The No.1 Website for Pro Audio
 Search This Thread  Search This Forum  Search Reviews  Search Gear Database  Search Gear for sale  Search Gearslutz Go Advanced
AB763 circuit Master Volume Mod
Old 3 weeks ago
  #1
Gear Head
 

AB763 circuit Master Volume Mod

Hi,

I'd like to add a master volume to my 64 Deluxe Reverb. I found this site a few months ago:

AB763 Mods by Robinette, Master Volume Mod

I sent the author of the site an email asking for help, but I've yet to hear back from him. So I come to you experts now.

I'm confident with a soldering iron, I'm sure I can tackle the project. I have some questions tho, I want to make sure I do this right before I go destroying a great amp.

1. I'm familiar with schematic symbols and signal flow, but I still struggle relating a specific area of a schematic to it's real-world physical location. In other words, if y'all could describe (or even have a picture on hand) where exactly the two wires reside in the amp for this mod, that would be super helpful.

2. The most convenient place for the pot is the space where the old auxiliary 2-prong outlet resides, I'm sure y'all know that. If I were to rip out the power outlet, what do I do with the leads that terminate at the outlet? Is it dangerous to just put a threaded cap on them (individually of course, not joined)?

3. Related to the previous question, it seems the outlet space is located directly above a transformer. The site suggests coax wire to elminate possibility of interference. I would want to use coax anyways to be safe, but I'm a bit confused where it says to only ground it at signal input. Does that mean only connect it to ground where the leads join the factory circuit? Leave the bare wire disconnected at the pot?

I appreciate any answers at all, thanks ahead for your time
Old 3 weeks ago
  #2
Lives for gear
 

Quote:
Originally Posted by BrassElephant View Post
Hi,

I'd like to add a master volume to my 64 Deluxe Reverb. I found this site a few months ago:

AB763 Mods by Robinette, Master Volume Mod

I sent the author of the site an email asking for help, but I've yet to hear back from him. So I come to you experts now.

I'm confident with a soldering iron, I'm sure I can tackle the project. I have some questions tho, I want to make sure I do this right before I go destroying a great amp.

1. I'm familiar with schematic symbols and signal flow, but I still struggle relating a specific area of a schematic to it's real-world physical location. In other words, if y'all could describe (or even have a picture on hand) where exactly the two wires reside in the amp for this mod, that would be super helpful.

2. The most convenient place for the pot is the space where the old auxiliary 2-prong outlet resides, I'm sure y'all know that. If I were to rip out the power outlet, what do I do with the leads that terminate at the outlet? Is it dangerous to just put a threaded cap on them (individually of course, not joined)?

3. Related to the previous question, it seems the outlet space is located directly above a transformer. The site suggests coax wire to elminate possibility of interference. I would want to use coax anyways to be safe, but I'm a bit confused where it says to only ground it at signal input. Does that mean only connect it to ground where the leads join the factory circuit? Leave the bare wire disconnected at the pot?

I appreciate any answers at all, thanks ahead for your time
I can tell by your questions that you have no business working on this amp.

Pack the amp up and take it to a tech and describe what you want to do....
Old 3 weeks ago
  #3
Gear Head
 

Quote:
Originally Posted by UKMK00 View Post
I can tell by your questions that you have no business working on this amp.

Pack the amp up and take it to a tech and describe what you want to do....
Its two wires and a pot, it's stupid simple, I just wanna make sure I'm putting the wires in the right place, and choosing a good spot for the pot to reside.

But thanks for your encouragement!
Old 3 weeks ago
  #4
Lives for gear
 

Quote:
Originally Posted by BrassElephant View Post
Its two wires and a pot, it's stupid simple, I just wanna make sure I'm putting the wires in the right place, and choosing a good spot for the pot to reside.

But thanks for your encouragement!

And another thing...Mr Robinette was nice enough to include a wiring diagram which shows exactly how to wire this mod. It could not be more precise and direct.


Do yourself a favor and take the amp to a tech.

High voltage is no place for hubris...
Old 3 weeks ago
  #5
Lives for gear
 
Radardoug's Avatar
 

It might look stupid simple, but it probably isn't.
Old 3 weeks ago
  #6
It is very simple. You lift the cap before the 12AT7 driver tube and wire in a 250k volume pot between it and the junction of the two 220k mix resistors.
Old 4 days ago
  #7
Here for the gear
 

64 deluxe

are you nuts it don't need a MV don't drill holes in it go buy a 5 watt amp anything but a MV in your vintage amp crazy fool
Old 4 days ago
  #8
You don't need to drill a hole or permanently modify the amp. Some use input jack #2 to fit it. Is it a tool or an investment?
Topic:
Post Reply

Welcome to the Gearslutz Pro Audio Community!

Registration benefits include:
  • The ability to reply to and create new discussions
  • Access to members-only giveaways & competitions
  • Interact with VIP industry experts in our guest Q&As
  • Access to members-only sub forum discussions
  • Access to members-only Chat Room
  • Get INSTANT ACCESS to the world's best private pro audio Classifieds for only USD $20/year
  • Promote your eBay auctions and Reverb.com listings for free
  • Remove this message!
You need an account to post a reply. Create a username and password below and an account will be created and your post entered.


 
 
Slide to join now Processing…
Thread Tools
Search this Thread
Search this Thread:

Advanced Search
Similar Threads
Thread
Thread Starter / Forum
Replies
Agent516 / So many guitars, so little time
28
gettempapa / So many guitars, so little time
39
Horsearms / So much gear, so little time
0
beaxarthur / Geekslutz forum
0
dtucker / So much gear, so little time
7

Forum Jump
Forum Jump