Reference line stage preamplifier
The Ruby STD preamp uses the latest development in grounded grid configurations which surpass all our previous designs. While lab experimenting, we happened to stumble upon an observation of stupendous consequences that would have seemed impossible beforehand. We have not only managed to simplify the circuit using less parts, but have allowed 3 useful and necessary functions to be performed by one precision Vishay 0.1% 25 ppm metal film 1 watt resistor.
As a consequence, we can state with certainty that this line stage is the fastest possible using tube circuits. While it would be possible with solid state devices to reach these speeds, very few of the ultra high end solid state line stages that we are aware of approach this extreme bandwidth. Not only is it flat from 20 Hz to 250 KHz but extends way out past 1,000,000 Hertz. As always the three stages are non-inverting maintaining absolute phase.
While the grounded grid configuration is known for its extremely wide bandwidth, this circuit has moved the bar way beyond the capabilities of any other tube configuration, including grounded grid circuits from other manufacturers.
The buffered output is capable of driving two pairs of outputs to accommodate bi-wiring or bi-amping. All stages are DC coupled and only one metallized teflon film capacitor is used in the output stage for DC blocking. No feedback and mirror image circuitry is implemented in the audio section for best channel separation.
The parts quantity is the lowest count yet achieved, using a superior Grounded Grid circuit over previous designs. This allowed us to use the highest quality parts while limiting cost due to the lower parts count and without resorting to using two chassis to implement this design, while at the same time exceeding the specifications of all previous line stages in the past. No tube product could hope to compete with the Ruby STD unless they copied the circuit and parts verbatim. The circuit cannot be simplified further, and the parts cannot be substituted, including the tube types.
We chose to append this Ruby with the abbreviation "STD" - meaning this is the STANDARD circuit by which all other tube circuits will be compared to and for which none can duplicate it's sonic attributes without outright cloning it. This is undoubtedly fighting words for all challengers, at all price points, come what may. There are no words to describe the majestic sound when operated with appropriate legendary products.
Gallery
Circuit Description
Power Supplies
A Toroid power transformer is employed to eliminate mechanical hum and contain the magnetic field from radiating to surrounding areas. A choke LC filter is used for the 300 Volt plate supply that effectively reduces ripple and noise to zero.
Because our unique circuit operates with very low power requirements, it wasn't difficult to build the perfect DC power supplies needed for this exceptional line stage. The use of pure DC 12 Volt power to the filaments insures that no AC ripple (120 Hz) will effect the audio signal.
Unit is supplied with a balanced 100% shielded power cord with the shield tied to earth ground
Mechanical Construction
- Machined aluminum plates (1/4 inch thick) bolted together with stainless steel machine screws is used to construct the preamp chassis. This provides excellent shielding from external radio frequency fields.
- Custom plated machined brass designer knobs with a Titanium look and notched indentation allow for precise settings. These knobs have dual hex set screws to secure to the shaft that insures accurate calibration and smooth reliable operation of switches
- Gold plated machined brass holder with 3M rubber feet inserts accentuates the styling and allows proper air flow for the vents under the chassis.
- The stepped Elma dual Volume control has 24 gold plated contacts with surface mounted 0.1% precision resistors to maintain channel balance to within +/- 0.05 dB
- Selector and Tape Monitor switches control relays and are not in the signal path
- Tape Monitor switch can also function as a processor loop
- Balance control uses a sealed electroswitch with silver plated contacts and 1% Vishay precision resistor networks
- NKK toggle switches for Tape monitor, Muting & Power on functions
- Noiseless toroidal power transformer
- Non magnetic stainless steel and brass hardware is used throughout
- Satin powder coat paint finish for extreme durability
- Polished Brass Handles accentuate the aesthetics of the front panel
- Herbie's tube damping isolators are used to restrict microphonics
Circuit Board
The circuit boards were designed using Express PCB layout software which allows for specifying the width of the traces (wiring) This enhances reliability and lowers the resistivity of the connections.
Each component is soldered by hand to the circuit board to insure a good solid joint. The double sided printed circuit board has been manufactured with the highest quality standards in the industry.
It has full solder masking on both sides of its premium glass epoxy board with white silk screening that identifies parts and there placement for fast efficient placement, soldering and assembly.
High quality teflon coated silver plated OFHC copper wiring is used in all analog wiring to and from the circuit board. Dual timing circuits control power up sequence and muting on power up.
Automatic power sequencing and muting
To allow for extended tube life a 30 second delay is applied before the high voltage plate supply is engaged. To allow circuit stabilization and quite operation a 90 second automatic muting is activated during power up. Muting is accomplished using a double pole relay that shorts the preamp outputs. When disengaged the muting circuit is not in the signal path.
You also have the ability to power off the preamp without powering down the amplifiers by enabling the muting switch before switching the power off.
What this means is that you can swap or change RCA cables for replacing source devices without powering down. You cannot however change cables to the amplifiers.
Specifications
Tube Complement
(2) 5687WB NOS JAN Philips USA military dual Triodes
(2) 12B4A NOS JAN GE USA military Triode
Frequency Response
( reference to a sine wave at 1KHz @ 2 V RMS output )
+ 0 - 1 dB 9 Hz to 1.25 MHz
Gain
12 db ( 4 x )
Input Impedance
45K ohms minimum
Absolute Phase
non-inverting
Channel Balance Control
11 position for +/- 5 dB adjustment in 1 dB steps
Attenuation
24 position stepped volume control ( -60 dB to 0 dB)
Output Impedance
450 Ohms
Rated Output
3.5 V RMS ( maximum = 15 V RMS )
Outputs
- 2 pre-amp outputs
- 1 tape output
- 1 line level output
Inputs
- 4 line level inputs
- 1 tape input
Tape Function
A processor loop can also be used using the tape in/out connection
Power Requirements
115/230 Volt, 50/60 Hz, 51 Watts ( 64 VA )
WEIGHT
Net: 15 lbs (6.8 kg)
Shipping: 18 lbs (8.2 kg)
Dimensions
15" W x 10.875" D x 3 3/4" H
Reviews
Tone Audio
No. 75 - November 2015 - Reviewed by Rob Johnson
This is a very special preamplifier, offering performance rivaling the world's finest…
In the context of the four different systems at my disposal… the main characteristics of the Ruby that came through loud and clear… were this preamplifiers spectacular bass drive, extension and control along with an incredibly deep soundstage…
…of the preamplifiers in my collection, I`d compare it the most closely to the $33,000 Koda K-10, with an almost absence of `sound` but with a few drops more of tonal saturation…
Tone Audio
December 2015
The Ruby STD received a TONE Audio 2015 Publishers Choice Award
…this one is as natural as they come with that ever so slight bit of tonal saturation that tubes bring to the table.
The longer you listen, the longer you will love it; the Wyetech Ruby is as honest as it gets.
The High Fidelity Report
December 14, 2013 - Reviewed by Joey Weiss
The Wyetech Ruby STD is a hidden treasure for the analog music lover.
The preamp is a breathtaking example of simple-yet-elegant audio engineering and the sonic results will make you believe in the magic of audio reproduction.
The Ruby STD is a serious contender that any analog aficionado with blood in their veins and music in their heart should experience.
The Audio Beat
August 11, 2014 - Reviewed by Ken Choi
The Ruby STD line stage was reviewed in The Audio Beat along with the Ruby P-1 phono stage.
…the Ruby STD presented music with complete and complex tonal and harmonic structures, and an organic (i.e., non mechanical) sense of flow…
The sound was anything but retro, though, being characterized by tremendous clarity, speed, and detail accompanied by an almost total absence of a noise floor…
Warranty
Note that due to the passing of Roger Hebert, we are no longer able to offer warranty coverage on new sales. The sale price has been adjusted accordingly. Sales made previous to January 2022 will have the waranty coverage period honoured.
Warranty coverage for sales prior to January 2022:
Tubes and components: 5 years parts and labor
