Ultimate VC System - Audio Board Walk Thru

[brian]

This board handles the audio signal and is fully DC coupled in/out and, since it's functions are self contained, can be positioned optimally close to signal I/O . There are:

* 5 INPUTS
* REC. can also be used as a direct in (ie single source). More about this later.
* DIRECT OUT which has an output impedance of 25Kohms
* JFET OUT which uses the optional JFET (LSK389-A) devices as shown installed and has an output impedance of 50 ohms

To use as a volume control in your amp or preamp just route all signal to the audio board and use the direct out connector block. EZ drop in to replace your existing attenuator.

But there is also a possibility to build a simple standalone linestage by using the JFET outs.
For example:

* Projekt chassis 240mm is perfect (we will be offering a premounted faceplate for the Ultimate VC)
* handful of RCA jacks
* Ultimate VC System with JFET option

Now you have a fully DC coupled, 50 ohm output impedance, unity gain linestage which has NONE of the problems of passive linestages. To paraphrase one of the masters: Sort of a like a 21st century Aunt Corey's Passive Preamplifier
We are doing a buildup of this now and will blog it shortly

Next: The Control Matrix

[brian]

The Control Board is the long one shown; front and back. The short board is the audio board in the previous post.

We refer to the Control Board as the Control Matrix because it is actually 3 modules -- Volume, Selector, Logic/PSU -- which can be snapped off and positioned to suit any size faceplate (the Volume and Selector modules communicate with the Logic Module through ribbon connectors). Or it can be mounted as one unit to a suitably sized faceplate. The 240mm Projekt chassis happens to be one that is.

The center module contains the Logic and the PSU. Note: no extra transformer is needed; as you can see, it is in place on the module and ready to be connected to either 115 or 230v mains. Signal stays on the Audio Board; the Control Matrix is programmed to do all the switching and housekeeping and tells the Audio Board what to do with the signal through a ribbon cable.

The selector and attenuator switches have a shaft which allows a knob and manual control from the front panel -- or remote control using standard RC5 encoding.

The blue LED are meant to be visible through the faceplate and a drilling template is provided. The selector module has 5 LED installed -- one for each input. The Volume Control Module has 12 LED installed BUT there are actually 127 steps! We didn't think you would want to drill 127 holes for 127 LED.

Native attenuation is -52db to 0db from a reference 3.5V rms. But you horn guys are going to love this: Shunt mode allows -66db to -15db!
DIY - Done Right!

[brian]

Now.

Check this out:
at the front we have the controls and the power supply. All the digital bits flow across those ribbons to selector (left), volume (right) and the audio signal board (chassis back).

The audio signal board uses end-to-end analogue potentiometers to adjust volume and vacuum silver relays to select source. The great thing is the audio signal board can be mounted beside the I/O jacks and the power supply can be put far away. This minimizes noise and maximizes musical fidelity.

Quiet it is. Next week I'll report some measurements.

Now notice the 2 little round circles with roach-like occupants, flanking the 2 red caps on the audio board. Those are the LSK389 JFET so that the JFetted outputs can drive any load (Zout 50 ohms!). But, these can be bypassed with the direct out connection going to another set of outputs. You'd want to keep the cables very short if used direct out.

EZ.

We will also offer a CNC'd front plate just like you see to premount the Control matrix board (the one attached to the knobs) to be used with your own chassis.

EZ'r.

Now how about those 127 steps? It's the first time we've ever had a device with 127 step attenuation. It's like having 5.5 x 23 step volume controls. What's it like to use? Jailbreak! Really. It's like the difference between looking at the world through prison bars or looking out a panoramic window.

And the sound: surprisingly smooth. Why surprisingly? Because it ain't got tubes! But it is passing along 100% of the tube-sound upstream.

More.

[brian]

Ultimate VC:

Quite a few have come through and listened and 100% unanimous: Ultimate VC = good sound!

I would characterize this as a very smooth, effortless sound, with no holding back.

On the Bench
our test equipment is 24bit/192khz. The Ultimate VC pushes our measurement abilities to the limit (JFET output into 10k load):
non-inverting phase
20hz - 80khz at -0.5db
THD: 0.007%
Dynamic range: 100.7 db
IMD + noise: 0.0076%

Our next step is to install the UTS in the same chassis together with the Ultimate VC

It seems everyone is ordering these with pre-drilled faceplates. I should have these in hand in 10 days.

UTS Phono stage:

the Cinemag stepup transformers arrived today and we will be offering the UTS phono with stepup transformer option. These are friendly little critters, nice and compact in their MU-metal cans.
Should have something to report on that by next week.

OK!

[jack34]

Hi All

I am sorry to post on the wrong thread. To be truly i could not find the proper thread to post my introduction. I am Jack from USA and just joined your community. I hope you all will welcome me.




-----------------------------------------------
Get the free quotes