Question About Luminous Audio Passive Preamp

[samtheman57]

Hello:

 

Seeking some advice. I hope I'm in the right place.

 

I started experimenting with Computer Audiophile sources and components (albeit MODEST) over the last 7 to 10 years.

 

I currently have  JRiver Media Center 27 on a Windows 10 64 bit system. 

 

That signal goes to an HRT Streamer HD>NHT Passive Volume Control>KRK Rokit8 sub>ADAM audio T7V powered studio monitors.

 

I want to use the HRT's balanced outputs, and balanced connections, exclusively, so that will require a different Passive Volume Control/Passive preamp.

 

I was looking at the Luminous Audio Axiom Mark II and a much cheaper version with balanced ins and outs from Nobsound.

 

My question is, is it worth spending 300 dollars on a passive preamp like the Axiom, or will the Nobsound suffice?

 

If it would make the difference in sound quality, this final tweak could be worth it, but for my relatively modest system, I'm wondering if it would be overkill.

 

Thanks for any input.

 

 

 

[samtheman57]

Links: https://www.ebay.com/itm/NEW-Release-LUMINOUS-AUDIO-Axiom-Mk-II-passive-pre-amp/130678286565

 

[davide256]

2 hours ago, samtheman57 said:

Hello:

 

Seeking some advice. I hope I'm in the right place.

 

I started experimenting with Computer Audiophile sources and components (albeit MODEST) over the last 7 to 10 years.

 

I currently have  JRiver Media Center 27 on a Windows 10 64 bit system. 

 

That signal goes to an HRT Streamer HD>NHT Passive Volume Control>KRK Rokit8 sub>ADAM audio T7V powered studio monitors.

 

I want to use the HRT's balanced outputs, and balanced connections, exclusively, so that will require a different Passive Volume Control/Passive preamp.

 

I was looking at the Luminous Audio Axiom Mark II and a much cheaper version with balanced ins and outs from Nobsound.

 

My question is, is it worth spending 300 dollars on a passive preamp like the Axiom, or will the Nobsound suffice?

 

If it would make the difference in sound quality, this final tweak could be worth it, but for my relatively modest system, I'm wondering if it would be overkill.

 

Thanks for any input.

 

 

 

A $49 Schiit pre is doing just fine in my setup. Worry more about getting keeper interconnects, the Kimber Hero RCA's are a safe purchase. From all

the reading I've done, balanced cable benefits required a more expensive system to hear and a lot of good gear doesn't have XLR jacks. I plan to go

to an Axiom or better passive pre in the future but don't see the need until  i've put another $7k into DAC and amplification

[davide256]

42 minutes ago, davide256 said:

A $49 Schiit pre is doing just fine in my setup. Worry more about getting keeper interconnects, the Kimber Hero RCA's are a safe purchase. From all

the reading I've done, balanced cable benefits required a more expensive system to hear and a lot of good gear doesn't have XLR jacks. I plan to go

to an Axiom or better passive pre in the future but don't see the need until  i've put another $7k into DAC and amplification

Sorry, should have included that the Schiit pre is the passive Sys

[samtheman57]

I pulled the trigger a couple of days ago after doing some additional research and reading. Again, for the use of balanced connections from the HRT, and the balanced inputs and outputs on the KRK sub and ADAM T7Vs. This is the first tine where all the components have balanced inputs and outputs. Another issue is that, after isolating the USB DAC to a seperate, powered hub, and putting the speakers on a seperate circuit I still hear faint but perceptible "artifacts" when the volume on my current NHT Passive Volume Control is maxed with no signal is coming through the chain. It's been driving me a bit nuts. Hoping this will help, but it's not a major issue. I'll report back once I get the Luminous.

 

[Martini]

The Axiom passive line controller is a very transparent unit that doesn't hog a lot of space on your rack or desktop. It will clearly pass on what your source transmits. If you don't need inputs for a large number of sources, than it certainly is worth auditioning > then likely owning. I auditioned it, but at the time needed a couple additional inputs. Last time I looked they offered a few different levels of the Axiom, but even the least expense was built around very good sounding ALPS pots and nice connectors. The great thing about Luminous Audio is the owner is an enthusiast, willing to take the time to help you select the right unit (or customize) to meet the needs of your source & amp. I've had a few of their cables, RCA & speaker, in my system over the years.👍

[samtheman57]

OK looking for further help here.

 

In order to get this preamp in my hot little hands, I am going to have to answer certain questions.

 

I tried numerous messages detailing my setup, but I'm not an audio engineer, and I feel like I have to pass a test where I have no knowledge or background.

 

I have an HRT Streamer HD as a source, which feeds a KRK 8s sub, ,which then feeds Two ADAM T7V monitors.

 

All I can do is relay these stats:

 

 HRT USB DAC:

Full Scale Output 2.25 V RMS (RCA), 4.5V (XLR)
Output Impedance 50 Ohm (RCA), 50+50 Ohm (XLR)
Frequency Response (20 Hz/20 kHz) -0 dB / -.2 dB
Noise Floor (DC to 30 kHz) 5 uV RMS (RCA), 9 uV (XLR)
S/N Ratio (DC to 30 kHz) 113 dB (RCA), 114 dB (XLR)
S/N Ratio (A-weighted) 119 dB (RCA), 122 dB (XLR)
THD+N (1 kHz Full Scale) .002%
THD+N (1 kHz -20dB) .0002%
Jitter Contribution (DC to 30 kHz) >144 dB below full scale
Isolation > 500M ohm
Sample Rate up to 192 kHz
Bit Depth up to 24 bit
USB Transfer Protocol asynchronous
Power Requirements (USB Buss) 480 mA

KRK 8S Sub:Powered: Yes
Speaker Size: 8"
Driver Type: Glass Aramid Composite cone
Total Power : 109W Class D
Frequency Range: 30Hz-205Hz
Crossover Frequency: Variable - 70Hz/80Hz/90Hz/100Hz
Maximum Peak SPL: 112.8dB
--------------------------------------------------------------------------------------
ADAM Audio T7V Monitors:
U-ART 1.9†Accelerated Ribbon Tweeter with HPS Waveguide

Polypropylene 7†woofer and rear-firing bass-reflex port

Cumulated Amp. Power RMS: 70 W

Frequency Response: 39 Hz - 25 kHz

Max. SPL Per Pair at 1 m: ≥110 dB

So after sending all this a week ago through E Bay,Tim said he was out of the office this morning in an e mail and he needed to know  : I REALLY need info on your amp and spks. Spk effic in db/watt. Amp's input imp. and sensitivity. Please, Tim                                                               

So, is ANY of the above sufficient information, or am I still not getting him what he needs?

 

Never worked so hard to buy something in my life.

[samtheman57]

On 2/20/2021 at 12:38 PM, Martini said:

The Axiom passive line controller is a very transparent unit that doesn't hog a lot of space on your rack or desktop. It will clearly pass on what your source transmits. If you don't need inputs for a large number of sources, than it certainly is worth auditioning > then likely owning. I auditioned it, but at the time needed a couple additional inputs. Last time I looked they offered a few different levels of the Axiom, but even the least expense was built around very good sounding ALPS pots and nice connectors. The great thing about Luminous Audio is the owner is an enthusiast, willing to take the time to help you select the right unit (or customize) to meet the needs of your source & amp. I've had a few of their cables, RCA & speaker, in my system over the years.👍

Thanks for your input on this Martini. I'm having some issues getting information to him (see post above) Appreciate your thoughts.

[samtheman57]

1 hour ago, samtheman57 said:

OK looking for further help here.

 

In order to get this preamp in my hot little hands, I am going to have to answer certain questions.

 

I tried numerous messages detailing my setup, but I'm not an audio engineer, and I feel like I have to pass a test where I have no knowledge or background.

 

I have an HRT Streamer HD as a source, which feeds a KRK 8s sub, ,which then feeds Two ADAM T7V monitors.

 

All I can do is relay these stats:

 

 HRT USB DAC:

Full Scale Output 2.25 V RMS (RCA), 4.5V (XLR)
Output Impedance 50 Ohm (RCA), 50+50 Ohm (XLR)
Frequency Response (20 Hz/20 kHz) -0 dB / -.2 dB
Noise Floor (DC to 30 kHz) 5 uV RMS (RCA), 9 uV (XLR)
S/N Ratio (DC to 30 kHz) 113 dB (RCA), 114 dB (XLR)
S/N Ratio (A-weighted) 119 dB (RCA), 122 dB (XLR)
THD+N (1 kHz Full Scale) .002%
THD+N (1 kHz -20dB) .0002%
Jitter Contribution (DC to 30 kHz) >144 dB below full scale
Isolation > 500M ohm
Sample Rate up to 192 kHz
Bit Depth up to 24 bit
USB Transfer Protocol asynchronous
Power Requirements (USB Buss) 480 mA

KRK 8S Sub:Powered: Yes
Speaker Size: 8"
Driver Type: Glass Aramid Composite cone
Total Power : 109W Class D
Frequency Range: 30Hz-205Hz
Crossover Frequency: Variable - 70Hz/80Hz/90Hz/100Hz
Maximum Peak SPL: 112.8dB
--------------------------------------------------------------------------------------
ADAM Audio T7V Monitors:
U-ART 1.9†Accelerated Ribbon Tweeter with HPS Waveguide

Polypropylene 7†woofer and rear-firing bass-reflex port

Cumulated Amp. Power RMS: 70 W

Frequency Response: 39 Hz - 25 kHz

Max. SPL Per Pair at 1 m: ≥110 dB

So after sending all this a week ago through E Bay,Tim said he was out of the office this morning in an e mail and he needed to know  : I REALLY need info on your amp and spks. Spk effic in db/watt. Amp's input imp. and sensitivity. Please, Tim                                                               

So, is ANY of the above sufficient information, or am I still not getting him what he needs?

 

Never worked so hard to buy something in my life.

On 2/20/2021 at 12:38 PM, Martini said:

The Axiom passive line controller is a very transparent unit that doesn't hog a lot of space on your rack or desktop. It will clearly pass on what your source transmits. If you don't need inputs for a large number of sources, than it certainly is worth auditioning > then likely owning. I auditioned it, but at the time needed a couple additional inputs. Last time I looked they offered a few different levels of the Axiom, but even the least expense was built around very good sounding ALPS pots and nice connectors. The great thing about Luminous Audio is the owner is an enthusiast, willing to take the time to help you select the right unit (or customize) to meet the needs of your source & amp. I've had a few of their cables, RCA & speaker, in my system over the years.👍

Thanks for your input on this Martini. I'm having some issues getting information to him (see post above) Appreciate your thoughts.

[samtheman57]

OK, Tim just contacted me and said he has what he needs with above info.

 

I will get back on the differences, if any between balanced and unbalanced connections, although it may be subjective.

 

I like that this preamp can be modded for upgrades.

 

 

[samtheman57]

Well, sorry to say that it's been three frustrating weeks since I ordered the XLR version, and another week with zero responses to my request for an ETA on delivery. It's like chasing a missing person.

 

Unfortunately, I had to now have EBay contact on my behalf, and If there is no response by the 12th, I am done with this. 

 

In theory, what if the unit had arrived and there were problems? If I'm not important enough to be notified of the delivery of the product, I'm sure I wouldn't get any further response, IF the product was delivered and needed tweaking.

 

Unfortunately, the worst consumer experience I've had yet, across the board.

 

As davide 256 mentioned above, the 49 dollar Schitt would have probably sufficed.

 

 

[samtheman57]

Sigh.. OK I just found out that the reason Tim wasn't getting back to me was because he was ill and in the Hospital.

 

He and his partner are way behind in filling orders.

 

He's OK now, and he acknowledged the unit would be shipped tomorrow.

 

So, I feel kind if selfish and childish, but when you hear nothing for weeks..

 

I will update the saga soon hopefully.

[davide256]

Sometimes the keepers are the ones with the longest wait. I had to wait 4 months for my Magnepan 1.7’s after order several years ago because the factory had die problems with the frame that supported the planar membrane

[samtheman57]

A final update.

 

I won't be getting the Luminous Audio Axiom after all.

 

After hearing nothing from Tim for weeks, I finally had to elevate a claim to item not received.

 

Tim at Luminous said (as mentioned above) that he had been ill, and that his partner was busy closing on a home, so they were buried in work orders they presumably couldn't catch up with.

 

eBay gave him the required time to ship (which he said would be done within 24 to 72 hours and he missed the deadline with no response and no apologies.

 

So, back in the passive preamp market. 

[davide256]

To be honest I think you won't get much joy out of the direction you are headed focusing on a pre + balanced cables. The biggest bang for the buck

for your setup would be a DAC upgrade. I've done DAC modding before, theres a good company called Burson Audio who makes hobbyists parts

as well as selling good gear, wouldn't be cheap but you could get a good combo headphone amp/DAC/ pre from them with XLR out.

 

https://www.bursonaudio.com/

[samtheman57]

That's not going to happen. I just upgraded to the flagship model by HRT (HRT Streamer HD) two months ago and bought it specifically for balanced outputs. It competes well with other at a larger price point. Sold my old HRT streamer II, so will still be looking the balanced passive pre route.

[jcn3]

18 hours ago, samtheman57 said:

That's not going to happen. I just upgraded to the flagship model by HRT (HRT Streamer HD) two months ago and bought it specifically for balanced outputs. It competes well with other at a larger price point. Sold my old HRT streamer II, so will still be looking the balanced passive pre route.

 

too bad about your experience with tim.  i've got a balanced version with the walker mods and tim was always very fast in responding and delivered a quality product.

[samtheman57]

1 hour ago, jcn3 said:

 

too bad about your experience with tim.  i've got a balanced version with the walker mods and tim was always very fast in responding and delivered a quality product.

Thanks, I was in a state of disbelief throughout really.The reviews and product reputation, especially for communication between Luminous, (Tim) and customers, were stellar. I was beginning to take it personally. I used to build and repair computers, and also sold and bought products on eBay for over 10 years and this was my worst experience ever. I never have left anyone hanging if I sold a product. At this point, I have to go to PayPal to retrieve the extra 100 dollars I paid for modding, as eBay is only refunding the initial cost of the product. Insult to injury.

 

At any rate I went out of the country to Poland and Hattor Audio and purchased a balanced version of the passive preamp with no input and single attenuator. Arek sent an e mail thanking me for the purchase, and then noted I needed to pay for shipping in another. Instant communication. We'll see how international trade goes.  https://www.khozmo.com/balanced_wo_input_selector.html

[samtheman57]

In fact,nearly INSTANT replies just sent him the stats of my system. Working to not promote anxiety and acknowledging customer needs is everything.

[samtheman57]

Hard to believe, but this train wreck is still going on.

 

Basically, when I elevated my claim on eBay(in order to get SOME response) it meant, (for any seller) that the seller has a limited amount of time to provide a valid tracking number and deliver the product.

 

I specifically stated my intent when I first elevated my claim, you have a choice to either get a refund, or take delivery of the product, I chose delivery of the product. I agreed to close the claim upon receipt of a valid tracking number.

 

What I didn't know, (and unfortunately, Tim didn't know) is that once you agree to deliver you only have a matter of days to do so. Tim waited another week and eBay auto refunded anyway. 

 

So I get a frantic email this morning from Tim saying his partner Bill is ready to ship, and that.somehow, this is ME reneging on our personal agreement.

 

He also reiterated that he had been ill, that Bill had been closing on a house etc.

 

I responded that as an eBay merchant, you have to go by THEIR rules and THEIR timeline. Also that we ALL have side issues in life to deal with, I'm currently reroofing the house I'm in, I'm sweating it out alone.

 

Anyway, I'm trying desperately to move on.

[samtheman57]

I was just notified  that Arek at Khozmo Acoustic is shipping an XLR model, with silver front and black knob within three days. Looking forward to it.

[GregWormald]

When it arrives I hope it is all you expect.

 

Sometimes sh*t happens and it really is no-one's fault. There's not much work done or communication possible from a hospital bed—but—with a partner on the outside at least the communication (about any delays) should be a major priority. This is basic good business practice but is somehow often ignored. How to go broke in one easy step: don't communicate with your customers.

 

I'm in the process of ordering a system of custom cables and the replies come almost before I've sent the message. Yes, there is a delay in the shipping of one of the very special components, the construction will start as soon as the components arrive—but the communication turn-around is measured in minutes. I guess/know he appreciates my business!

[samtheman57]

13 hours ago, GregWormald said:

When it arrives I hope it is all you expect.

 

Sometimes sh*t happens and it really is no-one's fault. There's not much work done or communication possible from a hospital bed—but—with a partner on the outside at least the communication (about any delays) should be a major priority. This is basic good business practice but is somehow often ignored. How to go broke in one easy step: don't communicate with your customers.

 

I'm in the process of ordering a system of custom cables and the replies come almost before I've sent the message. Yes, there is a delay in the shipping of one of the very special components, the construction will start as soon as the components arrive—but the communication turn-around is measured in minutes. I guess/know he appreciates my business!

Greg, Thanks for that. YES Communication brings assurance and piece of mind, no communication promotes looming anxiety.  I've been around long enough to remember when "Made In Japan" was not only an album by Deep Purple, but a sort of insult, as Americans were leading in manufacturing, and it was implied that phrase meant cheap and mass produced low quality. Poland was behind the Communist Iron Curtain, and it was INCONCEIVABLE the Americans would ever trade there legally for ANYTHING, much less audio products. Yet here I am buying  hugely innovative products like the Furutech socket abd NCF filter and Kozmos passive pre. Glad I could be around to take advantage.

[samtheman57]

OK Finally, Arek from Khozmo Audio came through with flying colors. The preamp cost a bit more, , but for BOTH sound, (balanced sounds AMAZING) and aesthetic quality and workmanship I couldn't be happier. Been a bit distracted with a DIY roofing project, but gaining on that and relaxing and enjoying music .

[rruffin]

I was searching for a comparison of the Nobsound NS-05P and the Axiom II passives. Bought the Nobsound as a "test case" as I have never used a passive previously. Now considering upgrading...

 

Found your interesting thread. Wondering how your adventure with the Khozmo has been?

 

(Funny, I have not found an audio forum post about the Axiom besides reviews. Wonder how many of them area out "in the wild?")