mains power is 120v 15amp
am using a homemade 250w bulb current limiter, series hot side iirc.
also inline is a cheap consumer level watt meter
Marantz sr18 plug into this draws 60w at idle and does not cause bulb to glow / only slight heat if any.
Harman Kardon AVR7300 plugged into this draws 125w at idle and bulb glows solid orange is HOT. AVR plugged in without the bulb current limiter the power draw is 150 watts at idle.
was using the Harman as main amp, and regular is used at volume.
Wanted to try out dying Marantz (only amp section works) and after this test am shy to use the Harman Kardon.
Any ideas what this means; if not obvious from above I know little to nothing about EE stuff.
Also the power draw when using the marantz even at low volumes I see it goes up a bit in watts, so I guess it's much less class a watts, and the harman is more class a watts comparatively (has hgh idle in spec sheet comparatively) but that glow bulb with harman tells my limited experience there is a mild short somewhere.....i think lol oh and is strange to me that power draw goes UP without the bulb current limiter. Is that difference in measure (25 watts) the amount of direct short within the harman kardon?
maybe am answering my own question, but do not have another heavy class a or all class a amp to see if it makes bulb glow more than the sr18
am using a homemade 250w bulb current limiter, series hot side iirc.
also inline is a cheap consumer level watt meter
Marantz sr18 plug into this draws 60w at idle and does not cause bulb to glow / only slight heat if any.
Harman Kardon AVR7300 plugged into this draws 125w at idle and bulb glows solid orange is HOT. AVR plugged in without the bulb current limiter the power draw is 150 watts at idle.
was using the Harman as main amp, and regular is used at volume.
Wanted to try out dying Marantz (only amp section works) and after this test am shy to use the Harman Kardon.
Any ideas what this means; if not obvious from above I know little to nothing about EE stuff.
Also the power draw when using the marantz even at low volumes I see it goes up a bit in watts, so I guess it's much less class a watts, and the harman is more class a watts comparatively (has hgh idle in spec sheet comparatively) but that glow bulb with harman tells my limited experience there is a mild short somewhere.....i think lol oh and is strange to me that power draw goes UP without the bulb current limiter. Is that difference in measure (25 watts) the amount of direct short within the harman kardon?
maybe am answering my own question, but do not have another heavy class a or all class a amp to see if it makes bulb glow more than the sr18
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A small part of the mains will drop across the bulb, so the mains at the amp, after the bulb, is less than full mains.
Obviously, it you remove the bulb, the mains at the amplifier goes up, and if it draws the same current, that means more power. All as expected.
Another factor is the power your amp is able to put out. The higher the power available, the higher the internal power supply voltage of the amp. So two amps that draw the same idle current (that is what is set in the output stage) can still draw different values of power, because power is current x voltage. The amp with higher internal supply voltage will therefor draw more power, all else being equal.
I have no idea what is meant by 'a mild short' though.
Jan
Obviously, it you remove the bulb, the mains at the amplifier goes up, and if it draws the same current, that means more power. All as expected.
Another factor is the power your amp is able to put out. The higher the power available, the higher the internal power supply voltage of the amp. So two amps that draw the same idle current (that is what is set in the output stage) can still draw different values of power, because power is current x voltage. The amp with higher internal supply voltage will therefor draw more power, all else being equal.
I have no idea what is meant by 'a mild short' though.
Jan
Thanks so much for the reply; so to word that for the question at hand it seems like all is normal.
"mild short" is me making up term for lots of resistance I guess.
One normally tests a solid state amp if 1 DC voltage is coming out the speaker jack, or if protected by a relay or triac, DC is present at the input of the relay. >200 mv is a problem. Protection light or lamp on is a problem requiring removing cover to test at input of relay.
2 what watts will it put out on a load resistor of bigger watts rating than the amp is? P=(v^2)/Z where Z is rated speaker impedance. P= rating, no problem. V can be tested by a RMS qualified DVM (expensive), analog VOM with 20 or 50 vac scale (cheap) oscilloscope (expensive).
3 I sound balanced & clean?
If amp fails 1 2 or 3, that justifies taking the cover off & determining the cause.
I've found that some class AB amps of a power rating that requires 15 amps in the 120 VAC line, cannot operate properly with a 100 w bulb in series. I used a 1200 W heating element out of a room heater with a bad tip-over switch in series with my PV-1.3k to prevent exploding parts. Switcher supply amps also cannot properly operate with a light bulb in series. Due to mains voltage on the power supply, these are too dangerous for amateurs to start learning repair techniques on.
Again general safety tips, use only one hand to measure or adjust an amp with the power off. Voltage >25 across your heart can stop it. Wear no jewelry on hands wrists or neck, 1 v at 25 A can burn your flesh to charcoal through a ring. Wear safety glasses, parts explode (like metal transistor tops) and solder splashes, especially when removing it.
2 what watts will it put out on a load resistor of bigger watts rating than the amp is? P=(v^2)/Z where Z is rated speaker impedance. P= rating, no problem. V can be tested by a RMS qualified DVM (expensive), analog VOM with 20 or 50 vac scale (cheap) oscilloscope (expensive).
3 I sound balanced & clean?
If amp fails 1 2 or 3, that justifies taking the cover off & determining the cause.
I've found that some class AB amps of a power rating that requires 15 amps in the 120 VAC line, cannot operate properly with a 100 w bulb in series. I used a 1200 W heating element out of a room heater with a bad tip-over switch in series with my PV-1.3k to prevent exploding parts. Switcher supply amps also cannot properly operate with a light bulb in series. Due to mains voltage on the power supply, these are too dangerous for amateurs to start learning repair techniques on.
Again general safety tips, use only one hand to measure or adjust an amp with the power off. Voltage >25 across your heart can stop it. Wear no jewelry on hands wrists or neck, 1 v at 25 A can burn your flesh to charcoal through a ring. Wear safety glasses, parts explode (like metal transistor tops) and solder splashes, especially when removing it.
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Yes, all looks normal.
BTW you probably mean 'very little resistance'. The more resistance, the less 'short'.
Jan
I did read the post but much of it I cannot follow.
But I can follow the part about being safe. Am not even able to take voltage measures; am unable to tell if negative is ground or not.
am of the age to know "my safety is in my own hands".
That SHOULD be what I mean; but no I was messing up my understanding of the concepts I read on the internet 🙁
my bad and is kind of funny imo
was intuiting instead of reasoning the physics.
narrative - presumed bulb was dissipating the energy that would otherwise be "excessive resistance" [another made up term of mine and is crux of error, totally baseless axiom lol] within the amp. lapse in good reasoning / human moment.
Oh and thanks for confirming all is good / setting me straight!
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Making up terms nobody knows about generally lead to waste of time and effort by you and others.
Generally not productive in any sense.
It's much faster to read up on your issues so you can have a reasonable discussion solving your problems.
In the old days we used to use an advanced technique called 'study', but that has fallen out of favor lately 😎
Jan
Generally not productive in any sense.
It's much faster to read up on your issues so you can have a reasonable discussion solving your problems.
In the old days we used to use an advanced technique called 'study', but that has fallen out of favor lately 😎
Jan
Absolutely! was just meaning to highlight that exact problem. I just made up a term. (my intuition, am not meaning I consciously decided this is a new physical phenomenon in electronic engineering lol)
And in turn completely mis-intuited what i was seeing in the "experiment".
oh just read the last line in your post and comes across as a dig at me; but uh study IS what i do, and am poking fun at myself for being human; that is intuiting something....it slipped through this time...whoops 😉
irony....your term "in the old days" implies you have an age greater than mine and are referring specifically to experience....an assumption of our age difference.
It must be that because in the old there was no internet; effectively the worlds library of knowledge....implicity there is FAR more studying today then "in the old days".
tl:dr ur a f'ing boomer lol
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Yes, we were very fortunate at the time.
Whatever you read, you could be fairly sure it wasn't total BS. ;-)
Jan
More meant like a friendly poke; once in a while someone picks it up as an encouragement to educate themselves. Most not, and that's OK.
All for good fun.
Jan
I think that's just a case of nostalgia; either way as stated is just opining.
fundamentally you're point is the source is crucial when taken in the info, highlighting the internet is full of random sources....touche random stranger with no credentials.....who is implying they trust printed information because...it is printed. just fyi, Textbooks are available....on the internet....all the books you trust in part because were printed on paper...also on the internet (if worth it's salt) and MUCH MUCH more...all the advances of the field since...and accelerated as a DIRECT result of the internet
Sorry, someone who seems to have interest / knowledge in EE AND implies dislike for internet is a juxtaposition that REALLY irks me. am emotively out now lol
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We're not friends and you know that...your premise is false...I call bs....ur just grumpy / mean / negative personality type.
Ohh no, don't get me wrong! I love the 'net; the whole Linear Audio publishing would not have been possible without it!
When I started out with this stuff, it was almost impossible to read nonsense audio - but now you often read a post: '... I read somewhere on the internet ...' followed by a lot of nonsense you can't even make up! It's very hard when you start out to separate the chaff from the corn, you need some basic knowledge to get there. With all the short, two-syllable word chunks available, who will read a book, even online?
Jan
WRONG
"Studying" implies a commitment and following start to finish a block of knowledge such as found in a textbook.
Randomly jumping from an incomplete, often WRONG, poorly made video to another, similar abysmal quality one, does not qualify, even if you watch 1000 of them.
Or 100000
And to boot, even plain textbook "reading" is not enough.
If you had ever assisted an University or similar learning Institution, you would have known that:
1) a block of knowledge considered enough to be understood by Students is taught
2) if applicable (such as in Physics, Chemistry, etc.) Lab work is done, so Students learn about the practical side of it; if pure Theory (such as in Math), TONS of exercises are to be done by Pupils, in both cases to make knowledge "stick" and deeper.
3) even that is not enough, then Students must pass Tests posed by Teachers which are then evaluated by them.
Now YOU tell me which of these criteria does "Internet/Youtube University" meet.
Laughably WRONG.
Not even 1% (if that many) of any University Library books are available on the Net.
Now THIS is funny (sad?)
Mike Tyson famously said "check first WHO are you picking a fight with" before smashing a cocky stranger to pulp.
Just FYI and before you continue ridiculing yourself, read around: https://linearaudio.nl/ and feel honoured that somebody that high level is even talking to you.