Radiance Phono Preamplifier
- Product Code: Radiance
- Availability: In Stock
-
$3,250.00
- Ex Tax: $3,250.00
Highlights
|
|
Hardware
The custom discrete amplifiers inside Radiance (we call them "Top Amps") have a discrete JFET high impedance fully differential input. Stage 1 is a trans-conductance amplifier, direct coupled to the virtual ground input of a trans-impedance amplifier (stage 2). This combination provides 50dB of current gain to give the lowest possible noise and distortion. RIAA frequency adjustment is tailored with high accuracy 1% C0G capacitors with low temperature coefficient, low voltage coefficient and no microphonics. Input loads and output gain are switched with custom optically isolated high voltage, low distortion, low capacitance switches.
Top Amp has a class A+B combination bipolar+MOSFET diamond buffer type output stage to drive capacitive loads without oscillation, with up to 70mA output current. Current is limited by a feedback protection circuit, so you can plug headphones directly into Radiance's outputs, or whatever cables you like, with no concerns. Top Amps have a 4MHz unity gain bandwidth.
It's all controlled from Wifi Hifi, a browser based remote control running on custom software written specifically for Radiance.
Numbers
Frequency Response | High accuracy RIAA in two active stages, see graph below |
RIAA Response | ±0.2 dB from 20Hz to 20kHz |
Distortion (THD) | 0.002% THD @ 2mV input (output is RIAA adjusted) |
Maximum Output | 27Vpk-pk |
Input Impedance (software selectable) | 0pF to 750pF in 50pF steps |
Input Impedance (software selectable) | 20Ω, 65Ω, 110Ω, 260Ω, 350Ω, 400Ω, 47KΩ |
Unweighted Noise (Equivalent input noise) | 200nV rms, -88dB ref. 5mV, -132 dBu |
Unweighted Input Noise Density | 2.6nV/√Hz @ 20Hz, 1.4nV/√Hz @ 1kHz |
Dynamic Range | >100dB at <1% THD |
Signal to Noise Ratio (MC) | >87 dB (IHF A-weighted), >67 dB (unweighted) |
Frequency Response, RIAA compliance and channel gain match
Harmonic Distortion and Noise
input=2mVrms@1kHz, gain=70dB, THD=0.002%, output=6Vrms
Intermodulation Distortion
input=3.16mVrms@19kHz and 20kHz, gain=50dB
Radiance can be evaluated at your home for 30 days. If you are not fully satisfied, the unit can be returned for full credit.A returned unit must in original condition with all pieces in original box and packing material to receive full credit.
What is delivery time?
Voltage regulators and other components typically ship within 2 or 3 days. Time from us to you depends on the delivery method you select. Will ship worldwide via USPS, FedEx, UPS and others.
Audio products such as Brilliance or Radiance phono preamps are built to order, so allow two weeks before shipment, then transit time based on the delivery method you select.
Where are Belleson products made?
We design and build everything we sell, in Greer SC USA. Some products, mostly SPX Superpower regulator PCBs, are assembled by another US based board factory.
How do I connect Radiance to my local Wifi?
At first power-on, Radiance has its own internal network. You will use your phone, tablet or computer to connect to this network, then control Radiance from a browser at http://belleson.int. From there, you can connect Radiance to your local wifi network. Then any browser on wifi connected device can control Radiance. Full connection information is contained in the user manual... Until Radiance user manual is ready, you can read about it in the Brilliance user manual (PDF)
Note: Belleson Superpower voltage regulators have a separate warranty.
Belleson audiophile products are backed by a 5 year warranty. This includes parts and labor for repair or replacement of internal components or of the full product, as determined by Belleson after evaluation. Customers are responsible for shipping to and from Belleson factory, and for adequate packing and insurance.
Products that are non–functional due to modification or physical damage are not covered by this warranty and can be repaired after a discussion with customer.
Why is Radiance so quiet, so clear and so dynamic?In late 1982, our chief engineer built a preamplifier with a phono stage made from vacuum tubes. Over the next 40+ years he built more, some good, some not so much, in search of the ultimate performance from a vinyl playback system. As part of that work, in 2009 he designed and patented a highly respected voltage regulator, the Belleson Superpower series as used in high end audio playback and recording equipment. Electronic phonograph amplifiers have been with us for nearly 100 years. For most of those years, audio signals have been modified before they are transcribed to their permanent form on a vinyl record. On the playback side the signals are “unmodified” to their original form while being amplified from their tiny signal levels. These tiny levels make a phono amplifier stage one of the most difficult problems in audio playback, similar to the problem of a microphone amplifier in audio recording. A solid foundationBelleson® Superpower voltage regulators are known world–wide as the best regulators for audio. Radiance has a linear power supply with two levels of voltage regulation to make the most solid, quiet and stable power rail foundation possible. The critical input stageAs is well known in analog design, the input stage is the most critical part of an amplifier. It sets the system noise floor and is responsible for most of the distortion. Inspired by Bob Cordell’s VinylTrak™, Radiance was conceived in 2021 starting with a new idea for an input stage. A novel open loop current-output trans-conductance op amp design (we call it a “Top Amp™”) has internal local feedback to keep distortion low, while having fully balanced high impedance inputs. Low noise JFETs from specialty manufacturer Linear Systems at the input present essentially no load to a phono cartridge, allowing both resistive and capacitive input loading to be set independently. Its internal architecture also uses pseudo-Tziklai pairs combined with a folded cascode current mirror to fix all voltage nodes, avoiding voltage-variable-capacitance induced distortion. Output current from the first stage feeds an identical op amp, trans-impedance connected. The output of this second stage is the first node where any voltage swing occurs; all signal amplification to this point is via current gain. Thus the first two stages deliver 30dB or 50dB of gain before any appreciable voltage swing. Stage two also includes the 2122Hz pole to roll off the RIAA boosted treble. Having this early in the amplification chain reduces higher frequency audio before it is amplified enough to cause clipping. Vinyl playback harshness can often be traced to clipping of treble frequencies (above 2kHz) because of poor internal RIAA architecture, including systems where all RIAA equalization is done in a single stage. Stage 3 and 4Radiance has four inverting stages, meaning the output signal polarity is same as the input. It also means all four op amps in the RIAA amplification chain are inverting. Inputs for all stages are at virtual ground, essentially static at 0V vs. inputs of non-inverting op amps, follow the signal voltage. In latter stages of a phono amplifier the signal reaches a level of volts, which can generate distortion due to common mode rejection error in non-inverting op amps. Thus inverting in stages 3 and 4 again reduces distortion. Output currentRCA and XLR cables present a fair amount of capacitance to the output of a phono stage amplifier, generally 30pF to 80pF, sometimes more. Off the shelf monolithic op amps are prone to high frequency oscillation when driving a capacitive load. Often they are stabilized by adding a resistor between the op amp and the output connector, which increases output impedance and can slightly limit dynamic response. The Top Amp used in Radiance has a dual driver output stage. One driver is class A complementary bipolar transistor pair, to deliver clean output current up to 5mA. The other driver is a class B complementary MOSFET pair that is activated when current approaches 5mA, and can deliver up to 80mA output current. Top Amp is fully protected by an internal sensing circuit that shuts down the output as current exceeds 80mA. Bass response and the servoRIAA playback requires a 20dB treble cut and a 20dB bass boost. Amplification of 70dB at 1kHz means bass amplification is 90dB due to the bass boost; 90dB equates to an amplification factor of 31,623. Real (i.e. imperfect) op amps have DC offset voltages. This means if their inputs are set to zero volts, a DC coupled amplifier will have a non-zero DC output voltage. The majority of the offset voltage is due to mismatches in the input circuit amplified by the total circuit gain. In the case of a phono stage with 90dB gain at DC, a 1mV input offset voltage will generate 31.6V at the output, which can destroy a preamp or amplifier system and/or a speaker. The simple, cheap solution to DC offset error is to add a blocking capacitor in series with the audio signal to block the DC and pass the audio. Unfortunately real capacitors are also imperfect. First, bass exists down to 20Hz and the lower the frequency sent through a capacitor, the higher the capacitance needed to allow it to pass without attenuation. Higher value capacitors are typically ceramic, polypropylene or electrolytic. Their dielectric properties are non-ideal for high accuracy signals; specifically ceramic caps have voltage variable capacitance and electrolytic caps have dielectric absorption to distort low frequency signals. Polypropylene caps are much better but due to their dielectric constant they are physically large and/or expensive to get high value capacitance. A low pass filter can be optimized with a low(er) value capacitor and a high(er) value terminating resistor, trading off resistor noise for capacitor distortion and/or cost. More insidious, putting a capacitor in series with the signal introduces frequency dependent phase shift. If done carefully it can be negligible; if not, it can phase distort low frequencies at the cross-over point. Depending on the architecture and total gain, a blocking cap may be needed at multiple points along the signal chain. If one is used at the output, low frequency response can depend on the input impedance of the preamp or amp that follows the phono stage. The not-so-simple, more expensive, better solution is to use a servo correction loop. The output DC voltage is sensed and a correction voltage is applied to a point early in the signal chain to null the output DC to zero. A servo loop presents its own set of challenges: it is slow and takes time after power-on to stabilize at zero; it needs large value resistors and capacitors; it affects total stage loop gain and stability; its servo amp needs to be low offset and high input impedance. A separate servo loop is required for each gain path. Belleson developed a special hardware loop convergence accelerator to quickly stabilize the servo loop and special optically isolated analog switches to prevent power-up transients from ever reaching the Radiance outputs. However, IT’S WORTH THE COMPLEXITY. There is no better bass than a DC coupled signal path. What does all this tech talk mean?It means extremely low noise, even with gain of 70+dB for low output moving coil cartridges. It means extremely low distortion. It means treble clarity, with crisp cymbals and sweet violin. Fluid, true-life vocals and strings in the mid-range Low bass with tight kick drum. Deep, clear low strings and horns. Most importantly, it means accurate reproduction of whatever was stamped on the vinyl. |
- Power consumption: 8W
- Dimensions: 8.5”W x 8.5”D x 3.1”H [214mm x 214mm x 80mm]
- Weight: 6 lbs [2.7kg]
Radiance stereo phono preamplifier
Hear your vinyl reproduced exactly as it was recorded!
Featuring
|
Remote control of all functions with Belleson Wifi Hifi |
Built on the technical prowess of our Brilliance dual stereo input phono preamp, Radiance sports a single stereo phono input with the same amazing low noise, low distortion, accurate reproduction of vinyl. The laser engraved 5mm thick solid aluminum chassis houses a new generation of custom electronics to deliver a classic sound stage and musical presence with the ease of full parametric control of all aspects of reproduction using a wifi based remote.
Sit in the comfort of your listening chair and fine tune cartridge loading as you listen to the music. No fiddling with switches or jumpers on the rear panel or worse, inside the chassis, to adjust to the optimum load resistance and capacitance for your cartridge and cabling. Unmatched vinyl reproduction with the ease and convenience of streaming and the lowest noise floor you never heard.
Radiance is available in brushed black or aluminum to best complement your audio system.
- Inputs are balanced, with high input impedance and very low noise. At the highest gain setting (an amplification factor of over 30 000), low noise is very important and noise is lower than the noise contributed by the vinyl itself.
- Capacitive and resistive loading are remotely switchable so you can sit in your listening chair to evaluate the proper load for your cartridge. There is no need to shut off the phono preamp, get out of your chair and fiddle with little rear panel switches, no adding components via screw terminal or worse, opening the case to change loading. The remote control also allows setting gain and even changing from moving magnet (MM) to moving coil (MC) gain ranges. Once everything is set, you can lock the settings to prevent accidentally changing them.
- One RCA stereo input pair is available, and can be set for MM or MC. Load settings are updated and saved, and can be locked.
- There is a mute (via remote control), in case you need to take a call or converse with someone.
- Radiance uses 40 custom optically isolated analog switches (Octal Opto) to control capacitive and resistive cartridge loading, gain and cartridge type (MC/MM) switching.Octal Optos also disconnect the outputs whenever anything is switched, to mute any switching transients.
- Radiance is direct coupled from input to output because a direct coupled signal path (with no coupling capacitors) delivers the deepest, tightest, most chest thumping bass reproduction. Direct coupling also amplifies any DC offset; The circuit uses a servo correction loop to null DC offset and make direct coupling possible.
- Servos, because they operate at very low frequency, have long stabilization times at power on. Belleson solved that by adding a unique hardware servo accelerator that keeps the start-up transient small and allows fast settling. You get the best of both worlds—bone-rattling bass with no turn-on thumps.
- The Wifi Hifi remote control is a browser based app, so it runs on any device with a web browser.
- Wifi Hifi can be connected into your local wifi network, so you can control Radiance from your own tablet, from your phone or from your music server where your other music services are running.