Ca-1000ii pushing and pulling speakers

[Nashou66]

Maybe there is two different problems, one could be the speaker relay itself arcing, on that channel, louder pop in class a mode with higher current makes sense.
The speaker driver "pumping" i would try another turntable to eliminate.

I was thinking the same thing. On one of my A-1's my speakers were making noise even with no input connected Also some times the wooofers would move in and out a lot with no input selected and volume all the way down . Turned out to be the voltage to the relay was not stable. it was a loose transistor for the relay voltage, soldered it up and That stopped almost all of the problem. However this A-1 might have been doing this for a long time as replacing the relay fixed the rest of the issues.

Did the recap you mentioned include a replacement of the speaker relay as well? if not I'd change it anyhow.

nashou

 

[mbz]

What do you think about that ac current between the frame and earth?

Any AC is not good, suspect that it is just ripple that cheap MM like mine think it's AC. Repeat the measurement then swap the polarity of
the probes. One orientation will give "ac", the other zero.

The 112V between +/-50 concerns me greatly. Measure +50 to chassis and -50 to chassis. Looks like a problem with the voltage regulation
on the relay board. Maybe measure the AC voltage at the switched or unswitched outlets, expect about 104-105Vac for a no load stepdown.

Thanks Mbz I have 22volts dc

That's ok

 

[clinic-audio]

Hello Elasticus

You did not answer to my question
Does this problem exist on any other high level input ??

 

[elasticus]

I tried to reproduce the speaker movement with the ca800. I pushed the speaker even closer to the turntable and increased the volume but nothing unusual occurred.

 

[elasticus]

Hello Elasticus

You did not answer to my question
Does this problem exist on any other high level input ??

I have been too cautious to have my newly acquired speakers hooked up to this amp for further testing with the risk of a faulty transistor.

 

[mbz]

I have been too cautious to have my newly acquired speakers hooked up to this amp for further testing with the risk of a faulty transistor.

Sounds like a wise move to me.

If you have some cheap headphones you may hear the pulsing, I would have thought it could be measured at the speakers on 2Vdc scale
but you've confirmed no volts at speaker.

Again, I think the +/-50 volt rails are a problem. You've measured 112-113Vdc, it may turn out that they are +/-56V each or one is +62V
and the other is -50V clearly indicating a problem with the positive supply. Need those measurements.

 

[elasticus]

Here are some reading needed beer to do this on a Saturday night.

switched outlet 104v ac unswitched 104 vac

Class AB

B+ to B-
red on B+ 245 ac red on B- zero ac
red on B+ 112 dc red on B- -112 dc

B+/B- to Frame
red on B+ 112 ac red on B- zero ac
red on B+ 56 dc red on B- -56 dc

50+ to 50-
red on 50+ 236 ac red on 50- zero ac
red on 50+ 107dc red on 50- -107dc

50+/50- to Frame
red on 50+ 118ac red on 50- zero ac
red on 50+ 54dc red on 50- -54 dc

I just couldn't stop so for anybody this way inclined I have the data for Class A also.

 

[elasticus]

Sorry about the mess all the spaces got removed.

 

[mbz]

104Vac at (un)switched outlets is fine.

Service manual has +/-B at 53V, and since you are running at 104Vac
+/-56Vdc is fine by me. Importantly they are both the same.

Your AC measurements with red on B- confirms that it's not AC but
something like 300-800mV ripple on top of 56Vdc which your (and my)
dumb MM thinks is huge AC. That's why they say you should use a true
RMS meter ($$$).

Regarding 50+/-. SM has them at +52, -53V. 54V is ok with me, again
importantly they are the same.

Dead end, voltages appear ok or is it just that problem is intermittent.

Revisit symptoms,
Right channel speakers pulsating
Right channel pop at power off and relay activation at power on.
Pop louder in Class A. Left channel also pops but much quieter.
Intermittent short load buzz
Right channel bias drifts from min to max approx 37-57mV AB and 890-990mV Class A
ie, some instability
DC offset 10mV both channels
Amp refurb'd, relay, class A snap switch replaced

The power ON pop is not due to the "normal" power on transients. Pop coincides
with relay action.

Need to sleep on this.

 

[clinic-audio]

I tried to reproduce the speaker movement with the ca800. I pushed the speaker even closer to the turntable and increased the volume but nothing unusual occurred.

Sorry but my english is maybe not enough good , I am asking you if your trouble does exist with AUX, TAPE, TUNER input (high level input do not mean high volume ) or any other input but not PHONO .
Making a try with a CA800 is not a good idea because if PHONO stages are different you will not get the same problem
You said your tried with another amplifier in PHONO input , but did you did it with a record with the stylus on the surface on this record ? Turning platter is not clear for me because it can spin without a record on it and don't proove anything
I think (from here) you are making research in a wrong direction

 

[elasticus]

Yes I was playing a record at a louder volume. I removed it from the speakers immediately because I wanted to prevent damage to my speakers so I did not observe this behavior on other inputs.

 

[clinic-audio]

I did not observe this behavior on other inputs.
Good !
Very difficult to certify from here but you can trust me , you can't damage your speakers because the unit has a protection circuit .
I don't understand why you look in a wrong direction . Probably because you don't understand the phenomenon . Don't look for defective part , I am pretty sure that everything is working well in your amplifier because you have this probem in PHONO only ! .
A defective transistor can't know if your are in AUX or in PHONO . You are in front of an acoustic phenomenon (like Larsen)

If you want to proove to yourself that everything is fine do this :
- do the same test in PHONO by connecting your speaker in opposite phase (for the both speakers), this way you can't get it again because the phase of the input is opposite at the phase of the output .
Try and report us your result

42 years Working on YAMAHA products and I own a CA1000II

 

[elasticus]

I did not observe this behavior on other inputs.
Good !
Very difficult to certify from here but you can trust me , you can't damage your speakers because the unit has a protection circuit .
I don't understand why you look in a wrong direction . Probably because you don't understand the phenomenon . Don't look for defective part , I am pretty sure that everything is working well in your amplifier because you have this probem in PHONO only ! .
A defective transistor can't know if your are in AUX or in PHONO . You are in front of an acoustic phenomenon (like Larsen)

If you want to proove to yourself that everything is fine do this :
- do the same test in PHONO by connecting your speaker in opposite phase (for the both speakers), this way you can't get it again because the phase of the input is opposite at the phase of the output .
Try and report us your result

42 years Working on YAMAHA products and I own a CA1000II

 

[elasticus]

Thanks Clinic-Audio, the truth is that I didn't test the other inputs. I did switch off the amp immediately for a few seconds when I switched it back on with the stylus reset to the same position on the record and the same volume the behavior had stopped. The Amp is now packed for transport to a technician friend. I would love to have your collection of amps and receivers. Can I ask how the ca-1000 compares in sound to the ca-1000ii.