Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: JCSIFU on December 17, 2010, 02:41:14 pm

Title: Filter choke to replace a power resistor?
Post by: JCSIFU on December 17, 2010, 02:41:14 pm
Hello,
Can anyone help me?
I have a Yamaha T100 head from the late 80's (Soldano designed) and I am looking to do a mod to the amp where a Filter choke is used to replace the power resistor. The guys at Soldano were nice enough to email back to me that the mod was to replace a 500 ohm power resistor with the choke. How does one go about finding the right replacement choke for the job? I believe it is on the top right corner of the schematic I am tagging on to this post.

thanks,
jc
Title: Re: Filter choke to replace a power resistor?
Post by: FYL on December 17, 2010, 03:40:53 pm
A > 4 H / > 80 mA choke such as the 125C1A sold by Doug
should be fine. Soldano used a 10 H / 80 mA choke.


Title: Re: Filter choke to replace a power resistor?
Post by: JCSIFU on December 17, 2010, 05:42:24 pm
A > 4 H / > 80 mA choke such as the 125C1A sold by Doug
should be fine. Soldano used a 10 H / 80 mA choke.




Awesome, thanks.  I'll order it now,

jc
Title: Re: Filter choke to replace a power resistor?
Post by: Dave on December 17, 2010, 07:41:20 pm
How does that Yamaha sound? I've always been curious about those things.

Dave
Title: Re: Filter choke to replace a power resistor?
Post by: plexi50 on December 17, 2010, 10:01:42 pm
The amp will loose some of the Sparkle (Chime) it now has using a choke in place of the resistor

If you use a choke it will sound smoother but you will definatley notice the difference

I like the resistor and the tone it gives in some amps. You just have to try it and see if you like it
Title: Re: Filter choke to replace a power resistor?
Post by: FYL on December 18, 2010, 04:34:03 am
Quote
How does that Yamaha sound?

The Yamaha sounds quite like an SLO with a crappy reverb section. Adding the choke brings it closer to the 50/100 sound.