Q: Can I use the Radial JPC like a regular DI box for instruments?
A: Although the Radial JPC was designed to work with computer sound cards and other consumer level hi-impedance devices, it can also be used with active instruments such as acoustic guitars that have built-in pick-up pre-amplifiers with internal batteries. We do not however recommend using the JPC with passive instruments like a bass guitar, as the input transformers low impedance may introduce some loading due to the impedance mismatch.

Q: Will it then harm the JPC if I connect a bass to it?
A: No of course not. We only state this advisory as we make DIs for instruments such as the J48 and JDI that are simply better for instruments. The JPC will certainly work in a pinch.

Q: Can I use the JPC on keyboards?
A: Yes. Just make sure you do not overload the JPC by driving too much signal through it. The JPC’s smaller transformers are designed for consumer type levels and keyboards, samplers and drum machines are usually much more dynamic and uncompressed. The JDI, the Duplex, and JD6 are better suited for this.

Q: What is the difference between the JPC and the JDI Duplex?
A: The Radial Duplex employs larger and much more expensive Jensen transformers to allow any instrument to be connected without fear of saturation. The JPC uses smaller transformers and an active drive circuit that has been optimized for sound tracks from CD’s or computers. These are generally ‘mastered’ and compressed while instrument sources are not. The JPC’s input impedance is also lower to properly match devices like computer sound cards while the Duplex has a higher input impedance to reduce loading with high impedance instruments. The JPC is also half the price!

Q: What is the advantage of transformer isolating the inputs?
A: When any two pieces of electrically powered equipment are connected together, they form a circuit. Most often, the reference voltages from each device differ, causing stray voltage to appear at the connections, which in turn can cause system noise commonly known as ground loops. By isolating the inputs through a transformer, we are in fact using a magnetic bridge thus eliminating any opportunity for ground loops in the system.

Q: Why not simply use a passive transformer as an interface?
A: The problem here is both impedance matching a drive capability. A single good transformer is extremely expensive costing upwards to half the price of the JPC. Because we use an active circuit to drive the signal, we can employ amore cost effective 1:1 transformer to isolate and active electronics to do the balancing and impedance matching. Ultimately, you get better sound for your money!

Q: Why am I not getting any sound?
A: Check to see if you have the 48V phantom power is turned on at your mixer. The two LEDs on the JPC will illuminate when phantom power is present.

Q: The sound is distorted?
A: Try turning down the level from the source or depressing the –10dB pad to reduce the input signal from the source. Excessive levels can saturate the input transformers, which could cause distortion. Make sure you are supplying the JPC with a full 48V phantom supply. Some inexpensive mixers will supply lower voltages, which could starve the JPC’s circuit.

Q: Where can I buy a Radial JPC?
A: Radial products may be ordered from professional audio and video outlets throughout the USA, Canada and around the world through our network of distributors. If you cannot find one locally, send us an email at info@radialeng.com and we will put you in contact with a dealer near you.

Radial - True to the Music™