Featured Facts or Fiction

[ThxOne Premium Member]

OK. But since we are not in the Lounge, an effort should be made to not promote fictions that others, who are less informed about audio, may take as a truth because they read it from an old-timer.

That is not what the thread is and it doesn't need a fact checker.

 

[Jimi77 Premium Member]

Back in the early 90s (may have even been late 80s), I had bridged mono amp. Really nice PPI amp - 800wrms class a/b stable into 4 ohms. Massive sucker. Picked up super cheap too. The muting circuit was defective on that series amps so the guy I got it off thought it was dead. PPI ended up repairing it for my under warranty. I'm sure it could have been run in stereo with some modifications. They probably had a stereo version of the same amp.

 

[1aespinoza Premium Member]

I will start it off. I believe there are such things as "Bridged - Mono Amplifiers." Some would say you can't bridge a mono amplifier. Believe it or not, many mono amplifiers are bridged. Here is what I would present as proof.

Please feel free to insert your opinions, proof, disproof, facts or other.

Bridged-Mono Amplifier.

I believe what this shows is two mono amplifiers in a strapped configuration. Two monos but as a whole they are calling it "bridged".
A misnomer? Maybe, but electrically I think they are the same thing. When repairing my 2 channel US Amps 500a I noticed that the positive wire of the left channel was soldered in the negative through hole of the circuitboard. I asked the tech that was guiding me about this and he said it was common design. He said it is basically two mono amplifiers in one case.

 

[ThxOne Premium Member]

I believe what this shows is two mono amplifiers in a strapped configuration. Two monos but as a whole they are calling it "bridged".
A misnomer? Maybe, but electrically I think they are the same thing. When repairing my 2 channel US Amps 500a I noticed that the positive wire of the left channel was soldered in the negative through hole of the circuitboard. I asked the tech that was guiding me about this and he said it was common design. He said it is basically two mono amplifiers in one case.

That is exactly correct. The additional amp is there increase the rail voltage and make a more powerful mono amp. I linked the site where they discuss it. It is all the same circuit on the same board with 1 input and 1 output.

 

[ThxOne Premium Member]

Back in the early 90s (may have even been late 80s), I had bridged mono amp. Really nice PPI amp - 800wrms class a/b stable into 4 ohms. Massive sucker. Picked up super cheap too. The muting circuit was defective on that series amps so the guy I got it off thought it was dead. PPI ended up repairing it for my under warranty. I'm sure it could have been run in stereo with some modifications. They probably had a stereo version of the same amp.

I miss the old PPI stuff.

 

[Jimi77 Premium Member]

I miss the old PPI stuff.

The amp was before the Art series. The amps were so massive back then. 800wrms and the thing was probably 30 inches long. I don't have it my basement, so I must have sold it somewhere along the line.

 

[ThxOne Premium Member]

The amp was before the Art series. The amps were so massive back then. 800wrms and the thing was probably 30 inches long. I don't have it my basement, so I must have sold it somewhere along the line.

This JP77 is probably the longest amp I have owned.

 

[Jimi77 Premium Member]

This JP77 is probably the longest amp I have owned.

Nice amp. A little pricey, but that's a lot of power in one chassis.

 

[ThxOne Premium Member]

Nice amp. A little pricey, but that's a lot of power in one chassis.

Here is a nice fact, D4S has a lot of sales often. I got that amp cheap, got the JP63 cap bank cheap and the DSP. all were on sale at various times... oh and the JP13.

 

[Jimi77 Premium Member]

Here is a nice fact, D4S has a lot of sales often. I got that amp cheap, got the JP63 cap bank cheap and the DSP. all were on sale at various times... oh and the JP13.

Is D4S reliable? I have no experience with them.

 

[ThxOne Premium Member]

Is D4S reliable? I have no experience with them.

LOL not sure yet... what I am using in this install is installed but not hooked up yet.

 

[ThxOne Premium Member]

Is D4S reliable? I have no experience with them.

Looks good though...

 

[Old_Slapper]

Haven't experienced it, but if they have the same excursion at the same frequency, and are the same size, does paper move less air than poly?

Are you swapping in drivers that have a lower output in general? Crossovers different? Higher LF dropoff below a certain threshold?

More excursion does not mean you will have more bass. Excursion is desired if you want to feel the bass.

 

[ThxOne Premium Member]

More excursion does not mean you will have more bass. Excursion is desired if you want to feel the bass.

True... I have often wondered at what size and mechanical limits does a subwoofer become too slow to keep up with music?

 

[Old_Slapper]

True... I have often wondered at what size and mechanical limits does a subwoofer become too slow to keep up with music?

A lot of people believe it takes excursion to make loud hard-hitting bass. It does not. Power, speaker design, and the box determines how loud and hard the bass will hit. Excursion is only nice because it allows us to feel the pressure of the bass.