Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: Redfishbum on January 26, 2017, 02:51:32 pm
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Greetings.....having finished a recent build, this is a bit addictive....
I want to build a small amp for my son to be played primarily with a Gibson Les Paul.
This will use an 8 inch alnico speaker and will be single ended.
Schematic suggestions? I've considered a GA-5 with a 6V6 and a Schedule 40.
I'd like some opinions on others that I should consider?
Thanks!
Bart
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Any Champ-style circuit should sound great. I like using 6SL7 preamp tubes, just my preference over the 12ax7. But millions of amps were built with those, so what do I know?
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You can't go wrong with any 5ish Watter's
My Son wanted a little more loudness, so I did a GA-8 6V6PSE
here's the schematic.
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Im currently building a Vibro Champ in a head format. I got a chassis for it off E-bay and everything. I'm in love with the tone of these amps pushing 4x12's. Pretty cheap build really too. There's layouts available, and Doug has all the parts you need. The JJ multi-cap doesn't fit through the hole in the chassis, but it's fine flush. Youtube a few videos, there's one where a guy plays a Vibro Champ through a 4x12" with a Les paul and a 6L6 power tube.. It's pretty awesome.
-Brett
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Another option:
VHT Special 6, head or combo. All handwired with eyelet board, it's a breeze to modify for someone with build experience. Very affordable too.
I added a Master to control of power amp gain, changed the bias resistor for 5881 tube, and added NFB like 5F1 circuit.
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AA764, I'm planning a 6SL7 version but it is yet on paper
The original (6ax7) version is well documented to be cloned
if you google an image search for AA764 or Vibro Champ you can find some layout (Fender original or not)
Franco
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Thanks for all the great selection suggestions! I'm gonna keep this build simple....just a volume knob. The GA8 is a interesting option and still simple.
I've already "accidentally" built the cabinet but far from finished. Once I choose a schematic, I'll bend up some sheet metal; been experimenting with that.
Once I make up my mind in a few weeks (work travel) I'll reply back.
Bart
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FWIW, I really like a 5881 in place of the 6V6 power tube. Not for power output, but for tone. They sound (imo) much smoother. I've used the Tung-Sol Reissues, and also the wafer base Russian tubes (find 'em on ebay). I think they are 6PSE, or something like that.
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Thanks John....good tip!
B
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The GA8 is a interesting option and still simple.
One of the nice "features" of PSE, you're all set up for push pull when you get bored with SE, swap the ot, adjust bias , maybe speaker load. New tone from an old dog :laugh:
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Shooter....thanks for that clarification. I looked at the schematic too quickly and initially was thinking push pull, but I see it is parallel single ended. I have three builds and have done something different each time....this is different!
Thanks man!
B
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You're welcome
this is different!
I like different, I like to take interesting "pieces" and glue them together.
You will need a PI if you change to P-P, but Gibson and some old amps used a tranny, makes "modding" easy and the sound different!
Whatever you choose, dig into the weeds enough to get the jest of why n how it's "supposed" to work.
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Really think about using a 10" instead of an 8" - if you insist at least make/order the cab an inch or two bigger and deeper to take a baffle for a 10" when you get tired of the eight, especially since it won't be with single coils. I have certainly not tried all and there are many now, but of those I couldn't find a modern 8' I liked all that much, none were bright enough, and actually the options are limited in that many modern 8" choices have big iron and won't fit. Sux to throw money after speakers but throwing it after 8"s will really wind you up. Staring down at the carpet at six different 8" is a bummer.
NOTHING small beats a 5F1, don't forget the 25mf bypass cap, don't mod it anywhere, it's dead-on perfect as is - I like NOS tubes in Champs, I like old (but good) molded caps in Champs, don't up the capacitance much in a 5F1, the low filtering helps it sound fuller. The Allen Champ OT is an improvement that keeps the Fender sound. Otherwise, stick with 6V6 SE circuits, EL84s are great but you need four of them for really good tone :w2:
BTW the 5F1 is a pretty wild, dynamic circuit, if your son is young or starting out it'll teach him how to work an amp - as will the step up, the 5E3. Unless of course he's into shredding and effects, little tube amps are all about straight in.
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I don't know if the AA764 is too complicated for you because of the presence of the Tremolo
I remembered I've seen a redrawn version of the original Fender Layout
and if you are interested, here it is
(http://i.imgur.com/16ZPA1U.jpg)
(http://i.imgur.com/BqNgMCX.jpg)
Franco
p.s.: Attached the .pdf files
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Dudes.....I'm diggin' all the thoughts and suggestions! Keep them coming.
Looking for something small for my son to take to lessons. My son is 18 and has been taking lessons since he was 9. He has amazing fingers and loves metal. He is currently in music theory and jazz lessons and the amp his teacher has is not his favorite so this gave me the "excuse" for a scratch build.
Tremolo not too complicated for me. I cut me teeth on a scratch build at the deep end of the pool with a Supro S6422-TR modified clone. The 4 months of debugging tought me a LOT! Build this whole thing, cabinet and everything. I did use a blank Hammond steel chassis which I drilled all the holes. This amp has a switchable bias for either a 6V6 or 6L6. The reverb is a Fender Princeton circuit grafted in. The clip below doesn't demonstrate the T or the R.
Here is a clip of the amp with my son on guitar:
https://youtu.be/2cazQ_JdsMQ (https://youtu.be/2cazQ_JdsMQ)
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Cool Amp :thumbsup:
Franco