"'I can't assume a dedicated power amp will solve the problem till I try."
It's an assumption until you try but based on sound supporting evidence that the amp is not the best amp for those nominal 4 ohm load speakers. Other than this, pretty much all else is pure speculation at this point. So address the known issue first. It will persist no matter what else you try or do otherwise. |
What was the most recent change to your system? |
I can't assume a dedicated power amp will solve the problem till I try. |
One thing to add is that a less than optimal speaker/amp pairing does not necessarily mean that either device is faulty or defective. Just that they are not the best match for each other electronically.
Given that, depending on how long you have owned the amp or speakers, the best one might expect from a dealer is perhaps some trade-in value towards an upgrade. That's fine. Live and learn! If it has not been too long, a good dealer might offer full trade value, but even that is not a guarantee.
So if you want to move forward, find out what your dealer can and will do for you, but consider other buying options as well, including buying used to help minimize the loss when you try something that may or may not work out, which is often the case when one has discriminating ears. |
I expect to try Musical Fidelity M6 amp 250w next week
I also have someone coming over with SPL meter
In addition,CablePro Revelation power strip to try.
Otherwise I'm exhausted
Thanks to everyone
I will report back |
Fish, until you make a change to try a more effective pairing of speaker and amp, not sure there is much else to say.
Once you have that in place, then additional tweaking may or may not be needed as well from there. IT all depends on how "finicky" you are able getting a particular sound that you seek. Its the typical scenario for any "audiophile" . It may take some time and money but if enjoying your music to the max is your goal, it should be worth it in the end. |
"What is the solution?"
Hasn't changed.
Need to change amp or speakers, until you find the combo that floats your boat. It's called a system upgrade, right? Assuming speakers stay for now and amp changes, switching to a more beefy dedicated power amp that can double down to 4 ohms would be the most effective strategy to follow to help cut to the chase. |
3D bass sounds exactly what is leaving
When I haven't listened to music for at least 1 hr.
The bass is 3d sounding wide & deep
After about 30 minutes or so the music changes and bass looses full sound becoming anemic.
Also Dynamics have decreased.
Sound goes from robust to comprimised
What is the solution? |
Hi George. Yes, I will observe it climbing from turn-on to warm-up also. By 'cold' I meant not having yet played music. But as the amp is taxed, current will fall off ime. |
http://www.me-au.com/html/me850hc1.html
Cheers George |
"04-20-13: Csontos
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.
Csontos (Threads | Answers | This Thread)"
Not so with the two powerhouse ME850's I have here, both are at 20mv accross the emiter resistors 12 per channel when cold and by 20mins they have climbed and stablized to 50mV. My bass is ultra tight but 2 dimential when cold then it looses precieved tightness for a more 3 dimentail bass when warm. I believe this is what's happening to the poster. Or his supply is sagging as the bias climbs if it goes up like mine as it's warming up.
Cheers George |
Fishing's girlfriend hears the same differences. So there should be no doubt that its a real phenomena. |
I have analyzed and listened to "good" and "bad" recordings which Fishing created of Dawn's "Candida," in similar fashion to what I previously reported doing with a recording of "Respect Yourself."
It appears that the recordings of "Candida" were done with reasonable level settings, and with ALC and peak limiting properly disabled. I found that the "good" recording was about 0.4 or 0.5 db lower in both peak and rms volumes than the "bad" recording. Essentially the same 0.4 or 0.5 db difference existed between the volumes the two recordings when frequencies above 300 Hz were filtered out, and also between the volumes of the two recordings when frequencies below 300 Hz were filtered out.
The sound quality was generally very poor in both recordings. I suspect that the major reason for that was the low quality of the recorder's built-in mic. The single built-in mic, of course, also resulted in the sound being monophonic. Nevertheless, I sensed a VERY slight loss of definition in the bass on the "bad" recording. Not looseness, not weakness, just an almost unnoticeable loss of definition. Presumably the difference would have been much more apparent if the recorder and its built-in mic had not been in the loop.
Fishing also provided yesterday a "good" and "bad" re-recording of "Respect Yourself." I did not listen to those, but my software revealed nothing more than about 0.2 or 0.3 db differences in volume, frequency content above 300 Hz, and frequency content below 300 Hz. As with "Candida," the "bad" recording was the (VERY slightly) louder of the two.
Finally, today he provided a second set of re-recordings of "Respect Yourself." However, the recording level on these apparently was set too high, and the waveforms were clipped in numerous places, so I didn't do anything further with them.
FWIW.
Regards,
-- Al
|
I'm wating for confirmation from my dealer to send new amp.Obviously he would rather not. |
I agree with Rrog. Its another way to look at what has been said regarding your specific amp/speaker match, ie the amp can drive the speakers, but not OPTIMALLY, which is what is required for good bass and dynamics. The upcoming amp change should be a big step in the right direction. We'll see... |
It's called tonal balance and it's all about setting up a system to your liking. I mentioned this a couple of times on this thread and I think a couple of folks agree with me when I say your system is leaning out as it warms up. For the majority of systems this is a good thing because the system resolution is increased, distortion goes down and the system opens up. In your case you are already there when the system is cold and as it warms up the balance becomes too lean. As I mentioned in an earlier post on this thread, I have had a similar experience several years ago. I corrected the problem by changing the speakers. So, the system should not sound it's best when it is first turned on and improve as it warms up. In my opinion you need to change one or more components to get the desired sound. This is just my opinion. |
How does midbass go down in level?
|
That's what happens when the midbass is down in level. |
I Listened to my system all morning and discovered what is changing in addition to the bass is overall dynamics & timing..When the sound changes the music seems to sag and it's hard to get into the music.
Like getting on an escalator and "riding" with the music/The second version blocks or prevents following the music in the same way.
Like being "out of sync"
So Weird |
Or even just with the top cover off. Better yet, two sets of recordings should be done; with and without added cooling. This could end up being a very fruitful case study on due diligence by ss amp manufacturers. No wonder there's separate tube and ss camps. Tubes and mosfets do after all share some similarities. |
Fishing, Have you tried putting a fan on the amplifier?
Based on all that we have discussed, it does seem that heat plays a huge role. The fan should be able to cool the amp's heatsinks. |
Hello AL:
I re-recorded the two versions of "Respect youself" with the proper adjustments.
What is your email,I will send them to you.
Or anyone else that would like to hear good/bad bass versions(as they sound to me).
tonypoid@aol.com |
I suspect quantitative analysis of recordings of the system will be inconclusive at best do to difficulty of assuring all parameters that went into the recording. But ya never know...
I'm willing to bet the new MF amp will do much better. IF dynamics and bass is what OP is missing when listening, as best I can tell that amp should do it from what I read, and I would expect OP to hear better results in those regards and overall.
Although specs or bench measurements into 4 ohms would be re-assuring, advertised current delivery capability and verbal claim in MF literature to be able to drive more challenging speaker loads sounds promising.
I had MF A3CR amp prior to current BEl Canto Ref1000ms. They seemed up to the task of handling my larger more difficult load speakers, OHM 5 series 3s. These are a challenge but possibly not as much so as the OPs PSBs from what I read. THe OPs new trial amps would appear to be significantly beefier than the A3CR on paper in regards to both power output and current delivery, a good omen.
We'll see.... |
After the sound drops out I leave the amp on w/o music playing.
I Return after an hr.or the next morning
Generaly the sound has improved by then-
For another brief listening session |
Yes I see those parameters
I will record them again |
My comments about the CDR420 also apply to the CD300. Looks like it has a front panel switch that selects between ALC, Manual, and Limiter. It should be set to manual, and the recording level set such that its volume meter never gets near the 0 db full scale reference point during any of the recordings. On the other hand, if you set the recording level too low, then noise levels will increase, relative to signal levels, which is why I suggested allowing a margin of perhaps 6 db or so, relative to the 0 db reference point.
Regards,
-- Al |
I absolutely leave the amp powered up much as possible including overnight.. |
My apology
Marantz CD Professional CD Recorder CD300 |
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. |
I petitioned my dealer to lend me a dedicated 250 w amp from Musical Fidelity. Do you feel this will resolve the problem? Could be, but I'm by no means certain. I would expect it to be more capable of handling low impedances than the integrated amps you've used, but once again it unfortunately does not appear to have a 4 ohm power rating. I use Marantz Professional cd recorder CDR400 w/built in mic. Couldn't find any info on a Marantz CDR400, but I did find this on the CDR420. If it is the same as or similar to that model, it does provide both AGC (referred to in the writeup as ALC) and peak limiting. To obtain recordings that are as meaningful as possible for present purposes, both of those functions should be switched off, and the recording level set such that the maximum level that is reached during the track at any time (whether or not the problem is present) is several db (perhaps 6 db or so) below the 0 db reference point. All settings should then be left exactly the same for both recordings. Regards, -- Al |
http://www.musicalfidelity.com/products/m6series/m6prx/
Musical Fidelity M6 power amp to be borrowed next week |
AL I petitioned my dealer to lend me a dedicated 250 w amp from Musical Fidelity.
Do you feel this will resolve the problem? |
I use Marantz Professional cd recorder CDR400 w/built in mic.
|
What is the goal of what what you are discussing? The goal is to characterize the symptoms as precisely as possible, in technical terms. Hopefully that would help to identify or at least narrow down the possible cause(s). Can I ask when you listen to both versions if one sounds more satisfying than the other? Hard to say. Partly because neither sounded satisfying, due to the excessively hot treble, and to some extent also due to a general lack of transparency. I have no way of knowing, of course, the extent to which all of that may have been contributed to by the original recording, vs. your system's reproduction of it, vs. your recorder and microphone. Also, as I indicated, precise equalization of volume levels was problematical, which further increases the difficulty of making any judgments. Can you provide an answer to my question about whether or not your recorder applied AGC and/or peak limiting when your recordings were created? If you are not sure, let us know the make and model of the recorder. If an external microphone was used with it, let us know its make and model as well. Regards, -- Al |
HI AL
What is the goal of what what you are discussing?
(which I don't understand)
Can I ask when you listen to both versions if one sounds more satisfying than the other? |
Fishing, when you left the amp on did you stop the music or leave it playing? Some amps do not get warmed up or stay warm unless they are playing music.
Just trying to totally eliminate "warmed up" as the cause. |
04-22-13: Atmasphere
Al, 0.7 db across a spectrum can be quite noticeable to the ear, whereas on a sine wave is undetectable. Thanks, Ralph. FWIW, though, note that the 0.7 db was between maximum instantaneous values, which might have occurred on as little as one sample out of the many millions of samples in the track. Averaged on an rms basis across the entire track, the difference was 0.4 db (comparing the sub-300 Hz content of the "good-3db" and "bad" waveforms). You might normalize the two tracks, invert the phase of one and play them simultaneously, then you could hear the 'missing' bass. Actually, prior to posting my report I spent a good deal of time trying to do exactly that. Inverting one 2-channel signal and summing it together with the other 2-channel signal whose volume had (at least approximately) been equalized. And alternatively, playing them both at the same time. Unfortunately, I couldn't get the software to accomplish that properly, after trying several alternative approaches using two different software programs. Not sure why. Also, "normalizing" is somewhat ambiguous in this case, because the differences between the "good" and "bad" waveforms are different depending on whether peak or rms values are considered. Best regards, -- Al |
It would be a fabulous experience to get together with you guys:) |
Update
I have not turned off the amp when the bass has left.
I would return with the amp still on and the bass has returned in 30-60 minutes
Therefore the full dynamics come & go throughout the day
|
Al, 0.7 db across a spectrum can be quite noticeable to the ear, whereas on a sine wave is undetectable.
You might normalize the two tracks, invert the phase of one and play them simultaneously, then you could hear the 'missing' bass.
Csontos, I used to work at the Allied Radio Shack service department, and put myself through college there and at other consumer electronics service departments. Transistor amps that came in with the bias a mile off was a pet peeve of mine. Funny that nothing has changed in 35 years...
I'd be surprised though if a minor deviation from nominal bias is what is causing this. However I'm not saying that isn't it, just that I would be surprised. IMO/IME it is very telling any way you look at it that turning off the amp for a while does the trick. It really does suggest that heat or 'warmup' has something to do with it, and that whatever it is when it is not warmed is preferable to Fishing. That is what made me think of MOSFETs at the get-go of this thread, as I have experienced that plenty of times with MOSFET amps.
It does sound to me a like a fan is in order! |
The absolute difference is the "good" version has imputus,groove,the kick is firm w/deep bass that moves air.
All these contribute to an effect that stimulates the senses and you are rewarded with a connection to the music.When these attributes are muted the result is sound with no emotional resonance.
All this speculation has failed to resolve one desire:
To have the full dynamics I hear in my system stay without playing hide & seek/
On a positive note my dealer & friend @Audio Salon has agreed to lend a dedicated amp for me to compare.
Musical Fidelity M6 power amp/250 watts
|
I've been following this OP with fascination. I'm going to record my stereo too. ;>') Kidding.
Bottom line: should Fishing simply turn the volume up to get to the sweet spot?? If so, 300+ posts later, it sounds like a pretty simple solution. I surmise that Fishing won't need Zeros. Just a remote control to increase gain by roughly 3 db after warm up.
It's actaully quite interesting to me. By contrast, tube amps usually sound better after warm up. Is this a common problem with most SS amps? If so, I wonder why more folks don't raise the same issue?? |
Kudos to Al for doing the heavy lifting and writing it up so well. |
You got it! Unless of course you decide to either set up the amp optimally yourself or have it done if you're too squeamish. If you do, you won't be complaining about the issue I brought up and you can go ahead and leave it on 24/7. |
Csontos and Ralph,
So, if I'm understanding what you're saying, some amps sound better cold than when they're warmed up? If that is the case, anyway it goes, it seems that a person needs to leave the amp on and accept the way it sounds warm.
That is, unless you want to listen for an hour, turn it off, let it get cold again and then turn it back on and listen for another hour. That just doesn't seem to be an ideal way to listen to your system.
If a warm amp is at least consistent even if it doesn't sound as good, at least you have a known sound that you can count on.
Am I thinking wrong?
Chuck
|
Ralph, I need to state that the bi-polar amps I have do in fact reduce current when hot, however not as profoundly as the mosfets do. But I don't think it's an 'overheating' issue at all. Simply an incidental one in that because the outputs are operating under an optimal (factory) setting, the difference in performance from cold to hot is more pronounced.
No proof this is the case but I would be willing to wager bias is set to a conservative sub-optimal level in any brand new ss amp. Whether this is what the op is experiencing is imo unclear. |
I listened to the two recordings on my main system, via both speakers and headphones, after transferring them to CD-R. I also performed various analyses of their waveforms using Sony Sound Forge 9, a professional caliber audio editing program.
By far the most notable difference was in the volume levels. Would I be correct in assuming that you created both recordings with the same setting of the volume control on the amp, and the same setting of the recorder's level control? And would I be correct in assuming that if the recorder provides AGC (automatic gain control) and/or peak limiter functions, that you disabled them?
Before doing any analysis, I cut out dead times at the beginning and end of each recording, because those dead times were slightly different between the two recordings, and that difference might have introduced a small bias in the waveform analyses, in one direction or the other.
With 0 db representing digital full scale (the maximum possible instantaneous volume), I found that the maximum instantaneous volume that was present on the "good" recording was 0.0 db, and the rms average value across the entire recording was about -18.6 db (the two channels being slightly different, but both very close to that number).
On the "bad" recording, the maximum instantaneous volume was about -1.9 db (slightly different between the two channels), with the rms average value across the entire recording being about -21.7 db (again, the two channels being slightly different).
I then produced a CD-R containing (1)the "good" recording, (2)the "bad" recording, and (3)the "good" recording with a 3 db level reduction. The volume difference between (1) and the others was, of course, completely obvious. My wife commented on it immediately from another room in the house. (2) and (3) had some subtle differences, but nothing that I would remotely characterize as missing bass, or even a fundamental change in the character of the bass. And the differences between (2) and (3) were small enough that I suspect they might have disappeared if I had done enough trials to more precisely optimize the 3 db level reduction.
I also used the software to do waveform analyses after applying brickwall (essentially instantaneous cutoff) 300 Hz high pass and low pass filters to the "good -3db" and the "bad" recordings. The high passed content of those signals showed almost no difference in instantaneous peak level (0.2 db, with the "bad" recording being lower), and zero difference in rms level. The low passed content of those signals showed slightly greater but still small differences, about 0.7 and 0.4 db lower on the bad recording in peak and rms levels respectively.
I would agree, btw, with DRubin's characterization of the sound quality of the recording. Parts of the treble region are boosted excessively.
The bottom line: All of the differences, if any, were slight, except for the difference in volume, which on an rms basis across the entire track was about 3 db.
Regards,
-- Al |
Csontos, you may have missed the post where Al found out that all three amps have bipolar output devices. My understanding of bipolars is that the hotter they get, the more current they pass- which leads to more heat. This is why they have to have large heatsinks and some sort of bias feedback circuit to control temperature, else they go into thermal runaway. I think it might be interesting nonetheless to try a set of ZEROs on the system and see how it behaves. http://www.zeroimpedance.comThen we could put the whole 'system overheating' idea to bed once and for all. Right now I am thinking that Fishing does not like the sound of the system warmed up. Right now if it were me I would run the system for at least one hour and see how it sounds, and then see how it sounds 3 hours later, after it has warmed up for all that time. I've seen some amps that you don't want to turn off because they need 24 hours to sound right... |
If you read Atmasphere's and my posts, you will discover that with this school of thought, a warmed up amp is in fact detrimental to optimal sound in that the outputs are then operating with reduced current. It does perform better when cold. But only because factory settings are deliberately conservative in an effort to allay future warranty issues. As I stated, most people don't care about this even if they notice. Factory settings are typically lower than optimal even when cold. Published specs have nothing to do with this issue so the manufacturers just cover their ass. In a class A/B amp for bi-polar devices, about 150ma per ch. is optimal regardless how many outputs there are. Mosfets are a different story. Typically between 200 and 300 ma per ch. Bottom line is heat is the killer so whether they're bi-polar or mosfet, if the temperature of the heat sinks at idle is around 120F, that amp is going to sound great for a long time. I don't believe this is an issue with class A amps, however. |
Krellman, Well said. FWIW, I agree with I with you on all three points.
One of the reasons I recommended the SPL meter was for the OP to see for himself that his problem was not with absolute volume level of the bass. He just likes his system's sound when it is cold and the HF's dominate the sound and the sense of speed that can impart to the bass. Most of us, I think, would not consider this to be a balanced sound, but he does and that is why most folks couldn't really figure out his problem or how to solve it, we just don't listen to things with his ears nor his preferences. We have just assumed that he listens with our ears and priorities.
As someone suggested, if that is a sound he really wants, he needs to evaluate his components after they have warmed up and select components that will give him the overall sound he is seeking. A daunting task I suspect.
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