Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: kagliostro on December 03, 2017, 02:05:39 pm
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I want try to plan a Turret Layout for the Gibson GA-5T Skylark '61 (5Y3GT - 6BM8 - 12AX7)
and .... as it is more easy to plagiarize than to invent I'm looking for a Board Layout of a 6BM8 based SE Amp
to be used as a start point to plan the GA-5T Skylark Layout
Thanks
Franco
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Good pictures here, text says EL-84 power tube but if you look at the pictures the power tube is clearly ECL82
http://truevintageguitar.com/inventory/1960-gibson-ga-5t-skylark-tremolo/ (http://truevintageguitar.com/inventory/1960-gibson-ga-5t-skylark-tremolo/)
hope this helps
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Many Thanks VMS
I've also some other photo of the original, one very good
(https://i.imgur.com/bUFjprV.jpg)
However I'm thinking to a new layout (not an exact clone), one where all components are on the board
so I was hoping to find a Board Layout of any amplifier that uses 6BM8 as to be used as a base
the photo I've is very good, but some parts of the connections are unreadable
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Meanwhile I've find this GA-1RVT Layout that isn't the best option but I can use if I don't find other better option
(https://i.imgur.com/6EZWrpg.jpg)
Franco
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It's probably difficult to find layout with same tremolo. Here is one more gut shot of ga-1rt amp that has same ecl82 section. It shouldn't be too hard to make a layout comparing all these pictures you have now.
https://reverb.com/item/2278257-vintage-1961-maestro-ga-1rt-reverb-echo-tube-amp-gibson-made (https://reverb.com/item/2278257-vintage-1961-maestro-ga-1rt-reverb-echo-tube-amp-gibson-made)
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Good inside photo :thumbsup: :thumbsup:
Thanks VMS
Franco
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Little off topic and don't remember if i have talked about this before but a while ago i was thinking that amp using only 6bm8 tubes could be a fun project. I draw this schematic then using preamp from svetlana datasheet, vox type tone stack and power amp from dynacord kv10.
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Ciao VMS
I'm not sure about, but to me seems you or one other guy posted something similar some time ago
Franco
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might have been me, i don't remember what i post here half the time :laugh:
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In the Hoffman .sch library there is a GA-5T layout and schematic. Also two more that say with mods.
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(https://i.imgur.com/k6vCxQp.gif) :BangHead:
I didn't recognized that there was a Layout on the .sch library
Many Thanks MFowler (http://blob:https://imgur.com/58993722-5271-440f-ba45-948876551c8f)
I'll give a look also to the other versions with mods
Franco
EDIT:
Also two more that say with mods
I need help, I'm not able to find where are those files :w2: :dontknow: , can you post the link to the page ?
I discovered I've all those file on my archive since some years ago :bump1: , but I'm not able to find them on the site pages
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Yes some more that say mods GA-5T
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Thanks for the files, but where they are in the forum ?
Franco
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The ones I uploaded were in my Hoffman files on my computer collected over the years.
I tried to find them on the Forum but could not locate them.
Mark
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LOOK...
http://el34world.com/Forum/index.php?topic=3783.msg33774#msg33774
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Many Thanks Steve
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Some time ago (may be years) there was a compressed file with the .sch library of schematics
seems that it is no longer present on the forum
Franco
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I want try to plan a Turret Layout for the Gibson GA-5T Skylark '61 (5Y3GT - 6BM8 - 12AX7)
and .... as it is more easy to plagiarize than to invent I'm looking for a Board Layout of a 6BM8 based SE Amp
to be used as a start point to plan the GA-5T Skylark Layout
Thanks
Franco
Here is a GA-1RT-1 layout with a few mods (SS rectifier, LED oscillator bias, some values, no vestigial reverb).
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Many Thanks also to you Svejkist :thumbsup:
do you know the origin of that layout ?
Franco
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I drew it years ago. The second layout I ever did, so maybe not ideal. But the amps I built from it worked fine. I have the DIYLC file, but it wouldn't let me attach it here. If you want me to email it, PM me.
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Thanks for the answer
Not to refuse your offer, but what you posted is enough
Franco
p.s.: To solve problems about files that are not allowed to be post, compress it and post the compressed file
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Thanks, I wondered if that would work, but didn't see zip, gz etc in the allowed file types. Could probably also just change the extension.
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> didn't see zip, gz etc in the allowed file types.
"Allowed file types: doc, gif, jpg, pdf, png, txt, zip, sch, jsch, xls, xlsx, csv, dxf, vsd, vss"