The TwoGearGeeks decided it was time to test out some DI boxes (Direct Input) for you folks! We focused on DIs that would be good for both bass guitar and acoustic guitar, two instruments routinely run through DIs live and in the studio. We hope to do some bass- and acoustic-specific DIs in future posts.
Here is what we tested, along with its respective price:
A-Designs Audio REDDI – $795
Manley Labs Mono Tube DI – $575
Tech21 ParaDriver DI – $209
Radial JDI Mk3 – $220
At the outset, let’s get two things out of the way. First, sound is a tricky and subjective thing. The TwoGearGeeks prefer classic tones and mainly play and listen to roots rock, country, Americana, etc. So, put our comments about tone in that context — we don’t typically like over-effected basses that make a weird “meow” sound or a lot of guitars that sound like the guitar riff in “Owner of a Lonely Heart” (except when Yes plays it, of course).
Second, we did not test every DI on the market (although in our 40+ years of combined experience, we’ve played a good chunk of them), and we focused on DIs that would be suitable for bass and acoustic guitar. For this review, we don’t have unlimited time and couldn’t get every single DI out there to test. Plus, using a bass-specific DI (like the Aguilar Tone Hammer) or an acoustic-specific DI (like the LR Baggs Para Acoustic DI) would defeat the purpose of the roundup. So, we figured that we would try to get a good cross-section of higher-end DIs without being 100% extensive across the market.
We tested the DIs in a variety of studio and live environments with:
- 2005 Modulus Guitars VJ 4-string bass with Bartolini pickups and active Bartolini preamp, DR Black Beauty strings;
- 1965 Fender Jazz Bass (stock), with Rotosounds;
- Evidence Audio Melody instrument cables; and
- Vintage Crown acoustic guitar (Hummingbird copy) with LR Baggs M1 active pickup.
We also used Bob’s 1966 Ampeg B-15N for comparison purposes.
So, let’s get to it!
A-Designs Audio REDDI
The first thing to note about the A-Designs REDDI is that it looks cool — it is fire engine red and is housed in a serious metal box complete with heat vents and a brilliant blue power light. It certainly looks like it means business, and is by far the largest and heaviest of the DIs tested. It is not fitted for rack mounting, and will not fit in an average gig bag or guitar case. The REDDI has impeccable build quality, but it seems appropriate to expect perfection when you spend $800 for a DI.
Tech specs
- Input Impedance: 1 meg
- Gain Range: 16 dB
- Noise (EIN): -126 dB
- Instrument Jack Input: 1/4 phono combo XLR
- Balanced XLR Output:
- Output Impedance 600 Ohm
- Maximum Level +22 dBu
- Output: Low-Z, transformer-balanced
- Frequency Response: 20 Hz – 60k Hz
- Distortion: THD: > .08 @ 1 Khz
- Power Requirements: 100/120/230 VAC – 42 Watts
- Dimensions (W x H x D): 3.5″ x 3.5″ x 14.5″
- Weight: 10 lbs. (4.54 kg.)
Bass
Before receiving the REDDI, Bob had a nice chat with Peter Montessi, the President of A-Designs Audio. Mr. Montessi indicated that the REDDI was designed with a vintage Ampeg B-15N in mind, and, after some testing, that tone definitely came through. The REDDI really did sound a lot like a bass through an amp, not simply a bass through a DI. Good stuff.
With either an active or passive bass in the studio, the REDDI offered warm, round and clear tone that really sits well in the mix. We thought that it smoothed out the “active” tone of the Modulus, without robbing any of the character of the graphite neck. The REDDI offered a nice hot signal and it was really even along all the strings. It has an adjustable gain setting, which is great.
With the passive bass, the REDDI sounded nothing short of amazing. It sounded so good, in fact, that we kept soloing it in the studio, yearning for a song with a lot of sonic space so that the REDDI could shine. There was plenty of satisfying low end both recorded and live, without any mud.
We first encountered the REDDI a few years ago at a bar gig in Seattle. We overheard the sound guy tell the bass player after soundcheck that the REDDI was probably the best DI he’d ever heard. We didn’t — and still don’t — disagree.
Acoustic Guitar
With an acoustic, the REDDI offered plenty of tube warmth, with lots of presence and clarity in the studio. It really would be great in a sonically-open song or solo/small band acoustic setting live, i.e., vocals, guitar and piano. The guitar got a little lost in a crowded song, but we would certainly use the REDDI in any solo acoustic performance. It just sounds darn good.
Overall
Without a doubt, we can easily say that the REDDI is amazing piece of audio equipment. It was the warmest of the DIs tested, and sounds a good deal like a vintage Ampeg B-15N flip-top (but portable and new!). The REDDI is a perfect DI for bass and good for a sonically-open live or studio acoustic guitar. However, we will acknowledge the obvious point that not everyone can afford an $800 tube DI. But, if you have the money, give the REDDI a serious look.
Manley Laboratories Mono Tube DI
The Manley Labs Mono DI is a nice looking piece of equipment, with a subtle purple tint on the brushed-metal face. and simple, easy to access controls. Being roughly one rack space tall and wide, the Manley seems more at home in a studio than at a gig, especially since it had no visible signs of the rack mounting capability. Even though the shape is a bit confusing, the good news too is that it puts hair on your chest (get it — Manley?? Ed. — that was Josh, not Bob).
The test unit kindly provided by Manley Labs came equipped with an Electro Harmonix 12AX7 tube. The build quality was quite impressive, and it would look great in any studio environment.
Tech specs
- Vacuum Tube: 5751 (Ed. — the lower noise and gain version of a 12AX7)
- Gain: -6dB or -26dB
- Input Z: 10 Mohm to 1 Mohm
- Output Z: 150 ohm xfmr
- Frequency response: 12 Hz – 15KHz (-3dB)
- EQ: LF rolloff -3dB points: 12, 42, 100, 250Hz
- Transformer-Coupled Balanced XLR Output
- Console Out Boost Switch
- Ground Lift Switch
- Factory set for 100V, 120V or 220-240VAC operation for original destination country’s mains voltage.
- Operating Mains Voltage changeable with power transformer re-wiring and fuse value change.
- Mains Voltage Frequency: 50~ 60Hz
- Mains power consumption Mono Tube DI:
0.050 Amps (50 milliamps = 50mA) @ 120V = 6 Watts
0.025 Amps (25 milliamps = 25mA) @ 240V = 6 Watts
The Manley Mono Tube DI has a few items of note to discuss. First, on the front of the unit, there is a toggle switch labeled “Console Boost” and “Unity.” According the owner’s manual,
“UNITY” refers to power conversion similar to the way a good transformer works. The voltage is lower and the current is stronger but the power stays the same. The voltage loss is 23 dB and in a good range for all console mic preamps to handle well. “CONSOLE BOOST” mode adds 17 dB of voltage gain over “UNITY”. The voltage loss is about 6 dB. This is a good setting when the instrument has a low output or when feeding several consoles in a live setting due to losses in splitters.
We found that we used the “Console Boost” when recording but “Unity” live. You may have a different experience.
Second, the Manley DI also has a five-position knob that allows allows users to adjust the output frequencies, which is really handy to get some EQ tweak on the fly. The knob
[s]elects between five types of 6 dB per octave low frequency rolloff: BASS FULL is the closest to a “flat setting”. BASS FULL = 12 Hz / -3 dB, BASS MED = 42 Hz, GUITAR/SYNTH = 100 Hz, GUITAR MED = 250 Hz, GUITAR BRIGHT = 550 Hz. All settings have a gentle roll-off on the highs (15 kHz -3 dB) to avoid some of the harshness of typical DI’s and to better approximate a clean amp-like sound.
Bass
Not surprisingly, we tested both the active and passive basses with the full spectrum position (i.e., “Bass Full”) in live and studio settings. The Manley Labs DI offered ample tube warmth to bass along the full spectrum, although with the active bass it was not as punchy as the REDDI. The tone was clear and round, and the higher notes popped out nicely in the mix. With the passive bass, the Manley was actually a bit punchier than the REDDI. However, it is like comparing a Porsche to a Ferrari — they’re both awesome, just different, and people could argue about which is better indefinitely.
For either passive or active basses, the Manley is a very high quality tube DI that we would recommend. It offers warm, rich tube tone that sits well in the mix.
Acoustic Guitar
We tested the acoustic with all five frequency positions, but ultimately settled on the middle position (i.e., “Guitar/Synth”) during our recording sessions. The Manley offered warmth and a smidgen more clarity than the REDDI. The Manley sounded great solo or in the mix, with mellow highs free of harsh overtones. It’s nice that it has a few settings so you can match the sound to your instrument, especially live.
Overall
The Manley Labs DI offered a warm, rich tube tone that sits well in the mix. For the price (which admittedly is beyond many people’s budgets), we were not disappointed. It is a great-sounding tube DI, and the bells and whistles really add value for the price.
Tech21 ParaDriver
Tech21 is a company well-know for its SansAmp line of pedals. Most folks have seen or used a Tech21 product, and they generally don’t disappoint. The ParaDriver sported impressive build quality for the price, and it came delivered in a nice metal tin with a sticker. The manual was informative, easy to comprehend and access, and had some great sample settings. In this day of overseas outsourcing, we like that Tech21 still makes their products in the good ol’ US of A.
Tech specs
Because the ParaDriver is more than just a DI, we decided to include a guide for the controls (from the manual):
- DRIVE: adjusts the overall amount of gain and overdrive, similar to when the output section of a tube amp is being pushed.
- BASS & TREBLE: These active tone controls cut or boost ±12dB from unity gain at 12 o’clock. Bass is 80 Hz, treble is 3.2 kHz.
- MID SHIFT & MID: Sweepable, semi-parametric EQ controls range from 170 Hz to 3.5 kHz, ±16dB, respectively. With Mid Shift, you can select the center frequency of the mid-range control (MID), enabling you to notch out specific frequencies that may be causing your acoustic guitar to feed back.
- BLEND: allows you to blend the direct instrument signal with SansAmp Tube/Microphone Emulation circuitry. In most cases, you will probably have this set at maximum (100% SansAmp). If you should want to hear some of the distinct timbre of a piezo pickup, or reduce the amount of “compression,” you can simply adjust accordingly by turning the Blend control counter clockwise. At minimum, the SansAmp circuitry is bypassed. However, all the other controls remain active. The unit then functions as a standard DI with EQ.
- LEVEL: adjusts the output level of both the 1/4” and XLR outputs.
Bass
After using the ParaDriver in the studio, live and in rehearsal, we found that it really shines as a live/rehearsal tool. In the studio, the ParaDriver gave both the active and passive bass a high-tech, detailed sound. As noted above, this is not really the type of sound that we like, but others may disagree. C’est la vie.
Using the ParaDriver as an amp simulator (either in rehearsal or live) really allowed it to come into its own. The manual has several sample settings, including “Deep Tube Bass” and “Active Bass Simulator,” each of which did a surprisingly good job of tone transformation. During our first session with the ParaDriver (during a rehearsal), we tested the “SVT® Bass” setting and it made my little Eden combo come alive with growl and beefy bass goodness!
Acoustic Guitar
To be perfectly honest, we had a hard time finding satisfying tones using the ParaDriver with an acoustic. We tried the sample settings, we tried the DI straight, and then we tried some more, but we found the tone a bit dry and brittle compared to the other DIs tested.
That said, the ParaDriver did sound really great as an overdrive pedal for electric guitar.
Overall
Overall, the Tech21 ParaDriver DI offers a really good option for a bass player with about $200 to spend who needs both a dependable DI and tone shaping capabilities. The ParaDriver was not our favorite studio DI, but it is a great live tool.
Radial JDI Mk3
The Radial JDI tested is the only one of the four that was not made in the USA. Radial’s products are proudly made in the Great White North, eh. Perhaps its Canadian roots explain its sturdy build and nice evergreen color. The JDI is built to last, and to take abuse while it is around, so it is not surprising that it has a high-quality Jensen transformer and welded steel construction. The JDI was the most traditional DI-like in appearance, and is at one with the Force (get it — JeDI?? Ed. — that was Josh again. Sheesh.).
Tech specs
- Dynamic range: 135dB
- Signal to noise: 119dB
- Maximum input level: +19dB
- Frequency range: 10Hz~40kHz
- Linearity 20~20kHz: 0.1dB
- Phase coherence: 4º at 20Hz, 0º at 1kHz
- Distortion at 20Hz: 0.006%
- CMR rejection 100dB @60Hz
- Input impedance: 10kW
- Output impedance: 600W
- Construction: Welded steel
- Finish: Baked enamel
- Input connectors: Two 1/4” phone
- Output connectors: XLR male
Bass
With the active bass in the studio, the Radial JDI offered a more balanced tone than the Tech21 ParaDriver, but perhaps not as much warmth as the tube DIs. No surprise there. With the passive bass in the studio, the JDI was much warmer sounding and had a nice low-end beef.
Either live or in the studio, the JDI provides a nice, warm tone (although a bit low-mid heavy), with excellent clarity in the mix. It is a solid, portable piece that fits easily in any gig or utility bag, and can handle the road like a champ. Bob has been personally using a JDI as his “go to” DI for smaller live shows (at home and on the road) for the past several years. Now, a REDDI purchase may be warranted too…
Acoustic Guitar
We were both surprised at how well the JDI sounded with the acoustic. The tone was remarkably warm and balanced for a solid state DI. It seems to have the correct sonic range for the guitar — great bass response and a full sonic palate of mids and highs.
In the studio, the JDI translated a real “woody” sound, even in a relatively crowded mix. Live, the JDI manages to maintains warmth, but translate clarity as well. This is certainly a “go to” piece for an acoustic player, and a workhorse that will be with you for many years at home and on the road.
Overall
The Radial JDI Mk3 is an excellent DI, especially for the money. It gets a special nod for how well it handled the acoustic guitar. You really can’t go wrong.
Conclusions
Of the four DIs that we tested, each offers a different tone, a different price point, and a different recommended use. If you’ve got the money and need to have the absolute best, grab yourself an A-Designs Audio REDDI. You won’t be disappointed.
If you’ve got some money and want a tube DI, but want a few more bells and whistles than the REDDI, the Manley Labs Mono Tube DI will treat you well. It offers tube warmth, gain control and some tone shaping options all in one.
If you only have about $200 and you need a solid, reliable DI with serious tone shaping options, the Tech21 ParaDriver DI is a good choice. It is a great tool for the working bassist.
If you only have about $200, you like simplicity and want a DI that will be good for bass or guitar, and will operate flawlessly night after night (after night…), the Radial JDI Mk3 is a great choice. It just works, period.
Overall, you really can’t go wrong with any of these items.