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JohnKuthe

Just got a new amp, and tons of 60Hz HUM!!

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I just received and connected a TechnicalPro (tpro.com) 1000W per Stereo Receiver/Power amp, and it works great EXCEPT for the very annoying 60Hz HUM!!

Back connections

And I CANNOT trace WHY!!

Power connections, 3 wire grounded

Any ideas? Seems to be generating IN THE AMP which to me is incredulous! I mean, it's a cheap amp so I figured meh! I'd give it a try for a while, but never expected THIS! :-(

I'm stymied! And WITHOUT MUSIC via my La Scalas!! :-(

John Kuthe...

 

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6 minutes ago, JohnKuthe said:

Any ideas? Seems to be generating IN THE AMP which to me is incredulous!

My guess is the same as yours, there is something in the receiver causing the hum.

 

Try switching your inputs from AUX to CD and see what that does.  Also try running the Tuner and see if you still have the hum.

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9 minutes ago, wvu80 said:

My guess is the same as yours, there is something in the receiver causing the hum.

 

Try switching your inputs from AUX to CD and see what that does.  Also try running the Tuner and see if you still have the hum.

Yep, get the hum inherently INDEPENDENT of the RCA input or internal crappy Tuner (not even an indicator of a RF channel!)

John Kuthe...

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If it's this one it may have a problem because it's really cheaply made, it has to be for under $100, it's a no name with no where near 1000wpc.

 

I don't know just a guess, considering normal prices it has to be made cheaply, it might be called Technical Pro but there is nothing pro about it. I hope I am wrong but it sure looks like it. When it a knock off, off brand from walmart it's got to be the bottom of the barrel ?

 

SORRY, I would return it, a bottom of the line with a name brand would be better, NO RCA or junk like it. BS claims of 1000watts will blow your speakers by under powering them, I would bet it's not even close to 100 wpc. Beware of BS advertisements

 

 

https://www.walmart.com/ip/Technical-Pro-1000-watts-peak-power-Professional-Receiver-with-USB-SD-Card-Inputs/46689815

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1000watts... lol.

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I agree with the others.  Hum issues aside, I'd be afraid something so inexpensive (and from such an obscure company ) would present a fire risk.  ..Is it UL listed at least?

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I wouldn’t bother with that amp.  At only 8lbs, it’s not even a decent doorstop.

 

Don’t get me wrong, the low price alone is not what scares me.  I routinely enjoy music from Heresys using a mildly modified TDA7297 chip amp purchased from eBay for less than $5.  

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Anything I plug into an outlet in my home would have to be from a reputable mfg.  ..Given the efficiency of your LaScalas you don't need a high-powered amp section.  ..My Cornwalls begin shaking the walls when driven with more than 15-20 watts. And I think your speakers are even more efficient.

 

If you're on a budget and want a receiver (am/fm reception), consider this... from Crutchfield for $150.  A very reputable gear company and a very reputable seller.

 

https://www.crutchfield.com/p_022RS202/Yamaha-R-S202.html

5ab246197d578_ScreenShot2018-03-21at7_42_50AM.thumb.png.0cea80c10b3ed9e3c16042cad7b10d5c.png

 

 

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We used to stock that brand in our Dallas and Houston warehouses when I was a rep (thankfully not for Technical Pro).  Those were about the worst thing that ever shipped out of there on any given day.  El Cheapo.  So, the old saying goes, you get what you pay for.  Not to mention you're connecting it to very efficient and revealing speakers.  You might not notice the noises as bad on low efficiency speakers but you will with LS's.

 

My suggestion?  Send it back/get rid of it/unload it and get something built right.

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36 minutes ago, avguytx said:

We used to stock that brand in our Dallas and Houston warehouses when I was a rep (thankfully not for Technical Pro).  Those were about the worst thing that ever shipped out of there on any given day.  El Cheapo.  So, the old saying goes, you get what you pay for.  Not to mention you're connecting it to very efficient and revealing speakers.  You might not notice the noises as bad on low efficiency speakers but you will with LS's.

 

My suggestion?  Send it back/get rid of it/unload it and get something built right.

Yeah, I was just hoping. :-(

I guess I'll have to go back to the Receiver I WAS using, a Technics 110W RMS or maybe I'll see what my local stereo shop has in the way of power amps.

Thanks all! :-)

John Kuthe...

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With those speakers, you just don't need lots of power for playing loud, if  that's what you're looking for. 20 to 50 wpc of a good "real" amp should be puh-lenty.  Small tube amps either new or console rebuilds, Harmon Kardon 430 receiver, Concept 2.5,  Dynaco ST-70, and a ba-jillion others.  If they are older amps, they should be gone through and not reliant on 30, 40, 50+ year old caps, etc., to do the job.  You just don't need lots of power.

 

And I would personally avoid "surround sound receivers" running them.  But that's just me.

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1 hour ago, ODS123 said:

Anything I plug into an outlet in my home would have to be from a reputable mfg.  ..Given the efficiency of your LaScalas you don't need a high-powered amp section.  ..My Cornwalls begin shaking the walls when driven with more than 15-20 watts. And I think your speakers are even more efficient.

 

If you're on a budget and want a receiver (am/fm reception), consider this... from Crutchfield for $150.  A very reputable gear company and a very reputable seller.

 

https://www.crutchfield.com/p_022RS202/Yamaha-R-S202.html

5ab246197d578_ScreenShot2018-03-21at7_42_50AM.thumb.png.0cea80c10b3ed9e3c16042cad7b10d5c.png

 

 

Same crappy speaker outputs as my Technics!

How/why does a good powerful audio amp have crappy speaker terminals? Shoots any power low-distortion claims they make right out of the water!! Bottleneck at the speaker terminals because of crappy LOW CURRENT CARRYING CAPACITY PLASTIC LITTLE SPEAKER TERMINALS!!

John Kuthe...

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Because it keeps cost down.  

 

They make crimp on connectors with "pins" on the end of them that will go right into those.  You don't need a huge wire going to the LS's for a short distance.  16ga would be plenty as you're not sending hundreds of watts over a long distance of wire to inefficient speakers.  How long is the wire run to each speaker from the amp?

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10 minutes ago, JohnKuthe said:

Same crappy speaker outputs as my Technics!

How/why does a good powerful audio amp have crappy speaker terminals? Shoots any power low-distortion claims they make right out of the water!! Bottleneck at the speaker terminals because of crappy LOW CURRENT CARRYING CAPACITY PLASTIC LITTLE SPEAKER TERMINALS!!

John Kuthe...

 

That is simply not true.  Spring loaded terminal were used for years by many reputable mfgs inc., McIntosh.   IMHO, A great deal of what we see in home audio - 1/4" faceplates, super thick speaker cables/ interconnects/ power-cords/ fancy banana-plugs, extravegant dampening-factor & low impedance claims, - and so on and so on, are all meant to confer "quality!" on gear but the fact remains that modern day amps that are operating w/ in their design limits (which is easy for LaScalas) sound pretty much the same.  Bottomline: That is a perfectly fine piece of gear, despite it's humble speaker terminals.  I would have no reservations having that in my house.  

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Just now, avguytx said:

Because it keeps cost down.  

 

They make crimp on connectors with "pins" on the end of them that will go right into those.  You don't need a huge wire going to the LS's for a short distance.  16ga would be plenty as you're not sending hundreds of watts over a long distance of wire to inefficient speakers.  How long is the wire run to each speaker from the amp?

 I put new 12AWG 35 foot speaker wires on my La Scala's and I found some solder-on spade terminals to connect them directly to the crossovers in my LSs, for MAXIMAL power transfer. I don't play around with electrical power. I'm an electrical engineer by degree and know a thing or two about electricity/magnetism! 

Thanks !

John Kuthe...

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5 minutes ago, ODS123 said:

 

That is simply not true.  Spring loaded terminal were used for years by many reputable mfgs inc., McIntosh.   IMHO, A great deal of what we see in home audio - 1/4" faceplates, super thick speaker cables/ interconnects/ power-cords/ fancy banana-plugs, extravegant dampening-factor & low impedance claims, - and so on and so on, are all meant to confer "quality!" on gear but the fact remains that modern day amps that are operating w/ in their design limits (which is easy for LaScalas) sound pretty much the same.  Bottomline: That is a perfectly fine piece of gear, despite it's humble speaker terminals.  I would have no reservations having that in my house.  


I have a Technics SU-V98 and when my La Scalas 12 AWG speaker wires aren't FALLING OUT of the cheap plastic speaker terminals in  my Technics SU-V98 it sounds pretty good! BUT!! :-(

I HATE Musicus Interruptus ESPECIALLY due to the "not plugged in" Error! ;-)

John Kuthe...

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 As others have said, the hum could be a build quality issue, it could be a ground loop issue as well.   As a test, try a cheater plug, which lifts the ground.  If the hum goes away,  then you have a ground loop issue to solve. The cheater plug is not the solution if the hum goes away, as the amp won't be grounded, but it is a cheap way to find hum problems and address them. 

 

 

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Just for fun if you want to determine it is the amp itself, put shorting plugs on the inputs. If it still makes the noise it is the amp itself. And as Shiva said DO NOT LEAVE THE CHEATER installed permanently.

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