Tube + Solid-State Blending: Universal Audio 4-710d Review & Studio Examples

What's That Sound
Written By Justin LaPointe

The Universal Audio 4-710d is one of those pieces of gear that can really do it all. With four channels of mic preamps that let you blend between tube and solid-state tones, it’s one of the most versatile tools in my studio.

I’ve used it for everything—from tracking acoustic guitars to mixing full sessions.

The Twin-Finity blending feature is what makes the 4-710d special. It’s not just a switch between tube or transistor—it’s a continuous blend, meaning you can dial in exactly how much tube warmth or solid-state punch you want. This opens up a ton of tonal possibilities, from clean and fast transients to rich, harmonically complex sounds.

I’ll walk you through how this unit works, compare some tube and transistor tones on acoustic guitar, and show you how I use the 4-710d in both tracking and mixing sessions.

To see how this works and hear things for yourself, check out our YouTube video:

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Why the Universal Audio 4-710d Stands Out

At its core, the 4-710d is a 4-channel mic preamp with built-in compression, but it’s so much more than that. Here’s what I love about it:

  • Tube + Solid-State Blending: This gives you complete control over your tone. You can go for a tight, punchy sound with the transistor side, or switch to the tube side for a warmer, more naturally compressed feel—or land somewhere in between.

  • Built-in 1176-Style Compression: Each channel features true-bypass 1176-style compression, renowned for its fast attack times and distinctive tonal character.

    While the attack and release are fixed, you can push the gain to drive the compressor for some added character and glue.

  • A/D Conversion and Extra Line Inputs: You get up to 8 channels of audio input for your DAW. That’s a huge bonus if you’re running out of inputs but still want pristine conversion.

 

Tube vs. Transistor: How They Sound

To show off the tonal flexibility of the 4-710d, we ran some A/B tests on acoustic guitar using a ribbon mic (the Avantone CR-14). Switching between the tube and transistor settings, here’s what I noticed:

  • Transistor Mode: This setting has a sharper transient response—it’s clean, punchy, and feels like the sound gets into the mic and out of the speakers faster. It’s great when you want the guitar to cut through a mix without too much added color.

  • Tube Mode: The tube side adds warmth and softens the transients. It’s a bit thicker and has a natural compression that feels more “human” to my ears. It’s perfect for adding richness and smoothing out aggressive playing.

I blended between the two modes and found that a mix of both gives you the best of both worlds—solid-state clarity with just enough tube warmth to keep things interesting.

 

How I Use the 4-710d at Barnhouse Sound

I’ve been using the 4-710d for years, and it’s become a key part of my workflow for both tracking and mixing. Here’s how I typically use it:

Tracking Acoustic Instruments

The 4-710d’s blend knob is a game-changer when recording acoustic instruments. You can start with the transistor side for a clear, detailed tone, then blend in some tube warmth to add depth and character.

Mixing with the 4-710d

One of my favorite tricks is to use the 4-710d as a hardware insert in Pro Tools, just like I do with my Warm Audio WA273-EQ. Think of it like adding an analog plugin to your mix. You can run individual tracks—like vocals, drums, or bass—through the 4-710d and adjust the settings in real time.

Pro Tools handles all the delay compensation, so once you’ve committed the track back into your session, it sits perfectly in the mix. This approach adds a subtle analog color and dimension that’s hard to replicate with plugins alone.

 

Final Thoughts: Why the UA 4-710d Belongs in Your Rack

The Universal Audio 4-710d is a workhorse preamp that has earned a permanent spot in my studio. Its ability to switch between tube and transistor tones—or blend the two—gives me the flexibility to shape sounds for any genre or recording situation.

If you’re serious about recording and mixing, this unit will open up a lot of creative possibilities. Whether you’re tracking guitars, mixing drums, or sweetening vocals, the 4-710d is a powerful tool to have in your rack.

Thanks for reading! If you want to hear these examples for yourself, be sure to check out the video above.

 

For more insights on recording techniques, pro audio gear, and music production tips, stay tuned to What’s That Sound.

 

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Justin LaPointe
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How to Mic an Acoustic Guitar for Studio-Quality Tone