Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: tubenit on August 14, 2020, 09:13:29 am

Title: Trem-o-nator schematic & layout question?
Post by: tubenit on August 14, 2020, 09:13:29 am

I am often wrong and could be on this also?

It appears there is a discrepancy in some of the schematics and layouts showing the vactrol wiring for the trem-o-nator?

Can someone help me get this straightened out in my thinking, please? 

My trem-o-nator works fine in my amp, I am just trying to get my documentation to be consistent.

Thanks, Tubenit

Title: Re: Trem-o-nator schematic & layout question?
Post by: sluckey on August 14, 2020, 09:48:47 am

That part of the Vactrol is just a resistor. And like a resistor, it makes no difference which way it it connected. I'm guessing this is related to the thread on TAG?

Title: Re: Trem-o-nator schematic & layout question?
Post by: tubenit on August 14, 2020, 10:42:44 am

I wondered if that was the case.  Yes, the TAG thread prompted my reviewing of what I had in documentation.

THANKS!  Tubenit

Title: Re: Trem-o-nator schematic & layout question?
Post by: yorgle on August 14, 2020, 02:22:10 pm

Somewhat related to this- even though it's just grounding the signal, should wires in that path be shielded?  I ask because in my latest build, I'm getting a slight buzz that varies with the trem speed and disappears altogether when the resistor side of the vactrol is disconnected from the volume pot.

Title: Re: Trem-o-nator schematic & layout question?
Post by: PRR on August 14, 2020, 09:34:01 pm

> should wires in that path be shielded?

Or minimized.

It's gotta be a high-impedance point. So the more wire you hang off it, the more crap it will pick up. The LDR can perhaps be right AT the audio path; the LED wires can be long.