Ampeg SVT410HLF - Treble and A#

[Tim_the_Stoner]

Hello y'all and Happy Christmas!


I bought a 2006 Ampeg SVT410HLF a year ago and I've used it with a V4BH from 2003 since then, with a BATW Revelation SuperBass Preamp/OD/Dist pedal infront.

In the last few months I've been driving myself insane trying to figure out why when the treble is turned up or when I turn up the tweeter there's a certain note (A#) that hizzes, buzzes and crackles. The amp does not stop working, it just adds that disgusting sound that become louder and louder as I turn up Treble freq. and when I roll up the tweeter on the cabinet.

I've learned now that distortion can harm the tweeter, but if I turn the tweeter completely off I can still hear (although much, much less) that disgusting sound.

What more is, when I put the head on another cabinet while still plugging into the 410 (physically separating the two) the disgusting sound dissapears almost 99%.

It leads me to think that either:

1) There's a loose component somewhere that rattles and causes the sound, but that doesn't explain why the treble makes it louder when the more obvious would have been the bass freq and it wouldn't be just the one note, A#.

2) The tweeter is broken! But wouldn't it be completely out of the circuit if the tweeter control is turned off? The one on the back of the cabinet.

3) There most be something else wrong or a combination of the two.


The two techs I've sent it two couldn't figure out the problem.

I've tried all sort of cables and combinations, and I tried another head on the cabinet that didn't cause it to rattle althought that head blew after 30 minutes because it was old and very sh*tty... So I couldn't compare more after that. I've connected guitar heads to the cab without problems and I've played the guitar through it with no problems.

Please, somebody here who's an experienced Ampeg gear user (and abuser) please help me out! I'm a guitar player, so it's really just my gear but my bass players borrows it and it's driving me nuts that I can't figure it out and I hate spending cash on something that I can't fix.

 

[JimmyM]

I had this happen once with my SVT. Turned out to be a bad power tube. Tap them all lightly with a wooden stick while it's turned on (for obvious reasons, use only wood) and see if you have a bad one. If not, could be some padding inside the cab that's loose, or a loose screw somewhere in the cab, or it could be vibrations from elsewhere making you think it's coming from the cab. Happens.

 

[RickenBoogie]

yeah, I was thinking sympathetic vibration. Could be anywhere. Does it do this in different rooms as well? And, +1, check the tubes too.

 

[Tim_the_Stoner]

I forgot to mention I had all tubes, both power and preamp, changed about a month and half ago. The sound was there before and after.

I'll try tapping them again, just in case.

How can I see if any component is loose and caused to rattle by vibrations? What are some methods to evaluate it?

 

[Tim_the_Stoner]

PS: I also know it's not rattling from any other piece of equipment, furniture or anything loose in the room or outside. I've doublechecked everything and I can clearly hear it comes from the speaker and not from places like the snare drum or the window.

 

[Right_Butterscotch64]

See if its the side handles rattling

 

[thedudebrah]

My 410HLF did (does) this, but only in my house. Gigged it a few times without issue. I chalked it up to an old house with dirty power or interference.

 

[Tim_the_Stoner]

Side handles... I'll check that out, but it wouldn't explain why when the head is on the cabinet it rattles waaaaay more than when I put it on the floor or on another cabinet. Physically speaking (I think) the rattling on a certain note means it rattles on a certain frequency that somehow moves something just enough to cause the disturbance, but I still am very curious how when a bass amp such as this and with as much use as I give it wouldn't be rattling the same on all notes.

 

[Tim_the_Stoner]

My 410HLF did (does) this, but only in my house. Gigged it a few times without issue. I chalked it up to an old house with dirty power or interference.

Then I suppose I'd have the same problem with other amps, and I don't. Wouldn't that be the "logic"?

 

[Passinwind]

Side handles... I'll check that out, but it wouldn't explain why when the head is on the cabinet it rattles waaaaay more than when I put it on the floor or on another cabinet. Physically speaking (I think) the rattling on a certain note means it rattles on a certain frequency that somehow moves something just enough to cause the disturbance, but I still am very curious how when a bass amp such as this and with as much use as I give it wouldn't be rattling the same on all notes.

A#-1 is really close to AC line frequency, so harmonics thereof could be "lighting up" if your power supply filtering is mechanically or electrically compromised. I've definitely observed this on occasion, but it could be a complete red herring as well.

 

[Tim_the_Stoner]

I'll try another socket in another room, another building even, and see if anything changes. But I can't do that until tomorrow, so please keep on coming with suggestions and I'll make a list to try them all!

All this exploring also thought me why I need a Speakon speaker cable insted of a 1/4" speaker cable...

 

[Tim_the_Stoner]

Could anyone please tell me what a broken tweeter sounds like and if the treble and tweeter work together on some level.

 

[JimmyM]

They do work together, as the treble knob will increase the amount of high end content that goes to the tweeter. Doubt it's broken, though, because it would make that sound on every note if it was.

 

[Tim_the_Stoner]

Thanks,

Any chance we could make a list of all possible broken things caused by a certain frequency?

- Physical response to frequency causes rattle.
- Possible AC line level at A#, although I don't know if this is true for Europe.

 

[AntiTreble]

I am hearing the same thing out of my 410HLF Classic. I run an SVT3PRO + RBI (bypassing the Ampeg pre-amp). The "fuzzy" tones are most apparent on the second string on/around the fourteenth fret (E/F/F#). I turned the tweeter knob all the way down/off, and it diminished a bit, but it's still there. Until your thread I was willing to assume it's something in the 3PRO power tube; I really need to take the head offline get it bench-checked. Rack is pretty well isolated (rubber grommets on all screws; Ebtech hum suppressor; Furman power conditioner; good cables; and it stays put on the church riser; etc.).

 

[Tim_the_Stoner]

Thanks AntiTreble, it comforts me that I'm not the only one experiencing certain frequency alterations.

If and when you get it solved, please, please, please get in contact with me about it and I'll do the same if I get it fixed first before hearing anything from you.

Does your sound like a statis response, too? Crackles and hizz, like if you take an old televisions and dial the radio signal back and forth, only continuously?

 

[nysbob]

The 3Pro doesn't have a power tube. It's a preamp tube.

 

[Tim_the_Stoner]

I changed my preamp tubes and I still experienced the same troubles... But maybe I should look into that. Anyway to check it? Two of the tubes are inside the head where I can't see them...

 

[Tim_the_Stoner]

Bump.

Tomorrow I'll give it to the tech (hopefully I won't have to haul the head AND cab to the store for him to listen to the problem) and hopefully he can tell me what's wrong. Hopefully.

 

[Doll]

Did you figure out the cause of the problem?