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  #1  
Old 13th July 2017, 01:11 PM
bob orbell bob orbell is offline
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Default My Cathode follower with active load.

Hi all, about 5 months ago I lashed together, CF with active load and a White CF, after a lot of listening I chose the former and built it on a nice experimenters board supplied by another member, well, it worked, but, I had a rustling sound from the speakers when turning the volume knob, it is a Alps motorised, and a thump when pressing the mute function on the remote, when using the remote to turn the volume up or down, a tick tick tick noise came from the speakers. I dismantled many times and tested everything, all seams correct, and it sounds good, it was when I tested the voltage to the upper valve with my meter and the system was on that I noticed the thump had gone and the rustling sound had gone as I turned the knob, removing the meter, the problems returned, so, I tried adding some capacitance, 220nF 400v, but no improvement, out of frustration I cut the 0 volt wire off, and now silence on one channel, so a second cap has been added to the other channel, and all is well, but how is this doing it, there is only one connection to to capacitors, see photo, it beats me. BOB
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  #2  
Old 13th July 2017, 01:13 PM
bob orbell bob orbell is offline
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Default Re: My Cathode follower with active load.

Sorry, can't get the picture on yet.
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  #3  
Old 23rd July 2017, 12:52 PM
bob orbell bob orbell is offline
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Default Re: My Cathode follower with active load.

Just lost my temper with this and trashed it, so, I have ordered a John Bronski Akido buffer. BOB
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  #4  
Old 23rd July 2017, 06:19 PM
colin.hepburn colin.hepburn is offline
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Default Re: My Cathode follower with active load.

Quote:
Originally Posted by bob orbell View Post
Just lost my temper with this and trashed it, so, I have ordered a John Bronski Akido buffer. BOB
Yes itís a very different feeling you get when it doesnít work
Can you post image of trashed version Bob as that would be of different interest a failed projects thread just joking hope the Akido buffer go;s well Colin
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Old 24th July 2017, 09:26 AM
bob orbell bob orbell is offline
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Default Re: My Cathode follower with active load.

Hi Colin, and all, I will try again to get a picture of the project on here, the problem with it was not always present, it would go for weeks without a problem, but then the next time I switched on, I was greeted with a buzz that did not go away, tick tick tick as the volume was powered round and a grating sound as I manually turned the volume, too many times I checked everything including the power supply, connecting it up to the scope revealed what looked like a firework display, massive spikes and HF reading in many megacycles, so, its history, shame, because it did sound very good, anyway, looking forward to the Akidio. BOB
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  #6  
Old 24th July 2017, 10:27 AM
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pre65 pre65 is offline
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Default Re: My Cathode follower with active load.

Did you use ferrite beads on any of the valve pins ?
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