Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: sdp1234 on October 05, 2014, 07:41:27 pm

Title: Circuit Question
Post by: sdp1234 on October 05, 2014, 07:41:27 pm

I'm not sure if I can post complete schematics but I've attached a couple snapshots from the schematic.  It is from a Spectra 212-T.  I don't understand the schematic.  Typically the output is coming off of pin 6, 1, 3 or 8.  Can someone explain what I'm looking at here.  Looks like the input and output to the stage is in the grid

Title: Re: Circuit Question
Post by: John on October 05, 2014, 08:44:09 pm

Mis-drawn schematic?

Title: Re: Circuit Question
Post by: HotBluePlates on October 05, 2014, 09:48:46 pm

Post the whole schematic (or a link to the full schematic).

I'd assume that each case shows 2 circuits each feeding a single triode grid. I would not interpret that as a grid is being used as both an input and an output.

If it is a drafting error (no plate output drawn, but the intended plate output is drawn at the grid), it might be telling that both files appear to come from the same site ("Musicparts"?). Maybe just don't waste time looking at their schematics...

Title: Re: Circuit Question
Post by: sdp1234 on October 05, 2014, 10:14:20 pm

Here is a more complete set of schematics.  I didn't attached the powersupply section.

Title: Re: Circuit Question
Post by: HotBluePlates on October 05, 2014, 10:43:34 pm

Yep, mis-drawn schematics with the plate output drawn at the grid.

Title: Re: Circuit Question
Post by: sdp1234 on October 07, 2014, 03:35:14 pm

Thanks for the help.