Rodyweil RO-04 Pro Mic Preamp 0~72db Adjustable Gain Boost with Hi-Z, 48V, HPF, Phase for Dynamic Condenser Ribbon Microphone, Guitar, Bass Recording and Podcasting

⭐⭐⭐⭐⭐  By  Bleeding Roses Records 

Punches WAY above its price range

Reviewed in the United States on July 7, 2025

Im genuinely blown away by the fact a preamp can sound this good, for this cheap. Its super functional with the mic input and Hi-Z, HPF, and even a phase toggle. Fits comfortably on my gear racks or desk, and can be powered just about anywhere due to the USB C power connection.

In a quick A/B test on a bass synth, its pretty obvious this thing adds some serious low end punch, and clarity to the top end. Transformers must be never than the price tag suggests, because this thing sounds super clean, and has little to no noise.

Tested on a Behringer CAT, running through ADAM monitors - and It sounds competitive in quality to most the other preamps on my rack that are 4x the price or more. No tube, but not everything needs one. Id imagine this will be my new DI or be a dedicated pre for my bass synth.

⭐⭐⭐⭐⭐  By  Anonymous

 Solid sound, good value

Reviewed in the United States on July 14, 2025

Thank you to Rodyweil for sending me this preamp to try out! Overall I am impressed with the quality and functionality packed into the price point. I compared it to the preamps on my Behringer UMC1820 interface, and used that interface as A/D conversion for the Rodyweil unit as well.

The Rodyweil RO-04 is a compact preamp that comes in a road-worthy box with a USB-C power supply and a short braided XLR cable. The large gain knob is a tad unsteady but otherwise the front panel controls have a premium feel to them, complete with indicator lights on the buttons and a classy backlight for the Rodyweil logo.

All the connections are on the back of the unit, which I found inconvenient for hot-swapping mics during testing, but I imagine in a travel rig or permanent setup this wouldn't be as big of an issue.

I tried this preamp with four sources: guitar DI, bass DI, SM57 dynamic, and MXL 990 large-diaphragm condenser. I found a similar performance in all tests. Compared to the built-in preamps in my Behringer interface, the Rodyweil preamp offers more gain, better definition in the high-end, and a more controlled low-end. The sound signature is fairly neutral, which is good for my in-the-box workflow. The high-end ranges on brittle at times but is not harsh, and I found it easy to control with filters/EQ or adjusting the sound source. Predictably, the DI signal responds well to amp modeling. Similar to other reviewers, I was impressed with the lack of noise floor, even at high gain.

I've given it 5 stars because I believe this is an excellent option at the price point. I am happy to have this preamp in my arsenal and plan to use it on vocals, guitars, and percussion.

⭐⭐⭐⭐⭐  By  Len Mcwilliams

 Incredible combination of quality features for this price point!

Reviewed in the United States on October 4, 2025

I'm initially uisng the RO-04 to boost to line-level the signal from my amp's DI out to my in-ear monitor (IEM) wireless system.

In order to obtain adequate volume in my IEMs, my Xvive U45 in-ear monitor wireless system requires line-level input (not mic-level). I encoutered this requirement because the only available output channel on my Loudbox Mini charge is a DI out at mic-level. To get this setup to work required my inserting a mic preamp between the amps DI out and the U45 transmitter. For this purpose, I purchased the RO-04 Mic Preamp. Using the RO-04, I boosted the DI signal 36db and acheived adequate IEM volume. The sound is high-quality and noise-free.

The fact that this preamp is battery-powered allows me to maintain a simple performance setup for Jazz workshops and jams: battery-powered Fishman Loudbox Mini Charge (no power cords), wireless connectivity to my electric violin, wireless IEM system, and NOW the battery-powered RO-04 preamp to provide the required line-level signal to my IEMS.

I'm sure I will eventually use this amazing preamp for connecting my Shure SM58, lavalier mic, accoustic instrument mic, and piezo pickups to my audio interface and mixer.

This preamp should definitely be an Amazon's Choice item!

⭐⭐⭐⭐⭐  By  Sevastian Golston

RodyWeil

Reviewed in the United States on July 30, 2025

The quality of this MicPreamp is exceptionally premium and extremely good; the Trim Lavalier is outstanding. This MicPreamp fully lives up to its hype and all of its other reviews. Everything is quiet, with no bad distortion/saturation, pink noises free , white noises free no static of that nature- it's glitch-free, with just pure, warm gains and crystal-clear gains , with the touch of the HPF feature .You will not be disappointed. Having dealt with a substantial amount of studio equipment over my time, and as someone who owns an Antelope Zengo, I would choose this mic preamp over my preamp inside the Antelope preamps on most occasions. I also own some high-class preamps, such as the Gyratec XI, VPA76, BAE-1073MP, RD-47, and BA-31. This RodyWeil is now my number one on-the-road mic preamp; it’s compact. Thank you, RodyWeil Company.

⭐⭐⭐⭐  By  Terrell LaSean Clayborn-Nix

Worth 4 stars easy and will be getting a review/comparison video. They're pushing past entry level!

Reviewed in the United States on July 9, 2025

This product is a solid performer with a few enhancements from the engineering team at Rodyweil. It may say "Made in China" on its case; however, there are US components in it as well which make it a hybrid build originally from China. The hardest thing to do overall is to deliver high quality in a entry level price point. They have achieved their goal in a potent preamp. This "No frills" solid state-based design has a few features that many its class lack. Notably a stepped gain knob (upgraded from the digital rotary), dedicated "Trim" knob (to fine tune its 72+dB of gain surgically), Hi-Z 1/4" input (with 50dB of gain) and, front separated phantom power/Phase/Highpass (@100Hz) buttons. You even get a dedicated lavalier 1/8" input (40dB with a +10 button on the back panel of the unit). Just an insane amount of value and innovation. Let's not mention that its USB C compliant, can be ran off a decent sized power bank standalone, a laptop or, even a tablet. The core of a good mic signal chain will always be its preamp and starting here's a good value. Surprise there's more. Clean, linear sound with very low noise. I suppose the gold-plated connectors transfer the power of any instrument thrown at this thing very efficiently. The only things missing would be a digital Vu meter (5 small LEDs) and bypasses to isolate the "Main" signal from its own other internal sources (lavalier/Hi-Z inputs). Maybe a 5 unit carrying case (for additional RO-04 units or other additions to the signal chain). To be "No frills" this thing's got POWER! I would be comfortable running these in podcast, studio, broadcast or, any situation I need a lot of horsepower in a small footprint. Great value!

⭐⭐⭐⭐⭐  By   Rob M.

Works as intended

Reviewed in the United States on October 8, 2025

Works as intended and easy to use, it sounds like high-quality audio; you could tell there is a significant enhancement in sound quality after using it.
It feels sturdy with the 5yr warranty gives me paice of mind.
The best part is their customers support, Alex was able to answer my inquiries and resolve. Don't hesitate to contact them with any questions.

⭐⭐⭐⭐⭐  By  Marco F.

Great workhorse preamp

Reviewed in the United States on July 9, 2025

It’s a solid little box with clean gain and great volume control. The trim knob makes it easy to dial things in just right. A nice upgrade from stock interface preamps … affordable, versatile, and perfect for studio or content creation.
Why did you pick this product vs others?:
Low noise , Affordable 

⭐⭐⭐⭐⭐  By  Brittney Patterson

New to Audio Gear. Works Great for Capturing Waterfall Sound!

Reviewed in the United States on July 27, 2025

I’m pretty new to audio equipment, but I wanted to level up the sound in the landscape videos I shoot especially when I’m filming waterfalls. I’ve been using a Nikon D5600 and a Blue Yeti X, and I got this RO-04 Pro preamp to help clean up and boost the sound. So far, it’s been awesome.

It took a little trial and error to figure out how to connect everything, but once I got it going, the difference was clear. The preamp gives the audio way more clarity and presence, especially when I’m recording the rush of water or natural ambience. Everything sounds fuller and more real.

I love how compact and simple it is, and it plays nicely with my setup. Definitely didn’t expect this much quality at this price. If you're just starting out like me and want to make your videos feel more immersive, this preamp is a solid choice.

⭐⭐⭐⭐⭐  By  Jamison DeBolt

Premium product at an entry-level price.

Reviewed in the United States on June 28, 2025

TL/DR: Premium product at an entry level price. The RO-04 has phantom power, a built in high pass filter, toggled with a momentary switch on the front of the unit. A phase switch, accessed the same way. Separate inputs for lapelle mics and instruments. It is very clean, and doesnt have any background noise in my tests. Built like a tank. 4/5 - would be a 5/5 if it was true bypass!

In depth review:
Final Score: 4 out of 5
If it had true bypass, this would easily be a 5-star product. But even without it, the RO-04 delivers in just about every other category that matters for home and professional studio use.

The Highlights:
Ultra-Clean Signal:
The noise floor is practically non-existent. It's dead silent, even with gain turned up—something I usually only see in much more expensive gear.

Feature-Rich:
For its size and price, the RO-04 is loaded with functionality. It’s equipped for just about any setup—from bedroom producers to mobile engineers to small studios needing reliable preamps on the go.

True Portability:
It powers via USB-C, which is a game-changer. You can run it off nearly any phone charger or portable battery bank, making it ideal for mobile recording rigs.

Premium Build Quality:
It’s built like a tank. The all-metal casing feels solid and durable, the knobs turn with satisfying resistance, and all the inputs/outputs are secure and professional-grade.

Desk-Friendly Design:
With a low footprint, the RO-04 won’t clutter your workspace. All the I/O is on the rear of the unit, which keeps your cable management clean and out of sight.

Aesthetic Fit:
Its sleek black finish integrates seamlessly into any studio setup, whether minimalist or maximalist.

Unbeatable Value:
Considering its features, the RO-04 is one of the most affordable preamps out there. You'd typically have to pay double—or more—to get this kind of quality and flexibility.

Minor Drawback:
The only real knock is the lack of true bypass, which could be a deal-breaker for some purists or live-use applications. For me, it’s a small compromise in light of everything else the unit offers.

Final Thoughts:
If you're looking for a budget-friendly mic preamp that doesn’t skimp on quality or features, the Rodyweil RO-04 is an incredible option. It punches way above its weight class and feels like a premium piece of gear without the premium price tag.

Highly recommended—especially for those building out a small studio or needing a compact, travel-ready preamp with serious performance.