Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: TitaniumValhalla on January 21, 2017, 04:37:40 pm
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I finished up my first amp build today - a Schedule 40/GA-5/5F1. It sounds fantastic! I had to reverse the OT primaries to get the NFB to behave. I set it up with a 10k resistor and 500k pot in series as a variable resistor but I'm probably going to swap the pot for a 100k since 500k seems to be wayyy overkill.
I had some LEDs and LED holders lying around so I didn't order a standard pilot lamp when I got the parts for this build because I didn't know at that point that everybody uses them as a tie point for their heaters. Rookie mistake. I ended up using a couple of free pins on my rectifier socket for that instead.
By far the hardest part of this build was the chassis! If I was going to build a combo I could've used a premade Champ chassis but I wanted a head so I bought a blank aluminum chassis and made all the cutouts myself. Here's a pic mid-process:
(http://i.imgur.com/dmwEMwG.jpg)
Once the chassis was done it went together pretty smoothly. Being my first time I probably didn't use the right mounting hardware in the right places. I used what I had handy and what was convenient for me. Here it is almost done. I made a few changes afterwards but didn't take another picture.
(http://i.imgur.com/vS6WVmt.jpg)
All done! I'll build a cabinet for it once I've decided I'm satisfied with the internals.
(http://i.imgur.com/GeFr6gd.jpg)
I was kind of expecting this amp to sound better with humbuckers than single coils and they did sound alright but when I plugged in my Strat instead it was heaven. I used a boost pedal to drive the preamp a little and it just sings. I think this is going to be my go to amp for my Strat for the time being. With my 4x12 cabinet it gets majorly loud when cranked but it breaks up early and sounds good even at low volumes. What surprised me the most was how quiet it is. It has the least hum, buzz, hiss, etc. of any of my amps, even with my amateurish lead dress.
This site is a godsend for a newbie like me. Every question I had during the build, I found answers in Doug's information library or in posts on the forum. Now I just have to figure out my next project... :m11
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Nice build, my 1st build was about the same, and into a 4X12 and a real guitar player, I was grinnin :icon_biggrin:
Now I just have to figure out my next project
welcome to amp builders anonymous :occasion14:
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Nice work!
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Congrats! Nice job. Thanks for sharing your success.
with respect, Tubenit
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That looks good!
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Thanks guys. I ordered a few supplies for the cabinet, knobs, etc. Also a few different caps to try as a bright cap for the volume pot and a 100K for the NFB pot. If I have time this week I may get started on building the cabinet.
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Looks good
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that looks awesome
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Thanks guys. I ordered a few supplies for the cabinet, knobs, etc. Also a few different caps to try as a bright cap for the volume pot and a 100K for the NFB pot. If I have time this week I may get started on building the cabinet.
I think you should do some crazy MOD to it now like add reverb or similar!
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Thanks guys. I ordered a few supplies for the cabinet, knobs, etc. Also a few different caps to try as a bright cap for the volume pot and a 100K for the NFB pot. If I have time this week I may get started on building the cabinet.
I think you should do some crazy MOD to it now like add reverb or similar!
I've got a lot to learn before I go off the deep end but I'm getting there. There is plenty of room in the chassis for mods so we'll see.
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before I go off the deep
An easy one might be changing the OT, As "quality" as the wife n wallet allow.
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before I go off the deep
An easy one might be changing the OT, As "quality" as the wife n wallet allow.
For an amp this small even the really high end ones aren't too expensive. I might have to look into that.
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It WILL change the tone, part of the champs "appeal" is diming everything and saturating that poor little iron!
I used a Hammond 15W, she had a great punch, still had an attitude, but that I believe comes from the 6V6.
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Looks real nice. :icon_biggrin:
1 thing though, you have the PT wires going through a hole in the chassis with no rubber grommet.
The highest dcv in the amp goes through there. If the OT high dcv wire gets cut and shorts to the chassis it will be big trouble.
You really need to install a rubber grommet or a plastic type insulator in that chassis hole for safety.
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Looks real nice. :icon_biggrin:
1 thing though, you have the PT wires going through a hole in the chassis with no rubber grommet.
The highest dcv in the amp goes through there. If the OT high dcv wire gets cut and shorts to the chassis it will be big trouble.
You really need to install a rubber grommet or a plastic type insulator in that chassis hole for safety.
Good call, thanks! I'll grab a grommet for the OT hole when I pick up my wood supplies for the cabinet.