Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: cesibley on July 28, 2011, 11:12:12 am
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I preparing for a new build, and am considering including the Hoffman "Hot Switch"
http://www.el34world.com/projects/hotswitch.htm (http://www.el34world.com/projects/hotswitch.htm)
Has anyone here actually performed the Mod, and how happy were you with the results? Would it make sense to use a 12ay7 in this configuration?
Anyway, I'd love to hear some first hand reports before I go forward....
Thanks,
Curt.
P.S. - First post here. Consider this my introduction :-)
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You'll have to add at least a triode section, unless you plan on stealing one of the input channels, but part of the charm of the 5E3 is the interaction between the channels using the volume controls. You could change V1 to a triple triode, or just add another dual triode (or even a single pentode) somewhere, if your chassis has room for it.
You may find the 5E3 gets crunchy enough without the "hot switch" stage, especially if you hit the front end with a booster.
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It is my intent to sacrifice the second channel. Not really sure I'd ever use it with just a single instrument - or is there something fun I haven't considered for the dual channel?
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Many people have built Doug's "hot switch". It's really a high gain Marshall thing though, ie, goes well with a Plexi or Stout (Doug's 18W Marshall). I don't recall anyone ever talking about putting it on a Fender tweed amp though. You may be the first. Please let us know how it turns out.
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There is an interactivity between the volumes on a 5E3. If you've never messed with one, you should try to before adding a hot switch to your build. Maybe you could build it without and then add it if you think you need it. What happens is when you plug into a channel of the amp, if you turn one channel up and the other down some, it's BF clean. Switch the volumes the other way and it's OD heaven. I can't remember which way does which; it's been too many years, but you'll get all the OD you want without a hot switch. Lots of people use two and an A/B switch live. Neil Young (bad as he is) uses a 5E3 with a servo motor on the pots to change from clean to OD on stage.
My guess is you can get the OD tone you want and control it with the guitar's volume and leave the amp simple. That being said, my main amp has a 5E3 power section and a 5F6a preamp with a hot switch and it is sweet. I also have one with a 5E3 power section and an SF Deluxe preamp (BF with higher voltages)... the next one will have a hot switch.
It's all preference, very subjective.
Dave
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My only comment about adding the Hot Switch to the Tweed is that it's going to be loud and probably too fat. You will probably want to squeeze the bandwidth coming out of the added tube.
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I don't know if mine really even can be categorized as a tweed 5E3 anymore but...it LOOKS like one! :)
http://www.el34world.com/Forum/index.php?action=media;sa=item;in=31 (http://www.el34world.com/Forum/index.php?action=media;sa=item;in=31)
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If you add a stage of gain to a tweed amp, my only comments would be that Fender tweed amps are really sloppy and the power supplies are primitive. (that's what people like about them.
You may have to divide the power supply up (decouple it) and add filter caps and also tweak some of the caps to get rid of the flabiness.