"Get a 5150 they said, it will be fun they said".
- Thread starter JMP/HBE
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Rex_Rocker
Well-known member
Yeah, well... USA-made or not, those were always built to a price point. For the most part, I think most people have had positive experiences with their reliability, tho.
I personally don't like the bias mod. Yeah, it's pretty common knowledge that those come biased super cold, but biasing the tubes hotter kinda takes away from what makes them sit so well in a heavy mix. Those amps don't really strive for volume either.
I personally don't like the bias mod. Yeah, it's pretty common knowledge that those come biased super cold, but biasing the tubes hotter kinda takes away from what makes them sit so well in a heavy mix. Those amps don't really strive for volume either.
People are unfortunately uninformed about bias in general. The problem generally arises from thinking all tubes act the same, and therefore the same bias point for all will result in X outcome. It doesn't work that way. Cold biasing actually increases headroom, and many modern high-gain tube amps do that intentionally for two reasons:
1. To keep the power amp section as clean as possible with good clean headroom and low distortion.
2. To keep the tubes from burning up when the amp is ultimately run at high volume levels.
Metal amps are generally used in metal bands, and metal bands are generally louder than your grandpa's jazz trio. The general rule of thumb for biasing is just that, a general rule. It slips on the line between too much and too little. Tube amp biasing in my opinion is traditionally done as a goal, not a result. Where I feel that it should actually be done as a result and not a goal. Most techs and musicians shoot for a goal of X % of dissipation, as opposed to biasing for the result you want to actually achieve. Biasing hot sounds great on paper, it adds a little warmth, the amp will distort sooner, and it will have a little more oomph. Biasing cold will increase headroom, stay cleaner longer and the tubes will last longer.
99% of fixed bias amps actually increase bias naturally as the volume is increased. It is a result of how the bias circuit functions with the power supply. As you turn up and achieve sag in the power supply, you have to imagine that the ceiling is coming down as the floor also comes up. The bias is created from the same thing that the B+ is created from, just a negative voltage instead. So if the peak voltage goes down ( sag ), the bias voltage then becomes less negative, which means the bias warms up.
So as you may be able to imagine, in amps where you are going to be running at higher volumes and you want to maintain good clean headroom in the power amp, it is better to cool the bias down a little. I believe this is why the 5150 amps are biased so cold.
1. To keep the power amp section as clean as possible with good clean headroom and low distortion.
2. To keep the tubes from burning up when the amp is ultimately run at high volume levels.
Metal amps are generally used in metal bands, and metal bands are generally louder than your grandpa's jazz trio. The general rule of thumb for biasing is just that, a general rule. It slips on the line between too much and too little. Tube amp biasing in my opinion is traditionally done as a goal, not a result. Where I feel that it should actually be done as a result and not a goal. Most techs and musicians shoot for a goal of X % of dissipation, as opposed to biasing for the result you want to actually achieve. Biasing hot sounds great on paper, it adds a little warmth, the amp will distort sooner, and it will have a little more oomph. Biasing cold will increase headroom, stay cleaner longer and the tubes will last longer.
99% of fixed bias amps actually increase bias naturally as the volume is increased. It is a result of how the bias circuit functions with the power supply. As you turn up and achieve sag in the power supply, you have to imagine that the ceiling is coming down as the floor also comes up. The bias is created from the same thing that the B+ is created from, just a negative voltage instead. So if the peak voltage goes down ( sag ), the bias voltage then becomes less negative, which means the bias warms up.
So as you may be able to imagine, in amps where you are going to be running at higher volumes and you want to maintain good clean headroom in the power amp, it is better to cool the bias down a little. I believe this is why the 5150 amps are biased so cold.
80's_Thrash_Metal
Slightly_Glazed_Believer
I've never had any issues with my 6505's at all... Plug em in and rip!
I like keeping a PV in the stable, especially come recording time to give a different flavor.
I've also never modded an amp.
I like keeping a PV in the stable, especially come recording time to give a different flavor.
I've also never modded an amp.
Rex_Rocker
Well-known member
Yeah... I don't think Peavey's are THAT unreliable. They certainly have a better track record than most contemporary Marshalls, LOL.
Rex_Rocker
Well-known member
Oh, I remember the episode of undercover Boss, LOL.
Yeah, not high quality for sure, but they weren't boutique expensive amps either. Comparatively speaking, I mean.
I think EVH's reasoning was he needed something more readily available than his boutique hand-built SLO, so he went with Peavey. I mean, it's obvious there was money involved, but that was his "official" reason, I think.
Yeah, not high quality for sure, but they weren't boutique expensive amps either. Comparatively speaking, I mean.
I think EVH's reasoning was he needed something more readily available than his boutique hand-built SLO, so he went with Peavey. I mean, it's obvious there was money involved, but that was his "official" reason, I think.
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