5150 phase inverter tube.

[guitarguru1969]

I tried out two recommended tubes for the 5150's P.I. tube slot and wow, what a difference it's made. Do yourself a favor and try a nice one in that place. I tried the Electro Harmonics 12AX7 and the Sovtek 12AX7 LPS, both balanced triodes, and I chose the Sovtek. I had a JJ in that slot and after trying both new ones out I put the JJ back in and couldn't believe how much better both of the other tubes sounded. More even harmonics and overtones, not to mention greater dynamics overall. it's like the amp has a new life. I'd say it's the greatest improvement to my tone in a lonnnnnnnnnng time. Try it, ........ you'll like it!

 

[GuitarHack]

Are you able to make comparison clips to demonstrate this big difference? I have tried different PI tubes in my 6505, including the Sovtek and noticed bugger all of a difference.

 

[Tachy]

How is placed the phase inverter tube? is the last from the preamps tube?

 

[Sickan]

Tachy, it is!

5150/6505

Tube order Right to Left looking from the back is:
(RIGHT)V1 V2 V5 V3 V4(LEFT)

V1 First Gain Stage
V2 Second Gain Stage
V5 Third Gain Stage???
V3 is for the Loop
V4 is Phase Inverter

 

[Tachy]

ooooook, in the case of the 5150II the phase inverter will be the v6.......thanks, i'll try to change it

 

[guitarguru1969]

I will post clips this weekend of the difference. I either had a real bad JJ in the first place or the other two were just that much better. I am leaning towards a bad JJ, and yes, the P.I. is closest to the power tubes furthest left as you face the amp from the back side.

 

[TheWinterSnow]

Tachy, it is!

I have to correct your quote

V1: 1st gain stage
V2: 2nd gain stage
V5: Tone Stack
V3: FX loop
V4: Phase Inverter

I have a balanced JJ for my P.I. and I love it. Something about JJ's that are really warm.

 

[Tachy]

I have jj also in my 5150II, I ordered the hi gain kit from eurotubes some times ago, I love it! but now I have in my hand some sovtek lps.....I must try......