Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: fiftynine on February 12, 2017, 05:20:40 am

Title: Extracting a Single Channel - Mixers, Gain and Blocking
Post by: fiftynine on February 12, 2017, 05:20:40 am

What's everyones opinions on leaving the mixing resistors and grounded resistor (in say the AB763) when extracting the normal channel? If you went straight into the 0.001, would you get more power-amp clipping (the reverse effect of a master volume) which always sounds good to my ears? Will removing those components lead to instability and/or blocking distortion or will it open up the amp? Or, is this point in the circuit the perfect place to tame gain? Is there anywhere else better suited to reduce gain if needed?


Thanks.

Title: Re: Extracting a Single Channel - Mixers, Gain and Blocking
Post by: sluckey on February 17, 2017, 06:18:25 am

If you go straight into the LTPPI input cap you will have more signal available to drive the power amp. Could be up to twice the signal level, depending on the particular circuit. You'll be able to hear a little more grind on an AB763 Deluxe Reverb if you turn the volume up. But you'll lose that grind if you turn the volume down. I've never experienced any instability or blocking distortion.

Title: Re: Extracting a Single Channel - Mixers, Gain and Blocking
Post by: fiftynine on February 20, 2017, 06:39:40 am

Oh the stress of retaining redundant parts vs loosing vintage mojo.


Thanks as always, Sluckey.