#1
First, I'd just like to list my gear so you guys have an idea of what I'm running
-Fender MIM Jazz Bass
-Ampeg SVT Classic
-Avatar 410 Cab With Eminence Delta Magnet Pro Speakers (1.4k Watts total)
-Big Muff Pi
-ProCo Rat
-Aguilar TLC Compressor

So basically what's been going on with me is that my pedals seem to run the tubes in my SVT too hard, causing the Safety switch to go off. My tech suggested I run everything lower, but the downside is that It'll possibly be harder to get the amp loud enough to hear without tripping the safe-mode when using my distortion pedals.

I was wondering if having higher-output pickups would help ease the burden on the tubes? My logic is that since the pickups will have a higher outut, I will be able to run the Amp at a lower level, and still get the desired volume, compared to what I've been running at now. I was wondering if this would ease the burden on the tubes a bit?

(Also, currently, getting another 410 to daisy chain, or 810 to get the headroom I need is a bit too expensive and unrealistic transportation-wise.)
#3
Quote by Roc8995
What safety switch are you talking about?


When the Amp is run too hard, or if there's a fault in the tubes, or power supply etc. The safety mechanism kicks in and automatically kicks the amp into Standby mode (Red LED) in order to avoid causing major damage. (Older SVT Models did not have this feature, and would often allow the amp to run on with a blown tube)

My tech tested it and ruled out False-Switches/Falty Detectors.
#4
Oh, I'd also like to add, the tubes are brand new, only about a month old.
#5
I don’t see why a passive bass with a distortion pedal would push the amp too hard. Are you sure you aren’t just playing too loud? And have you contacted Ampeg customer service to be sure that you really are running the amp too hard? SVTs are supposed to be played godawful loud with crazy distortion.
#6
It won't help. Whether the power tubes are pushed by a tube in the preamp or by a stronger input, the result is the same as far as the power amp is concerned.
Sounds to me like dodgey tubes. I had a faulty tube out of the box not long ago. Could also be biased too hot. If it was mine, I'd first check the bias - and I'd check every tube to make sure one isn't out of spec with the others, ie. faulty.
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#7
Have you tried another set of tubes? That indicator isn't meant to trip with the amp in normal operation. Are you running this thing on 10 with all the pedals on or something? Even then I'd be concerned if this happened.

Is the LED turning off completely or is the amp just reverting to standby? The manual doesn't seem to corroborate your experience; it indicates two issues, either the light going off completely, or the LED flashing green and red.

Whatever is happening, your pedals are not running the amp too hard. Tubes can take an outrageous amount of input without having issues. A few pedals aren't going to tip that balance, and of course high output pickups would simply do the same thing as turning those pedals up.
#8
What's the impedance on the individual speakers (and on the overall cabinet)?
Do you have the bass boosted?
Do you have an HPF filter?
Are you running both the muff and the Proco at the same time?
How do you have the compressor set?
Is there a chance you're simply underpowered? I'm running a 1500W SS bass amp...
#9
Quote by jpnyc
I don’t see why a passive bass with a distortion pedal would push the amp too hard. Are you sure you aren’t just playing too loud? And have you contacted Ampeg customer service to be sure that you really are running the amp too hard? SVTs are supposed to be played godawful loud with crazy distortion.


It's a strange occurence. The las time I was running it, the settings on the SVT were

Gain- 12 Oclock
Bass-1:30
Parameter-4
Mids-12:00
Highs:3:00

THe fuzz pedal was at 3:00 (Pretty high)
And I accidentally left my Compressor Level at about 3:00 as well.

These arent normally the settings I use, they'd probably be at 12:00 on the pedals. My tech tested it by running the SVT at 9:00 gain and full volume. He said that the amp ran for days without the Pedals, but once he introduced the pedals (at relatively low settings) it caused the amp to trip into safe mode.
#10
Bad preamp tube? Rrunning a couple pedals into this thing should not cause it any issues if it's working properly.
#11
Quote by Roc8995
Have you tried another set of tubes? That indicator isn't meant to trip with the amp in normal operation. Are you running this thing on 10 with all the pedals on or something? Even then I'd be concerned if this happened.

Is the LED turning off completely or is the amp just reverting to standby? The manual doesn't seem to corroborate your experience; it indicates two issues, either the light going off completely, or the LED flashing green and red.

Whatever is happening, your pedals are not running the amp too hard. Tubes can take an outrageous amount of input without having issues. A few pedals aren't going to tip that balance, and of course high output pickups would simply do the same thing as turning those pedals up.


My tech tested each tube before he installed them to insure they weren't faulty out of the box. He then re-tested them during this incident

the LED just went red, no flashes. So, standby.


What's the impedance on the individual speakers (and on the overall cabinet)?
Do you have the bass boosted?
Do you have an HPF filter?
Are you running both the muff and the Proco at the same time?
How do you have the compressor set?
Is there a chance you're simply underpowered? I'm running a 1500W SS bass amp...


4 Ohm total Load (SVT has a 4 Ohm switch)
I hit the High-Boost on the SVT and dry on the Muff
No HPF filter
Just the Muf
At the time, it was set relatively high. About 7/10 the rest all at 12 o clock
And not sure what this question means, sorry :33
#12
Quote by Roc8995
Bad preamp tube? Rrunning a couple pedals into this thing should not cause it any issues if it's working properly.


Pre-amp tubes were also changed and tested before being installed
#13
A tube tester won't tell you if the tube is acting differently with a higher input signal. Most tube testers don't approach the sorts of voltages your amp puts out. At least throw a different preamp tube in there and see what happens.
#14
Quote by Roc8995
A tube tester won't tell you if the tube is acting differently with a higher input signal. Most tube testers don't approach the sorts of voltages your amp puts out. At least throw a different preamp tube in there and see what happens.


I believe he re-tested the tubes with them in the amp when i gave it back to him to check out. I'm not too familiar with the feild, so i could be wrong? The amp works perfectly fine without any pedals running through it, even at full volume.
#15
Ok, so you tested the tubes by using the amp without the pedals, and now you've added the pedals and the amp doesn't work. What I am trying to tell you is that it is very unlikely the pedals are the problem. It seems that your amp, for some reason, cannot handle the pedals; it should be able to handle the pedals, so your amp needs further work.

A properly working amp shouldn't even sneeze at five Muffs running in front of it. You shouldn't be able to overload your amp with one. If your car tires deflated every time you went over a bump, you would want to address your tires before deciding the road was too bumpy. Same principle here. Something is wrong with your amp. The tubes are the place to start diagnosis. If all you've done is used the same tubes and had the same problem, you have not ruled out the tubes at all.
#16
Quote by Roc8995
Ok, so you tested the tubes by using the amp without the pedals, and now you've added the pedals and the amp doesn't work. What I am trying to tell you is that it is very unlikely the pedals are the problem. It seems that your amp, for some reason, cannot handle the pedals; it should be able to handle the pedals.

A properly working amp shouldn't even sneeze at five Muffs running in front of it. You shouldn't be able to overload your amp with one. If your car tires deflated every time you went over a bump, you would want to address your car before deciding the road was too bumpy. Same principle here. Something is wrong with your amp. The tubes are the place to start diagnosis. If all you've done is used the same tubes and had the same problem, you have not ruled out the tubes at all.


Alright, I'll start with the Pre-amp tubes and see if it has any difference. Thanks!
#17
Surprised your tech didn't, honestly. This seems like a very unusual problem, and I would hope he'd want to look into it more than just telling you to turn your pedals down.

Let us know what happens!
#18
Did you try using the -15dB Jack?

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