Just opened boxes for two Alesis RA500 power amps sent me by Simon for very reasonable s/h price. Having had the gain controls removed (by Simon) the amps have 150 watts per channel or can be set to mono-block mode with 500 watts each. "They are basically as close to a blameless power amp as you will likely find."\r\n\r\nMy plan is to assess these as monoblocs, running in fully balanced mode from my Dax Decade and into epos es22 standmounts - or into some future speaker upgrade. If that doesn't work out then, the options are to give them as stereo gifts to offspring or sell them on. \r\n\r\nI decided to sit and read the manuals while I listened to some music, especially the bit on setting them to mono mode. The manual has some nice features, readability being one. These include a final page entitled "Architect's and Engineer's Specifications". There are also the following passages about speaker cables and impedance, the first two amusing, the third, the subject of a question to them that knows:\r\n\r\n1. "In recent year years, expensive audiophile cables of high current capacity have appeared. these have been somewhat controversial; some feel ... "\r\n\r\n2. "Never use shelded guitar cords as speaker cables."\r\n\r\n3. "... it is possible to use it as a mono amplifier with twice the power. This uses both sides of the amplifier in a push-pull configuration, so the speaker must be wired differently. .... However. note that the minimum load impedance is 8 ohms, instead of the the 4 ohms in stereo operation"\r\n\r\nThat last remark had me thinking.\r\n\r\nThe impedance for my speakers is 6 ohms; sensitivity 87 db. They have a 1 inch dome tweeter and twin 6 inch midwoofer and bass driver. This loudspeaker does not use a crossover, just a capacitor to protect the tweeter. The amplifier connects directly to the drivers.\r\n\r\nShould I be concerned?