DCM Time Window 7 - AMP & PREAMP

Hifihvn, I did some testing. for starter the THX gain on the back is set to 50%. I turned off the MONO mode but still left the connection in bridge mode style (speakers connected to the positive posts only)...all its happening is the sounds level drops by about 5 clicks on the volume. Right now I've left the Mono button off and am going to listen to it like this for a while.

I dont know about pushing the Amps hard, but these speakers have a thermal light bulb fuse and I've had it kick in and cut off the highs. essentially these speakers are great for listening and running loud, but they are in no way shape or form a party speaker. That thermal protection kicks in llike a tax auditor and shuts it down. I've been thinking about switching over to Tube, but a 100wpc tube amp will set me back 2K at the absolute least for an entry level amp. I guess for now I have to find a tube preamp first.

Johnnyb53, I checked out those Heatkits...eh too vintage. I've been thinking about Emotiva's XPA1's, their Flagship monoblocks.
when I first put my system together I had full matching set, all Carver gear. my Pre and CD broke and had to return them. I've been foundling w/the idea of going all out and getting Full Emotiva set, but the curiosity of Tube sound is stopping me.

Dfgkali, I'm not familiar with the amp you have now. But, I did have a Carver TFM series amp that came out right before that one. It was also bridgeable. When I tried it in bridged mode, it was not as clean and transparent, as it was in stereo mode. It took a couple of tries, but the results always favored non-bridged. This seemed to happen with any other amp I tried bridging that had the option. I don't even bother trying the bridge mode anymore, due to the similar results I've received, no matter what brand amps. The sound does have to go through a lot more parts in bridged mode. My amp looked a lot like yours, but it was made when Bob Carver himself was still there. I don't know if any sound changes were made between the two.

The THX logo doesn't mean too much. They just want an amp to be able to provide enough power for movies. Any good potent amp can pass this. Amps like Krell and others don't bother getting it tested by THX, but I'm sure they would pass. Some cheap amps and a lot of receivers may fail THX standards.

Doubling the power of an amp only gives you about a 3 decibel increase in sound. That's not much. I think if you wanted to actually double the volume, you need about ten times the power (in watts). So in other words, just one amp may sound better, and still give enough power. I guess you'll find out, since you already have everything to compare it. I wish I could recommend you a tube amp that would work, or another solid state amp. I hope you come out happy.

Hifihvn, thank you for all the information you've provided. I understand your logic and make sense to me. I've for now left the amp in non bridge mode and am enjoying it the same. going through some more CD's.
My next smaller system will be all Tube, and by small I mean monitor speakers and possibly an integrated Tube amp vs. separates, but class A/B for sure. I will be introducing a Tube Pre. to this system sometimes this year.
I like..make that love these speakers, and wouldn't want to do anything to harm them.

Thank you again for the information.
Doc.

Just to clarify something- a 3dBa increase in SPL (Sound Pressure Level) is double the loudness. dBa is a log scale so amplifier power must double in order to double the loudness of the speaker. It takes a just about a doubling of the loudness for our ears to perceive a change. It is important that speakers maintain a linear relationship of loudness output to power input. Overall average SPLs may not get that high when listening to music, but the peaks can require a lot of power and that is the advantage of having a high powered amp. It can generate those peaks to make the sound more realistic.
Take for example, a speaker with an efficiency rating of 89dB. That means it generates an 89dB SPL 1 meter away at 1kHz with 1 Watt input. Double the SPL, 92dB requires 2 Watts. Double again is 95dB and requires 4 Watts. 98dB, 8 Watts. 101dB, 16 Watts. You can see that since even loud listening levels are around 85dB average amplifier power needed is very low. The power is needed for the musical peaks. A bang on a bass drum, even a sharp clap can peak at over 105dB. The closer an amplifier can come to duplicating those real life high power peaks, the more realistic the sound is to us. But the other problem is that speakers start to become non-linear at some point around or above 110dB. Some speakers hit their maximum output there. It is hard to say, not many manufacturers publish maximum output or loudness vs. power curves.

Dfgkali,

There is a great thread on TW7's-- search for "Whatever happened to DCM's Steve Eberbach?" on the AVS forums. There is a guy there (Jamie Hauser) who not only owns a pair of 7s, he's probably one of the most knowledgable guys out there when it comes to sharing info about them (the only other person I'd consider more knowledgeable is the designer, Steve Eberbach, whom Jamie has talked to on numerous occasions regarding crossover design, rebuilding, etc).

Worth checking out.

-Russ in Napa