Flabby Bass

[straycat]

What would cause a trainwreck to have flabby sounding bass? I have Tung Sol preamp tubes and Winged =c= el34 power tubes biased at 33mv. I have tried biasing as high as 43mv with the same results. Using a new avatar 2x12 openback with vintage 30 and G12H30 speakers. Sprague atom and mallory 150 caps. I did order some JJ tubes to try to see if they would make a difference. Any ideas on what would cause this amp to have a flabby bass?

[lastwinj]

are any of the pots scratchy?


germ

[paulruby]

Reduce the coupling cap value from the third stage to the PI.

[straycat]

I have clarostat pots and they are not scratchy. This is my first amp build so I have 2 newbe questions

1. Which cap(s) is that in this layout ? I know it is the part of the circuit feeding V3. 47pf mica to a .002uf?

2. What value would you use?

[paulruby]

Actually, I lied anyway.. Reduce this one... Try 10nf and see if you like it... Then tweak up or down by 5nf and listen again...

[paulruby]

Jeese... I'm still a liar... try 1nf and the tweak up and down around that...

Are you sure you used the value stated? The layout shows 2.2nf. Did you use a 22nf bay mistake?

Anyway... make it smaller.

[straycat]

Yes I used a .0022 cap in that postion. Smallest in physical size. Thanks for all your help Paul I appreciate it!!