Amps that are fan cooled questions

[DavidEdenAria]

Won't make any significant difference to the caps. 12 years old is just broken in for a modern cap. If the cap is rated at 85 deg C or greater, I would expect a lifespan of ~20-30 years. Just changing out parts, you run the risk of disturbing something mechanically that you might regret, and there is always the chance of installing a defective new part. Your old caps are proven good performers.

Won't make any significant difference to the caps. 12 years old is just broken in for a modern cap. If the cap is rated at 85 deg C or greater, I would expect a lifespan of ~20-30 years. Just changing out parts, you run the risk of disturbing something mechanically that you might regret, and there is always the chance of installing a defective new part. Your old caps are proven good performers.

From your experience what exactly causes the cap to degrade or fail after 20 to 30 years?

What about surging or high wall volts?

I measure up to 126 wall volts commonly, though its normally around 122...this is measured with several multi meters fyi.

 

[BadExample]

I measured the resistance of the speakers and they measured lower than similar 16 ohm speakers resistance.

The 16 ohm rating is not DC resistance, as you would measure with an ohm meter. It is AC impedance (Z), and it is a "nominal" rating, as it varies with frequency. With an ohm meter it is normal to read a lower value than the impedance.

 

[DavidEdenAria]

The 16 ohm rating is not DC resistance, as you would measure with an ohm meter. It is AC impedance (Z), and it is a "nominal" rating, as it varies with frequency. With an ohm meter it is normal to read a lower value than the impedance.

Thank you sir.......my point was the resistance I measured seemed a bit less than other 16 ohm speakers.

The Metro pair of 10" speakers at 16 ohms each which are paralleled to 8 ohms actually measure 5.7.

Whereas other 16 ohm speaker pairs I have, wired in parallel, vary from 6.1 to 6.9.

Not much difference....but enough that I went ahead and pulled the speakers out to measure them individually for kicks....that's when I found the dangly speaker connectors which I installed new ones, crimped very tightly.

 

[xk49w]

If you want to improve the reliability of the cooling, stack two fans.

Once I repaired a 4U rackmount power supply that supposedly came out of a submarine. The owner was utilizing it as a battery charger in an old 30's era forty-five foot sportfisher called the Cuda Catcher. He had connected it up to the batteries wrong, it was busted but he was leaving for the Bahamas the next day and needed it fixed Right Now! With a trip to Radio Shack to buy some sand-filled resistors I fixed it. Sort of. At least it was regulating the next day when he left the dock.

The point of this digression is that this thing had an impressive amount of built-in redundancy. Not surprisingly, everything electronic was coated with a waterproofing sealant, but what impressed me the most was the two stacked cooling fans. There would be no reason to do this really, other than redundancy. A higher volume fan would have moved more air.

 

[BadExample]

Good thing you had a look inside!

 

[DavidEdenAria]

If you want to improve the reliability of the cooling, stack two fans.

Once I repaired a 4U rackmount power supply that supposedly came out of a submarine. The owner was utilizing it as a battery charger in an old 30's era forty-five foot sportfisher called the Cuda Catcher. He had connected it up to the batteries wrong, it was busted but he was leaving for the Bahamas the next day and needed it fixed Right Now! With a trip to Radio Shack to buy some sand-filled resistors I fixed it. Sort of. At least it was regulating the next day when he left the dock.

The point of this digression is that this thing had an impressive amount of built-in redundancy. Not surprisingly, everything electronic was coated with a waterproofing sealant, but what impressed me the most was the two stacked cooling fans. There would be no reason to do this really, other than redundancy. A higher volume fan would have moved more air.

Could that have been in case one fan failed, the other would still work?

 

[agedhorse]

From your experience what exactly causes the cap to degrade or fail after 20 to 30 years?

What about surging or high wall volts?

I measure up to 126 wall volts commonly, though its normally around 122...this is measured with several multi meters fyi.

Well, after 20-30 years, I would expect the aging effects to become a problem (if it actually tests degraded).

Normally, designers will design power supplies to accommodate a line voltage of +10% of nominal, making a 120 volt power supply safe to 132 volts. In fact, all amps that are safety agency tested, are actually tested at +10% of nominal line voltage. I wouldn't worry about it.

 

[Rip Van Dan]

Thank you VERY much for that info!!

My fan setup is different, it has the fan in the middle with its vents, then on each side of the little heatsink chamber there are 2 more vents.

I assume this is the upgraded design or is this the original Metro fan design?

I was going to mention I read about some Eden amps having revised fan designs but had no actual info or links regarding this.

So YES, apparently there were revisions on some Eden amps in terms of the fan & cooling setup.

Anyone have pics of their Metro fans?

Here's a pic off of E-bay of the oval holes on the back of a Metro. Odds are yours are the same. The earlier model had round holes in the same place. You could modify the center section of holes to be like the pic of the WT800b I posted, but the biggest improvement will come from making sure the fan is exhausting air out at the fan and NOT sucking air in.

And yes there have been numerous improvements to the cooling of Eden amps over the years as I mentioned previously.

 

[BadExample]

Well, after 20-30 years, I would expect the aging effects to become a problem (if it actually tests degraded).

Normally, designers will design power supplies to accommodate a line voltage of +10% of nominal, making a 120 volt power supply safe to 132 volts. In fact, all amps that are safety agency tested, are actually tested at +10% of nominal line voltage. I wouldn't worry about it.

I wish the smps used in amps were all 90-250VAC. Smaller Carvins are, but higher wattage Carvins are not. I guess once you reach a certain point in power it costs less to stock more parts, design two models and have separate builds. They might not ship many overseas. I would have paid more for a wide mains voltage range or even a switch.

 

[BadExample]

Could that have been in case one fan failed, the other would still work?

I think yes. In this case redundacy. A lot of computer server stuff is failover meanining the backup takes over quickly rather than always full on. Thats my next project for our 20 TB storage array. Just got all the parts. Its supposed to switch over before any of the servers know their hard disk failed.

 

[agedhorse]

I wish the smps used in amps were all 90-250VAC. Smaller Carvins are, but higher wattage Carvins are not. I guess once you reach a certain point in power it costs less to stock more parts, design two models and have separate builds. They might not ship many overseas. I would have paid more for a wide mains voltage range or even a switch.

There are different ways to accomplish multiple AC supply voltages, auto-switching at high power requires more parts (and more expensive parts). When you add PFC into the equation, it gets more complicated as well. Cost does come to bear in some of these decisions I'm sure.

 

[BogeyBass]

Could that have been in case one fan failed, the other would still work?

old believe stacking two fans increased airflow.
but it has been tested and proved stacking 2 fans increased the ability of smaller motors to overcome the resistance of a load. so it's been done before if the fan is used with a high resistance load like a cooling radiator

in your case adding a higher cfm fan could give you more assurance, at the trade off of possible noise increase and more load on power supply. but the computer industry drives the need for better fans, by now there's probably a higher rated fan that pulls same current as the factory unit

 

[FunkHead]

I would not change the design of the air flow system. Nor would I "reverse" the direction of air-flow. It's designed to pull air over the critical components and exhaust the heat out the back. The only thing I would do is put in a more powerful fan.

Oh and Being too close to a wall will absolutely increase the temperature inside the head. That's just pure common sense. I always leave some room behind my head for sufficient air flow. I also avoid being too near a heat source. "An ounce of prevention is worth a pound of cure.

 

[Thor]

Thank you sir.......my point was the resistance I measured seemed a bit less than other 16 ohm speakers.

The Metro pair of 10" speakers at 16 ohms each which are paralleled to 8 ohms actually measure 5.7.

Whereas other 16 ohm speaker pairs I have, wired in parallel, vary from 6.1 to 6.9.

Not much difference....but enough that I went ahead and pulled the speakers out to measure them individually for kicks....that's when I found the dangly speaker connectors which I installed new ones, crimped very tightly.

Measuring the DC resistance pretty much gave you what you measured. DC resistance. The values you measured are all within normal ranges one would expect for a 16 ohm driver or 2 drivers that are connected electrically in parallel.

Doing this doesn't tell you much of anything about the driver's performance. What is does do is allow you to differentiate between a 16, 8 and 4 ohm driver because each has a different expected DC resistance component or range. It also tells you that the voice coil windings are continuous i.e. DC Voltage went in one end and came out the other.

The point I think you missed here, and badexample noted, is that the (DC) "resistance" of the driver coil does not equal the impedance of the system. People tend to use these terms interchangeably, but they are not the same thing.

The short answer is that in an alternating current circuit, impedance includes resistance and reactance.
Reactance includes effects which vary with frequency due to inductance and capacitance.

There are other factors that influence Z. For example, mechanical impedance relating potential to flow. Examples of potential include Voltage and flow would included Current. Sometimes the system has a resonant frequency where less force is required to achieve optimum flow. That all being bundled together with phase and phase shift creates a complex number to describe the system including real and imaginary mathematical parts.

To address your other question, the connection in parallel of your 3 8om loads presents a 2.66 ohm load to your amplifier (using Ohms law) and that is perfectly well within the design parameters of this amp.

Finally, I would take Agedhorse's advice to heart. If it ain't broke, don't fix it. Your speaker wires fit the "needed fixing" definition, your caps don't.

 

[DavidEdenAria]

Measuring the DC resistance pretty much gave you what you measured. DC resistance. The values you measured are all within normal ranges one would expect for a 16 ohm driver or 2 drivers that are connected electrically in parallel.

Doing this doesn't tell you much of anything about the driver's performance. What is does do is allow you to differentiate between a 16, 8 and 4 ohm driver because each has a different expected DC resistance component or range. It also tells you that the voice coil windings are continuous i.e. DC Voltage went in one end and came out the other.

The point I think you missed here, and badexample noted, is that the (DC) "resistance" of the driver coil does not equal the impedance of the system. People tend to use these terms interchangeably, but they are not the same thing.

The short answer is that in an alternating current circuit, impedance includes resistance and reactance.
Reactance includes effects which vary with frequency due to inductance and capacitance.

There are other factors that influence Z. For example, mechanical impedance relating potential to flow. Examples of potential include Voltage and flow would included Current. Sometimes the system has a resonant frequency where less force is required to achieve optimum flow. That all being bundled together with phase and phase shift creates a complex number to describe the system including real and imaginary mathematical parts.

To address your other question, the connection in parallel of your 3 8om loads presents a 2.66 ohm load to your amplifier (using Ohms law) and that is perfectly well within the design parameters of this amp.

Finally, I would take Agedhorse's advice to heart. If it ain't broke, don't fix it. Your speaker wires fit the "needed fixing" definition, your caps don't.

Measuring the DC resistance pretty much gave you what you measured. DC resistance. The values you measured are all within normal ranges one would expect for a 16 ohm driver or 2 drivers that are connected electrically in parallel.

Doing this doesn't tell you much of anything about the driver's performance. What is does do is allow you to differentiate between a 16, 8 and 4 ohm driver because each has a different expected DC resistance component or range. It also tells you that the voice coil windings are continuous i.e. DC Voltage went in one end and came out the other.

The point I think you missed here, and badexample noted, is that the (DC) "resistance" of the driver coil does not equal the impedance of the system. People tend to use these terms interchangeably, but they are not the same thing.

The short answer is that in an alternating current circuit, impedance includes resistance and reactance.
Reactance includes effects which vary with frequency due to inductance and capacitance.

There are other factors that influence Z. For example, mechanical impedance relating potential to flow. Examples of potential include Voltage and flow would included Current. Sometimes the system has a resonant frequency where less force is required to achieve optimum flow. That all being bundled together with phase and phase shift creates a complex number to describe the system including real and imaginary mathematical parts.

To address your other question, the connection in parallel of your 3 8om loads presents a 2.66 ohm load to your amplifier (using Ohms law) and that is perfectly well within the design parameters of this amp.

Finally, I would take Agedhorse's advice to heart. If it ain't broke, don't fix it. Your speaker wires fit the "needed fixing" definition, your caps don't.

Thank you sir...I am aware that resistance is not impedance but its the easiest and quickest way to make sure things are indeed connected......I didn't miss the point but thanks for reminding me.

Otoh, how would you know if someone didn't insert an 8 ohm speaker where a 16 ohm would be without measuring the resistance?

Years back, I bought a 4x12 16 ohm cabinet that when I opened it up had one 8 ohm speaker and 3 speakers that were 16 ohm...I ALWAYS measure each speakers resistance to see if it has an open coil as well as the resistance.

I cant tell you how many times I have found dangling speaker connections in the past 40+ of Hi-Fi and guitar gear but its been in the dozens of times where the connection was not secure.

I always pull speakers on any "new to me amp cabinet" (i've done this for the last 40 years unless for some reason I cant get the access to the driver easily) to see what the speaker connection is.....I prefer crimped & soldered speaker joints overall.

Thanks again for mentioning the 2.66 load with three 8 ohm speakers....I was fairly close in mentioning 2.7 ohm load but yes, 8 divided by 3 is 2.66.

As for "if it aint broke" I agree for the most part, but, at this point, I am trying to determine if there was indeed a revision to the cooling fan system on my 2004 Metro....I heard rumors about this topic in which case I think I will contact Eden....since I do plan to run at 2 ohms rather than 8 ohms.

There are some veteran authorized repairman that disagree about leaving caps in for 12-15 years, even new design caps...my SS amp repair guy has 55+ years as an authorized repair center...I'm going to take the amp to him for a once over

 

[DavidEdenAria]

The 16 ohm rating is not DC resistance, as you would measure with an ohm meter. It is AC impedance (Z), and it is a "nominal" rating, as it varies with frequency. With an ohm meter it is normal to read a lower value than the impedance.

That was a brain fart when I was very tired, sorry.....some guitarists at other forums know what we mean when we say things like this or "melted transformers" which refers to the tar substance that melts as a transformer is likely running too hot.....not that the transformer steel actually melted down!

If you measure no resistance at the speaker or speaker jack then something is amiss.

Some of us at the guitar forums get in the habit of measuring resistance to make sure things are at least connected....I don't like to just 'assume' its okay in this case.

 

[agedhorse]

There are some veteran authorized repairman that disagree about leaving caps in for 12-15 years, even new design caps...my SS amp repair guy has 55+ years as an authorized repair center...I'm going to take the amp to him for a once over

Sure, everybody has an opinion. Some opinions might be better backed up with design experience AND decades of tracking these reliability metrics. I can't tell you how many "repairmen" who say they know more than the "dumb-ass engineers" that designed the amp (not knowing it was me they were talking to) I have tried to walk through troubleshooting a circuit while they are insisting that they know exactly what the problem is... well then if you know so much, why are you calling me for help? That usually leaves them babbling in their own drool.

I can't confirm other engineer's designs, but any design that I have been responsible for has a REAL WORLD capacitor life of over 20 years, and in most cases will be good for 2x that. I don't care what your "repairman might think, he is not an engineer and he doesn't know as much about this particular subject as I do, nor does he have YEARS of reliability data that make me 100% positive of my comments.

Sorry for trying to help, no good deed goes unpunished I guess. Go ahead and do what makes you feel good. Your ideas do not relate very well to the real world as I see it.

 

[DavidEdenAria]

Sure, everybody has an opinion. Some opinions might be better backed up with design experience AND decades of tracking these reliability metrics. I can't tell you how many "repairmen" who say they know more than the "dumb-ass engineers" that designed the amp (not knowing it was me they were talking to) I have tried to walk through troubleshooting a circuit while they are insisting that they know exactly what the problem is... well then if you know so much, why are you calling me for help? That usually leaves them babbling in their own drool.

I can't confirm other engineer's designs, but any design that I have been responsible for has a REAL WORLD capacitor life of over 20 years, and in most cases will be good for 2x that. I don't care what your "repairman might think, he is not an engineer and he doesn't know as much about this particular subject as I do, nor does he have YEARS of reliability data that make me 100% positive of my comments.

Sorry for trying to help, no good deed goes unpunished I guess. Go ahead and do what makes you feel good. Your ideas do not relate very well to the real world as I see it.

Sure, everybody has an opinion. Some opinions might be better backed up with design experience AND decades of tracking these reliability metrics. I can't tell you how many "repairmen" who say they know more than the "dumb-ass engineers" that designed the amp (not knowing it was me they were talking to) I have tried to walk through troubleshooting a circuit while they are insisting that they know exactly what the problem is... well then if you know so much, why are you calling me for help? That usually leaves them babbling in their own drool.

I can't confirm other engineer's designs, but any design that I have been responsible for has a REAL WORLD capacitor life of over 20 years, and in most cases will be good for 2x that. I don't care what your "repairman might think, he is not an engineer and he doesn't know as much about this particular subject as I do, nor does he have YEARS of reliability data that make me 100% positive of my comments.

Sorry for trying to help, no good deed goes unpunished I guess. Go ahead and do what makes you feel good. Your ideas do not relate very well to the real world as I see it.

I didn't say I was going to replace the caps in this amp.

I said I was going to have my repairman, who has a very good reputation and has a trained electronics background, take a LOOK at the entire amp while its out of the chassis box.

 

[BadExample]

If you measure no resistance at the speaker or speaker jack then something is amiss.

It's a legitimate test, it's just not an impedance test. Best if you know the value of R for the driver or at least have another to compare it to. The value of R can be found in the T/S specs. If measuring a cab, you would have to know what the resistance measurement was when it was new or at least known good. Individual drivers would have to be disconnected from wiring to get a useful reading.

 

[BadExample]

Sure, everybody has an opinion. Some opinions might be better backed up with design experience AND decades of tracking these reliability metrics. I can't tell you how many "repairmen" who say they know more than the "dumb-ass engineers" that designed the amp (not knowing it was me they were talking to) I have tried to walk through troubleshooting a circuit while they are insisting that they know exactly what the problem is... well then if you know so much, why are you calling me for help? That usually leaves them babbling in their own drool.

I can't confirm other engineer's designs, but any design that I have been responsible for has a REAL WORLD capacitor life of over 20 years, and in most cases will be good for 2x that. I don't care what your "repairman might think, he is not an engineer and he doesn't know as much about this particular subject as I do, nor does he have YEARS of reliability data that make me 100% positive of my comments.

Sorry for trying to help, no good deed goes unpunished I guess. Go ahead and do what makes you feel good. Your ideas do not relate very well to the real world as I see it.

I used to train and support our distributors techs overseas (as well as my own techs). Most techs were good once trained. A few knew it all. A few shotgun troubleshooters. Some wanted to go after a good handful of op amps and lift traces before even verification that there even was a problem. Not good on an instrument that measures a fraction of a nano amp full scale! A couple always had engineering complaints. No data to back it up and never returned any of the stuff they said was broken by design. I'm glad to be out of that biz! Work on my own now, my own stuff no one else touches for the most part and never run out of new stuff to learn.