The color of IGS Tubecore 3U (Blind Test)

I’ve been working a lot with my IGS Tubecore Mastering Edition lately and I’ve been so satisfied I’ve been almost strapping it on every master bus, on every production. I love the sound of it and the features dry/wet and mid/side really make it a game changer. It’s such a WARM piece of gear that my cat also loves to sleep upon it.

I’ve wanted to investigate a little deeper on the actual color that it gives the instruments, so I made a test.

1) I’ve recorded a 16bar piece of metal song with 9 tracks:

• Drums
• Bass / Bass Dist
• Guitars / Double Gtrs
• Vocals / Add Vocals
• Reverb/Fx for Vocals

2) I’ve mixed roughly the song

3) I’ve “reamped” each single track thru the Tubecore with no gain reduction. Gain at 13, output at 9.5
That’s a small amount of gain, btw. Halfway the total gain available on this monster. We’re not going for massive distructive gain differences.

4) I’ve re-reamped each already reamped track thru the Tubecore again, this time with gain at 11, output at 9.5

5) I’ve matched each reamped and 2x reamped track’s RMS to the originals

6) I’ve mastered the 3 versions (1st version with no tubecore, second with tubecore on each track, second with 2x tubecore on each track) and bounced the 3 wave files  A, H, Z.

7) I’ve strapped an additional tubecore with compression on (30att, 0.1rel, 1db GR) on each of these 3 wave files, generating 3 more versions (1: no mixbus comp, 2: mixbus comp) This one’s just a slight difference btw.

My aim here is to listen purely to the color of the unit itself, of the tube gain.
So the result are 6 files, where we have 3 letters and 2 numbers.
Each letter corresponds one of the 3 versions (dry / 1x TC / 2x TC) while the numbers will be 1: with no additional tubecore bus compressor, 2: with additional tubecore bus compression.

Here they are.
What’s your favorite?


A2 (same take as A1 + additional Tubecore on the master bus, 1db GR)


H2 (same take as H1 + additional Tubecore on the master bus, 1db GR)


Z2 (same take as Z1 + additional Tubecore on the master bus, 1db GR)

I’ll unveil the results next week or so!


The colors of analog compressors. (SSL vs 1176 vs VariMu)

Analog compressors are mythological beasts.

Since the first radios started using limiters to raise the volume of the broadcasted music, they have been implemented in studio and some models have become legendary for how they very uniquely color the sound. 
As a result, nowadays you can buy all kind of clones and plugin emulations and each brand swears by the perfect imitation of the original vibe of those historical units.
Since I’ve been producing music, I’ve become more and more passionate about some of them so I ended up with my small but very precious collection of analog compressors.
I’ve recently started to endorse IGS Audio‘s Tubecore 3U Mastering Edition Vari-Mu compressor, which adds to my stereo Hairball 1176 Rev. D Fet limiter, my modded G SLL (project by Gyraf Audio) and more analog beauties.

Amazingly fat mastering vari-mu all tube all analog compressor
(Bellezebu loves its “warmth” too!)

Analog compressors: The test!

I’ve tested them next to their plugin emulations to understand better how each model really affects the sound during my mixing sessions, and to make it clearer how each emulation/clone really behaves.

Here are the protagonists of my comparison test:

UREI 1176 models
• 2x 1176 Hairball Rev D (Linked stereo)
• Slate FG 116
• Waves CLA 76 (Blacky)
• Ik Multimedia Black 76
SSL Bus Compressor models
• Custom built G-SSL (w/Sidechain filter mod)
• Slate VBC FG-Grey
• Waves SSL G Comp
 Vari-Mu models
• IGS Tubecore 3U ME
• Slate VBC Fg-Mu
• Waves Puigchild 670

Analog bus compressor
Custom made G • SSL

Some technical stuff before going to listen to the files
orHow the test was done

Analog compressors
My stereo 1176’s

I’ve used a stereo stem of drums to drive the compressors and I’ve accurately matched both input and output levels among the same models, same thing for the gain reduction.
You can imagine how that’s a not-so-easy task to do, for the reason that each unit has a different monitoring & GR philosophy, but still I’ve been pretty meticulous.

That said, this test doesn’t want to be – at all – a scientific test for comparing noise levels, exact RMS/ Peak levels, etc.
The reason why I’ve done it, instead, is because I wanted to capture to the different coloration that each compressor is capable of, during tracking/mixing, confronting hardware vs software, and that’s why the drums have been compressed twice.
Therefore the files feature a first round of compression and a second round of compression starting at 0.31 (where the first round is sent again into the compressors).


I’ve connected everything with balanced cables and the AD/DA converters are those of my Yamaha MR816x interface.
Ps: The 1176’s and SSL’s have been fed 4db input gain more than the Vari-Mu’s because I wanted to keep the studio routing/settings of the production I’m now working on, but still the i/o gain and GR are matched between sw/hw.

The settings
1176 compression

Attack: 11 o’clock
Release: Fastest
Ratio: 20

 SSL compression

Attack: 10
Release: .1
Ratio: 4

 Vari-Mu compression

Attack: 0,3 
Release 0,3 
Input Gain: 6db

Let’s listen 
(0:00 – 0:31 – First round of compression)
(0:31 – end – Double compression)

Have you made up your mind? Which one is your favorite? I have my preferences…

Download the files (right click – save as):

Dry :