. Preamp is Atma-Shere UV-1; Line stage output...12V, 17V RMS at clipping. Output impedance... 400 Ohms. No specs for input sensitivity. It must be low since VC is at about 8 to 9 o'clock, 11 o'clock for TT. Ralph installed a 6 dB pad in the AUX input for a digital device. I am now bypassing the preamp and DAC is going direct to amp. Amp is a TAD-60 (Tube Audio Design); Input Sensitivity is 1.0V with variable gain control, Input Impedance…100K ohms. TAD recommends that the gain control be turned to max when using a preamp. I need to leave it at 12:00 on the dial. The DAC has a fixed output. @willemj , thanks for that very interesting Harbeth link. |
@willemj , maybe I wasn’t clear about #4. The problem still exists when the preamp is out of the system (DAC direct to amp input). When using the amp gain control, music is very loud at about 11 or 12 o’clock on the dial, about 80 dB at listening position. Before I purchased this amp, I checked with Ralph (atmasphere) who believed preamp and amp were a good match. 100 kOhms input impedance with variable gain. With preamp inline, I leave the amp gain pot at about 3 o'clock. |
@willemj , thanks. Attenuators may be the easiest way to test this situation. And good point about analogue. I have season tix to the Philadelphia Orchestra and the brass section can definitely sound harsh at times, plus that is the nature of the trombone or Wagner tuba in some symphonies. But violin in a well damped concert hall should not present harshness, well maybe during a solo. Steve N, DC offset was checked when I had new dedicated lines installed, not long ago. Forgot to mention that my SS Sunfire amp with high gain also presented this problem after I received this DAC. BTW, my Chord DAC sounded very smooth. |
I think the attenuators may be a cheap way to test the analogue output of the DAC. I would really like to find a DAC that I could audition for a trial period, and in the meantime save for a new unit. As I stated earlier, the Cable Company's fee is too high to borrow a DAC from them. I think I was able to reload software on my Mac so that I can play from the hard drive. The music players seem to working with no hiccups, so I'll test some downloads. |
My experience with curing 'digititus' has been via multiple tweaks that addressed each of the various elements in the digital chain. It was cumulative. There was no one 'silver bullet'. Most of the significant improvements were based on cleaning up the power supplies. Digital backwash was one of many contributing culprits. Harshness/shrillness is most noticeable in the high frequencies - but, the entire musical spectrum is affected.Thanks, Steakster, you speak the truth. When I combined the digital and analogue components into the same power strip (no filtering), the result was a higher level of harshness. Returning to separate dedicated lines was a relief to my ears even though I was back to the baseline issue of 'digititus.' For the next test, I ripped a Bruckner symphony to CD-R using XLD and the copy has the same hard edge to the brass section as the original. |
I still think you may have a gain mismatch (2.8V into a power amp with a 1.0V sensitivity). It does depend a bit on the design of the amplifier's gain control. Does it come after an input stage? If so, that input stage could still be driven into clipping. willemj, it makes sense that the gain control comes after the input. The way the specs read is Input Sensitivity 1.0V. The variable gain is listed as one of the features of the amp, as well as variable feedback control. |
But like Steakster says eveything in the chain is adding or subtracting the digititus and the results are cumulative. Its probably not one thing.I agree with this concept. So, here’s what I’ve been doing since my last post: - Tried Harrison Labs attenuators, the highs were rolled off, so not a good test. - Tried the soft dome speakers again and highs have a rough edge (sounds like distortion). - DAC has the same harshness with my SS amp (Input sensitivity of 1.64V). No direct input like the tube amp, so preamp with 6db pad was used. - Currently using the ifi SPDIF reclocker, but I2S still has better imaging with holographic sound thru my tube amp. Still sounds like distortion during high peaks. - I got my Mac up and running and played CD rips thru USB. The sound is smoother than the transport, but still sounds harsh in the highs. Music was more enjoyable than with a spinner, so I will be expanding into computer audio. I’d like to give the Schiit Wyrd a try. - Tried my backup CDP into the DAC via iFi SPDIF, same result as PSA transport. - Now using all PS Audio AC-3 power cords; they are highly recommended for digital devices and sound terrific. - Separate dedicated AC for analogue and digital. The Wyred 4 Sound DAC 2 was suggested, so I’m looking for opinions on the this unit. There are several available currently. But I’m wondering if this unit is too old; no femto clock, no DSD, but it will interface thru I2S with my PS PWT. Don’t have the funds to move up to higher-end due to unexpected medical bills. As always, I appreciate any help. |
@leemaze, Sorry for not updating this thread, I usually do. I upgraded to a used Audio Note DAC2.1 Signature, it's a NOS ladder dac. I decided to stop trying to put band-aids on a budget DAC. The AN has transformed my system, it sounds wonderful. It's very well built with a huge PS, tube rectification, tube gain-stage, and in-house dac chips. It's also possible that I prefer the sonics of a well executed NOS dac. Regarding the iPurifier, I tried it on both DAC's and w/o an external LPS it did not influence the SQ. I still have it and may be able to use it for it's optical capability into the new Dac. Thanks for asking, Jim |
@leemaze, Agon member jond recommended Audio Note after i posted a qwery about NOS dacs. Border Patrol and AN looked the most promising and as luck would have it, a dealer was selling a 2.1 Signature in XL condition. There was a 3.1 available, but I couldn't swing the extra cash. Regarding the iPurifier, every member here stated that it will not perform well with the stock wall-wart. It needs a linear PS with fast regulation and control of ripple current. There's a lot of info in the archives. I contacted Steve N. and the Synchro-mesh seems to be the best reclocker on the market today. I could have gone in that direction, but decided to first increase my budget and buy a better DAC. I have the PS Audio PWT, so my source is providing a well clocked data stream. You should check the archives about the iPurifier before giving up on it, it's only $150 plus the cost of a linear PS. Or go directly to the Synchro-mesh. |
@leemaze, nothing under $100 that I know of, except maybe used. For a low cost LPS, check the archives for info on the Teradak or Swagman Labs. The Teradak seems to be well liked by quite a few members (made in China). The iFi Purifier requires a 5V power supply and 3 Amps would be more than enough (Teradak). These seem to be the most popular for powering a digital device... https://www.ebay.com/itm/TeraDak-DC-30W-TOUCH-DC5V-3A-Hi-Fi-For-Audio-Linear-Power-Supply/1811442340... Also for digital... https://www.ebay.com/itm/TeraDak-DC-30W-TOUCH-Linear-Power-Supply-5V-3A-9V-2-5A-12V-1-8A-15V-1A/2530... The Sbooster seems to be very highly rated, but at a higher cost... https://www.amazon.com/Sbooster-High-Performing-Various-Preamps-Headphone/dp/B06XTXRPMP/ref=sr_1_2?i... |