Rumbling/Rustling Noise at Start-Up
Moderators: pompeiisneaks, Colossal
Re: Rumbling/Rustling Noise at Start-Up
OK, this may be from left field. I've had amps that didn't behave right on initial start up. After a bit of use and cycling on and off, everything cleared up. It's been my theory that sometimes the filter caps need to be exercised a bit before they perform well. Maybe that's the problem?
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David Root
- Posts: 3540
- Joined: Fri Aug 04, 2006 3:00 pm
- Location: Chilliwack BC
Re: Rumbling/Rustling Noise at Start-Up
tubeswell, it occurs with all volume pots turned full down, including the loop pots and the master, so I don't understand how it could be coming from the preamp?
passfan, I simply don't like plastic jacks, it's too easy to overtighten them and crack the body, and if I were to use them I'd see Leo rolling in his grave every time.
Phil_S, I'm hoping that is the case. It does not last as long as it first did. The plate/screen cap is a double cap can, ARS, 16+32 which measures 20+39. I bought it new a few years ago. The preamp PS caps are older Illinois brand which test "marginal", but I have found quite a few new e-caps test that way on the e-cap meter I use.
I will check it out with the preamp tubes out, then if all OK I will drill the combo cab and mount it.
passfan, I simply don't like plastic jacks, it's too easy to overtighten them and crack the body, and if I were to use them I'd see Leo rolling in his grave every time.
Phil_S, I'm hoping that is the case. It does not last as long as it first did. The plate/screen cap is a double cap can, ARS, 16+32 which measures 20+39. I bought it new a few years ago. The preamp PS caps are older Illinois brand which test "marginal", but I have found quite a few new e-caps test that way on the e-cap meter I use.
I will check it out with the preamp tubes out, then if all OK I will drill the combo cab and mount it.
Re: Rumbling/Rustling Noise at Start-Up
Because if the GFB switch (that you have in place of a presence pot in the LTP) is dodgy, it could be that. Perhaps see if bypassing the switch solves the problem.David Root wrote:tubeswell, it occurs with all volume pots turned full down, including the loop pots and the master, so I don't understand how it could be coming from the preamp?
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David Root
- Posts: 3540
- Joined: Fri Aug 04, 2006 3:00 pm
- Location: Chilliwack BC
Re: Rumbling/Rustling Noise at Start-Up
OK, that makes sense, I hadn't thought of that.
Update:Presence switch is OK. Nothing misbehaving with preamp tubes out. Drilled the cab and loaded the chassis. Seems to work OK, still rumbles and rustles a bit for a few seconds after HT comes on.
When it was on my bench I had it connected to my 2x15 closed back cab w/JBL E130s, totally clean and uncolored, but puts clams under a microscope!
After I put in in the cabinet I tried it with the internal Altec 417B and a parallel satellite Altec 417B in a 1x12 open back cab. Matched 2x8 ohms into 4 ohm OT. Warmer, more forgiving clamwise but not as punchy compared with the 15" speakers. Closed back vs. open back I guess.
With certain amp settings and a bit more juice with the Altecs it sounds like a little reverb is in there in clean mode. Two-speaker interaction?
Update:Presence switch is OK. Nothing misbehaving with preamp tubes out. Drilled the cab and loaded the chassis. Seems to work OK, still rumbles and rustles a bit for a few seconds after HT comes on.
When it was on my bench I had it connected to my 2x15 closed back cab w/JBL E130s, totally clean and uncolored, but puts clams under a microscope!
After I put in in the cabinet I tried it with the internal Altec 417B and a parallel satellite Altec 417B in a 1x12 open back cab. Matched 2x8 ohms into 4 ohm OT. Warmer, more forgiving clamwise but not as punchy compared with the 15" speakers. Closed back vs. open back I guess.
With certain amp settings and a bit more juice with the Altecs it sounds like a little reverb is in there in clean mode. Two-speaker interaction?