Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: bullkelp on January 27, 2025, 11:13:44 am
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Hi All,
Thought i'd share my recent builds.
Ive been off work following a couple rounds of surgery so thought I'd tick of some bucket list amps.
A friend of mind asked if I'd make him a brown face amp. We decided on the 6g2.
I've built it more or less to fender spec, with the obvious variances that using hammond iron and NZ wall voltages/frequencies.
I also bought the filter caps onto the main board and used a ground bus rather than the coper plate.
I left the NFB stock, added an impedance switch and implemented a bias pot.
This was my firs tube amp build in years so I felt very rusty. My good friend is an electrician so I had him check it over safety wise before I let it out the door. He also whipped up a current limiter for me for testing which proved very useful....
Any how I spent a lot of time researching my builds and the knowledge on this forum along with Robs instructional info has been invaluable.
Please if oyu see something I've done in my build/s that looks mad/wrong/dangerous/silly then let me know as I'm on a real learning phase at the moment.
Thanks in advance
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First off I built myself an amp cradle. Here is a test fit on a bassman chassis (thats a clue for for later)
I used some Rimu wood that was salvaged from a broken coffee table found on the roadside.
(https://i.imgur.com/mlmOAOP.jpg)
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For this I used a 3mm pre drilled board. I didnt like the look so in future boards a swapped to solid and drilled my own turret holes.
But here is the 6g2 board post staking
(https://i.imgur.com/Gov8m8k.jpg)
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Now the friend who Im building this for specifically asked for blue sozos. i do believe in retaining old blue moulded caps in vintage amps. Im less convinced about spending on repros. But here we are.
Here is the populated board and mounted bus wire.
(https://i.imgur.com/nkQxkw5.jpg)
(https://i.imgur.com/nesHITq.jpg)
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And here more or less is the finished article
(https://i.imgur.com/HHt1jDG.jpg)
(https://i.imgur.com/lXOnxRI.jpg)
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Now I ordered face plates that were unlabeled so I had a screen printer do some wok for me.
Lucky one of the dudes on the NZ guitar forum was able to work some magic and get a great font for me.
(https://i.imgur.com/7iDq82s.jpg)
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Now I did have some teething issues getting the bias right and one near catastrophe where I had wired a dead short in one of the output tubes. Luckily my hand dandy current limiter came the the rescue before any tubes were harmed.
Here are some clips of the tone from this amp.
I have it sitting ontop of my vibrolux going through its 12" jensen jet tornado. Please excuse the extremely precarious balancin gof the amp.
My friend is making his own cab for the 6g2
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Ahhh I see I may have put this in the wrong section.
Any way the mods can shift it ?
Or delete it if you like
Sorry !
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Sounds and looks great! The first amp I did was a 6G2 that I built about two years ago - I used a Fender Sidekick 35 as a donor for chassis and cabinet, and it was a tight fit. I added a three-way NFB switch and a Framus mid-control (both from RobRob's site) to add some variability to the sound. I also did a bias pot, but had to hide it under the bias board because of space. Still working on the faceplate and backplate.
I have to say that mine ended up being to me the nicest sounding amp I've ever played through. I've got a vintage 12 inch Oxford 12T6 speaker in there, which has way more power handling capacity than the amp needs, but definitely adds to the tone.
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thanks !
It was hard to give this away once I’d played thru it !
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Smooth playing Ant. Amp sounds great
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Mr. Bullkelp; If you don't mind divulging, what is the B+ voltage figure you ended up with, which model is the Hammond power transformer and what rectifier tube are you using? Thanks in advance, I'm building a 6G2, but it will have a charm of its own, being just a varnished pine cabinet with a molested old Garnet chassis which has had a few different circuits and incarnations living in it over the years. My transformer is the Hammond 290CAX. Thanks in advance!
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Ahhh I see I may have put this in the wrong section.
No, this is where it should be.
Very nice work. :icon_biggrin:
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Mr. Bullkelp; If you don't mind divulging, what is the B+ voltage figure you ended up with, which model is the Hammond power transformer and what rectifier tube are you using? Thanks in advance, I'm building a 6G2, but it will have a charm of its own, being just a varnished pine cabinet with a molested old Garnet chassis which has had a few different circuits and incarnations living in it over the years. My transformer is the Hammond 290CAX. Thanks in advance!
Thanks
You can see some more detail on this thread at nzguitars
https://www.nzguitars.com/forum/viewtopic.php?f=41&t=43357&p=1030273&hilit=6g2+brown#p1030273
Looks like 328v was the B+
I used the same Hammond as you
Rectifier is a 5y3 - NOS. Not sure what brand it was.
Cheers :)
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The Vibrolux must be an earlier build of yours? Delicious chocolate amps. The circuit that was last inside the "Brownie" was a 6G3 with a 10". If I turned it into a 6G2, then it won't weigh as much! I have everything on hand. Thanks
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The Vibrolux must be an earlier build of yours? Delicious chocolate amps. The circuit that was last inside the "Brownie" was a 6G3 with a 10". If I turned it into a 6G2, then it won't weigh as much! I have everything on hand. Thanks
I have an original vibrolux and a vibrosonic 6g13
I will pop a post up on those too if there is interest. Ive just finished servicing the vibrosonic :)
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Outstanding job all around!