Bass leaves after amp warms up?

I'm jumping in here since I own PSB Synchrony's and I think Almarg and Mapman are correct in that your 4 ohm speaker requires an amp with higher current. At times, your speaker may even drop below 4 ohms.

mapman..."One red flag I see that might help account for what the OP hears is that his PSB speakers show 4 ohm nominal impedance and the MF amp specs indicate power into 8 ohms only."

Fishing716, if your amp is rated 200 watts/8 amps, you really would need about 350-400 wpc into 4 ohms. My amp is 300wpc and doubles to 600 watts/4 ohms; there is a ton of bass pumping out of my speakers continuously and at various volume. Try and look at amps that rate the current output, not just wpc. This spec is usually not listed, maybe ask the dealer or call the manufacturer.

"Yes but why is the amp running hot if they sell them by the thousands and no report of this problem?"

Each system is unique. You have different speakers than the next guy, diff cables, different power, etc.

There have been other threads where an amp was being pushed too hard and was running hot. One of the troubleshooting tools is to take the cover off.

Agree...take the cover off, it's the only thing you haven't tried. Put your trust in Al and Mapman.

As I stated earlier, I am a Synchrony owner and have been in agreement with Al and Mapman from the start, due to the below 4 ohm impedance of the spkr in combination with integrated amps which do not list specs for 4 ohms.
BUT, Fishing716, I agree with using a SPL meter for the bass. Take a reading when amp is cold, then after an hour take another reading when amp is warmed-up. We'd all like to know the result.
After the test, I would move speakers 3' away from wall and 8 feet apart, toe-in and tell us what you hear. That is how my setup is and was recommended by my dealer.

I agree with Mapman regarding a power amp. One option is an Emotiva; order online with a 30 day audition return policy. But first let's get the SPL test results.

Props go to Tls49 for catching the conditioner issue.

And Bifwynne, looking at that impedance curve, these PSBs need some power to push them to their potential.

Fishing, You've had so much good advice here, I believe the solution lies within. I don't think you should make any major decisions (like new speakers) until you've measured the SPL.
On the subject of amps into PCs, just FYI, my Sunfire manual states "do not plug the amp into a power conditioner."

Fishing, I can feel your frustration, but IMO nothing can be done w/o measuring the SPL. Wait for your friend to measure and then we'll have a more definitive diagnosis. (Underpowered amp as many of us believe). OK, my last post.

One more time...Go to Radio Shack, then test the SPL.

Fishing- you can try to message someone like Al like this;
to give him your email, spread the words out...
joeshmow at so and so dotkom

I admire all you kind people you have tried to help a brother out. Also, who doesn't love a good mystery.

Fishing, it would be great to test your system with the MF
M6PRX Power Amplifier. Once again, they give no power rating into 4 ohms; but state 260 wpc/8 ohms and claim it provides high current (around 140 amps), with a peak voltage output of 130 volts. This will drive those PSBs.

I keep thinking about the impedance curve of these speakers, and I think this has played a major factor in your problem. (or inconsistent line voltage).

Also, some advice...you should leave a SS amp powered-up 24/7. Those who don't always let the amp warm up one hour before any critical listening.

Good Luck.

Let us know results with the new amp and congratulations...
you reached 400 responses.

Fishing716... understandably you're selling the amp, but why the Synch One's?

I dunno, Mapman...going from 40 inch, 4 driver towers is very different than headphones.

Fishing ... Class D as compared to class A, AB amps....

http://en.wikipedia.org/wiki/Class-D_amplifier

Don't know, but again the issue of of output power comes up. You need an amp that doubles down it's power from an 8 ohm load to 4 ohms. The Yamaha does not. (Remember the impedance curve of the Synch One drops below 4 ohms).
That's the solution to drive those speakers IMO.

Look for this topic in the earlier comments. Go looking for Almarg's postings....and Dan Wright's info.

Have read nothing but good things about that amp.

But he also said he reversed the phase on the interconnect

Right you are, Al.

It's too bad this thread ended on a sour note. These 10 pages are full of well intentioned good advice. So many concerned Agoners willing to do research such as checking specs, reading white papers and the like. With such a perplexing problem the OP had, there needed to be some comic relief thrown in.
Hopefully Fishing now has a system he can enjoy.