GlideOn
Member
Have 67 or 68' Yba-1. Love it.
Changed out some things:
1M volume pots.
47uf cathode bypass cap @50v, Xicon brand
.022 tonestack change
.1 to .022 presence control (done by accident but removed lots of fizz and retained some usability)
50k neg feedback loop
22k 2w between screens & PI
22k 2w between PI and preamp filter
The amp sound greats at the moment, but the time has come to change out the caps. I mainly mean the filter caps.
The amps sounds great but is a little dull and amplifies the crap out of the lowend still. I think it still believes it is a bass amp...that will change in due time.
(if any of you guys have a suggestion on how to change the frequency response in the preamp section, lemme know )
I happen to have the model that has the twin Mallory 40uf sitting above the inputs and that is kinda an ugly spot for them. I also have that huge "dynamite stick" brown Mallory cap inside the chassis that takes up a lot of room and ground right next to the power switch. Would like to try to improve a bit on the placement and design of the caps and yes - I will need to remove those twin Mallorys soldered onto the chassis. Ugly, but no way in hell am I gonna leave there for historical value. They're old and farty. They need to go.
Anywho, I wanted to arrange the new filter cap(s) in such a way that would allow me to make use (and room!) of future mods such as Master Volume, better grounding for gain mod, transfidelity mod, 2 channel mod - who knows. I do know that this this is a pandora's box of possibility...
I already have some F&T combo caps cans:
X1 F&T 100/100uf @ 500v
X1 F&T 50/50uf @ 500v
X1 F&T 32/32uf @ 500v
Obviously I'm not going to work with all of them but I got options on which ones to use.
Here's the real estate I'm working with:
Notice the space next to the power tubes. That's a circular cutout for a potential rectifier tube but I also see it as a potential slot for a multi-cap to go in.
I can always use the F&T's for later projects, but if I can get one of these:
http://www.tubedepot.com/cp-ce-80-40-30-20-525v.html
It would fit perfectly and would bring the power filtering into a much better location and have a better chance of altering the gain stages next to an otherwise sensitive location in the amp. In other words I would have less chance of developing and parasitic oscillation problems due to changing the gain.
Opinions?
Changed out some things:
1M volume pots.
47uf cathode bypass cap @50v, Xicon brand
.022 tonestack change
.1 to .022 presence control (done by accident but removed lots of fizz and retained some usability)
50k neg feedback loop
22k 2w between screens & PI
22k 2w between PI and preamp filter
The amp sound greats at the moment, but the time has come to change out the caps. I mainly mean the filter caps.
The amps sounds great but is a little dull and amplifies the crap out of the lowend still. I think it still believes it is a bass amp...that will change in due time.
(if any of you guys have a suggestion on how to change the frequency response in the preamp section, lemme know )
I happen to have the model that has the twin Mallory 40uf sitting above the inputs and that is kinda an ugly spot for them. I also have that huge "dynamite stick" brown Mallory cap inside the chassis that takes up a lot of room and ground right next to the power switch. Would like to try to improve a bit on the placement and design of the caps and yes - I will need to remove those twin Mallorys soldered onto the chassis. Ugly, but no way in hell am I gonna leave there for historical value. They're old and farty. They need to go.
Anywho, I wanted to arrange the new filter cap(s) in such a way that would allow me to make use (and room!) of future mods such as Master Volume, better grounding for gain mod, transfidelity mod, 2 channel mod - who knows. I do know that this this is a pandora's box of possibility...
I already have some F&T combo caps cans:
X1 F&T 100/100uf @ 500v
X1 F&T 50/50uf @ 500v
X1 F&T 32/32uf @ 500v
Obviously I'm not going to work with all of them but I got options on which ones to use.
Here's the real estate I'm working with:
Notice the space next to the power tubes. That's a circular cutout for a potential rectifier tube but I also see it as a potential slot for a multi-cap to go in.
I can always use the F&T's for later projects, but if I can get one of these:
http://www.tubedepot.com/cp-ce-80-40-30-20-525v.html
It would fit perfectly and would bring the power filtering into a much better location and have a better chance of altering the gain stages next to an otherwise sensitive location in the amp. In other words I would have less chance of developing and parasitic oscillation problems due to changing the gain.
Opinions?
