I built 2 Tube Lab SSE amps last year and have been very pleased with both of them. I built a SSE 6L6 and then another SSE, KT88. Both of them operate perfectly and sound amazing except when I use a potentiometer inline with ether amp. At first I assumed the pot I was using was at fault but came to find out that it may be something related to the amp.
The symptoms are as follows. Regardless of whether or not anything is plugged in the amp sounds really clean. But when turning the pot down anywhere below max, an intermittent, crackling, static (sometimes squealing) sound starts to come from only one of the speakers. This follows when switching speakers and appears to be affecting both of my amps. I thought it was a bad pot and replaced the one in my KT88 amp, but it only made things worse. I tried a solid state amp (Gainclone) and have no issues at all (except it isnt a class A tube amp)... Originally I discovered this issue when making a little source switcher with a pot installed but it turns out this occurs in the amp directly. Please see the post below that I originally put online which led me to this discovery. A lot of people suggested RF filtering, but I want to be sure there isn't anything wrong with my amps. If requested I can post a recording of the noise.
The symptoms are as follows. Regardless of whether or not anything is plugged in the amp sounds really clean. But when turning the pot down anywhere below max, an intermittent, crackling, static (sometimes squealing) sound starts to come from only one of the speakers. This follows when switching speakers and appears to be affecting both of my amps. I thought it was a bad pot and replaced the one in my KT88 amp, but it only made things worse. I tried a solid state amp (Gainclone) and have no issues at all (except it isnt a class A tube amp)... Originally I discovered this issue when making a little source switcher with a pot installed but it turns out this occurs in the amp directly. Please see the post below that I originally put online which led me to this discovery. A lot of people suggested RF filtering, but I want to be sure there isn't anything wrong with my amps. If requested I can post a recording of the noise.
POSTED in Analog Line Level:
http://www.diyaudio.com/forums/anal...t-static-one-side-system-pot-around-half.html
I decided to build a little 2 way source switcher and passive preamp using 100k Pot and a DPDT switch. Everything is great except when the pot is around the half way position. I start hearing what sounds like faint intermittent static on the left channel only. The right side is completely clean. Any suggestions?
My signal path
-Raspberry Pi with HiFiberry DAC + Pro (Input 1)
-Turntable built in preamp out, line level (Input 2)
-Passive 2 way source selector/preamp (2 Inputs, switch, 100k Stereo Pot - Output)
-Tubelab SSE with KT88s + Tannoy SYSTEM 800 Speakers
Note: This happens when either source is plugged in to either input. It also occurs when nothing is plugged in to any input.
I have not swapped any tubes yet or tried switching the speakers yet and will do this asap, but thought Id see if anyone had any ideas.
Thanks!
http://www.diyaudio.com/forums/anal...t-static-one-side-system-pot-around-half.html
I decided to build a little 2 way source switcher and passive preamp using 100k Pot and a DPDT switch. Everything is great except when the pot is around the half way position. I start hearing what sounds like faint intermittent static on the left channel only. The right side is completely clean. Any suggestions?
My signal path
-Raspberry Pi with HiFiberry DAC + Pro (Input 1)
-Turntable built in preamp out, line level (Input 2)
-Passive 2 way source selector/preamp (2 Inputs, switch, 100k Stereo Pot - Output)
-Tubelab SSE with KT88s + Tannoy SYSTEM 800 Speakers
Note: This happens when either source is plugged in to either input. It also occurs when nothing is plugged in to any input.
I have not swapped any tubes yet or tried switching the speakers yet and will do this asap, but thought Id see if anyone had any ideas.
Thanks!
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. It's usually not that bad, normally its just kinda crackle and static'ey. This was a particularly harsh example, but accurate none the less. That's one of the bizarre things about it, the inconsistency. Any suggestions on how to fix that? Should I take the pot out entirely? What causes it to oscillate on one side but not the other?
