elan120

This is the DIY amp that I started two weekends ago...

Hi guys, I am new to Klipsch speakers, and a friend of mine asked me about this pair on e-bay: http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=3075385514&category=14993 Since I don't have a lot of knowledge with Klipsch speakers, I am hoping you guys could provide more in-depth views on what would you consider to be an good choice. What do you think? Is this a good pair? Any thing I should be watching for? If this isn't a good choice, what else? Any suggestions are appreciated. Thank you, Kevin

Dean, Let me give it a try to answer your questions. First, when you have a preamp with a gain of 20dB, that means the voltage gain is 10X. Therefore, if you have a 1V input to the preamp, it will give you 10V at the output. Next take a look at the input sensitivity of the amp. Lets assume that is 1.5V to full output, and the preamp gain is 20dB, then to get to the maximum output from your amp, you will only need 0.15V at the preamp input. Following that, you can take a look at the attenuator. Obviously, you don't want to listen at maximum output from the amp, so some amount of attenuation is needed. Here, lets assume you need 1/5 of the maximum power from your amp, so the preamp input requirement is now 0.030V. Typical CD player output is at 2Vrms max., so to use that value as base to calculate the amount of attenuation required, it is equal to about -30dB. Lets say if you have a step attenuator that is capable to do the attenuatiion from -44dB to 0, that means from the -44dB position, when you turn up around 5 clicks(assume -3dB per click), you will get the preamp input voltage you need. All these are just a sample. Actual result will depend on the maximum amplifier output power, speaker sensativity, room size, CD player output voltage, the recording level, listening loudness level, and the type of music you play...etc. I hope this make sense. If anyone sees any mistake I made, please feel free to correct it. Kevin