Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: jaydeshan on April 11, 2022, 02:37:53 pm

Title: First Build report - Schedule 40 GA-5
Post by: jaydeshan on April 11, 2022, 02:37:53 pm

I just finished my first amp. The schedule 40 GA-5, and I love it. I added a multi-tap impedance switch and a RFB loop pot. Attaching some pics and the final schematic. I'm sure there will be errors in the schematic as this is new to me.

I want to thank this forum, Hoffman in general, hours of Uncle Doug videos, and especially Jim Nickelson of Lil'Dawg amps. Jim is as good of a dude as I have ever met.

I'm extremely pleased with the circuit.

Jay

Title: Re: First Build report - Schedule 40 GA-5
Post by: jaydeshan on April 11, 2022, 02:43:11 pm

another view

Title: Re: First Build report - Schedule 40 GA-5
Post by: tubeswell on April 11, 2022, 06:01:22 pm

FWIW, Seeing as how its a single-ended amp, your 50mA choke (that you spent money on) would be more effective at cancelling ripple hum if it is utilised in a CLC filter in the power supply rail between the rectifier and the OT primary winding node (which means adding another 20uF-50uF cap). You'd also put a 1k-5k resistor in place of where you have the choke shown presently on your schematic.

Title: Re: First Build report - Schedule 40 GA-5
Post by: jaydeshan on April 11, 2022, 09:07:21 pm

Quote from: tubeswell on April 11, 2022, 06:01:22 pm

FWIW, Seeing as how its a single-ended amp, your 50mA choke (that you spent money on) would be more effective at cancelling ripple hum if it is utilised in a CLC filter in the power supply rail between the rectifier and the OT primary winding node (which means adding another 20uF-50uF cap). You'd also put a 1k-5k resistor in place of where you have the choke shown presently on your schematic.

Thanks, tubeswell, for your advice!