Voltsecond, popping stepped attenuator

Bottlehead Forum

Welcome! Need support, you got it. Or share you ideas and experiences.

Sorry for the long query, I wanted to include as much information as I could up front.
I have been using a discrete stepped shunt attenuator. It worked flawlessly for about five months. Then, the right channel started to pop when I changed the volume. Soon after, the left channel also started to pop when the volume was changed. I tried a few different brands of contact cleaner on the switches to no avail. I searched to archives and your website and found the "make before break" fix. I installed a 270K resistor on each grid/wiper lead to ground. It worked. The popping was reduced greatly just as you had experienced. But now, about two months later the pop is back and even louder than before.
I have a SPG installed, the reverse recovery spike filter, filament snubbers (6.3V version), and the safety ground filter from pRC's website, and the C4S upgrade.
To confirm that it is indeed the preamp, I used different sources into it as well as a shorting plug. Not on the source side; pop is still there. I also connected the output to my Yamaha receiver to see if it was my Paramour amps. Nope, the popping is there with the Yamaha in place.
I installed a completely new attenuator on the right channel in the hopes that the switch was cheesy or I had used so much contact cleaner that it was gunked up. It wasn't. The right channel still pops as much as the left.
I have checked that the ground connection is good from the grid of each tube to the SPG. Each resistor of the attenuator also reads the correct value. The input selector switch to grid reads a perfect 100K.
Since the popping is on both channels and I changed out one of the attenuators I suspect that my ground is messed. Any ideas? Any help would be appreciated. Thanks in advance.

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Topic - Voltsecond, popping stepped attenuator - GDaddy 13:43:13 01/06/02 (5)

Re: Voltsecond, popping stepped attenuator - petef 20:49:14 01/06/02 (0)

Re: Voltsecond, popping stepped attenuator - VoltSecond 13:53:43 01/06/02 (3)

Found the problem. - GDaddy 17:25:03 01/09/02 (2)

Great Idea! - VoltSecond 20:39:46 01/09/02 (1)

Re: Great Idea! - GDaddy 09:40:59 01/11/02 (0)

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