Amp Hiss

[surl3y]

Can someone please explain what might be causing my amp to Hiss so loud when its not being played. Les Paul in a Orange tiny terror. I need to quiet this thing down and I don't know exactly where to start. I also have a similar issue with a Peavey 5150 head.

[defaced]

I have zero experience with the Tiny Terror, but the 5150 is notorious for hiss. In that amp, it's excessive gain and going through a boat load of preamp stages. There's a true technical reason why cascaded tube circuits hiss, but I don't know what it is.

[Jazz P Bass]

Amp Hiss

Are you using humbucker pickups?
Does the amp hiss with no input?
Does the amp hiss with guitar input & guitar volume down?
In other words, when does it hiss.

[Prairie Dawg]

I have zero experience with the Tiny Terror, but the 5150 is notorious for hiss. In that amp, it's excessive gain and going through a boat load of preamp stages. There's a true technical reason why cascaded tube circuits hiss, but I don't know what it is.

Simple, really. Everything gets amplified, not just the parts you like.

[Chuck H]

IIRC a discussion here revealed that most hiss is thermal noise from series resistance. So any multi stage high gainer, especially with all the little stability enhancing bleeders and filters like the 5150, is bound to hiss. Carbon comp resistors exhibit more thermal noise than other resistors in high voltage applications and, again IIRC, metal film are the least prone. So if you want to avoid hiss...

1) Keep circuits simple. Carefully design fewer gain stages to the work.

2) Try to keep series resistance to a minimum.

3) Don't use carbon comp resistors in high voltage or high resistance applications like plate loads, cathode follower cathode resistors, slope resistors and high signal path series resistances (like that 3.3M series resistor in BF reverb amps).

All amps hiss. High gain and top end excacerbate the problem. IMHE most people complain about hiss when they notice it for the first time even though it's always been there. Either they start playing at higher volume or using more gain and all of a sudden they notice whenever they stop playing... SSSSSSSSSSSSSSSSSSSSS!!!!!!!!!! And they think "Wow, that's really annoying ain't it." And they start to wonder if it's always been there or if it's a fixable problem. Most of the time it's not a fixable problem. Though circuit or gear modifications can reduce hiss you end up with a different tone than you had. Hiss is really an unfortunate reality of high gain guitar amps.

JM2C

Chuck

[axpro]

Hiss is annoying.

I agree , the 5150 has too much gain, and tends to amplify the noise quite nicely. I switched the first stage to a at7 or au7 to reduce the gain. still had LOTS of buzz saw gain, but cleaned up a little nicer.

The tiny terror has cascading stages, and also suffers from the builder trying to hit a price point. well designed circuits, extra filtering and things like DC filaments (and CHOKES!) can help a lot with quieting down a circuit... but when you are trying to hit a "Street price" number... things get filtered out to hit the mark. cheaper components, less QC,

For high build quality you gotta pay. either in cash, or in research and practice so you can "roll your own" so to speak.