#1
so when the time comes I want to be familiar with how my amp works. unlike the 5150's of old this amp is not plug and play....or is it? from most of the research ive been able to find it seems like its older brothers the 5150iii is biased cold as hell from the factory.

The Gear Page had a few threads on biasing a 100w but not much on a 50w and Rig Talk had a thread on both. someone on there stated that the 50w is biased at 30mA. so whats the deal? why cant I find much on this?

all I seem to gather is people arguing over plate voltage. I understand that to properly bias you need to know the plate voltage that the amp runs at but if its biased so cold what does it matter? an overall bias of 30mA with 6l6 tubes is pretty cold to me. but if my memory serves me right its still below 70% dissipation and still warm enough to be out of crossover distortion.

seems like the plan is to grab a matched pair and throw em in, check and adjust to 30mA?

Thoughts?
Live Rig
Michael Kelly Custom Shop Plum Telecaster
Michael Kelly Custom Shop Plum Patriot


EVH 5153 50w
Jet City 2x12
Custom Board

It is NOT trash metal it is tHrash metal...get it right
#2
Quote by iheartgun


seems like the plan is to grab a matched pair and throw em in, check and adjust to 30mA?


Yeah. Pretty much. Tell them what amp you have and that you are looking for around 30mA. You'll probably be good go. I have a biasing 'blog' FYI if you are interested. Good luck mang!
#3
sorry for the late reply....ive been quite sick lately.
I don't know what the big fuss is then....if its biased so cold then why not have it be cathode biasing? then there is no room for error. idk it seems silly for some reason that everyone is arguing over what to do with this amp.

I learned to bias off of your tutorial good sir! and I thank you a plenty. I used it for my carvin legacy and a few other amps.
Live Rig
Michael Kelly Custom Shop Plum Telecaster
Michael Kelly Custom Shop Plum Patriot


EVH 5153 50w
Jet City 2x12
Custom Board

It is NOT trash metal it is tHrash metal...get it right
#4
Ha. That's right. I remember now. Glad you found it useful.

Here is my meager opinion. I'm not familiar with the squabbles about what to do with the 5153 bias wise. If you don't mind providing a few links I'll look them over.

Now the original Peavey 5150 amp circuit was cathode biased and yes often biased cold out of the factory. If I had to guess - I'd say it was to save on tubes and keep it simple for the customer. People complained and then the bias mod came out for that amp to increase the range of the variable resistor so people could make it 'hotter'.

I honestly do not know how the EVH 5153 is set up. Is it cathode too? Keep in mind, the EVH circuit is completely different. There is more that goes into the design or the decisions on a circuit than just whether or not they want to make it easy or not. Fixed bias to me is better because I like the ability to adjust the bias but just because an amp builder has a fixed bias amp doesn't mean they want to make it difficult for people.

Not sure if any of that even made sense

If you ask for matched tubes and maybe verify yourself with a probe that they are all pretty close and it sounds good to your ears then that's it. You're done.

If they don't come in very well matched and you don't think it sounds that great then bias the amp.

What is the issue exactly with 5153 owners?