Scott 130 power transformer fix revised.

[Destructor]

Somewhat off topic, I have a 130 in generally good condition. I’ve replaced nearly every Pyramid cap with OD’s. Unfortunately it’s never quite worked correctly, mostly a volume imbalance and intermittent hum in the phono section. I did have a tech go through it years ago and get it working relatively well but the imbalance remained. It certainly worked well enough to realize that the 130 is a great sounding preamp. Maybe I should just bite the bullet and bring it to someone who will thoroughly go through it and do what is necessary to bring it up to par.

 

[s-petersen]

As far as the imbalance,most likely a nonlinear volume pot,it's pretty common.Better to start a new thread

 

[NOSValves]

Somewhat off topic, I have a 130 in generally good condition. I’ve replaced nearly every Pyramid cap with OD’s. Unfortunately it’s never quite worked correctly, mostly a volume imbalance and intermittent hum in the phono section. I did have a tech go through it years ago and get it working relatively well but the imbalance remained. It certainly worked well enough to realize that the 130 is a great sounding preamp. Maybe I should just bite the bullet and bring it to someone who will thoroughly go through it and do what is necessary to bring it up to par.

Its pretty easy to determine if the imbalance is in the volume control. It would take a bunch of typing to lay out the procedure here which I do not have time for now and it would not do this thread justice to sidetrack the OP's great work. Feel free to give me a call and I can walk you through it on the phone. My number is on my website.

 

[Destructor]

Thankyou NOS

 

[NOSValves]

Hey no problem. Gove me a call anytime between 9am and 9pm EST 7 days a week.

 

[stanko]

Bump for the guy with transformer issues.

 

[stanko]

Again.

 

[pjrengineer]

Thanks so much for sharing this. Great read. It will surely help others. And lead to lots of questions .

 

[Selmerdave]

Sometimes seeing old threads is funny, in this case this is amazing!

 

[Sam Cogley]

Well, somehow I missed this thread ages ago. I guess now I know how to replace the really odd power transformer that's missing from the more dilapidated of my Fisher 400C / 400CA preamp pair...

Even worse...now I'm thinking about experimenting to see if I can cook up a reasonable approximation of the wild double-C core Fairchild OPTs. I think I need to wander off somewhere and smack myself with a 2x4.