Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: mcasey1 on June 14, 2014, 01:46:29 pm
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Hi everyone!
I am putting together a Deluxe Reverb and am seeking to have a more "tweed" voiced Normal channel while retaining the Blackface tone-stack on the Vibrato channel. Not being too well-versed in topology and tweaking parts values, I looked up mods to accomplish both this re-voicing as well as adding tremolo and reverb to the Normal channel.
First of all, here is a link to the layout I am following:
http://fenderguru.com/wp-content/uploads/2010/04/Deluxe-Reverb-AA763-AB763-changes-layout.png (http://fenderguru.com/wp-content/uploads/2010/04/Deluxe-Reverb-AA763-AB763-changes-layout.png)
(.033 coupling caps changed to .047 in preamp stages)
Now here are the two circuit changes I plan to implement for normal channel voicing and addition of reverb/tremolo, respectively:
http://fenderguru.com/wp-content/uploads/2010/04/Deluxe-Reverb-AA763-AB763-changes-layout.png (http://fenderguru.com/wp-content/uploads/2010/04/Deluxe-Reverb-AA763-AB763-changes-layout.png)
http://s963.photobucket.com/user/pdf64/media/ChannelLinkMod.jpg.html (http://s963.photobucket.com/user/pdf64/media/ChannelLinkMod.jpg.html)
My question is, since I am removing the .047uf cap that connects to one of the plate resistors off V1, and that particular capacitor is mentioned in the re-voicing mod as needing to be changed to .1uf, are the two mods going to conflict in any way? In other words, would I be able to add reverb and tremolo to the normal channel while re-voicing the normal channel appropriately? If these two modifications conflict, is there a way around that?
I apologize if my lack of knowledge makes for a less than intelligible post!
Thank you for reading!
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Now here are the two circuit changes I plan to implement for ... addition of reverb/tremolo...:
http://s963.photobucket.com/user/pdf64/media/ChannelLinkMod.jpg.html (http://s963.photobucket.com/user/pdf64/media/ChannelLinkMod.jpg.html)
Don't do it that way. Do it as shown in this thread (http://el34world.com/Forum/index.php?topic=17193.msg172033#msg172033).
I am putting together a Deluxe Reverb and am seeking to have a more "tweed" voiced Normal channel ...
Now here are the two circuit changes I plan to implement for normal channel voicing ...
http://fenderguru.com/wp-content/uploads/2010/04/Deluxe-Reverb-AA763-AB763-changes-layout.png (http://fenderguru.com/wp-content/uploads/2010/04/Deluxe-Reverb-AA763-AB763-changes-layout.png)
I think you posted a link other than what you intended. This shows differences between the AA763 and AB763 versions of the Deluxe Reverb.
If you want "tweed voicing" you don't want to swap cap or resistor values in the preamp. Instead, you need to ditch the blackface tone control circuit in favor of the simpler tweed tone control circuit. Copy the 5E3 Deluxe bright channel (which is the one with the tone control).
The reason this will work is the blackface tone circuit has a big midrange cut to establish the overall amp sound, and that amounts to a big signal loss in the midrange. The simple 1-knob tone control in the 5E3 Deluxe doesn't cut mids, and will seem both more midrangey and louder due to the reduced loss.
If you wanted to keep the option of the stock tone circuit, some people add a switch between the midrange control and ground. When the switch is open, the tone stack is defeated and signal level and midrange increase dramatically.
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Thank you so much for the info! I'm off to work on it again. Have to wait on some components in the mail.