Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: chuggy on February 19, 2011, 12:12:26 pm

Title: need input jack circuit help
Post by: chuggy on February 19, 2011, 12:12:26 pm

I seek help with an input jack circuit with two inputs to a single grid to accomplish the following-
Channel 1-  33K to grid, 1 meg to ground
Channel 2-  33K to grid, 5 meg to ground

Thanks-
Jim R

Title: Re: need input jack circuit help
Post by: Geezer on February 19, 2011, 01:25:23 pm

Curious.....Why? What are you trying to accomplish?

G

Title: Re: need input jack circuit help
Post by: chuggy on February 19, 2011, 05:08:29 pm

Hi impedance crystal mics used for harmonica are thought to sound best with a high (5 meg) load.  I wonder if the large load is detrimental to other mics, so would like to be able to compare different loads with different mics in one amp.

Jim R

Title: Re: need input jack circuit help
Post by: RicharD on February 19, 2011, 05:49:04 pm

.

Title: Re: need input jack circuit help
Post by: PRR on February 20, 2011, 01:27:57 am

> I wonder if the large load is detrimental to other mics,

No.

Title: Re: need input jack circuit help
Post by: LooseChange on February 20, 2011, 05:34:28 am

I've read that a higher impedance input (ie: 5meg) works very well for acoustic guitar pickups too.