Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: BrianS on April 03, 2014, 01:04:57 pm
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Well, this will be my last post about this little amp. Sorry for clogging up the board with all my questions. I've got the amp up and running, including the tremolo, which gave me the most problems.
Here's a link to a write up I did on the process for my website. It's short on details, but the main audience is potential repair customers:
http://treestrings.com/repair-gallery/maestro-ga-1rt-amplifier-rebuild/ (http://treestrings.com/repair-gallery/maestro-ga-1rt-amplifier-rebuild/)
Deciding to refurbish this amp rather than just try and flip it as is has really helped to get my "groove" back when it comes to electronics. Having this board has also helped immensely. Thank you!
Here's a link to a short video I did as well. The playing is terrible, but in the latter half, you get to see how the reverb circuit works and sounds. This may be the only video on youtube that shows this!
https://www.youtube.com/watch?v=PbJ47p5FVE4 (https://www.youtube.com/watch?v=PbJ47p5FVE4)
The trem circuit was a real bear. It still is pretty weak, but I think it may just be the design, or use of that particular tube in the oscillator circuit. It did sound marginally better with the LED on the cathode, as suggested by Sluckey, but I didn't want to leave it there. Anyway, on to new projects.
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Could you take a picture of the hook up method for the reverb? I'm curious about it, as I haven't seen one of these in person.
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Could you take a picture of the hook up method for the reverb?
If you mean how it hooks up to the other amp, it is just two alligator clips that clip onto the speaker terminals. These are hardwired into the amp chassis of the GA-1.
If that doesn't explain it well enough, I will take a pic.
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No, that's cool.
I looked at your website write-up; the amp label is "Reverb-Echo" instead of "reverse-echo". "Echo" was the usual marking for a switch or knob on recording consoles for the dedicated send to a reverb chamber, tape echo, plate reverb, etc.
I also found a scan of the 1962 Gibson Catalog (http://s928.photobucket.com/user/olejoeclark/library/1962%20Gibson%20Guitar%20Catalog?sort=4&page=1) online. The GA-1RT is in it, as well as the upgraded GA-2RT.
You were correct all along that the GA-1RT was intended to provide reverb & trem to a separate amp, or you play through it as-is and get only trem. It seems it was conceived as a way to add the impression of stereo along with the reverb to your existing amp.
The GA-2RT is interesting as they upped the power, made reverb an on-board effect, and yet still allowed for it to be used to supply effects a la the GA-1RT.
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Thanks for the info. I updated my site.