Tube amp Thump! (Not in a good way!)

Fourstrfury

Fourstrfury

Supporting Member
Apr 21, 2024
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#1
Ever since my son was born I've had to switch to practicing with headphones. My amp is a V4B. I picked up a torpedo captor and ran a D.I. from that to an Ampeg SCR (this acting as a headphone amp/aux in). This allowed for the power amp to "season" the sauce if you will. Lately I changed it up, keeping the Captor attached, I took the D.I. directly from the amp (pre power amp) and went to the Ampeg SCR. This is how I used it for the past month or so.
Today I went back to taking the signal from the Captor. I know have a constant thump, almost like a metronome. What could be causing this? Bad tube?
Thank you
 
#3
My apologies I should of mentioned this in my previous post. I had been playing for about an hour, D.I. into the SCR. I decided that I'd like to hear any differences in tone with/with out the power amp in play.

I've had it off for about two three hours now and tried it with a cab and going into the SCR. There is no thump now. I'll have some time later to play for a little longer to see if it develops as the tubes heat up more.
 
#9
byacey said:
How are you connecting the SCR DI when playing through the cabinet? Are you hearing the low frequency oscillation through the cabinet, or the SCR headphone output?

I would suggest just using the SCR DI as a stand alone device for headphone practice, and save the tube amp for stage use with a cabinet.
Click to expand...
99% of the time it's to the SCR no cabinet.
 
#14
Have an old Peavy amp that I don’t use much and when I do I get the thump you describe.
If I rotate one of the pots (multiple times) I can get it to go away. Dirty I’m guessing.
It does it with or without my bass plugged in.
A bit of a mystery to me, but I only use the amp for practice so it’s not a big deal.
 
#16
agedhorse said:
I wonder if you are exceeding the capacity of the load box? Some have overload or overtemp protections built in.
Click to expand...

The captor will very clearly warn you about over temp/overload both in the control app and on the unit. When it starts the run hot the fan runs at a higher rate (may not be audible over headphones) and the unit lights up red instead of blue. Input and output levels are displayed in the app.
 
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#17
coreyfyfe said:
The captor will very clearly warn you about over temp/overload both in the control app and on the unit. When it starts the run hot the fan runs at a higher rate (may not be audible over headphones) and the unit lights up red instead of blue. Input and output levels are displayed in the app.
Click to expand...
Assuming that it’s working correctly.
 
#18
Hi Guys, Just thought I would weigh in here - Ross from Two notes here. We have 2 devices in our Captor Range, the analog Captor and the Captor X. Captor X features clipping indication but both devices feature overload protection. Both are also rated up to 100W. If you have any specific questions, let me know, I am always happy to help out my bass playing brethren!
 
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