Cables and connections
We recommend balanced input wiring; this does not mean unbalanced is not possible. Please refer to our amplifier input wiring application note.
https://www.hypex.nl/FAQ-Hypex/Cables-and-connections/Can-I-use-balanced-and-unbalanced-signals
An easy way to change your input signal from unbalanced to balanced is the use of a decent interconnect cable. We offer ready to use interconnects at www.diyclassd.com
That basically amounts to a source selector. Refer to our application note "Dealing with legacy pin 1 problems" for information of how to wire an RCA connector to the UcD module. Install a DPDT switch to connect the hot/cold inputs of the UcD module to either pins 2/3 of the XLR connector or to the signal and shell contacts of the RCA connector. Note that pin 1 of the XLR connector is not switched, but remains hardwired to chassis. The RCA shell contact also remains hardwired to the chassis. This means that when the DPDT switch is set to RCA, the cold input of the UcD module is grounded via the RCA connector. See schematic in this the application note "Dealing with legacy pin 1 problems"
https://www.hypex.nl/FAQ-Hypex/Cables-and-connections/I-would-like-to-switch-from-XLR-to-RCA-and-vice-versa-without-the-need-of-pulling-the-unused-cable-out-of-the-amp.
Fundamentally there is no problem of course. However, most tube preamplifiers are designed alongside tube power amplifiers which are always AC coupled. As a result, many tube preamplifiers lack precautions against turn-on/turnoff transients. Some are liable to produce the full anode voltage at their outputs during turn-on and turn-off. We find that a large proportion of repairs are due to tube preamplifiers discharging their output caps into the UcD™ input circuit. Note that most solid-state amps dislike such treatment, not just UcD™ or NCORE® amplifiers.
https://www.hypex.nl/FAQ-Hypex/Cables-and-connections/Can-I-use-a-class-D-amplifier-with-a-Tube-pre-amplifier
We have cable sets available for connections between the amplifier and SMPS, beside that, in our datasheets you can find the pinouts of every connector on board of the product.
A: Indeed you can. There’s no good way of adding a potentiometer to a truly balanced connection, but in a “pseudo balanced” connection it is possible. You'll need to use microphone cable (shielded twisted pair). There are 2 stretches of cable. Cable 1 goes from the RCA terminals to the pot. Cable 2 goes from the pot to the UcD input.
https://www.hypex.nl/FAQ-Hypex/Cables-and-connections/I-have-no-preamp.-My-source-is-unbalanced-and-I-would-like-to-use-the-RCA-to-XLR-cable-method.-Can-I-add-a-potentiometer-and-retain-some-of-the-benefits-of-this-connection-method
1) Cable 1 (RCA end): shield and white wire to RCA ground. Blue wire to RCA signal.
2) Cable 1 (Potentiometer end): white to potentiometer "common". Blue to potentiometer "input". Shield of cable one is connected to shield of cable 2 AND TO NOTHING ELSE!
3) Cable 2 (Potentiometer end): white to potentiometer "common". Blue to potentiometer "output" (wiper). As said in 2) the shield connects to the shield of cable 1 and to nothing else. RESIST ANY URGE to connect the shield to the pot common. 4) Cable 2 (amplifier end): white to pin 1, blue to pin 3, shield to pin 2. So that means that the shield of cable 1 continues as the shield of cable 2, so you get a contiguous shield all the way from the RCA to the amplifier. Any circulating currents that go through the shield will never mix with the audio ground because the audio ground is kept separate (white wire) and sensed differentially by the amplifier.
A: With each connector pinout table, the connector type equivalent is given. Instead of entering some limited specifications in our datasheet, Hypex choose to give the part numbers of the connectors (or equivalent) used on the modules. This allows you to find that specific matching cable part, which is easily available in your country. Furthermore, a datasheet of a connector gives you much more valuable information, including pin plating, alloy, latch type, contact resistance, insulation resistance, insulator material, dielectric withstand voltage, flammability rating and pin position.
https://www.hypex.nl/FAQ-Hypex/Cables-and-connections/In-the-datasheet-pin1-of-a-connector-is-indicated.-Why-are-other-pins-not-numbered
Finally, Hypex advices to order the cables set of the specific modules via our webshop. This ensures you always have the correct cables and connector for your modules.