Radial PZ-DI (new) -- best Active DI ever for passive basses

[mhschmieder]

I had a chance to try this puppy out at the AES Show in SF this autumn, where it was announced, and ordered one the next day. No regrets; mine arrived this week and I put it through its paces today.

Essentially an upgrade and expansion of the J48 (which I am about to put on eBay), the PZ-DI is phantom powered (no batteries or wall wart), has a variable low cut and a switched high cut filter, and a three-way impedance switch for 1 mega-ohm (i.e. J48 mode), 10 mega-ohms (i.e. piezo pickups), and 220 kilo-ohms (i.e. magnetic pickups, or tube emulation mode for basses and guitars).

The price is right (just over $200). The only J48 feature it is missing is the two-channel mono merge function, which I don't tend to use anyway. Even for keyboards or active instruments, where I use my Radial JDI Duplex Stereo Direct Box, I trust the mono merge on the keyboard more than the questionable quality of the mono merge on the direct box. I think it has to do with where the merge occurs in the signal path as to how coherent the resulting signal is.

Anyway, the clarity and detail coming out of this DI surpasses any I have ever owned or used; including the Avalon U5 (passive) and Summit Audio TD100 (active) which I sold last year after deciding to go the Radial route. Those are excellent units, of course, and very flexible, but I feel the PZ-DI now makes Radial's Active DI entrant as flexible as the Summit Audio TD100 -- though of course that unit is a hybrid DI/Pre-Amp, just as is the Avalon U5.

At any rate, I think this unit would be of extreme interest to anyone here who does large-scale gigs that require direct boxes, or professional studio work.

I do not yet have a Fishman piezo pickup installed on my URB so can't yet vouch for how well the PZ-DI represents the Upright, but it was fine on other piezo sources.

Just to reiterate for those who aren't terribly experienced with DI boxes: Active DI is generally best for passive instruments, and Passive DI for active instruments (the latter category includes modern keyboards, but not traditional keys like the Rhodes Electric Piano).

[Prime Mover]

Nice. Actually, I've been pretty happy with the mono merge on the Jensen's. I have a few sound guys that I trust that always use it, and it's always been great. Above and beyond simply merging the stereo sound (which Jambalaya has a switch for, anyway), it doubles the signal level, which is good to do before analog boards. I use it even when both left and right are putting out the same waveform. Now, I personally only have a Radial ProDI, but all my sound guys use the Jensen's.

[mhschmieder]

Just to clarify, the Jensens are only in the top-line passive DI's. The active DI's use a variety of approaches, but the J48 and PZ-DI are FET based. The JDV is stereo and uses a different technology altogether (I can't look it up right now because I need to reboot my computer quickly and finish a song I'm writing -- my MIDI controller keeps crashing DP).

[Prime Mover]

Ah, I assumed the "J" in J48 referred to Jensen. But what I was really getting at is that the Jensen passive DIs have the mono merge, where-as the "Pro DI" (non-Jensen passive) do not. Since I've only ever used passive, this is where this feature is found.

From what I understand, DIs modify the signal in two or three ways:

A) Balancing the signal
B) lowering the impedance
*C) boosting the signal (actives only)

Line inputs like keyboards already have low impedance and high voltage, so all you're looking to do is balance the signal. Does transformer quality really make much of a difference in this case? Or is it much more noticeable on high-Z, low voltage signals?

[BKK-OZ]

I love my JDV (Class A direct box).

Methinks Radial knows what they are doing. They are obviously a geek-engineering driven company, all their stuff is just so solid and smart, perhaps even sometimes slightly over-engineered. But that is why I like their stuff, I guess.
Overkill, in situations like this, is good in my book.

[mhschmieder]

I recommend everyone read all the FAQ's and white papers at Radial's website. They are very concise and easy to understand without a lot of background in audio. There's no way I could do a better job of summarizing than they did themselves. And they say nice things about the competition too, which is rare. I talk to these guys at the trade shows and they impress me more than any other company in the industry. They won't sit still; there is always room for improvement. How many vendors keep improving successful products year after year?

So, in short, the answer to your question about using DI's with keyboards is best answered at the Radial website. I would just be repeating what they said if I tried to summarize it myself.