Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => PC Express and JSchem - Schematics and Layout diagrams => Topic started by: munkeyboy on January 01, 2021, 06:36:45 pm

Title: Bell and Howell Model 621
Post by: munkeyboy on January 01, 2021, 06:36:45 pm

This is work in progress.  Thought I post here in case others are interested or want to improve it.  The original schematic is unreadable in most places, so I've try to transpose what I could to a new schematic.  I used the original model 621 schematic, the model 179 schematic (which should be close) and my physical amp.

Still tracing down components, so this is probably wrong, especially around the tone circuit.

Also included an altered version, that matches what I've done so far in removed unneeded components. (plus mod to the input that I'm still testing).

Updated: new schematics below

Title: Re: Bell and Howell Model 621
Post by: munkeyboy on January 02, 2021, 11:02:58 am

updated files

Title: Re: Bell and Howell Model 621
Post by: Nukemdave on May 24, 2021, 03:37:46 pm

Hi Munkeyboy, Any chance that you could Jpeg the modified wiring diagram as I have a 621 amp that isn't responding that well.

Title: Re: Bell and Howell Model 621
Post by: sluckey on May 24, 2021, 04:12:03 pm

PDF is better. Both files included.