Al, Ralph, or Kijanki, have you read my previous post? |
Oh I learned something alright. Early on. |
"Begin at the beginning", the King said, very gravely, "and go on till you come to the end: then stop". |
Interesting question I think Ralph may have hit on. I have lots of amps and they all exhibit the same behavior potentially. But I don't think it's limited to mosfets. I have both mosfet and bi-polar types and the same thing applies to both. This phenomenon is more prevalent when an amp is listened to "cold" and as it warms up, performance seems to fall off a bit. Not as noticeable with an amp left on 24/7. Mine are on 24/7 and sound better and better as they warm up. Why? Because quiescent current is higher when it's cold or cooler than when it's 'cookin'. So my solution is to set quiescent current to optimum when it's good and hot. The op has good ears. Not many people care about that even if they notice. It has to do with manufacturers' warranty issues. The cooler they run, the longer they last. |
Ralph, I have 4 Acoustat TNT amps just rebuilt by Roy Esposito. They are TO2 mosfet amps. I assure you they get better as they warm up. So much so that they are 'eerily' life like when in mono mode. I don't know what Roy did, but I have not experienced this kind of sound in my life. However, may not have anything to do with your assertion. |
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Try the screws that are turned in crooked. Then call Dr. Phil. |
Yes. If I'm not mistaken, the PS Audio P-3 connects one lead to the right temple and the other to the left. Be very careful in plugging in the ground:) |
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. |
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Or should I say Atmosphere's. |
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. |
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. |
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. |
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. |
Krell man, I take it you 'are' no more:) Those are some serious reviews. |
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. |
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. |
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. |
It would be a fabulous experience to get together with you guys:) |
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. |
I second that. You'll find my comment on the PS Audio P3 on page three but the P5 will be the same.
Good luck |
What? Are you on the right thread? |
It ain't over till the fat lady sings. |
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Just curious. What is your point of reference in comparison to your assessment? I don't remember if it's been mentioned. If it has, why don't you go and get one of those? |
I made my comment before your previous post. But I think you know that:) |
I think the law of diminishing returns has overtaken us. I never did like Danish cheese. |
Al, have you ever hi-jacke4d a thread? If I were you I would seriously consider it. |
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I think you've all got your speaker wires crossed! |
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Sorry, couldn't help it. If it's any consolation, it wasn't meant for you. You should maybe read the whole thread. You might get a kick out of it:) |
Yes. But in the case of this thread, I would say it's a seller's market;) |
