Ampeg SVT-3 Pro fan?

[g1]

Just more of the bigoted anti-asian bias from the "pontificator". Or is it just plain old racism?

[drewl]

Guys, why bother.
Just ignore.

[The Dude]

At least he's an equal opportunity bigot. He hates everyone who's not him. It's not limited to the Chinese. I think all of the heat trapped under his white hood has boiled his brain.

[Enzo]

Guys, why bother. Just ignore

Drewl, I'll tell you why I don't just ignore it. I speak only for myself. On forums like this, sometimes individuals pop up who rant and rave and spout nonsense. I don't mind ignoring them, in fact the forum has "ignore" features. They work well, and I use them. I feel more relaxed when certain posters are simply gone from my screen. But most of those either spout down in the politics section or they are so hung up on minutia in the theory section, no one else will be in their way.


But this guy spouts bullshit in the guise of "helpful" information to people who know no better and are honestly looking for help. I know I have tried to assist you a few times over the years, and I am sure you have some notion of how reliable my help is or is not. Now what if 2/3 of all the stuff I ever told you was false? What would you think then?

I grew up learning electronics on my own. There was no internet, no international hobby community to tap into nightly, no mentors. Kids today are SO fortunate to have places like this to find mentors. Man, if only I had such a place. I feel a certain need to help the less experienced along, and teach my own specialty, which is troubleshooting. So it is offensive when this Cliff Clavin clown jumps in with irrelevant and incorrect information.


So as I have said before, if you have a veterans' day parade and a bunch of old soldiers march down the avenue, you can applaud them and walk away. But when it is a horse parade, SOMEONE has to follow them with a shovel, or your street becomes a big pile of shit.

[drewl]

Wise words of a wise man.

[The Dude]

Drewl, I'll tell you why I don't just ignore it. I speak only for myself........

I wholeheartedly disagree. I'm pretty sure you speak for most of us in this particular instance.

P.S. In this case you need a backhoe. A shovel is not near big enough.

[DrGonz78]

As usual, Enzo you stated that perfectly! The points that SGM states are not bad, but his inability to always back up his points seems pretty apparent. That is my opinion and I can even see that much, even as a begining level type guy. Of course 1/3 of his advice is actually sound and well put. The parts that he goes off too far involves generalizing his points in specifics. When it comes to good troubleshooting and design it is all specifics. So when somone has a specific claim and then only generalizes his rationale that leads to more questions. Many times people here have challenged him to provide his backing for his OPINIONS and that usually results in no response. So he can pour lighter fluid on the fire pit but can't even strike a match to light it. There are times where he defends his claims but more times he never responds to people asking him to verify his claims. I like following his posts to see if he ever starts to break this habit and start explaining himself more fully.

[J M Fahey]

And, *besides* racism and plain old stupidity, what specially pisses *me* off is that, as Enzo mentioned, people with *real* problems comes here for help, and SGM fills them up with plain wrong, bogus data, pulled out of thin air, which can cause havoc to that stuff being repaired.

Not "opinion" stuff, such as Politics, Race, Religion or Sports, even human beauty, but big bold lies about stuff which can be easily proved wrong in 5 seconds browsing.

Unfortunately people who gets an answer here stops searching, trusting this is s serious Tech Forum ... which it used to be.

FWIW THERE ARE **NO** DIFFERENT VERSIONS OF LM35 , at least from a DESIGN point of view.

ALL of them show 10mV/degC slope , which is what you use to design your temperature compensation or meter or variable fan circuit.

All MINOR differences may reside in packaging and, as with any other component, there are hand selected ones with even closer tolerance, but ALL of them are specified 10mV/degC as said before.

The datasheet says (cut and paste):

LM35 Precision Centigrade Temperature Sensors
1) FEATURES DESCRIPTION
The LM35 series are precision integrated-circuit
2)• Calibrated Directly in ° Celsius (Centigrade)
• Linear + 10 mV/°C Scale Factor temperature sensors, with an output voltage linearly proportional to the Centigrade temperature. Thus the
• 0.5°C Ensured Accuracy (at +25°C) LM35 has an advantage over linear temperature
• Rated for Full −55°C to +150°C Range

While SGM writes his answer as if there were VERY different LM35, that they are not interchangeable, and implies they won't track each other or have different slopes.
The correct answer is: ANY LM35 WILL WORK PROPERLY THERE WITHOUT ANY NEED OF ADJUSTMENT

Let's remember SGM's SPD (stupid post of the day):

There is a huge variation in LM 35, and there is several different temperature ratings...
so they are not all the same.

The Chinese convention lets the amp get really, really hot, before the fan turns on....and I feel that this shortens the life of the components.

I would rather have the fan ON, when I turn the amp ON. At least, at a slow speed, and then increase the speed as the amp warms up.
And you can modify the circuit to do that.

But basically, I disagree with the Chinese design conventions. I think that it's very poorly thought out.
It's definitely not the best way to cool the components, to extend the life cycle.

And by the way, what will anybody searching for answers here think when instead of a question and a couple correct Tech answers he finds a page full of crap followed by cats and dogs fights?

OR, he follows an answer and he is either disappointed (SGM typical answer is "Junk !!!! Impossible to repair such a turd!!!" ) or burns it because of following some Tech nonsense.

[g1]

SGM is probably another counterfeit troll made in China.

[drewl]

Good points made, where I know whose opinons I value and trust, someone new to this forum may not.
So it's a great point to make to try and dispell rumor from truth and help those who need it.

[DrGonz78]

I am still laughing about the reference to Cliff Clavin!! Hope he don't go postal...

BTW: I was serious about adding a SGM disclaimer to the website... Perhaps make a sticky thread here stating the problem with his posts being inaccurate and misinformed.

[Enzo]

As much as he irks me, that is a slippery slope I do not wish to start down.


A disclaimer ought to be universal:

The thoughts expressed on this forum are opinions. Proceed at your own risk.

[DrGonz78]

Perhaps all the threads that turn into this sort of shoveling BS routine are disclaimer enough.

[soundguruman]

There are several versions of LM 35, with different temperature ratings.
They turn on / off at different points, with different performance curves.

But I lean to bypassing the LM 35 with a resistor, such as about 1 meg, from input to output.
This allows running the fan at a slow speed, when the amp is first turned on, then it speeds up as the amp gets hotter.

I would rather do it that way,
instead of waiting for the amp to get pretty hot, before the fan starts moving.

I feel that this prolongs the component life, longer than the original concept.

Chinese thermal management, in general, I do not agree with.
I think the thermal management in most of these amps sucks.

I would go for a much bigger heat sink, and a much cooler amplifier, overall.
The Chinese concept is too minimal for me.

And, I really don't give a crap if you agree or not. I don't care, at all.

[Jazz P Bass]

Just to clear the air, I ran a Comair Rotron 24Vdc Ampeg fan at various voltages & it starts spinning at around 6Vdc.(though weakly)
As G-One stated, the fan should spin at 16Vdc.(the static fan voltage)

So, my initial Post #2 was incorrect.

As the manual states that the fan should spin at all times (which at 16Vdc it will), the LM35 is there to ramp up the speed when the amp gets toasty.