Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: nash076a on May 13, 2021, 01:37:12 pm

Title: Feedback requested: AC4 schematic converted to layout
Post by: nash076a on May 13, 2021, 01:37:12 pm: I'm trying to convert my old AC4TV to something more like an actual AC4. I found the work done by Doug Circuits (http://www.dougcircuits.com/AC4buildnotes.html) and I decided to try to convert it to a layout. (https://pbs.twimg.com/media/E1SbQU8WYAMyTV9?format=jpg&name=4096x4096)

Some notes:

I'm replacing the attenuator with a simple VVR circuit, and I'm trying to reuse the original power transformer from the AC4TV as the voltages are close to what the original schematic called for (245-0-245 in the schematic vs 250-0-250 in the AC4TV). Hence why there's a couple of 220r resistors in there; I'm trying to keep the power section close to what it was in the AC4TV schematic.

Anyone mind giving it a look, make sure I haven't botched the layout?

Thanks in advance!
Nash
Title: Re: Feedback requested: AC4 schematic converted to layout
Post by: nash076a on May 13, 2021, 01:42:01 pm: Would probably help if I included the schematic, huh?

(http://www.dougcircuits.com/AC4V3S.jpg)
Title: Re: Feedback requested: AC4 schematic converted to layout
Post by: kerrvert on July 21, 2023, 11:13:53 am: I just want to thank you for posting this info! I'm currently working on a p2p version of this design and your post has been very helpful.

I'm surprised there hasn't been more interest in the DC AC4V3s. Seems like a very cool design to me.

Have you built this amp yet? How do you like it?
Title: Re: Feedback requested: AC4 schematic converted to layout
Post by: passaloutre on July 21, 2023, 01:03:08 pm: I love my AC4TV but I’ve often thought about modding it or converting to fully hand wired.

I’m curious how you plan to mount the tube sockets? As you know, the chassis is just an L shaped piece of metal, and the sockets are currently board mounted.
Title: Re: Feedback requested: AC4 schematic converted to layout
Post by: kagliostro on July 21, 2023, 06:38:59 pm: https://el34world.com/Forum/index.php?topic=29359.msg323046#msg323046 (https://el34world.com/Forum/index.php?topic=29359.msg323046#msg323046)

https://el34world.com/Forum/index.php?topic=29296.msg322207#msg322207 (https://el34world.com/Forum/index.php?topic=29296.msg322207#msg322207)

Franco
Title: Re: Feedback requested: AC4 schematic converted to layout
Post by: dwinstonwood on July 22, 2023, 07:52:40 am: FWIW, I've built/rebuilt my AC4 a few times. I finally got it working and sounding the way I want. The bright cap on the volume pot did wonders for low volume playing. The Tremolo works well; I added an Intensity pot. The grounding scheme in my layout - with just the one ground point, and the elevated heater CT - is very quiet for an SE amp.
Title: Re: Feedback requested: AC4 schematic converted to layout
Post by: sluckey on July 22, 2023, 08:03:19 am: Nice drawings! :worthy1:
Title: Re: Feedback requested: AC4 schematic converted to layout
Post by: dwinstonwood on July 22, 2023, 03:49:21 pm: I hope it's clear that my drawings are directly modeled on yours and Hoffman's excellent drawings. I just tried to copy your style. :icon_biggrin: