Solid State Power Amp Reviews

Manufacturer's Comments #1

Yesterday, we once again determined the maximum power output of another AMP V at a test setup in our factory. Basic conditions: constant mains voltage of 232V; 1kHz sinewave continuous output: THD+N=1%.

With this, we achieved the following results, with tests carried out in this order:

• 1: 8 ohms for 20 minutes—max. output: 912W
• 2: 4 ohms for 15 minutes—max. output: 1408W
• 3: 1.5 ohms for 5 minutes—max. output 1530W
• 4: 2 ohms for 5 minutes—max. output 1509W

After this treatment, the AMP V was hot, and it took around 120 minutes for it to cool down to a normal temperature inside. Nevertheless, directly after these measurements, the AMP V played without any problems. If we had continued with these measurements/treatments, the AMP V would have gone into protection mode (temperature safety switches inside) or the inside fuses could have blown (with a 2 ohm load only). In the future, we will publish the measurement protocols of the products on our homepage.—Jochen Voss, Managing Director Accustic Arts

Manufacturer's Comments #2

While measuring the Accustic Arts AMP V (January 2021), John Atkinson found that the AMP V did not meet its specified maximum output power. We measured it again and confirmed that our specification for the power output is correct. You can find the specified figures and the test setup on our homepage.

Then, as Atkinson was preparing to measure noise and distortion with high-frequency test tones at 200Wpc into 2 ohms, the amplifier turned itself off after about 10s, apparently going into protection mode. After cooling, it did not restart. John checked the external fuses and found them intact.

After the review, the AMP V was sent back to our distributor, Rutherford Audio. When it was unpacked, connected, and switched on, the red LEDs on the front panel were lit, and there was no sound. When they looked at the rear panel of the AMP V, they found the MUTE button activated. After the MUTE button was deactivated, the AMP V started playing immediately.

It is possible that the AMP V went into protection mode, as it should to protect the electronics. Probably John Atkinson activated the MUTE button when he disconnected the cables and didn't deactivate it again after the AMP V cooled off. Whenever the MUTE button is activated, the two red LEDs will be lit.

When the AMP V is driven extremely hard and goes into protection mode, it will begin playing again automatically after cooling off, unless the internal fuses have blown. Such a situation as occurred during testing can never be achieved in real life (with music) and is only possible with a special testing setup.—Jochen Voss, Managing Director Accustic Arts