I thought we wont be happy until we poke an eye out?
Damn this ever changing world!
Damn this ever changing world!
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Oh I don't know about thatMost folks that survive a finger poking incident never do that again
. Male dog-brain can take a few times to get trained. Well, mine, anyway .
- Feb 12, 2006
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Still chasing parked cars eh?Oh I don't know about that
You can substitute Engineer or Technician for Scientist, 'cause we all have a desire for repeatable results.Oh I don't know about that
Touche! guilty as charged.
At least these days we've got metal cages, blast blankets long g-10 sitcks , but that's when the fun happens , e.g.
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My brother once told me he was 'fixing' a 27" CRT and accidentally discharged a capacitor, said he woke up on the floor and his shoes were off and his toes were blackened on the ends. He said he had trouble reading for a few days, said things looked backwards. I always thought he was kidding.
So here's an update, I went to test it at home on Friday night and didn't hear anything. I do live in an apartment so I couldn't crank it - but still didn't hear anything noticeable. I would let the amp sit for an hour to cool down and come back to it and still never heard anything. I repeated that a couple times.
Figured that maybe it was some weird interference at our practice space.
Saturday I got to the rehearsal space, turned on the head much louder and I heard it again. I have a recording (using balanced out on the head) from a little jam we did while everyone was setting up. You can hear that the crackle is at a reasonable volume. 20-30 minutes go by and the crackle is non existent.
Brought the head home again and it's not making any funny sounds. I sprayed the socket with some zero-residue contact cleaner and will just have to try again at our practice next Saturday.
Figured that maybe it was some weird interference at our practice space.
Saturday I got to the rehearsal space, turned on the head much louder and I heard it again. I have a recording (using balanced out on the head) from a little jam we did while everyone was setting up. You can hear that the crackle is at a reasonable volume. 20-30 minutes go by and the crackle is non existent.
Brought the head home again and it's not making any funny sounds. I sprayed the socket with some zero-residue contact cleaner and will just have to try again at our practice next Saturday.
To my mind, a crackle isn't going to be any form of interference. Have you tried taking the head off the speaker cabinet? Could be you have a loose something that is being rattled around by your cab and only at a certain minimum volume.
No because we recorded the bass through the balanced out on the back of the head and it was present when we jammed and I didn't have the cab mic'd at all. If it was in the cabinet it would likely be very faint only because it might have bled through another microphone.
Also that wouldn't really explain why the sound goes away from 20minutes? I think it has to be something with the tubes since it goes away after they warm up.
You're misunderstanding me. I'm not saying the crackle is coming from your cabinet. I'm saying the vibration from your cabinet may be contributing to the crackle coming from your amp. If so, it just points even more to a mechanical/physical loose something-or-other.
If you're getting the noise on the DI out that limits your noise sources. The SVT-CL DI is fixed post-master right? I think the VR and IIP had a pre/post switch but the CL doesn't? If that is in fact the case your issue would have to be with the first two preamp tubes in the upper/front chassis if it was tube related, the DI is being tapped before the PI/driver tubes so the presence of the noise in the balanced out precludes the PI, drivers, and power tubes.
Could also be an issue of input signal problems. I think you went over the chain further up, but what is different between your rehearsal space and home?
Yes the CL is fixed post master.
The only difference is my cabinet. I usually leave my SVT at the rehearsal space but I took it home to test on my GK210. I tried the same speakon cable, different speakon cable, same patch chords, different patch chords nothing really did it. The rooms are very different. At home it's a tiny little apartment room and our rehearsal space is a very large basement in one of the guys houses.
I had the same symptoms years ago and brought it to a tech and all it was on mine was that the bias was not set right. I knew nothing about them back then and never checked it and it must have drifted way off. Aren't CL's self biasing or very easy to do though?
Very easy, not self. Indicator lights on back to calibrate bias with a little adjustment set-screw dial thingy. User do-able.
I was an apprentice for a few years when I was a kid, I knew a guy who used to just touch a wire to see if the circuit was hot, a lot of them lose their fear, I never did. Most of the ones I knew had had at least one very serious accident and were lucky to be alive.
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Yeah don't think it's tube bias. I checked that. This would be a lot easier if this issue was easy to reproduce. Sadly it's not. I just have to be prepared to test things when it does. I'm going to bring my other bass head on saturday and try bypassing preamp if it happens again.
Happened again, this time I was able to put in my other amp head and it looks like it's in the power amp section.
Another thing I noticed because I was playing at low volume is one red bias light would come on and the other was much more faint. I never noticed this at louder volumes in practice. I did tap on all the tubes back there and didn't hear anything microphonic. Any suggestions ... ? Is a simple tube replacement needed?
Another thing I noticed because I was playing at low volume is one red bias light would come on and the other was much more faint. I never noticed this at louder volumes in practice. I did tap on all the tubes back there and didn't hear anything microphonic. Any suggestions ... ? Is a simple tube replacement needed?
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