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This one has me stumped so calling on all of the computer guys for this one.
I recently started to build a PC based sound system and I’m running into some serious issues. I have blown the left channel of 2 integrated amps: first one was connected to the onboard sound and the second one was hooked to a Focusrite Scarlett 2i2 audio interface. The Focusrite receives its input thru my PC’s USB channel.
I can hear a bit of static when monitoring the Focusrite with headphone. With the first amp that was connected to the onboard output, I had used it for several years before my move connected in the same manner.
Before the 2nd amp blew, I tried to isolate the USB cables away from the power cords and away from the power amp in hope to isolate them from any EMF that could be emitting from those sources. I also tried different USB ports and cables and also ran some better speaker cables.
Any ideas on what could cause these amp channels to blow? Any suggestions how to eliminate the noise that I’m picking up on the USB channels? I’m leery to try another amp with this PC
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As long a s you are set up something like this below, the upper two speakers would be self powered the lower two would be if you are using an amp and then speakers you should be fine in your setup.
If so you might want to look at your setting in the ASIO driver. a smaller buffer size can introduce a static or what might sound like noise in the audio, if you increase the buffer size, mine is set to 512 it can eliminate any noise but the trade of is as that buffer gets bigger the latency increases also. another issue might be processing power of the computer you are using. better faster and you can decrease the buffer size and decrease latency. slower less powerful computer and you are back to having to increase buffer to compensate.
occasionally when i go through the computer my system sounds fine for a while and then everything sounds very static-y if i disconnect the guitar input for a moment and replug in it gets better. only thing i can come up with is overloading the processor as it happens differently with different programs, Guitar rig / native instruments i get it a lot, amplitube / ik multimedia hardly ever.
Good luck,
Larry -
Keith
The problem seems to be from the input to the amps. Having tryed two methods and still having problems it must originate with the signal from the PC.
RF from the lines is unlikely but I have had a similar problem i the past.
I was playing at a Military base when amps intermitantly went to thermal overload and shut down.
It turned out to be a radar dish, when it cycled by our location my amps picked up the signal.
Tinfoil over the amps stopped the problem, LOL. At least the amps had good protection circitry.You may be getting a signal that is above your hearing range. Ultra low frequencys may be an issue as well. It may originate with your PC itself, or perhaps the sound card. The USB should not be driven by the sound card so I suspect the PC or even the software.
You could try using the amps that you have already damaged and exchanging the inputs.
If the right channels blow consider a trip to the repair shop to get it checked out.Gordon
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The first amp that blew the left channel was a Samson DMS80. Its a legacy product for Samson, I’ve had it for about 10 years and never had any problems. We have recently moved and this unit was in the original packaging in a storage unit for about 3 months. When the left channel went out, I thought maybe it drawn some moisture in storage and with its age, it gave up the ghost.
It was hooked up to the sound output of the the motherboard, as I had used it it in the past
Here’s a link to it
http://www.samsontech.com/samson/products/miscellaneous-audio/miscellaneous-audio/dms80/The 2nd amp is a Radio Shack stereo PA amp. It had 2 inputs (R&L) with RCA jacks as any other stereo amp. I ran discrete cables from the Focusrite unit to those input. At first, everything was fine; 1st used a pair of JBL bookshelf speakers and then switched over to the speakers that had come with the DMS80
After a couple of hours, the left channel was gone.To double check the inputs, I reversed the cables from the Focusrite and the right channel was still the only one with sound.
Then I unhooked the audio inputs and used my mp3 player to rule out the Focusrite unit. Still, only the right channel was working.On the Radio Shack amp, the problem is in the pre-amp b/c I’m not getting sound thru the headphones.
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@sportstv wrote:
As long a s you are set up something like this below, the upper two speakers would be self powered the lower two would be if you are using an amp and then speakers you should be fine in your setup.
If so you might want to look at your setting in the ASIO driver. a smaller buffer size can introduce a static or what might sound like noise in the audio, if you increase the buffer size, mine is set to 512 it can eliminate any noise but the trade of is as that buffer gets bigger the latency increases also. another issue might be processing power of the computer you are using. better faster and you can decrease the buffer size and decrease latency. slower less powerful computer and you are back to having to increase buffer to compensate.
occasionally when i go through the computer my system sounds fine for a while and then everything sounds very static-y if i disconnect the guitar input for a moment and replug in it gets better. only thing i can come up with is overloading the processor as it happens differently with different programs, Guitar rig / native instruments i get it a lot, amplitube / ik multimedia hardly ever.
Good luck,
LarryThanks Larry
I’m only running 2 speakers and it was connected thru the amps like in your diagram.
I’ve dealt with a lot of stereo & sound equipment over the years and this one has me baffled. I’m getting a replacement for the Radio Shack amp and I don’t want to naively think that was a bad amp that came from the Ebay vendor. Doubt that they would give me a second replacement…..
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@luch_handt wrote:
Hey Keith, just wondered if you have it resolved yet. I’m just wondering if it has to do with the in/out settings in Reaper. If that’s what you’re using, and somehow sending it back to the amp rather than just out.
No, at this point, I’m at a bit of a loss.
As I was playing yesterday using headphones to monitor, I could hear constant and variable noise at all times. Before I moved, I would hear it but thought that it was due to the ham radio operator that lived close by. The PC is an older AMD dual core machine – it may be time to replace it
On the second amp that blew, I wonder if I may have over driven the preamp with the Focusrite. Once I get the replacement amp from the dealer, I may try to sell it on Craigslist and go with a set of active monitors
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Everyone is always blaming us for RFI. Lol…
I wouldn’t think that the PC would have anything to do with it, maybe the Focusrite, but not PC. Anytime I ad anything additional in my chain I worry about something overdriving. I guess I’ve been lucky so far. I hope you get it figured out. I’ll be having my own electronic woes come Christmas LOL.
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I just received this information from another member about cables, since I’m cheap and was considering going with cheap cables.
Use the Right Cable for the Job!
It’s easy to mistake cables… in our line of work, most of them are quarter-inch cables that look exactly alike, but there are differences… speaker cable and instrument cable are NOT the same thing.
Speaker cable actually has two cores, versus the single core of the instrument cable. A correct “speaker cable” delivers the amp’s output to the positive and negative terminals of the speaker equally; a single core guitar cable potentially creates an impedance mismatch between your speaker and your amp. Additionally, speaker cores are typically of heavier gauge and can better handle the load than the thinner wire of an instrument cable, which could then get overloaded and short out (which could even blow your output transformer entirely—a repair that is a lot more expensive than just replacing a blown cable)…
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