scootchu

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About scootchu

  1. That's what I figured. I am going to look for a D300a. That should be enough to power my Polks. Thanks Scott
  2. I have a friend that has a pair of D150A's and asked me if I wanted to use them with the intent to buy. The reason I would run them in bridged mode is the need for more power to run my Polk SDA-SRS II's. I have had a discussion with him about possible problems with this configuration. 1. The SDA's use an stock interconnect that relies on a common ground amp. Bad things can happen if you don't heed their warning. (You can build a special interconnect with an isolation transformer in the middle to let mono blocks or bridged amps work) So it would seem that this problem could be solved . Okay #2 The polks are 4ohm. I understand that 4ohm and bridged amps is a dangerous combo, but my friend said he thought Crown amps had special circuitry that made the amp think it was driving 4ohms instead of what would virtually be a 2 ohm load. Any advice???
  3. D-75 Amp Bridging Circuit

    Thanks for that info, but like all other info I see, close but no cigar. What if you are going unbalanced to unbalanced?? I have to put a phase inverter inbetween I know , but building one that will work is another story. The amps are Nikko Alpha 230's and I managed to bridge them with a borrowed Yamaha C-85 which has inverted outs on it. The D-75 I have already has the switch circuitry built in. If someone could look at a schematic of the Nikkos and tell me where to place a resistor that matches the feedback value in the LTP that would be awesome. I then know I have to place a 100ohm resistor from the signal to the ground on the right channel input. I have seen this theory on this site http://sound.westhost.com/project20.htm. I understand the concept, but not the procedure on locating the points I need to find to place the added resistor. Sorry about no Cigar for you how about a Cupie Doll. You did however originally ask about the D75 specifically "I have a D-75 serial 028586 and I am curious as to how the bridging circuit works ". So I went into basic Bridge-Mono as well as the basic D-75 circuit theory. The basic circuit theory, by the way, is almost a word for word quote from the service manual. The circuit designs used inside our amplifiers took engineers time to create and test to keep the amps stable and not let the smoke out. Just looking at someone else’s schematic and saying do this or that doesn't guarantee the modification will work on that amp design and puts a lot of liability on our part. At this point I have to say that redesigning another manufactures product and reverse engineering that product for a purpose the manufacture did not design it for, or design into it, is well outside the scope of this forum for Crown products. I know I just figured it was worth a shot Thanks for the Cupie Doll and the info. I wish I could think in electronics the way some can. I guess that is why I am not an electronic engineer. I do appreciate it though.
  4. D-75 Amp Bridging Circuit

    Thanks for that info, but like all other info I see, close but no cigar. What if you are going unbalanced to unbalanced?? I have to put a phase inverter inbetween I know , but building one that will work is another story. The amps are Nikko Alpha 230's and I managed to bridge them with a borrowed Yamaha C-85 which has inverted outs on it. The D-75 I have already has the switch circuitry built in. If someone could look at a schematic of the Nikkos and tell me where to place a resistor that matches the feedback value in the LTP that would be awesome. I then know I have to place a 100ohm resistor from the signal to the ground on the right channel input. I have seen this theory on this site http://sound.westhost.com/project20.htm. I understand the concept, but not the procedure on locating the points I need to find to place the added resistor.
  5. Hi I have a D-75 serial 028586 and I am curious as to how the bridging circuit works via a schematic. I am in the midst of trying to either bridge a couple of matching (non-Crown) amps or building a phase inverting bridge adapter and thought getting a basic understanding of how Crown does it in their amp circuits I could adapt it to these amp. I am mechanical enough to see the concept in the flesh, but have a hard time with reading just a schematic with nothing in front of me. Any help would be appreciated.