Ground Sound

** Discontinued **

3-Way Active Amplifier Solution with Digital Crossover CoolbackII600.pdf Manual Coolback II 600 is a sophisticated, luxurious and powerful 3-way active “plate amplifier” intended to be a part of the loudspeaker. All electronics assembled on it and acting as a heat sink for the amplifier modules. The only visible on the outside are the connectors (Balanced Input - Neutrik XLR, PC Communication - Neutrik USB and IEC mains Power inlet), Operation Switch (ON-OFF-AUTO) and LED Indicators (ON-StandBy). The Coolback II 600 is 180mm wide and 600mm high - a thickness of 15mm - a flange of maximum 18mm for mounting. The Coolback II 600 has substituted both the Coolback 300 series and the "old" Coolback 600 series.



Specifications: DCN23 * 24bit 96kHz Digital Crossover Module PA1CC * 100W (8Ω) / 150W (4Ω) Power Amplifier Module (tweeter) - min. load 4Ω PA3CC * 200W (8Ω) / 350W (4Ω) Power Amplifier Module (mid-range) - min. load 3Ω PA3CC * 200W (8Ω) / 350W (4Ω) Power Amplifier Module (bass) - min. load 3Ω PSU8SA * System Power Supply - 8 Nichicon Gold Tune Capacitors 54.400µF/80V TR600 * Silent Design Toroidal Transformer 2 x45Vac / 600VA (rectified +/-63V dc) Distortion : <0.08% Frequency response : 5-45kHz (-3dB) Signal/Noise Ratio : >108dB Thermal protection above 80°Celcius Weight: app. 12kg Cut-out dimensions: 565mm (height) x 145mm (width) - Internal Depth 95mm Overall dimensions: 600mm (height) x 180mm (width) x 110mm (depth)

Suitable loudspeaker projects for our active amplifier Coolback II 600:
The listed projects is all 3-way floor standing loudspeakers of high quality, some minor changes to the box design might be required

- designed by Kurt Hansen and Robert GS

XT612 - The XT612 page
Vifa/Peerless loudspeaker project
Vifa XT25BG60-04 - Ringradiator tweeter * 4Ω * 92dB * 2kHz-20kHz * 50W
Peerless HDS Exclusive - 6½" Nomex cone and phaseplug * 8Ω * 89dB * 40Hz-3kHz * 100W
Peerless XXLS Alu - 12" aluminium cone woofer * 4Ω * 91dB * fs=19Hz * 300W

Klang + Ton

	A/O - Published in issue 6/2007 + 1/2008 + 2/2008 Wilson Audio Watt/Puppy System8 inspired project developed by Holger Barske & Christian Gather Visaton KE25SC - 25mm ceramic dome tweeter * 8Ω * 89dB * 800Hz-25kHz * 80W / 140W ScanSpeak 18W/8545K00 - Carbon fiber/paper 18cm woofer * 8Ω * 84dB * fs=29Hz * 100W 2 x Visaton TIW200XS - Extreme long excursion 8" woofer * 8Ω * 87,5dB * fs=28Hz * 120W

	Duetta - Published in issue 1/2002 A very popular Klang + Ton reference loudspeaker project developed by the late Heinz Schmitt Eton ER4 - Air Motion ribbon tweeter * 4Ω * 88dB * 2500Hz-25kHz * 60W Eton 7-360/37HEX - 7" Hexacone mid-range * 8Ω * 89dB * 40Hz-4kHz * 100W Eton 11-581/60HEX - 11" Hexacone woofer * 8Ω * 91dB * fs=21Hz * 150W

	Minuetta - Published in issue 5/2005 Cheaper version of the Duetta - smaller mid-range and bass - two choices of tweeter Eton ER4 - Air Motion ribbon tweeter * 4Ω * 88dB * 2500Hz-25kHz * 60W or Eton 19SD1 - 19mm silk dome tweeter * 8Ω * 89dB * 2500Hz-30kHz * 80W Eton 5-880/25HEX - 5" Hexacone mid-range * 8Ω * 87dB * 50Hz-4kHz * 50W Eton 8-800/37HEX - 8" Hexacone woofer * 8Ω * 89dB * fs=36Hz * 120W

	ExMotion 04 - Published in issue 6/2003 Loudspeaker project with dipole mid-range and closed box bass Excel T25CF001 - 25mm fabric dome tweeter * 6Ω * 91dB * 2000Hz-25kHz * 90W Excel W15CH001 - 15cm magnesium mid-range * 8Ω * 85dB * 50Hz-3kHz * 70W Excel W 26 FX 001 - 26cm aluminium/magnesium woofer * 8Ω * 87dB * fs=20Hz * 150W

Hobby HiFi

	Cumulus - Published in issue 5/2004 High End loudspeaker project developed by Bernd Timmermanns Thiel/Accuton SC3 - High End Coaxial driver * 4Ω * 90/87dB * 800Hz-25kHz * xxW Visaton AL200 - 8" aluminium woofer * 8Ω * 88dB * fs=32Hz * 120W

	Faktum - Published in issue 4/2007 Super loudspeaker project developed by Bernd Timmermanns ScanSpeak R2904/700000 - Ringradiator tweeter * 8Ω * 88dB * 2500Hz-25kHz * 60W or ScanSpeak 15M 4531 K00 - 15cm mid-range * 8Ω * 89dB * 40Hz-4kHz * 100W ScanSpeak 22W 8851 T-00 - 22cm woofer * 8Ω * 91dB * fs=21Hz * 150W

	Audimax - Published in issue 3/2007 Powerful loudspeaker project developed by Bernd Timmermanns Audaphon Neo Pro 5i - Hornloaded ribbon tweeter * 7Ω * 96dB * 650Hz-40kHz * 60W 2 x Excel W18EX001 - 18cm magnesium mid-range * 8Ω * 88dB * 40Hz-2,5kHz * 100W 2 x Visaton TIW250XS - Extreme long excursion 10" woofer * 8Ω * 89dB * fs=31Hz * 200W

	Mezzoforte updated - Published in issue 5/2005 Loudspeaker project developed by Bernd Timmermanns Visaton SC10N8 - 25mm fabric dome tweeter * 8Ω * 90dB * 1000Hz-20kHz * 100W Visaton W170S8 - 17cm mid-range * 8Ω * 86dB * fs=36Hz * 50W Visaton W250S8 - 25cm woofer * 8Ω * 90dB * fs=31Hz * 100W

Acoustic Design Magazine

Blue Note - Published in issue Ausgabe 6
Eton driver loudspeaker project developed by Udo Wohlgemuth
Eton ER4 - Air Motion ribbon tweeter * 4Ω * 88dB * 2500Hz-25kHz * 60W
Eton 5-880/25HEX - 5" Hexacone mid-range * 8Ω * 87dB * 50Hz-4kHz * 50W
Eton 8-472/32HEX - 8" Hexacone woofer * 8Ω * 88dB * fs=24Hz * 90W

Dansk Audio Teknik - Danish Shop in Copenhagen

	Amadeus TNT S7 ScanSpeak driver loudspeaker project R2904/7000 00 - Ringradiator tweeter * 8Ω * 88dB * 2500Hz-25kHz * 60W ScanSpeak 12M/4631G00 - 12cm sliced paper cone * 8Ω * 87dB * 50Hz-4kHz * 50W 2 x ScanSpeak 18W/8531G00 - 18cm sliced paper cone * 8Ω * 89dB * 40Hz-4kHz * 100W

	Amadeus TNT S9 ScanSpeak driver loudspeaker project R2904/700000 - Ringradiator tweeter * 8Ω * 88dB * 2500Hz-25kHz * 60W ScanSpeak 15M/4531K00 - 15cm sliced paper cone * 8Ω * 89dB * 40Hz-4kHz * 100W 2 x ScanSpeak 22W/8857T00 - 22cm aluminium cone woofer * 8Ω * 86dB * fs=23Hz * 170W

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