Bass leaves after amp warms up?

Krell man, I take it you 'are' no more:) Those are some serious reviews.

I just put a cd recorder in my listening position.
Recorded one when the bass was full then 1 hr.later when it was not..
One version gives the groove of the song while the other is lacking

I did listen to the two files but had trouble identifying the difference (my current system does not go very low in the bass, however). Both sounded extremely bright and spitty. How did you record them?

I had a Musical Fidelity A308cr power amp for a few years and it was excellent. If the M6 is anything like the A308cr, I don't think that's the problem.

If it is, this is the Class D amp that I use and it will take a hold of your speakers and tell them what to do: http://app.audiogon.com/listings/solid-state-spectron-audio-musician-iii-mk2-w-free-v-cap-upgarde-new-sealed-2013-04-03-amplifiers-91325 Tell them that you want it without the V-Cap upgrade and see if you can't get it $3,500.00.

You may want to borrow someone's CD player that is better than yours and see if that's not a problem. If it is, relax and wait until you can afford a better one.

Chuck

I have request to borrow Musical Fidelity M6 250 dedicated amplifer from my dealer.That way I'll know if the amp or speakers need to be changed.
Hope he will lend it to me,I'll report back.
Did anyone listen to the 2 versions of Respect yourself by Staple singers that I set out?
You would hear one version has the right groove in the bass the other doesen't at all.

Rrog,

That's what it really sounds like to me too.

Chuck

Krell man, I'm going with number 3.

After 300 posts and all of the logical advice that's been given, I don't think that you're accepting the three apparent possible reasons for your dissatisfaction.

1. Power - you say that an electrician says that your home's wiring is fine. That's not what we're saying. The power draw on your grid has nothing to do with the wiring in your home.

2. Acoustical treatments and speaker position - maybe you need to seriously look into your room and system's setup.

3. Disappearing bass - if you left your components on all of the time you would actually hear what they sound like as the manufacturer intended. If you like the sound when the system is cold but not warmed up, and it's not the power draw, the room's acoustics or the speaker placement, maybe you just don't like the sound of your system and need to change components.

It seems like you have your mind set on one sight, and are not being open to an answer and solution that you don't want to hear or want it to be.

Chuck

Glad to hear that you will be able to try some other equipment. It will hopefully give us some new clues.

I'm not suggesting that your amp is running hot. I know it's a long shot but I am trying to deduce if the sound of the amp when it is "cold" has the good bass. There is a reason that most reviewers will go to great lengths to fully warm up the equipment before they listen because the sound will usually change some from dead cold to fully warm.

I'll try the fan but it's hard to belive amp's too hot
There are no signs of heat
My Dealer is pretty good but I'm hopeing he lends the necessary amp or speakers I requested.
He knows something is causing the bass to change(he agrees after hearing the tape I made.
But has no logical reason,and is skeptical

You have spent too much time dealing with this. There's only one thing in common and thats PSB speakers, which doesn't mean the integrated amps you've chosen aren't the problem. It sounds like your dealer is no help at all. I would find a new one or call mine. You need someone that can start you off on the right foot. My dealer would be at my house right now if I wasn't happy. I'm serious. He would be sitting in my living room on a Sunday night.

Okay. Not following your question. Atmasphere's first post is what I conceded to and my subsequent post is the position I hold. Simply my opinion FWIW.

And why doesn't anyone even in search report similar issues?
I reject your theory

Okay, but the operative here is that 'nothing' is perfect. Ivor Tiefenbrun, the inventor of the famed Linn Sondek TT started his quest after buying a system way back when and taking it home only to discover it had no semblance to reality at all. Well, he took it back to the store complaining it was defective. They unapologetically informed him that no, this is exactly how it should sound. He then(thankfully) went on to correct some of the problems. You clearly need a partridge in a pear tree.

Have you tried any type of fan to keep the amp as cool as possible to rule out warm up issues?

You could try any fan you have laying around and if that works you could install a very quite fan later.

You may be dealing with the inherent shortcomings of the gear

I took that into account that is why I've tried over the last 6 months
3 amps,2 pair speakers and a partridge in a pear tree

You may be dealing with the inherent shortcomings of the gear. Nothing is perfect. Hot running amps such as tubes or ss class A may satisfy you more. Or be brave and learn how to set your amp up yourself. I would second guess anyone's adjustments, factory or not. Even (respectfully), Ralph's. I can pretty well guarantee it will change just in transit, never mind during break in. And I wouldn't trust factory break in periods either, (respectfully). I have never received gear back from a tech or engineer or brand new for that matter that didn't need tweaking in regards to offset or bias, even in reference to factory spec. And the sonic differences can be dramatic.

Seems to work better,longer with no digital source plugged in.

No matter what I try the bass changes character about 20 minutes or so into listening.
This happens all day long so I really don't know what to.
The enjoyment of listening is comprimised because I'm waiting for the bass to go out.
Plugs have not solidifed the bass response after many attempts.

Or should I say Atmosphere's.

Enter my first post:)

Have you tried the speakers without the plugs? If so and it is even worse than I'd say we are on the right track. When you add the plugs you are lowering the "Q" of the speaker. Some speaker companies included different lengths of plugs so that the owner could tailor the speaker for the "Q" that works best for his room/amp combination.

The only other possibility is using a whisper fan on the amp so that it never warms up.

It sounds like you have about the same bass energy in both good and bad recordings. It seems to be the character or quality of the bass that is changing
Exactly!
I do have one of the bass plugs installed

IMO, It sounds like you have about the same bass energy in both good and bad recordings. It seems to be the character or quality of the bass that is changing. Tight and defined when amp cool, loser and woolier when warmed up. The Bryston amps I've used in the past had this quality to them. If you do not have the plugs installed in the lower vents I suggest you try them. The speaker will have an overly tight or lean bass until the amp gets warm upon which the bass should take on a more normal "Q".

Anyone shoot me an email:
tonypoid@aol.com

I will send 2 versions of recorded song with what I feel if different bass output

Thanks

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

Fishing, When you run your tests with the SPL meter, set up as Al suggested and using your test disc, be sure to chart your results on a graph. This will allow you to have visual evidence of the changes you experience and will serve as an easy reference if you try moving your listening chair or speakers which you should also note on your graph. This will serve you well on your current problem, but it will also serve as a base in the future should your start to move your stuff about. It's a bit tedious, but considering all of your efforts so far it's worth while to solve or rule out possible issues.

Also, room temps can affect sound levels at some frequencies somewhat so I would note the room temp when the tests are made so you can compare them to later tests at different temps.

Another thing you can do is to disconnect one speaker. Then set up your mic/SPL meter about 3ft from the center of the connected speaker. Then run your test and chart it. Then disconnect that speaker, connect the other speaker and run the same test. This will help you rule out problems with the cross over in either of the speakers because they won't measure the same. (I once had a new pair of speakers with a bass problem in one speaker created by the manufacturer's mis-wiring a cross over. One speaker was flat to 32hz, the other rolled off starting at 100hz.)

Hope that helps a bit.

Anyone would like to hear the two versions please mention your email addresss

I don't think that A'gon allows posting or communication of email addresses, and the onsite messaging system can't accommodate attachments. Can you upload it to a web hosting or file sharing service and provide a link?

Regards,
-- Al

OK I recorded a Song "Respect yourself" Staple Singers w/The bass the way it sounds right to me and with the bass not the same to me
I can send in email and will open in your real player
Anyone would like to hear the two versions please mention your email addresss
Thanks
AP

Are you using the "plugs" on the bottom woofer ports? If not you should try them. You may find that with the plugs the bass is lean at first but fills out after the amp is fully warmed up.

I will get a SPL soon as possible

Also I can record from my listeing positin when the
Problem is and is not present

I will upload on my computer & be able to send a copy by email

do you have a CD with frequency-specific tones you can use,like one of the old Stereophile Test CDs? One-third

Yes I have Stereophile test cd #3

04-19-13: Fishing716
I have a portable cd recorder & plan to record when the bass is there & not-maybe hear the difference from the cd I make.

The following was written before seeing Drubin's post just above, with which I agree:

What would really be ideal, if you can arrange it, would be to mount a good quality microphone on a stand at the listening position, and record its output when the problem is and is not present (using a suitable microphone amplifier together with the CD recorder, if the recorder doesn't provide a mic input).

You could then upload the two files to a web hosting or file sharing service, and we could analyze them with audio editing software some of us have (including me).

One reason that may be more meaningful than an SPL measurement is that unless you use a CD or other recording that provides test tones, in conjunction with the SPL meter, the SPL measurements may not be able to distinguish between a reduction of bass frequencies, and a reduction of volume that may be perceived as a reduction of bass as a result of the Fletcher-Munson Effect.

Regards,
-- Al

I'm betting the SPL test when it happens will be inconclusive.

Fishing, do you have a CD with frequency-specific tones you can use, like one of the old Stereophile Test CDs? One-third octave warble tones would probably be good and you want individually measure enough of them to cover the range from deep bass up through the midrange.

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

They were all integrates

"I didn't expect to have a problem with such high end equipment."

Now that's funny.

It is my understanding you have tried more than one amplifier. So, you think the power supply is sagging on all of the amplifiers you tried with identical results?

You're right I haven't made any progress
The problem persists

I didn't expect to have a problem with such high end equipment.
Apparently what you say about the amp seems to be happening:

"if the power supply is not up to the task it will sag on bass transients more when the amp is warmed up than when it's cold. As the bias is asking for more current when it's warm than when it's cold".

I should either change speakers or amp right?

Quiescent current is higher when the amp is cold and decreases as it heats up whether the outputs are mosfets or bi-polar. But more so with mosfets than with bi-polar outputs.

Fishing716. What I believe is happening is that when the amp is cold the bias is naturaly low, this does not tax the power supply as much as when the amp has warmed up, and the bias is at it's max adjusted setting.
However if the power supply is not up to the task it will sag on bass transients more when the amp is warmed up than when it's cold. As the bias is asking for more current when it's warm than when it's cold.

Cheers George

"Clearly we're making progress"

What progress have you made? I'm not seeing it. If you have an audio dealer close by I suggest trying a different speaker. Maybe your favorite stereo store will loan you a demo speaker. I have a feeling this problem will go away with another speaker.

I had a similar problem with a pair of Ruark Talisman speaker. I was driving them with a pair of Dynaco MKIII monos. After the system warmed up the sound became too lean. I replaced the Ruarks with Living Voice Auditorium speakers and the problem never revealed itself again.

Why don't you pick up a couple of very quiet "whisper" fans to keep the amp cool to see if it is truly a warm up thing.

Ralph after the bass diminished today I turned off the amp for one hr.
When I returned the bass was full & satisfying again

I believe this is the third time in a row that this procedure has worked.
I thought turning off my amp and fiddling with cables was the trick
Apparently turning of the amp was making the difference

I made it through an entire CD this evening before retiring.
And had satisfying bass most of the day
Clearly we're making progress

But something in the amp must be overheating for changes in the dynamics when warmed up.
That shouldn't be

When the electrician visited, did he monitor the power before, during and after you had these issues
NO
"did he not hear the issues too"?
No,I had deep bass while he was here
A few minutes after he left the bass changed
I called him back and he returned but was unable to hear the difference
The depth behind the bass notes was clearly diminished to my ears but not to him
So I guess draw what conclusion you seem appropriate..

Has anybody yet suggested cold solder joints somewhere in the speaker or DC saturated inductors.

Lets get back to the electrician visit....

When the electrician visited, did he monitor the power before, during and after you had these issues? If it included during your problems (what would be the point otherwise?), did he not hear the issues too?

I'll do that now as I lost the good sound again

It's been a while since I used stock power chords but will give it a shot.

Did you ever try a different power cord on the amp?

For the record I have a steady girlfriend that hears when the music changes..
Just the other day said "what happened" like the air out of a balloon.

NO listener fatigue here
The optimal sound rarely lasts past one CD/LP
The sound goes flat after being dynamic..sometimes before a song ends.
This has been happening for a year w/multiple components,cables & speakers.
But I did stay with Audioquest & PSB not knowing for sure if they were a problem for me.