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G-8000 protect mode

V

Vanbo73

New Member
I’ve had my G8000 for a while now, maybe 10 years. Last September I acquired new Polk Lsim 707’s. Fool heartily, I tried throwing my playlist at them out of the box and was very disappointed in the audio quality but even worse I sent the G8000 into protect mode on several different occasions. Some tracks the low frequency output was too much and once the watts surged pass 10w the receiver would enter protect.

Before the Lsim 707, I cannot ever remember the g8000 reaching those limits and in the last 10 years it never entered protect. I quickly realized after being educated by the fine folks at AK and Polk that the Lsim 707 requires at least 120 hours of break in. Im hoping the stiff coils were the cause of the multiple protect modes.

Now, fast forward to today and while listening to Spotify a heavy bass track started playing and before I could get across the room the g8000 entered protect mode again. I have not kept up with the break in hours but I’m pretty sure it’s been at least 120 hours by now.

I’m starting to wonder if the G8000 is just under powered for the Polks OR is it time to recap the old girl? Besides a couple of fuses and a relay switch everything is original.
 
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At its age, there's no way a restore won't help it. Impossible to pinpoint the reason it's going into protection without looking at it, but I have no doubt getting it redone by a competent tech will solve your issue.
 
ivandezande said:
At its age, there's no way a restore won't help it. Impossible to pinpoint the reason it's going into protection without looking at it, but I have no doubt getting it redone by a competent tech will solve your issue.
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Thanks for your input. I was hoping to hear just let the speakers break in more

it’s a funny deal. The g8000 performs great and no issues. It’s only certain songs with a loud low frequency that trips it. Examples are Alabama shakes(vinyl), Beginning of Sound and Color. The Proclaimers, I’m gonna be. there are others and to remedy the issue for the last 6 months I just turn the bass down One notch or turn the volume down a bit.

Does Recapping the Sansui alter the sound ?
 
Vanbo73 said:
Thanks for your input. I was hoping to hear just let the speakers break in more

it’s a funny deal. The g8000 performs great and no issues. It’s only certain songs with a loud low frequency that trips it. Examples are Alabama shakes(vinyl), Beginning of Sound and Color. The Proclaimers, I’m gonna be. there are others and to remedy the issue for the last 6 months I just turn the bass down One notch or turn the volume down a bit.

Does Recapping the Sansui alter the sound ?
Click to expand...
Yes. In a very good way.
 
Does the problem happen with other speakers?

Yes recapping will change the sound. In my non technical opinion, you have old tired caps, some of which may be failing. You replace them and other components with fresh modern parts that meet or exceed the originals when they were new. Transistors are a bit of another story but I have yet to regret replacing a transistor. This is my opinion, however suggesting a recap when it may be a component or two isn't always the best answer. Up to you which direction you want to go.
 
MIJ_Pioneer said:
Does the problem happen with other speakers?

Yes recapping will change the sound. In my non technical opinion, you have old tired caps, some of which may be failing. You replace them and other components with fresh modern parts that meet or exceed the originals when they were new. Transistors are a bit of another story but I have yet to regret replacing a transistor. This is my opinion, however suggesting a recap when it may be a component or two isn't always the best answer. Up to you which direction you want to go.
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Great question. No. My other speakers are Rti8’s. Dual 6 1/2 inch woofers. For the last 9 or 10 years the sansui never had one hiccup.
 
Is it possible you have a variance in the amount of power it takes to drive the new speakers and are chasing the same volume as what you are used to and the amp is clipping into protection? I have many speakers that just don't get loud as others (Klipsch gets loud, B&W are power hungry and don't get as loud).

I'm not a speaker nut but coming from car audio subwoofers, the break in was always so you didn't damage the actually speaker (spider) not necessarily your amp. Although the change in impedance is a factor I never thought of from a stiff speaker.
 
Its triggering the overcurrent protection, those particular speakers must have a fairly severe impedance curve.
So what it happening is when the impedance dips in the low frequencies, it trips the over-current trigger diodes.

There is not really much you can do about it, except delete the trigger diodes. On both my G9000's I did this and also on my G22000 I have disconnected the over-current protection.
The circuit is pretty basic and not set up very well, its very trigger happy. As long as you are not stupid and try to drive 2Ω loads or something, you will never have any issues.

There are two diodes to remove, let me know if you are interested and I'll look up what I did to mine.
 
kevzep said:
Its triggering the overcurrent protection, those particular speakers must have a fairly severe impedance curve.
So what it happening is when the impedance dips in the low frequencies, it trips the over-current trigger diodes.

There is not really much you can do about it, except delete the trigger diodes. On both my G9000's I did this and also on my G22000 I have disconnected the over-current protection.
The circuit is pretty basic and not set up very well, its very trigger happy. As long as you are not stupid and try to drive 2Ω loads or something, you will never have any issues.

There are two diodes to remove, let me know if you are interested and I'll look up what I did to mine.
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Wow. Never doubt the brilliance of AK members. Thanks for your reply. I think I will keep the diodes in place for now. I would hate to break something. I get nervous just taking it apart for a cleaning. Wonderful info and explanation though. Thanks
 
Was the loudness on at the time? Bass at zero? Tone defeat?

I also think it is the speakers causing the problems.
 
Vanbo73 said:
Wow. Never doubt the brilliance of AK members. Thanks for your reply. I think I will keep the diodes in place for now. I would hate to break something. I get nervous just taking it apart for a cleaning. Wonderful info and explanation though. Thanks
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Its very common with this G series and the GX700 series too.
Over-sensitive circuit at play....

Without the overcurrent protection circuit on my G9000, I had it easily and without overheating, delivering a staggering 240 watts into 3.2Ω, both channels operating.
The power amp in these receivers is well designed and very robust, it would take absolute stupidity to blow one up........
 
i Have the same receiver connected to some infinity floor standers. They probably live around 6 ohm with no problem. Looks like it’s time for multiple systems.lol. Use the g8000 on certain speakers go amps for the big boys.
 
Van73 said:
Yes, Yes and Yes.
Click to expand...


Evidently the loudness compensation switched on with these speakers and unit causes current overload. I suspect the speakers on lower frequencies are drawing excessive current for your unit to handle as intended. Dipping in impedance in the lower frequencies.
With the bass at zero and tone defeat on that leaves only the loudness. Some speakers have been known to be hard on amplifiers in this way.
 
kevzep said:
Its triggering the overcurrent protection, those particular speakers must have a fairly severe impedance curve.
So what it happening is when the impedance dips in the low frequencies, it trips the over-current trigger diodes.

There is not really much you can do about it, except delete the trigger diodes. On both my G9000's I did this and also on my G22000 I have disconnected the over-current protection.
The circuit is pretty basic and not set up very well, its very trigger happy. As long as you are not stupid and try to drive 2Ω loads or something, you will never have any issues.

There are two diodes to remove, let me know if you are interested and I'll look up what I did to mine.
Click to expand...
Could you explain the procedure to modify the protect circuit?
 
kevzep said:
Its triggering the overcurrent protection, those particular speakers must have a fairly severe impedance curve.
So what it happening is when the impedance dips in the low frequencies, it trips the over-current trigger diodes.

There is not really much you can do about it, except delete the trigger diodes. On both my G9000's I did this and also on my G22000 I have disconnected the over-current protection.
The circuit is pretty basic and not set up very well, its very trigger happy. As long as you are not stupid and try to drive 2Ω loads or something, you will never have any issues.

There are two diodes to remove, let me know if you are interested and I'll look up what I did to mine.
Click to expand...
Yes thank you
 
Might I suggest a solution that I used with my G 6000. Sansuis don't like 4 ohm speakers. I had some Kefs that were the issue as they were 4 ohm speakers. I bought a Niles speaker switch which I used to connect the two speakers per side and consolidate it to one set of wires to connect to the receiver's outputs. In addition to the consolidation, the Niles also converted the speakers to 8 ohm, into the receiver. After this, my receiver never balked at having two speaker Kefs per side. The Niles is fairly inexpensive and will solve your issue without having to tear into the guts of your G 8000. Be well.
 
Before modifying anything, do the basic adjustments. Check and adjust DC offset and bias current. If the offset is high, it won't take much to trip protection. Measure the DC voltage across the left and right speaker terminals with noting connected and the volume at zero.

- Pete
 
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