Yes, a fault in the power section. Is it under warranty - the 600i is quite a new product?

Its already two years. Out of warranty already. Its started when one of my speaker cable was defective. I replace it with ordinary wire cable with metal plug body. It function at first but last 2 days ago this happens it will power for a couple of seconds then it went off. Also i saw in the yamaha stagepas forum that the culprit is the replacement speaker cable wire that is not rated for the stagepas 600i. My mistake.

It would surprise me if the replacement cable was the direct cause of the amplifier fault that you describe. It's more likely that the defect in the original cable caused stresses in the amplifier that have, over time, resulted in the behaviour you now see.

Bad luck.

Thanks Mr. Boswell for your prompt reply. Its time to heed for repair. Your site is a big help for us who wants answer in solving many problems regarding music technology.
Once again thanks a lot
More power!
Regards,
Robatillo

Yup.. Bos is definitely our "go-to guy" around here for all things electronic.

He's our electronics diagnostics and repair Guru. Plus, he's a great guy. ;)

I have an EV RE20 that needs fixed... if I could afford to send it to the UK for him to work on, I would. :)

I have come to a site looking for correct specification of wire cable speaker. This maybe of a great help in choosing the correct speaker cable. link: https://www.audioholics.com/audio-video-cables/speaker-cable-gauge.

On table 1. There are specific cable gauge vs distance. Yamaha Stagepas 600i on the manual uses 4 ohms speaker load, and 6 meter or approximately 20ft length of speaker cable wire. But problem, it didn't specify what gauge it uses. Basing on the table correct me if I'm wrong. The nearest speaker cable wire gauge for Yamaha Stagepas 600i, for 4 ohms load and 20ft length speaker cable wire is 14AWG gauge. So this will matter. Similarly if you want longer speaker cable wire like in the example 30ft you need 12AWG gauge. Purpose for this is to maintain the correct resistance and insure topnotch fidelity of your system.

Mr. Boswell care to enlighten us, maybe you have more knowledge with regards to this matter and to all the guys who have knowledge on this matter please share your inputs.

Many thanks.

Best Regards,
Robatillo

My pal Bos ( Boswell ) has been occupied with other things lately, so I'll jump in with this:

At a 4 ohm load, 14 gauge cable is sufficient for runs of up to around 35 feet ( around 11 meters).

At the same load, 12 gauge cable is good to up around 60 feet ( 18 meters) , BUT... running cables past a distance of 50 feet isn't really advised, regardless of the cable gauge, as this can result in dampened hi frequencies.
If you need longer runs than 50 feet (15.2 meters), you may want to consider placing your power amp(s) closer to the speakers and using a shorter cable length.

There are variables at play, of course - the quality of the power amp and speakers being such.

I fact-checked my info before I actually posted, and I found this:

http://faq.yamaha.com/us/en/article/live_sound/pa_systems/stagepas_300/2521/7034

I was pretty close with my info, but you should follow the Yamaha chart, as they know their own systems requirements best.

-d.

Hi Donny, Thanks for the reply.
So for the Yamaha Stagepas 600i with 4 ohms speaker load and 6 meter speaker cable wire basing on the Yamaha table it should be between 16 to 18 gauge. Am i correct? 17 gauge to be approximate?
Please need help coz after the repair done on my yamaha stagepas 600i i need to replace new speaker cable wire with similar specs of the original cable.
Thanks for the input Donny.

Best regards,
Robatillo

You're always better off to go with a cable gauge thicker than what you think you need, just to be safe... While using a thinner gauge has its potential problems, there's no real downside to going with a thicker gauge, other than the possibility that a thicker gauge may be more difficult to fit into a banana plug/connector.

Honestly, I'm not sure if 17 Gauge cable even exists in audio cabling... they are usually numbered in even increments. I could be wrong about that though.

Thanks Donny,
I will heed your suggestion and im thinking also 18 to 16 gauge is so thin. Its final for me. I will be using 14 gauge speaker cable. Would you care to recommend what brand of speaker cable and the 1/4 PL cable plug.
Many thanks.

Personally, I use a 14 gauge Belden speaker cable - open leads on one end ( speaker terminals) and connected to a banana plug on the power amp end. My distance is only around 4' or so from amp to monitors, so 14 gauge is plenty sufficient.

I've had it for about 20 years, it's never failed me, then again, it's not being moved or constantly coiled/uncoiled... It's stationary, so it doesn't suffer any stress.

There are many good cables out there; Monster Cable, Mogami... make sure you get speaker cable with quality connectors, as this is where most cheaper cables tend to fail.

Thanks Donny.

Donny has given you very good advice there.

If you can get 14 gauge Belden cabling (e.g. their model 8814), you should be fine for runs up to 20ft (6 m) per speaker. If you have to run further than that, lower the gauge to 12 or even 10, but you may have trouble wiring the thicker gauges into jack plugs. Also, it is not vanity to specify gold-plated jack plugs, as they really can give a lower contact resistance over their useful working life.

Robatillo, post: 438194, member: 49836 wrote: Thanks Donny.

Glad to help. That's what we're here for. :)

Thank you guys for your advise. It helps a lot when you don't know what to do in time like this. Thats why i'm very pleased that you answered me and give suggestion to your best abilities.
More power to you guys
Best regards.

The last time I responded to a Yamaha StagePas problem the cause turned out to be using an instrument cable to replace one of the speaker cables.

Mine happens only recently, After replacing ordinary cable and using it, after 2 days it powered and a couples of seconds it went off. Yamaha stagepas 600i on the user manual, states that using other cables not rated for this unit may result in heat generation or short circuiting. My mistake because i use ordinary cable and the metal 1/4 PL plug. But my unit is already two years, maybe the stresses of the original speaker wire have, in overtime also contributed to the problem.

So...have you been using an instrument cable or have you been using a speaker cable?

Recently i use instrument cable because my original Yamaha Stagepas 600i speaker cable was defective and this problem happens. My unit now is under repair. So I'm planning to replace the stagepas 600i speaker cable with the same specs as the original cable. Thanks to our moderator and to all you guys for your great advise.
I learned a lesson from this. "If you don't know a thing, don't be rush ask the expert or else you might make it worse"

More power to all you guys!

Robatillo, post: 438230, member: 49836 wrote: But my unit is already two years, maybe the stresses of the original speaker wire have, in overtime also contributed to the problem.

Doubtful. I think that Boulder ( bouldersound ) nailed it:

bouldersound, post: 438205, member: 38959 wrote: The last time I responded to a Yamaha StagePas problem the cause turned out to be using an instrument cable to replace one of the speaker cables.

Robatillo, post: 438233, member: 49836 wrote: Recently i use instrument cable because my original Yamaha Stagepas 600i speaker cable was defective and this problem happens.

Let's see if I can explain the basics of this - I'm hoping that Boulder ( bouldersound ) or Bos
( Boswell ) will jump in here, and either clarify, specify, or even correct me:

While older amps had switches to select the ohms, most modern amps will pretty much automatically adjust for ohms on their own, as long as you aren't using mismatched ohms in your speakers ( using speakers with differing ratings)... BUT - if you are using an instrument cable as speaker cable; the first problem is that most instrument cable is around 26 gauge wire, designed to carry signal, and not voltage. Also, because of the mismatch between the conductor wire and the shield wire of an instrument cable, ( speaker cables do not require a shield) this can increase the resistance to your amp's output considerably, along with "confusing" it, because it doesn't know which ohm rating to switch to - and this can result in a failed output stage of your amp.

...waiting on clarification of the above from our resident electronics experts....

I'm no expert but I think it's the inductive effect of coaxial cable that screws with amps.

This page by Fender covers the subject pretty well.

The bottom line: instrument cables are for low-power / high-impedance signals, and speaker cables are for high-power / low-impedance signals. The result of using instrument cable for the task of a speaker cable = inefficient transfer of power and excessive heat for the amp. (heat kills electronics)

Maybe that's the reason why my Yamaha Stagepas 600i amps died. Because i use instrument cable. I should have consulted the expert first before doing replacing that will damage my amps later on. Lesson learned

DonnyThompson, post: 438235, member: 46114 wrote: Let's see if I can explain the basics of this - I'm hoping that Boulder or Bos will jump in here, and either clarify, specify, or even correct me:

While older amps had switches to select the ohms, most modern amps will pretty much automatically adjust for ohms on their own, as long as you aren't using mismatched ohms in your speakers ( using speakers with differing ratings)... BUT - if you are using an instrument cable as speaker cable; the first problem is that most instrument cable is around 26 gauge wire, designed to carry signal, and not voltage. Also, because of the mismatch between the conductor wire and the shield wire of an instrument cable, ( speaker cables do not require a shield) this can increase the resistance to your amp's output considerably, along with "confusing" it, because it doesn't know which ohm rating to switch to - and this can result in a failed output stage of your amp.

...waiting on clarification of the above from our resident electronics experts....

There are several points about amplifier outputs and speaker cables. Most of them are general, but one of them is specific to the Stagepas range of amplifiers. The general ones have been covered by the excellent contributions of my fellow contributers, and include the need for using speaker cable (not instrument cable) of a sufficient gauge for the cable length required so that the proportion of power lost in the cable (I2R loss) is small compared with that dissipated via the impedance of the speaker.

The Stagepas specific point is that it is one of a relatively new breed of medium-quality amplifiers that use "Class D" outputs, that is, designs that use a pulse-width modulation technique rather than a linear output. It's a bit like a switched-mode power supply that produces a variable-voltage output, and is a manufacturer's favourite way of producing 300 - 600 W amplifiers that run cool and fit in a small box. In order to reconstitute the audio waveform at the output and to keep the switching frequencies out of the load, there are high-current chokes and filters mounted immediately behind the output connectors. However, the correct operation of these depends on their driving the load for which they have been designed, viz. the associated loudspeakers attached via the cables originally supplied with the system. If either or both of the loudspeakers and cables are not the originals, then the load seen by the output chokes is liable to be anywhere from a little to very different from that for which the amplifiers were designed, with a result that could vary from failure to contain the excessive high-frequency switching harmonics to the output power stages burning out, taking the power supply with them. It is possible that the latter scenario is what has happened in this case.

I had been wondering if there was something specific to the StagePos (or maybe FauxPas would be better) systems. I suppose it's something like a powered speaker which has a precisely defined load and can run the amp right to the edge of its abilities rather than a general purpose amplifier that must be compatible with a range of loads.

Hi Guys,
Repair was done on my Yamaha Stagepas 600i, The technician told me that they replace the power amps on the board and I also replace the speaker wire cable as what you suggest for this amps that best suited for this model. I use 14AWG with 6 meter length. Sound is great again!

I thank you all guys.

Best regards to all!
Robatillo