Ca-1000ii pushing and pulling speakers

elasticus

Member
I have a Ca-1000 which as been recapped and had some transistors replaced with quality parts.
The other day I was playing vinyl on a well isolated turntable and i noticed the RH base speakers slowly moving in and out about 2cm but not in time to the music. The RH channel also makes a pop when switching off the amp and when the relay connects at start. The pop is also louder in class A mode.
In the past month this amp has made a short loud buzz sound.
If somebody has had the same experience I would love to hear about it.
I no longer use this amp
 
i noticed the RH base speakers slowly moving in and out about 2cm
Does this occur with any other inout ? Engage low filter switch. See if it influences the low freq speaker "pumping"movement. Check the DC offset on that channel while its moving.
 
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The RH channel also makes a pop when switching off the amp and when the relay connects at start. The pop is also louder in class A mode..
Check the DC offset in that channel as well.Have you replaced the protect relay ?
 
High DC offset/DC balance can cause popping at power on/off.
 
This phenomenon during vinyl listening ....
Because your cartridge is affected by your speakers ! this do not exist with other high level inputs , right ?
Do like Avionic says
 
Firstly the amp is a ca1000ii and it was the first time I hooked up my newly purchased Paradigm Tribute speakers. In response to Clinic-Audio the cartridge was 300mm from the speaker I will address this if the consensus is that it is safe to hook up my new speakers again. I have the amp set up naked on a bench with some small bookshelf speakers. The bias currents for RH channel drift from min to maximum tolerance in class A and AB.
The relay has been replaced.
The DC is .01 both sides but spikes to 5v when switched on and before the relay clicks the LH side only spikes to 1v.
 
The DC is .01 both sides but spikes to 5v when switched on and before the relay clicks the LH side only spikes to 1v.
Before the relay clicks.:idea: Are you measuring this at the amplifier board or the speaker binding posts ?
 
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I know what relay clicks are. I need to know where you made the measurements.
 
Now it only spikes to 1.5v when powered on at the wall. Returns to 1.5v after power off and remains for some time the other side is only a quarter of this.
 
LH side has a (lesser) pop on power off. I have always thought It was coming from the switch will check to see if it is making any more sound than my ca 800 switch.
 
This is what the amp is doing today. When the amp is switched on Rh speaker pops when the relay engages and also pops when relay disengages. Same result from switch or wall switch.
 
Just some ideas to stimulate the discussion. Like the suggestion on the power
switch arcing, bit left field for me. Worth investigating, both channels would be
affected?

The speaker protection circuit should provide a power on mute of 7 seconds
(R721, 150k, C715, 47uf). During this 7 seconds a dc spike of 1 or 5 or 7 volts
is not of any real concerns. That is the purpose of the mute to suppress the spike.
Is it likely these transients are lasting longer than 7 seconds or maybe the timer
has "failed" and only providing a 2-3 mute interval.

Suggest measure time from power on to relay click.

Also, the protection circuit dischages quickly releasing the relay so there should
be "no" pop at p-off. Problem with this discharge??

Could it be caused by drifting in either TR601,2,4. Remember that the bias is also
cycling.

Perhaps the dc is continually ramping up and down, mostly at a level that does not
trip the protection. It is this ramping that's causing the speaker movement. Get the
impression that it's at about a constant rate, maybe capacitor "involved".

Measure dc voltage at speaker terminals, maybe 0-2Vdc range, over a 30 minute period
(assumes relay engages)

Along the same lines as the power switch arching, what about a bad solder joint or wire
connection.

If you have 2 multimeters, measure/track voltages at +B and -B pins looking for a dip
in one of them. This may be difficult to spot since the mains is bouncing up and down.
If no joy repeat for +50 and -50 pins, the idea being to identify the faulty supply path.
 
On my ca800 and this ca1000ii the delay time is 3 to 4 seconds. The spike is all finished by the one second mark and is stable on zero for 2 seconds before engagement.
There is popping on both channels but RH is louder.
I have been testing the DC volts a lot and it is always close to zero.
I cant find any volts at the speaker terminals.
between +50 and -50 is a steady 111 to 112 volts I am using a 240 to 100 step down transformer.

This might be totally random but I get .3 to .2 volts ac between phono ground peg and the house earth but on the ca800 which works perfectly i get zero reading.
 
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between +50 and -50 is a steady 111 to 112 volts
Apologies, I meant measure red probe +50, black probe chassis on multimeter 1 and red probe -50, black probe chassis on MM2
Those voltages are a high, means each rail is running at 55, 56volts. Is the voltage correct 110V?

On my ca800 and this ca1000ii the delay time is 3 to 4 seconds. The spike is all finished by the one second mark and is stable on zero for 2 seconds before engagement.
Maybe my math is out 3-4sec or 7 seconds. Point is that transients are given time to settle, which they appear to do. Wondering if the pop (at
p-on/p-off) is somehow caused by the relay action/current draw. Maybe a problem in the power supply/zener diodes.

Measure dc voltage, red probe R721(150koms, brown/green/yellow) as shown below, black probe chassis, expect about 21Vdc,

R721.JPG
 
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.
 
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