The making of: The Two Towers (a 25 driver Full Range line array)

Anyone reading here that has experience with longer runs of optical SPDif?

At the moment I run a short optical SPDif from soundcard to DAC, from the DAC there's a 10 meter run of RCA cables out to the amp. Ideally I want to get the DAC closer to the amp. My RCA cable has a broken wire atm. which speeds up my decision making. I can't tell if our new kitten has something to do with that :D. I've had no worries for over 3 years. She even managed to get the wires loose at my left channel one day, so I do know she's a suspect.

I do have a 10 meter SPDif, though it has a POF (Plastic Optical Fiber) core.
That plastic core cable is tougher than a real glass fiber cable (usually consisting of 200+ small cores) and this "should" be a quality cable.
Here's what a cable firm says about the POF core material: Digital Audio Cables at Blue Jeans Cable
(my cable is a different brand though)

They prefer to use Coax, but use POF for optical cables up to 50 feet.

I've read a few horror stories about long runs of optical (jitter) but cannot simply go with Coax (due to the galvanic connection it creates from PC out to the DAC, as that will most likely pick up power supply hum, just as USB did earlier).

I can use my short run of optical and get a converter from optical to Coax so I can use the longer run as Coax cable out to the DAC, I can even do it the other way around as these converters seem to go both ways. However that would lead to the question of what converter to use, there are a lot out there, which one is good (enough).
I stumbled over this one as an example: SPDIF/Coax converter

I hate these kind of questions. I could hardly find an optical cable with true glass fiber core without having to pay top dollar for it. The one I could find was on Amazon USA (no shipping to the Netherlands), it was listed in the UK, though currently not available (figures). The long run of RCA performed pretty good so far, up until it broke just a couple of days ago. I can fix it easily enough with some new connectors, but I always wondered what the most logical or sane choice would be.
I my mind that would be a long run of differential from DAC out to the amp, but the amp only has RCA inputs. The DAC has Spdif and coax input and both RCA and differential out. Soundcard has both optical and Coax out.

Any help guys? Based on positive experience? That 10 meter distance is the route from the PC to the amp. No way around that as I want to keep the noisy PC where it is, in the corridor. Currently I run 2 sets of RCA beneath the floor, one for the mains, the other for the ambience channels.

The most offensive rodent seems to live above ground though.
Zoe.jpg
 
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Think remember race of beatiful kitten is Maine Coon, she will get much bigger and naughty over time :D

Joking aside think we wan't POF because there is something about wavelength and protocol that is superior and years ago saw a scientific article where they got POF to perform hundreds of higher numbers of bandwidth that was normal expected and numbers is way higher that is needed for simple audio protocol. Suggest try POF from German company (Link: www.clicktronic.com) in runs of a 7,5 10 or 15 meter length, 10 meter is in stock here (Link: CLICK CAS 70372: Toslink Kabel, Toslink inkl. 3,5 mm Adapter, 10 m bei reichelt elektronik)
 

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Should I be worried the Clicktronic site mentions the # 70572 as identification for their top rated model and that one seems to be double the price wherever I find it? The crazy world of audio.
Clicktronic Advanced Opto-Kabel: Amazon.de: Elektronik

I currently have a HQ 10 m from their silver professional series. That one screams trouble, mentioning OFC and Gold plating on their optical cables :D. It's in the same price link as that 70372 cable.
 
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Ha ha agree its worrisome when some marketing folks starts roll out their rubbish about OFC and gold plating for optical cables.

About cost of that brands 10 meter run try look at your link where they tax it at €54,90 because into same link they in middle of article point to the same brands 15 meter run and its costs is only €22.72 :scratch1:, think myself would try it at Reichelt for €26,90 and when ordered write a note if they sure its a 10 meter run because it was supposed to have 70572 number and not 70372 : )
 
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TOSLINK is 135Mbit/s (135MHz) so I don’t think it will be very susceptible to artifacts or interference due to fiber material or jacket material - basically it’s a light pipe for 650nm LED not a single mode optical fiber with a laser diode. It’s tough durable interference free stuff for audio frequencies. I don’t think you will detect a difference between plastic or glass, or metal or plastic jacks (except for durability).

I don’t think you answered my earlier question about regular XLR cable with balanced driver and balanced receiver? Proven low noise is noisy environments for long runs in pro audio applications.
 
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TOSLINK is 135Mbit/s (135MHz) so I don’t think it will be very susceptible to artifacts or interference due to fiber material or jacket material - basically it’s a light pipe for 650nm LED not a single mode optical fiber with a laser diode. It’s tough durable interference free stuff for audio frequencies. I don’t think you will detect a difference between plastic or glass, or metal or plastic jacks (except for durability)...

Good summary there and then comes the very welcome 100% isolation from computer hardware, back is then the few horror stories about optical (jitter) but think we could hope for that Musical Fidelity had done the best they could for that DAC generation.

...I don’t think you answered my earlier question about regular XLR cable with balanced driver and balanced receiver? Proven low noise is noisy environments for long runs in pro audio applications.

:) maybe into his first posted request you missed below written info so he actual thought it told for itself.
...a long run of differential from DAC out to the amp, but the amp only has RCA inputs...
 
That test is scheduled for today :). At least, the subjective part of it (just listening). A gold plated oxygen free copper optical cable does not inspire my confidence in this one though. I couldn't see that part before buying it quite a while ago.
It makes the "professional" tag a bit useless.

I have ordered a Clicktronic cable to replace it, no matter the results I get.
Even though their HIFItest.de award isn't confidence inspiring either. They tested all of the cables from Clicktronic there and the most expensive ones get the best ratings. Smells like a deal in advertising. It's hardly a test at all. Actually, it isn't.
 
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All these talks about connecting the computer to the DAC. Good timing!

With my Mac, I have no trouble using USB. Maybe their motherboard has better grounding?

With the PC, I was ok using USB until this week, where I started to hear distortion every time the hard drive started spinning. When the hard drive is idle, there is no distortion. Weird.

I ordered a SSD drive to see if that will fix it, otherwise, I will have to go optical.
Or, maybe there is a way to ground a motherboard?
 
I never had to deal with that kind of noise, perceval. However I've had my share of ground hum in the past. Mostly because there was a cable signal involved for TV etc.
I may even be alright with hooking up the PC trough coax these days, as a lot of things have changed. I did not intend to try it out right away, as optical has proven to be a real good option so far. I don't have a 10 m coax to try and prove this point.
The long RCA cable runs were never really optimal. As I said before, I'd love to have gone with differential for the long runs. However I'm not comfortable or skilled enough in electronics to integrate that in my present amplifier in any way. Ideally it should be part of the design I guess.

The first test with a relatively cheap optical cable went well. I did not measure anything yet, subjectively it was an improvement. However that could have several reasons I need to check. I still find it a bit strange to call an optical connection a cable. :)

I once opted to change the PSU and checked what I would need for that. With no guarantees up front I decided to go optical back then. It solved the problem.

I'll do more tests, but am more confident this is going to work just fine. There are many spook stories about any and every aspect of audio so it will remain hard to figure out where that all comes from anyway and what story is true.
 
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Great work in the amp! Looks amazing.

I've never had the best luck with TOSLINK, and at times it's been awful. It' easy to see why if you look at the waveforms or the eye pattern on an o'scope. I suspect that most of the optical receivers used in audio gear aren't very good. I'v'e used isolation transformers with good results, both balanced and unbalanced.

Counter to that, I run HD video over fiber all the time. As long as the ends are clean, it's reliable. Dirt is the enemy, tho. Coax is a sure thing, but sometimes long distance runs mean fiber is needed.
 
opps, a few posts late...

I think it's a bit too large to go there.

That was my first impression too - Or - too black:
tweak.jpg


But, that is not really it, if You went smaller, I believe You would still have the same problem... From what I can see in the photo, due to the reflective nature of your baffle, Your logo is getting lost in its own reflections, its shadow and reflections from other dark stuff in the room. I can not see all the strategically placed gaps between the letters or none of the points on the serifs:

logo.jpg


I think the logo could work at this size, it just looks too big due to the "reflections" I mentioned above. And the black is not helping, at least with how this logo protrudes out from baffle.

Here are some possibilities:

I believe the black could work if it was "painted" on flat. This would eliminate reflections and shadows. I know this would be hard to do, because of the mirror finish, but You could get a decal version made. At least You could remove it if You did not like it. ;)

As BRYTT mentioned, there are other color options. I personally would stay away from anything dark with a protruded logo - as it will act similar to the black. I agree with BRYTT, that any color You pick needs to be matte. I would like to see it in brushed aluminum. You mentioned You have a metal version, how hard would it be to get it back to bare metal?

If You where up to experimenting with different 3D profiling, like the drawing I posted below, You could use any color you like, as the triangular cross-section would eliminate the reflections and shadows. I am not sure if this profiling is possible in this size - but it is an idea. I realize this would require some "tweaks" in your logo, as some of the serifs do not align with the profile points in some areas.

Final option I can suggest would be to make shiny plates, like what You did with the amp, either with just the logo or the logo with your name and "The Two Towers". :)

Hope this helps to spark some ideas.

Good job on the branding, I can see your automotive passion reflected in these designs. :c_flag:

I wish I could help You with the optical wiring, but I am just as confused about that as You are. There is so much $#%& in marketing with stuff like that. I use Coax with my Buffalo DAC, and I have used it thru both the motherboard and M-Audio USB DAC. There is a subjective difference, but not one that discourages me to use one over the other. I have not heard any noise or hum - so that is good. So I will be checking in to see what You end up with, maybe I could learn to measure it somehow...
 

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