Direct Feed DS Senior to Active Speakers no Preamp


#1

Hello Everyone,

I direct feed my DS Senior Bridge II straight into active ATC SCM50 Towers, no preamp. Volume controlled by MControl app and/or DS remote control only. Room is professionally acoustically assessed and treated accordingly, all equipment isolated etc.
DS runs with low filter setting “on” with 70 to 95 registering on front volume panel.
I am wanting to explore if my XLR balanced Canare L4E6s StarQuad cables are as good as could be? I run over 9m around the room.

I ask as this is the only “cooking” grade component in the entire system, and cables have a way of influencing sound in many various and fabulous ways, often unknown to the likes of me.

I would like to hear the experiences of others who may have already trodden this path before me…pretty please


#2

While at Axpona this year, checking out active speakers was high on my list, I was not disappointed.
You are the first that I have seen comment on using them direct with a DS.
I run direct from my DS to OTL amps via 7.5 meter MIT 350 Ref balanced interconnects.
Not the same situation as yours, but I always wonder what effect output impedance vs input impedance combined with cable impedance has on the signal/sound, especially with long cable runs.
There are quite a few opinions on impedances, one is that the input should be 10 times the output impedance.
Another is that the input impedance should be as high as possible vs the output impedance.
From popular opinion it is difficult for me to nail down what, or if any information is most relevant.
The DS has an output impedance of 200 ohms balanced, my OTL amps have a 200,000 ohm input impedance, or 1000 times.
If I read the correct spec on your active speakers, they have an input impedance of 10,000 ohms, or 50 times.
I was used to running my DS in the 80 - 95 setting, but with recent improvements I am now in the 70 - 85 range.
Wanting to get back into the uppermost limit, I have been experimenting with making my own in line balanced attenuators.
The -20db setting of the DS just does not fall where I need it to.
I have had at least 3 pair of Rothwell -10dB balanced attenuators in the past, but wanted to try making my own this time.
The attenuation I was looking for was around -6dB, I found an online calculator for a balanced “H” attenuator pad.
Ordered matched Takman REX 1/4 watt resistors and male and female XLR connectors with set screws to experiment.
With the temporary attenuators in place, sound quality has actually gone up a notch, a nice surprise.
The next step is to build them into permanent inline housings.
So long story shortened, adding some attenuation before my amps improved the sound.
How much of a difference would 1 meter cables make?


#3

Mr Derrick,
I understand that what I would be looking for is lower capacitance. The impedance of many such cables appears to be 110 ohms and as long as it is well maintained over distance would be OK. I frequently read that my current cables Canare L4E6s StarQuad, are higher capacitance and over 9m runs may be causing a veil at higher frequency.

I can’t get to a 1 or even 2 meter run due to room layout constraints and dual usage needs.
Any blistering good ideas out there?

Thank you


#4

The capacitance between the two (pairs of) conductors of the L4E6 is about 150pF / meter and the capacitance between the conductors and the shied is about 185pF / meter. For 9 meters these are about 1.35nF and 1.67nF respectively.

Just by coincidence we did an experiment with similar values during the development of the DS. The circuit board has positions for 1nF caps at each output connector to smooth things out when cables are inserted or removed. We listened with them in and without them and checked to see if they were needed when connecting cables or not. Tho we could hear a difference it wasn’t pronounced.

Here’s the change in frequency response expected:

You definitely can get lower capacitance cables, but these things are very system and listener specific. FWIW and tho I don’t necessarily recommend them I use 20’ Peavy microphone cables (about $25) between my bench DS and my preamps. I’m sure you can get better sound with better cables, but there’s nothing wrong with starting out with cheaper cables as you get used to your system and then trying some upgrades. The Cable Company Lending Library is one resource for trying cables, tho I don’t know what cables they might have in the lengths you need.


#5

Sean - I’m a bit confused - unclear how long a run you’re talking here, 9m or 3m? But that seems to me somewhat more about cost, as good cables will work pretty well over fair distances, otherwise nothing much would ever get recorded ; ). Fretting over impedances, etc. in advance of listening is putting the cart before the horse. If you buy based on specs and don’t compare with something that may not meet that spec on paper, you’ll never know which sounded better, and you may have talked yourself out of something in advance that could be better.

Active monitors like yours are nearly always run in studio situations directly from a line out of a DAC with a volume control. I use ATC SCM25A’s in my home studio. Many like Mogami cables (on the affordable end of things - used by many studios), and sky’s the limit in the upward direction. Paul likes Boulder locals MG , but they ain’t cheap (and I believe he has said he doesn’t like Mogami - but that’s Paul in Paul’s system, which is not you and yours). There’s a thread on here on Belden Iconoclast which many there seem to like as well. My guess is that for the price of 9m of some of the pricier cables out there, you would be happier with the sound of a BHK with two sets of shorter, cheaper cables. But not knowing your budget…

The volume control in the DS DACs is one of the better volume controls you’re going to get, despite the fact that you can go down the rabbit hole of worrying about what volume level you’re running at.

Given a good quality preamp, most systems actually sound better with one. A big part of this is gain staging, which is a main reason mrderrick’s attenuator could concievably sound better than nothing. Having said that, I’m currently running my DSJ directly to my Harbeths’ amp and subs (since Redcloud, anyways).

As you note in Ted’s reply, professionals typically don’t worry about this sort of stuff. And the Cable Co. is a great option.


#6

Two wonderful replies. Thank you gentlemen!


#7

I run direct to my JBL M2’s from the DS to the amps. I use Belden 1800F wire from bluejeanscable.com and it really does work well. Very low capacitance too!