sda's and amps

Eiderlon

I have been using Crown amplification...

GUNTHER

Agree with all, Adcom will do ok, but just ok. not spectacular. Used to run my 3.1TL's with Adcom 555II in mono mode. Sounded very nice until I hooked them to a Krell 3250. Krell sounded crisper, faster response, lower lows and several other noticable differences. Now my Adcoms are relegated to driving my rear surrounds as needed in movie mode.

davidk0512

OK, I have to pose one of those questions I feel a little stupid about asking. I bought an Adcom GFA 555 to drive a pair of SDA 1Bs, all hookups were correct for 2 channel stereo, good power to the speakers, but they just didn't sound quite right. I went back and checked connections and also decided to change to a better interconnect cable. While double checking everything in the back, I noticed that the selector switch was set to mono bridged mode instead of stereo. I'm not sure when I inadvertantly moved the switch, whether it was during the initial set-up or when I went back to change the interconnect.

When hooking up to run 2 channels and with the switch in the bridged position, would the power output to the speakers be the same as if the switch were in the stereo position? In other words, is the function of the switch only to select either monaural or stereo signal output with no effect on power?

If power would have been affected by the incorrect configuration, I did not have the switch in the wrong position.

SLOCOOKN

davidk0512 wrote:

OK, I have to pose one of those questions I feel a little stupid about asking. I bought an Adcom GFA 555 to drive a pair of SDA 1Bs, all hookups were correct for 2 channel stereo, good power to the speakers, but they just didn't sound quite right. I went back and checked connections and also decided to change to a better interconnect cable. While double checking everything in the back, I noticed that the selector switch was set to mono bridged mode instead of stereo. I'm not sure when I inadvertantly moved the switch, whether it was during the initial set-up or when I went back to change the interconnect.

When hooking up to run 2 channels and with the switch in the bridged position, would the power output to the speakers be the same as if the switch were in the stereo position? In other words, is the function of the switch only to select either monaural or stereo signal output with no effect on power?

If power would have been affected by the incorrect configuration, I did not have the switch in the wrong position.

David,
If you bridge the amp it will only run 1 channel. Usuall the left channel.

bert26

I am a bit out of my depth here, but the power output changes dramatically when running in bridged mono. It generally jumps up quite a bit.

I have never connected both speakers with my 555 in mono (especially since the 1b's probably can't be driven by dual mono's without a pin/blade AI-1 interconnect, if at all) so I can't comment on what it would sound like. At present I have the 555 switched to mono driving my CSi5 center. In this configuration I am only using ONE of the left and ONE of the right binding posts on the amp per the diagram on the back.

Long story short, you can't/shouldn't try to run the 555 in mono in conjunction with the SDA1b's w/o the AI-1 interconnect cable. The SDA's are not compatible with non - common ground amps, which is what the 555 becomes when run in pairs as bridged monos.

Another alternative is to check with Adcom to see if you can strap the grounds of 2 555's together. If it is possible, you may be able to run dual mono's provided you have at least a regular pin/blade interconnect.


Hope you are enjoying the sweetspot.

Chris

davidk0512

Never any intention to run in bridged mono. The speakers were hooked up as basic right, left 2 channel. My thinking is that "if" bridged mono had been selected (incorrectly) but the speaker correctly connected to the amp for 2 channel, the resulting sound would have been a little wierd. I definitely had equal sound level coming from each speaker.

Either -
1) The selector switch was never in the wrong position in the first place and I must have bumped it while unplugging connectors

or

2) The selector switch was in the wrong position and driving both speakers mono instead of stereo.

I understand to bridge the amp to drive only one speaker, you would use only the right input from the pre-amp and connect the speaker pos to the pos right output and speaker neg to pos left output.

In my case, I used both the right and left input with right and left speakers connected to right and left amp outputs, the only variance would be if I had the switch setting in the wrong position.

I was only trying to figure out why the speakers were working as well as they were if the switch had truly been in the wrong position.