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Metal Gear: Kool Black 50 watt

By: Wouter

In this Metal Gear Special a Dutch designed and hand built tube amplifier by Kool Amplification. I used to rehearse with my band (Deluzion) in Zutphen (The Netherlands). In the gear storage room I saw a XXL 4x12 cabinet in white tolex, with the for me unknown name of Kool&Elfring. After some investigation I found out that they are the builder of robust and good sounding guitar cabinets. Since that time I have been specially interested in the brand and own two cabinets a 1x12 and 2x12.

Kool Amplification

The company is owned by Aryjan Kool who started his business in 2007 together with Floris Elfring by building guitar cabinets. The men started building amplifiers in 2011 and when they announced the high gain ‘Black’ amplifier I shortly after I started at Lords Of Metal contacted them for a testrun. With high expectations and a car loaded with Kool-gear I went to the rehearsal room for a test session.

Kool Black 50W

The Black is a two channel tube amplifier designed for guitarist with a love for fat tone and a big sustain. The amp is designed and hand built by Aryjan Kool and has a higher reach in gain then their earlier models. Channel 1 provides a mild and hot setting and channel 2 provides overdrive to high gain sounds. The amp comes with a foot controller which switches the channels, the true bypass effect sloop and a second master volume. The amp has SVC what stands for Seamless Volume Control, from bedroom to arena the amp gives a fat sound. The output of the amp is linkable to 4, 8 and 16 ohms speakers. Next to the 50 watts version, the Black comes in a 18 watt version.The amp has a smart design that creates his sound by combining a smart designed PCB and hand wired parts in the rigid housing. When you pick the amp up the slightly off centred handle shows that the amp is well thought through. In our test package is a speaker cable and a robust slipcover added.

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The specs from the Kool Amplification website;
• 2 channels: channel 1 (mild/hot) channel 2 (overdrive)
• 2 modes on channel 1: 'mild' and 'hot'
• SVC - Seamless Volume Control: from 0,1 watt 'bed room' levels to 50 watt 'Rock Arena' levels (no tone loss at lower volumes, no need for power-soak)
• Ultra wide gain range control for ultimate gain versatility
• True bypass effects loop
• SVC Volume boost
• 3 button footswitch: channel, effects loop, volume boost
• Outputs 4, 8, 16 Ohm or 2x16, 2x8 Ohm
• Output: 50 Watts R.M.S.
• Special designed oversized output transformer
• Power tubes 2x6CA7 power tubes (in our test version these are 6L6)
• 5xpre-amp tubes: 4x12AX7 + 1x12AU7(effects loop)
• Outputs 4, 8, 16 Ohm or 2x16, 2x8 Ohm
• Weight: approx. 15 kg
• Hybrid handwired plus handsoldered printed circuit board in the Netherlands by Kool Amplification
• Handmade A to Z bij Kool Amplification
• dimensions: H=25 cm W=50 cm D=25 cm
• 13 ply lightplex
• Finger joint corner construction
• Asymmetrical handle for perfect balance
• High quality vinyl covering
• Tolex: 'Black Rose'

Test setup

The test setup is my good old Bo~El Guitar Company built guitars, a MC6 and a MC7 TOL and a brand new prototype. My Kool & Elfring XL212 cabinet loaded with v30’s with the same tolex as the Black is the cab of choise. To tickle the amp I hooked up a Maxon 808 in front of the amp.

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Channel 1 in mild modus has a nice clean sound with a body. What really stands out is the fat sound and honest representation of your guitar tone, where also overtones sound through. Switched to the hot modus the amp has a mild crunch sound to a pretty solid rock sound. Usually I hardly use the volume pots of my guitar, with this amp it’s interesting to search for the versatility of the sounds this amp has.

Channel 2 has a thick 70’s rock tone in lower gain settings. The fat tone stands as a rock with full tone in low and low mids. You can’t not play a AC/DC riff with this sound. By driving up the gain you will need to cut the master a little bit to remain the possibility to setup your equalizer settings. The higher gain reminds me of a Soldano SLO100 with more low end.

What also is remarkable, the amp is dead silent when you do not play. All fiss and hiss that you are used to with a high gain amp just is not there. When the gainstructure is not enough for your taste, Kool can make your Black even hotter. After contact with Aryjan by e-mail and live at the Vintage Guitar Fair in Veenendaal he explained that custom options are possible. Only pink tolex, that is a no go.


A critical demanding guitarist who is in search of a hand built tube amplifier built in the Netherlands will be happy with a Kool Black amp. The fat tone and sustain is extraordinary. The 50 watt tube power is enough to play live and the SVC system keeps the tone at lower volumes without bleeding ears. The amp. The sound of the amp is versatile and has a wide gainstructure. The only point of critisism I can think of that is on the versatile part. Maybe is the amp too versatile for a metal guitarist, so you miss a typical own sound, like a Mesa or a 5150 does provide. Only with these amps the bad construction and hiss and fiss in your sound is part of the deal.


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