Clip: 6505/5150 Bias Mod Tests (and Diezel VH4)

[saxxamafone]

Did some testing on my 5150 with testing the bias at various levels.

All tracks are re-amped for consistency.

5150 21ma (lowest mine can go)
https://soundcloud.com/user-634306108/21ma-5150/s-NxaXw

5150 30ma
https://soundcloud.com/user-634306108/30ma-5150/s-PdPQf

5150 35ma
https://soundcloud.com/user-634306108/35ma-5150/s-KM4nd


and for the heck of it, I've included the same track through my VH4.
Having a hard time deciding between the drier tone of the VH4 or the more saturated tone of the 5150. I keep flipping between the 2

Diezel VH4
https://soundcloud.com/user-634306108/vh4-10nov19/s-EFudC

Thoughts?

 

[fek]

This is relevant to my interests. Picked up a 6505+ and am reading about the bias mods. Still need to rotate the bias knob fully counterclockwise so that the bias is as hot as it will go to see if I notice a difference. Non modded of course.

I liked the 35ma on the 5150 tone the best. Just think it would suit me better. The Diezel does sound really good also though.

 

[Qweklain]

The 5150 seems to get a more aggressive upper-mid/top-end snarl to it as you go hotter. The consequence though seems to be it also amplifies the fuzz/buzz and slightly amplify the muddiness of the low-end. Personally I liked the 30ma the best of the three 5150 clips.

With that said though, I also hear the same bleh low-end on your VH4 clip and mine is definitely not that, so maybe it is what you are recording with or something that makes me find that aspect to stand out.

 

[saxxamafone]

This is relevant to my interests. Picked up a 6505+ and am reading about the bias mods. Still need to rotate the bias knob fully counterclockwise so that the bias is as hot as it will go to see if I notice a difference. Non modded of course.

I liked the 35ma on the 5150 tone the best. Just think it would suit me better. The Diezel does sound really good also though.

Hope this helped mate - I've heard the 6505+ bias is a little limited and a mod can allow it to run a little hotter if needed

The 5150 seems to get a more aggressive upper-mid/top-end snarl to it as you go hotter. The consequence though seems to be it also amplifies the fuzz/buzz and slightly amplify the muddiness of the low-end. Personally I liked the 30ma the best of the three 5150 clips.

With that said though, I also hear the same bleh low-end on your VH4 clip and mine is definitely not that, so maybe it is what you are recording with or something that makes me find that aspect to stand out.

Thanks for checking it out. Agree that the muddiness starts to come through stronger.
I think i've preferred the more balanced tone i get at 30ma also. Retains some of that signature fizz the 5150 is known for.

I hear what you mean about the low end, i did have both amps with resonance and bass at 12oclock which is pretty high when playing in drop B. Especially since the hotter bias seems to muddy the low end a little also.
If i ran another pass, i'd lower the bass on both amps after hearing how it's come out.



Can definitely hear the difference in 'saturated' vs 'dry' when hearing the palm mutes between the 2 amps

 

[MetalHeadMike]

I honestly have never noticed a significant difference in tone/feel between different bias levels. I've tried hotter vs. colder on numerous amps with numerous tubes and to my ears its a VERY subtle difference. Same goes for different power tubes & preamp tubes.

I've read so many threads where guys claim that a bias adjustment completely changed the tone or response of an amp or that a tube swap from type x to type y or brand x to brand y was a night and day difference; like two completely different amps. I never got anywhere near that level of night/day difference from a tube swap or bias adjustment...not even close. Like I said...VERY subtle difference for me.

Not implying that's what this post is saying, just made me think of the countless threads I've seen on the subject.

Sorry...rant over

 

[saxxamafone]

^ you're not wrong at all there.
Think people can over exaggerate online about these differences.

The difference is subtly there... but it's not huge, especially when you put it into a mix also.

I would like to hear a 5150/6505 at 12-15ma (as some say theirs is at stock) to see if that's any difference

I no longer experiment with tubes.. i found brand and types i like so i just stick with it.

Enjoyed the rant

 

[MetalHeadMike]

^ you're not wrong at all there.
Think people can over exaggerate online about these differences.

The difference is subtly there... but it's not huge, especially when you put it into a mix also.

I would like to hear a 5150/6505 at 12-15ma (as some say theirs is at stock) to see if that's any difference

I no longer experiment with tubes.. i found brand and types i like so i just stick with it.

Enjoyed the rant

I recently acquired what should be a stock 6505. I'll throw a meter/bias probe on it tonight and see where it's at. Sounds great to me but I have been curious if it's that's low like you stated.

 

[saxxamafone]

^ thanks mate that would be awesome to know where yours comes in at!

From what I've read; stock 6505's can come in anywhere from 10ma to about 20(ish)ma.

 

[MetalHeadMike]

^^^
So this one is sitting at 21 mA. Don't know that I have any desire to even consider modding it honestly as I feel it sounds phenomenal as is. Ruby 6L6GLCMSTRs & no idea what preamp tubes as I'm guessing they're on a board underside of the chassis...WTF???

 

[GregM]

^^^
no idea what preamp tubes as I'm guessing they're on a board underside of the chassis...WTF???

They're behind the cover on the right side of the back of the amp.

 

[saxxamafone]

^^^
So this one is sitting at 21 mA. Don't know that I have any desire to even consider modding it honestly as I feel it sounds phenomenal as is. Ruby 6L6GLCMSTRs & no idea what preamp tubes as I'm guessing they're on a board underside of the chassis...WTF???

21ma seems on the higher end from what I've read.
Main thing is it sounds good to you

I've read some reading as low as 7ma.
Cheers for checking!