Vacuvox

Vacuvox 由荷蘭音頻工程師 Berry Goedemans 所創立，以客製化以及最大限度地改裝發揮音頻設備之潛力而聞名。其最成功的產品之ㄧ為 Vacuvox CL-2 真空款壓縮限制器，它是以 Rohde & Schwarz U-23 的原型設計為基礎，通常被稱為德國 Fairchild ，也就是指 Fairchild 660/670 壓縮限制器。但 Rohde & Schwarz U-23 並不是 Fairchild 的復刻產品，實際上卻是 Fairchild 的長輩。

1953 年，位於德國慕尼黑的 Rhode & Schwarz 開發了 U23，正式商業發表是在 1954年。當年 U23 在廣播錄音室是過載保護裝置，在那年代是錄音室設備的一項技術成就。U23 在設計及聲音表現都與 Fairchild 非常相似，這並非巧合！由於二戰後移民到美國的俄裔工程師 Rein Narma , 在 1959 年使用 U23 的設計，為 Les Paul 製造了一台原型機。就在為Les Paul客訂後，Sherman Fairchild 獲得了 Narma 於壓縮器的許可，並將其命名為 660 以及立體聲版本的 670。

Vacuvox U23 取代了 Vacuvox CL-2，其著名的用戶包括 Oasis、Coldplay、Madonna、Terry Briton、Paul Weller、Merlin Moon、Spike Stent、Michael Brauer、Al Scott、Devin Powers、Jeremy Stacey、Rafa Sardina 等。

Vacuvox U23
Compressor Limiter

Vacuvox U23 壓縮器限制器建立在 Vacuvox CL-2 之上，並以 Rhode & Schwarz U23 作為基礎。多項更新使得 CL-2 的設計和功能更上一層樓，同時保留了原版悅耳的聲音。  

Vacuvox U23 具有全A類真空管音頻路徑，以及基於 Rhode & Schwarz U23 原始電路的側鏈路徑，這些都確保了無與倫比的性能，並提供卓越的動態餘裕及透明度。

Vacuvox U23 之設計及功能性

Vacuvox U23 壓縮限制器皆全手工組裝，並使用高品質的客製化組件。客製的變壓器忠實的呈現最原始且音質出色的 Rhode & Schwarz 變壓器。四個音頻變壓器由透磁合金製成，其中鎳含量為80%，鐵含量為20%。扼流圈及電源供應由SiFi製成。電源變壓器升級，噪性及穩定性更好。

不同於以往的前端佈局、輸出增益和 Thresholds (閾值)的修改以及2個額外的增益是 Vacuvox U23 和 U23m 最顯著的升級。

Vacuvox U23 用於一般錄音Tracking和混音，並在 Input / Output / Attack / Release 使用精密的可變電阻。

母帶版本的 Vacuvox U23m，在 Input / Output / Attack / Release / Thresholds 使用 21 stepped 階進式的開關，當使用一對 U23m 時，可針對許多不同類型音樂的關鍵立體聲應用。即使是爵士樂和古典音樂也可以通過完美的立體聲平衡進行溫和壓縮，而不會犧牲動態和產生不需要的音像失真。

由 Pad / Input / Gain / Thresholds 組成各種增益結構組合，這巧妙地提供不同種類、不同級別的聲音飽和度。因此，通過降低 Thresholds、驅動輸入變壓器或真空管，聲音可在透明、密度和流暢之間變化。

Vacuvox U23 / U23m 規格差異

U23 及 U23m 共享下列規格：

  • Input Pad of 10 dB

  • 3-position tube Gain switch

  • 21-step variable Threshold

  • De-esser centered around 6kHz as part of the side-chain

  • Switchable stereo link

  • Balanced input and balanced output

  • Input impedance: 10k Ohms

  • Output impedance: 30 Ohms / 100 Ohms

  • Minimum load impedance: 300 Ohms

  • Frequency response: 20 Hz - 22k Hz [+/- 0.5 dB]

  • Noise: -93 dB [20 Hz - 22k Hz, unweighted, RMS] @ 0dB Unity Gain

  • Signal to Noise Ratio at +14 dBu = 100 dB [20 Hz - 22k Hz, unweighted, RMS]

  • Distortion in Amplifier mode: THD < 0.15% @ 1k Hz and 42 dB output gain

  • Power consumption: 60 Watt [120/240 VAC]

  • Two audio chokes with SiFe core

  • One power supply transformer with SiFe core [adjustable for 120V and 240V]

  • One power supply choke with SiFe core

  • Ceramic Tube sockets throughout

  • Tube complement of 2x EAF42, 3x EF86, 1x ECC40 and 1x EAA91

  • Combination of selected and stereo matched NOS tubes of Philips, Valvo, Siemens and/or Telefunken

  • Simpson Electric metering

  • Polypropylene film capacitors from Mundorf and Wima throughout

  • High quality carbon-film and 1% metal-film resistors from Kiwame and Koa Speer throughout

  • High quality Blore-Edwards and Grayhill switches, fitted with precision components, throughout

U23 特定規格：

  • Ratio: 6-step rotary switch with ratio's 3:1, 4:1, 5:1, 7:1, 9:1, 12:1

  • Input: precision full-range attenuator potentiometer

  • Attack: precision potentiometer for time settings between 1 mS and 50 mS

  • Release: precision potentiometer for time settings between 0.2 S and 1.2 S

  • Output: precision full-range attenuator potentiometer

  • The output level of the output transformer is set in our factory to the maximum level

U23m 特定規格：

  • Ratio: 7-step rotary switch with ratio's 2:1, 3:1, 4:1, 5:1, 7:1, 9:1, 12:1

  • Input: 21-step attenuator switch with 1 dB per step

  • Attack: 21-step rotary switch with time settings between 1 mS and 50 mS

  • Release: 21-step rotary switch with time settings between 0.2 S and 1.2 S

  • Output: 21-step attenuator switch with 2 dB per step for the first 5 steps and

    1 dB per step for the last 15 steps

  • Selectable output level ['normal' or +6 dB] of the output transformer

Reviews

Johann Scheerer - Clouds Hill Studios

“Oh my god. This thing is INCREDIBLE!! Just preferred it to my Fairchild. The Vacuvox U23m is one of the best compressors I heard for tracking and mixing! What an amazing tool!”
— Johann Scheerer

Matt Colton

Metropolis Studios

They are f..king great!. I never want this compressors to leave my studio. The scale of this thing is incredible! I have barely scratched the surface of what it can do.

Obsidian Mastering

The U23m is nothing like you have ever heard before. It’s subtle clarity, transparency and body are second to none. It really cleans up the low end, and gives so much depth to your tracks. We tried it on the mix and drum bus, on bass guitar and vocals (the build in de-esser works like magic) and it worked so so well everytime. It is hard to describe in words how friggin’ good the U23m sounds. Compared to the Fairchild 670, it had even more detail, more depth and the top end sounded a bit more open. Behold the new Rolls Royce of mastering compressors!

Dan Suter - Echochamber Mastering

I've been using my pair of u23m's for the first 3 days and have now mastered around 30 songs, hiphop, pop, jazz, urban, metal and punk.

It's pretty sobering when you listen to your old favorite devices in comparison and realize that you don't even come close to what you achieve with the vacuvox.

I have to admit that i find audible compression, especially with short attack times, disturbing in 90% of all cases in the mastering context - hardly any compressor regulates so well that it is a real benefit in all parts. the airfield limiter is a big exception, but more than 1dB is usually always unacceptable for me.

With the vacuvox, anything goes, short attacks, long releases, long attacks and short releases, medium times, fast control, slow leveling, whatever - you can shape the music very well, emphasize the slow or fast movements, shape the transients - and it remains very musical.

Then there is a basic sound that plays in another league - the transformers are a class of their own.

It's quite extreme in the bass range - it remains very pleasantly controlled, you can master very "big" without it starting to float - i've never heard anything like this before.
through the gain structure, different characters can be achieved, ranging from very clean to more transformer saturated and / or tube saturated.

All this happens on an incredibly high sonic level.
i can well imagine that the u23m will significantly shorten my chain, as it will make many devices redundant.

Resolution - July/August 2019

The U23m added a gorgeous open tone across everything I tried it on, tightening the bass end beautifully and adding punchy - or creamy - vari-mu magic without darkening things. The controls allow for many flavours and add immense flexibility. It's quite miraculous that such an old underlying design provides one of the best ever compressors

Moof Acoustics 墨禾聲學為 VACUVOX 大中華區之授權代表。