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.


128x128lowrider57
Chord Qute delivers superb detail.  If anything, it lacks the best bass response, even with a good LPS.  The Qute anyway could use some mods IMO.  Difficult because it's so compact....

Steve,

Aside from Chord and Resonnessence, I'm curious who else in your opinion makes well implemented DACs -

More expensive:

Empirical Audio, dCS, Ayre, PSAudio, Playback designs, Bricasti

Here is a top-tier PCM DAC shootout that has been ongoing for several years and involves many DACs (73 pages of posts):

https://forum.audiogon.com/discussions/absolute-top-tier-dac-for-standard-res-redbook-cd?page=73

Lower  cost to consider:

Sony HAP-Z1es, Wyred4sound (particularly driven using I2S), Metrum Acoustics, Rega, Bryston

Have not been impressed with the pro-audio/studio DACs...

Shadorne,

My Benchmark DAC1 is ... oh I don’t know, maybe seven years old. I runs warm and always did. I have it on 24/7 for most of that seven years. Yes this is true it runs all the time. Did this degrade the sound? Maybe, heck I don’t know. It just is dead sounding next to my Accuphase. I always felt this way since I first plugged it in.

What I learned when I purchased my Accuphase, a lesson that I keep relearning thirty years on now, is it is more about implementation than what chip does what.  The earliest chips sucked... then something happened, I think the chips became good.   The only two machines I thought were musical back then were the Accuphase and Ayre machines. That’s was it. Boxes that used the same chip sets were not nearly as good sounding as these machines.... it was not the chips that did it.

Peace
Bruce in Philly
@bruce_philly

If you left your DAC1 on for seven years straight night and day then I think you may have suffered what I observed. A dead sounding DAC due to capacitors aging (higher heat ages faster). I particularly noticed this when I got mine out of storage to compare to the DAC3 and DAC2 recently. I think my DAC had been on for about 10 years straight and as I mentioned it runs quite hot.

There is no way a properly functioning Class A component should sound dead! Stereophile are fairly reliable in their classifications.
If you left your DAC1 on for seven years straight night and day then I think you may have suffered what I observed. A dead sounding DAC due to capacitors aging (higher heat ages faster).

And might/would that apply to any DAC? Or for that matter, any piece of electronics with capacitors? Some manufacturers recommend leaving their equipment on 24/7.

@gdhal

Yes - rule of thumb is every 10 degrees Celsius higher in operating temperature will half the life of many capacitors.

Most caps are rated 105 degrees for 2000 hours. At 95 they will last 4000. At 85 they should last approx 8000 and so on and so forth.

So leaving your gear on 24/7 is usually a mistake. Good ventilation is very important
Yes - rule of thumb is every 10 degrees Celsius higher in operating temperature will half the life of many capacitors.

Most caps are rated 105 degrees for 2000 hours. At 95 they will last 4000. At 85 they should last approx 8000 and so on and so forth.

So leaving your gear on 24/7 is usually a mistake. Good ventilation is very important

I appreciate that information shadorne as I honestly wasn’t aware of it. As a matter of course, I do happen to power down all of my equipment after use and provide very good passive ventilation. It’s only just recently that I acquired a Yggdrasil DAC, and Schiit is insistent it be left on 24/7 for best performance. Of course, I would prefer not to have to do that. Based on what you’re saying, leaving it on now presents two problems/issues - electric cost and life expectancy. Frankly, I’m a bit torn/concerned over what I should do, but in the grand scheme of things, I suppose it’s a good problem to have.
On off cycling causes wear and tear too. Caps left unused for too long will fail too. So there is no single solution that is best.

I suggest you let your equipment warm up for an hour before a serious listening session and for casual sessions don’t worry about it.

I try keeping the temps in the house like Ozzie and harriet enjoyed. They always seemd to be wearing sweaters in every episode. Ricky? Not so much.

Having been deep into industrial electrical affairs including communication equipment for some years, having electronics energized indefinitely never seemed a negative consideration, PROVIDED the temperature surrounding it or them could be kept constantly lower.,

400Hz motor Generator sets, PA systems, etc., amps we used had huge output tubes and the gear necessary for them to operate were kept in a air conditioned space which was always brisk. 60F or less..

Experience proved maintaining lower temps kept these amps trouble free so far as I knew from being there over six years. Never wass one output tube replaced. Nor was there any failures otherwise. This information covered several venuews utilizing the same or similar gear.

At worst, a semi annual opening and thorough removal of dust and dirt accumulation was the only active function required beyond keeping operating temps low and constant..

It’s the main reason I have for keeping electronics apart from the listening area. So they can be kept at a lower steady temp. it amounts to use of an adjacent room and longer spkr cables, and oh, yeah, a dedicated AC unit just for that room.

A very prominent designer of very well regarded power plants once said to me heat kills. The lower you can keep the operating temps the better given the temps enable optimum performance of the amps.

It did not take long to see what temps the amps he made liked as ambient temperature.

Even a tiny little fan can be of great benefit if well placed.

RWV… so perhaps this or that item may take as long as two days under power, though I’d not suspect periods further than that were at all required for ANYTHING.

Those items whose endorsements say “leave on’, appear to be able to do quite well after run in with just a day or so of being re-energized. As was said, engage it all for an hour or so maybe less, and have fun. My SS amps took longer than my Tube amps but only by 30 mins, SS needing more foreplay apparently..

Makers are simply tending to having their caps fully loaded and other areas stabilized in terms of temps and energy.

On another note and not meant at all as disparaging, makers ideas of YOU having on THEIR GEAR at all times read as forever, is not hurting them at all, is it?

IMO, its one of those take with a large grain of salt thingys, as there are alternative means for extending the life of our energized components with simple cleaning and temperature control. Or by simply powering up periodically in advance of listening sessions on the primary system.

With a $900 HT rec I’m not really worried as each one I’ve owned has lasted easily ten years without issue prior to needing once a new IC chip.

With $30 to $$$$$$ worth of electronics , I’d seriously consider finding a way to keep that investment operating safely by maintaining a lower environmental temp. MO.

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.

I do indeed think you may well have a gain mismatch between the DAC and the amplifier. What you described is precisely how this would sound like: clipping of louder passages.
Part of the traditional criticism of digital comes from precisely this, as the 2V output for cd players as specified in the Red Book was too high for many amplifiers of the day. Hence Quad after the introduction of CD produced a special input board for their existing amplifiers. These days, there are still many amplifiers that cannot quite handle this signal level. In your case, the situation is aggravated because your DAC has a 2.8V output (what is your amplifier’s input sensitivity?). A telltale sign would be that you do not have to open the volume control very much to get a loud signal. Now you may ask why manufacturers would specify a DAC or CD player with an output level that is too high, or amplifiers with a high input sensitivity. The answer is that the human brain interprets louder as better. So in a demo room, the louder player/DAC or the more sensitive amplifier will always be interpreted as the better.
So how do you find out if this is the case (after all, the problem may be different from what I suggest, mine is only an hypothesis)? The first test is the volume control setting. If this suggests that you may have a gain mismatch issue, there are two options. The technical one is to have a look with a scope. Such clipping is easily visible. The second is to use a clean test tone and raise the volume until you hear trouble. The third one is to insert inline attenuators, and see if that improves the situation. If it does, you also have your (fortunately very cheap) solution.
See here for some demo material and discussion: http://www.harbeth.co.uk/usergroup/forum/the-science-of-audio/amplifier-matching-mismatching-and-cli...
Harshness could also be your power amp or your speakers.

@willemj 

Higher voltages on line level devices has nothing to do with making louder volumes to sound nice. (although loud does sound nice as you hear more low level detail as it lifts the low level sounds above the ambient noise floor)

Generally you only see high voltage levels on Class A+ and pro audio equipment. 

The use of higher voltage more expensive components in a line level device is to achieve better THD+N and better SNR. Better performance.

Consumer RCA = cheap crap that is popular because it is cheap manufacture and can often sound OK to non-discerning listeners

Pro Audio balanced is the gold standard = higher signal level and shielded conne tions with signal wires that arent grounded. Expensive and always equal or better than RCA. 

My Benchmark DAC 3 was recently testsd by Stereophile - it delivers 18 volts on XLR at max volume. This high cost high spec analog output circuitry is how Benchmark achieve market leading specifications.
I am not talking about absolute levels, but relative ones, i.e. a mismatch between output level of the source and input sensitivity of the amp. Pro audio is very good with a properly matching gain structure, but home hifi is often not. I agree about XLR.
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.

So:
1 problem also exists with other speakers
2 problem disappears using sources with lower output levels
3 already powerful signal with VC at 8 or 9 o’clock
4 problem disappears when pre amp is out of the chain.

4 has the greatest practical importance. For those who want to know the cause of the problem, I think it is now almost certain that the input of the pre amplifier was clipping because the input sensitivity was too high/ the source too hot. If this analysis is indeed correct, and if you want to keep your pre amplifier in the chain, all you need to do is replace the 6 dB pad with a 12 or even 18 dB pad.
You may wel have stumbled on what I think was the reason digital had/has a bad reputation. It was not the quality of the signal, but the gain mismatch between the players’ output and the amplifiers that people were using. Are you happy with the sound you are using now?
I am not quite sure what your current gear does or does not do, but an outboard volume control (passive amplifier by an inappropriate name) could be useful, and if not for you maybe for others. Here is one: http://www.tcelectronic.com/level-pilot/
The Harbeth article is a good one for beginner audiophiles. Thx Willem.

Frankly, if an audio enthusiast has never considered the points raised by Alan Shaw of Harbeth, then they are waisting their money by pursuing a high-fidelity hobby without any understanding of how anything works.

This is like flying without a pilot’s license only not as hazardous. This is like scuba diving or sky diving without taking necessary training and becoming certified. These are the type of uninformed audiophile enthusiasts (and there are soooo many) that are easy prey to the "you obviously need another high $$$$ cable" salesmen.


Hi Shadorne,
That is absolutely right, but the sad thing is that there are many consumer audio products that suffer from this issue. You use pro audio grade gear, and there gain matching is taken very seriously - and quite rightly so. In the old days designers like Peter Walker vary carefully tried to find the sweet spot between too much gain with clipping as a result, and too little, but excessive noise as a result.
Let's indeed hope that this did solve the problem, and that the OP can stop worrying about all kinds of imaginary issues.
@willemj    


This is why I always say,"If changing a piece of wire cable makes a big audible difference then your system problems run much deeper than mere cabling and it is critical to investigate further"
@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.

Maybe the solution is just an in-line voltage divider.  All it takes is 2 resistors to drop the voltage a little.  RCA in/RCA out and 2 resistors.  This would at least show if this is the problem or not.

Another cause could be DC-offset.  IF there is DC on the SE or balanced signals all the time, or DC that increases with volume, this can cause many amps to have problems, even self-destruct.  Measure this with no music playing with a DC voltmeter at different volume levels.  Should not be more than 10 millivolts.  .01V.

Steve N.

Empirical Audio

It is a bit hard to figure out from this end, of course. 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. A cheap experiment would be to get some inline attenuators from Parts Express: https://www.parts-express.com/harrison-labs-12-db-rca-line-level-audio-attenuator-pair--266-244
Short of using a scope to inspect the signal, you could also listen to a cd with different levels of a test signal, and listen if and when the sound starts to distort.
Alternatively, what you hear with the digital source may in fact be perfectly fine, but unusual for your ears. You hear a difference with your analogue sources, but why would they be superior? Go to a live concert of a symphony orchestra and you will at times hear the pretty harsh sound that some would call 'digital', but that is just the real thing. Do not forget that FM radio is seriously challenged sonically, with high levels of distortion, reduced high frequency response, and limited channel separation. The same is true for vinyl. Both may sound nice and warm, but it is not quite the real thing.
@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.

Well, maybe it is your DAC. A cheap test on that score would be to buy a Chromecast Audio and use its inbuilt DAC for analogue output. It will give you a convenient streaming device in the bargain. The inbuilt DAC is by no means harsh. It has two analogue output levels, one is called high dynamic range. That name is a bit misleading because it is just a higher (2.0V) output level. I would avoid it in your case. The normal one is about 1.2V if I remember well. Once you are done with the testing, you can use the Chromecast's digital (optical) output into a better DAC.
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.

Post removed 
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.




The sensitivity of your speakers and power of your amp will also dictate how far you can set the volume.
I agree with Steakster 100%.  Cleaning up the AC power and DC power with conditioners and LPS's is where I got the most benefit of clarity and quietness and relaxation.  The cables to and from the DAC can contribute to hi frequency hardness.  Once the power is cleaned up the differences and effects of cables are much more obvious.  I have 2 DAC's and neither sounded good with COAX but that may have been the lower end Kimber Cable I was using.  I have invested a bit in USB cables and reclockers and LPS on the reclockers with good results.  But like Steakster says eveything in the chain is adding or subtracting the digititus and the results are cumulative.  Its probably not one thing.

AC power and particularly DC power can have a huge effect.  I personally stay away from typical conditioners that have filtering in them because they can reduce dynamics.  I have found the Plasmatron from VHAudio to be the best AC regulator for digital.

DC power for digital is equally dicey.  If the regulators are not really fast responding, you get higher jitter and reduced dynamics.  This is why I design a version of regulator that is really fast for digital and a slower one for analog.

Steve N.

Empirical Audio

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.



I had the same results with the SPDIF in stock form. The LPS-1 took away all distortion, bass is better defined, soundstage, imaging, and 3D improved as well.

Ric Shultz at EVS does a $65.00 mod to and the results are said to be superb.

5-10-2017: For those that are using coax input on anything.....you must use a modified IFI SPDIF Ipurifier.   Simply amazing what this modded thing does. Stock, it gets nothing but rave reviews.....modified it is another thing altogether......incredible!   The mod consists of damping, removing two LEDs (toslink output and frequency/lock indicator, and hardwiring/shortening the power cable from the power supply.   The price of the mod is $65 plus return shipping .

The IFI spdif Ipurifier has an unpolarized AC plug on its power supply. Please try the power supply both ways into the AC socket. It sounds very much better in one direction. Please experiment for best sound.

http://tweakaudio.com/
http://tweakaudio.com/EVS-2/LKS_Mods.html
Scroll down the page from the LKS link for a letter from a customer regarding the mod. I will be sending mine to Ric soon for the mod.

Peace

- Tried Harrison Labs attenuators, the highs were rolled off, so not a good test.

Resistive attenuators must be installed at the destination or you will have roll-off due to the cables.

Sounds to me like your DAC is the problem.

Steve N.

Empirical Audio

Steve, attenuators were connected to the input of the preamp. Then preamp was removed from system and DAC output > ICs > attenuators > amp input.

What kind of IC’s are you using?  How long?

Steve N.

Empirical Audio

@audioengr , Purist Aqueous IC's ...1 meter.  Also have a pair of Purist Museous.
@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

@lowrider57 very cool! congrats!

How did you come to decide on the Audio Note?

Bummer about the iPurifier, I was thinking to try one on my cheapie Fiio DAC.  Maybe I'll just get new cables instead.

iPurifier is a great tool for Dolby Digital and DTS jitter reduction. I use it in my home theater.

For PCM, I recommend the Synchro-Mesh.  Some jitter plots:

https://www.audiocircle.com/index.php?topic=154408.0

For digital coax cables, I recommend my Reference BNC (RCA adapters) for $275.  Cable jitter plots:

https://www.audiocircle.com/index.php?topic=154425.0

Steve N.

Empirical Audio

@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.

I do use the iPurifier on my HT with a fast reacting LPS.  If you use a Sbooster, I think this would work good.

Steve N.

Empirical Audio

Is there an LPS in the $50 - $100 range that would provide the necessary power?

Maybe one from ciaudio.com would beat a wall-wart?

Steve N.

Empirical Audio

@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...