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[Andrew Hamilton]

tom eaton wrote on Wed, 07 March 2007 00:14

Dude, eyeryone knows the thick cables go from the amp to the speakers and the thin ones go from your gear to the amp.  Your setup must sound terrible.  No hospital grade outlet for your amp, either.  Lame. Oh...sorry.  Had to say something negative to make myself feel better.  Still waiting for a big enough room to get my own Dunlavys. How far back into the room is your listening position... and how much distance between you and the back wall? -tom

Hi Tom,
    The speaker cables are from Home Depot.  They are stranded 6 gauge and the mic cable interconnects are bundled in a black plastic hose.  So the speaker cables _are_ thicker than the gear cables!   The amp has large military-style capacitors and is balanced throughout.  Yes, the SC-Vs are far field monitors.  I sit about 12 feet from the tweeters.   My head is a few feet from the back wall, which has a huge bass trap behind me, containing about 5 feet of Roxul

[Andrew Hamilton]

punisher wrote on Wed, 07 March 2007 19:30

What I'd like to know is how much are selling that $hit per lb?

ha.  Would that I could harvest the walls.

As for the controversial carpet choice, the room is only rented, so I'm not going to change the aesthetics dramatically.  Also, I'd like to keep it vintage for historical reasons.  The room was built by Queen City Album (Cincinnati) for tracking in 1977.  That carpet is 30 years old!  I was 10!  When and if I vacate, I will restore its functionality as a (vintage) tracking room.  My few acoustical modifications would be beneficial for that and are invisible.


Interestingly, no one has asked about the little video camera mounted on top of the left speaker.  That's an in-house surveillance camera feeding the control room (behind me).  If I want to track a drum set and not have it in the iso room (also fitted with a cam), I can set it up in the mastering room.  Before I built the bass trap behind the listening position, it was a large studio glass between the tracking and control rooms.  That control room is still used for mixing-hat days and makes a handy machine room for the computers on mastering-hat days.  The computer and digi cables go through the patch panel on the back wall of the mastering room into the control room.



Andrew

[bblackwood]

Andrew Hamilton wrote on Thu, 08 March 2007 02:27

The amp has large military-style capacitors and is balanced throughout.

You sure about that? I'm pretty sure none of Nelson's design are fully-differential...

[compasspnt]

Congratulations on converting the tracking room...probably a good, and good sounding, idea.

But shouldn't you also place a tiny camera on the right monitor, to "keep them in balance?"

[Jerry Tubb]

My Room in 2002...



It looks & sounds much different now : - )

JT

[Matt_G]

You'd better watermark that photo Jerry or someone might steal it  

[Gold]

The first time I heard  an A7/mac combination was at the 2003 AES NY convention. I was shocked at how good it sounded. If I didn't live in close quarters in NYC there's no doubt it would be my home listening setup.  It was really fun to listen to.

[compasspnt]

Yeah, anyone with the A7/Mac combo: put on a vinyl copy of "River Deep, Mountain High," turn it up, and be totally amazed.

[Jerry Tubb]

OK guys, since your gettin' off on it... here's a close-up:



A cherry Mac 275, original tubes iirc.

We were using the rig to shoot tones & noise in the room, listening for modes.

and of course some enjoyable nostalgic listening.

Thought of upgrading the drivers and rebuilding the crossovers...

The room was a great reverb chamber at the time.

JT

[Andrew Hamilton]

bblackwood wrote on Thu, 08 March 2007 07:33

Andrew Hamilton wrote on Thu, 08 March 2007 02:27 The amp has large military-style capacitors and is balanced throughout. You sure about that? I'm pretty sure none of Nelson's design are fully-differential...

Hi Brad,
    This is one of his SuperSymmetry amps.


From the manual:

"The supersymmetric amplifier is a special subset of balanced amplifiers...  Supersymmetry is an approach that truly takes advantage of balanced operation like no other and requires a balanced input to retain the precisely matched behavior. Supersymmetry is ideally used to obtain high quality performance from very simple circuit topologies...   The supersymmetry topology does not use operational amplifiers as building blocks, nor can it be represented with operational amplifiers.  It has two negative inputs and two positive outputs and consists of two matched gain blocks coupled at one central point where the voltage is ideally zero.  The topology is unique in that at this point, the distortion contributed by each half appears out of phase with the signal, and we use this to reinforce the desired signal and cancel noise and distortion.  This occurs mutually between the two halves of the circuit, and the result is signal symmetry with respect to both the voltage and current axis, and antisymmetry for distortion and noise.  This means that the distortion and noise of each half appears identically and cancels."





_andrew  

[Andrew Hamilton]

compasspnt wrote on Thu, 08 March 2007 09:39

shouldn't you also place a tiny camera on the right monitor, to "keep them in balance?"

Actually, the right speaker stays level with the left, even though there's no camera on top of the right speaker.  ();  Fortunately it's so small as to be acoustically transparent - even more so than the Dunlavy grill cloth, which I leave off, for visual impact.  (:




_andrew