Enter the Octal - 5C1 build

[Jimmy Rocket]

There's a very important deadline looming in my life right now. I'm about to become a papa again in about 4 weeks, so to celebrate I thought I'd try to sneak in one last build before baby #2 arrives.

My goal is to be able to crank this up at least one time before the due date (which is St. Patrick's day) so here goes...


This all started with an old Stromberg Carlson PA amp that I've been scavenging for parts. I'm saving the transformers off of that for a cathode biased BF bassman, but I was able to harvest loads of good stuff including some nice old octal sockets, Carbon Comp resistors and a vintagy fuse holder that I'm using in this build.

here are the sockets


and the rest:



I've also got some old Sylvania 6SJ7 tubes, an excellent RCA 6L6GC and a couple of good 5u4gb tubes too. I'll probably run this with the tube compliment: 6SJ7 / 6L6GC / 5U4GB(or 5Y3GT) to see how it sounds. My OT is a 15watt SE with a 5k primary so the 6L6gc should be right at home.

With that, I want to say a big thanks to Dave @ Boothill amps for hooking me up with a 5f1 chassis punched out for 3 octal sockets, a turret board, and for throwing in some extras along the way. All I can say is that Dave's customer service and communication are second to none.

And here's the cab as of now



It's roughly sized after a 5e3 but squared off more like a Vox. I like the way that the baffle attaches in the tweed design, but I don't really like the slant front of old tweeds, so I compromised. It's going to get covered in fawn tolex too, so I'm hoping that'll look really cool.

I'm going to cram a 12" Weber alnico in there, so it'll be offset to one side and the chassis will go to the other. Not sure if I want the speaker on the left or the right, but I'm thinking speaker to the left (looking at it from the front) and the chassis offset to the right.

[motor_city_tele]

Jimmy,

Congrats on the child and on the amp. If you plan on using the weber
pdf for the layout, be careful, it is incorrect. The resulting build will have lotza hum to it, especially with a 12 inch speaker. I built a 5c1 using the weber schematic and layout and posted it to my thread. tubeswell spotted the error from half way around the world. When I switched the wiring to match the fender schematic, the hum went away.

[Jimmy Rocket]

What was the error?

I've been working from the Fender layout, but I ordered parts from a printout of the Weber layout.

EDIT: I see it. The way the power rail is wired with the OT.

[motor_city_tele]

yup, wired like the 5f1.

[Jimmy Rocket]

Got the chassis cutout done last night:



and test fit it today





which gives me just enough room to offset that 12" alnico bell with plenty of clearance off to the side of my rectifier.

:)

My speaker should be here tomorrow, so hopefully I'll get a shot at making the baffle and dry fitting for size and position.

[Telenut62]

Nice and subscribed

[hackworth1]

Nice work. Good looking finger joints.

[CraigB]

Congratulations in advance - there's nothing better than being a dad

[1955]

Lookin' good.

[Fatknuckle]

Nice offset cab!

[Jimmy Rocket]

Thanks! I should have some shots of the baffle today. I cut the back out as well last night but it's about 1/8" too short both ways. Curiously, just about the width of a table saw blade ;)

I know the cab is "tight" for a 12" but I really wanted something no bigger than a 5E3 or Princeton Reverb, so what the heck. I'm likely going to do a 1 piece back with a large oval cutout, something like the back I made for this head:



I love being a dad, and I'm looking forward to the new little one. I just know that I'm not going to get much tinkering done once he or she arrives on the scene, so I'm shoe-horning it in now. With a 15 month old and a newborn (not to mention Palm Sunday and Easter) I expect to be pretty busy.

Here's me and my little girl workin' on our chicken pickin'

[Petimar]

Congrats, and she's a cutie!

[Jimmy Rocket]

Here's a shot of the baffle before I painted and covered it to give you an idea of the fit:



and here's a shot of it with grill cloth



and from behind



I spent the evening mostly working on refinishing a dresser for my daughter, but I did manage to stain the inside of the cabinet a nice cherry. I didn't want to spray it flat black, but I did want to do something to make it feel more finished.

no pics of that, but you'll see it in future steps.

I also opted for the traditional split back rather than going for a solid back so I cut those tonight.

All in all it's coming together. There are a few bits and pieces I need for the amp yet, but I'm pretty happy with where it's going.

[brtele]

Cool amp. I recently built a 5F1 that utilizes a 6SL7 octal and it sounds pretty smooth. I'm using it with a 12" V30 in a closed cab or a Weber Alnico 10" in the combo. It's definitely not a bedroom amp as it'll keep up with a drummer just fine.

Good luck with the rest.

[celeste]

Cool build, cool thread, but that amp pales in comparison to this pic, makes me smile and giggle, good job

Originally Posted by Jimmy Rocket

.....
Here's me and my little girl workin' on our chicken pickin'

[fluid69]

Originally Posted by celeste

Cool build, cool thread, but that amp pales in comparison to this pic, makes me smile and giggle, good job

+1 I love when my little 2yr old girl "helps" me play. I built her a little jag bass for xmas. I cried like a baby the first time she played it.



Great amp build! Ive really enjoyed this one as well as your last.

"If you want rules, read the IRS tax code. If you want to build guitars, make some sawdust." -Colt W. Knight

[Jimmy Rocket]

Yeah, she's pretty great, and totally gets down whenever music is involved. Her current favorite is Dave Brubeck and/or the Decemberists. I do need to build her a little bass or something so I can start her early. She usually just hammers on an old ukelele.

I started the tolex tonight only to realize I'm about 20" short on the remnant I had. Looks good, but I'm going to have to order some more.

Here's a start:


I'm starting to gear up to build the actual amp and I'm wondering about voicing the amp. Any cap swaps I may want to consider using this with the 12"?

[boredguy6060]

One of my 5 grand kids is an 8 year old girl. Her favorite music is Johnny Cash.
No body knows where she picked up on Johnny, she lives with me, and nobody here even listens to country music.
Her ipod has every Johnny Cash song in the iTunes library.
The greatest thing that ever happened to me was having my daughter, and son in law and family move in with me, she has since had another child who Absolutely changed my life, she's and I have something in common that you never here about.
My grand daughter and I were born on the same day, and at the same minute.
When she was born on my birthday, I dung out my old birth certificate and noticed that she was born at the same minute of the same day 60 years apart.
Sorry to high jack your thread, but you started it when you put up a baby pic. 😀

[Jimmy Rocket]

Ha, awesome! Who knows where kids pick stuff up?

Yesterday was all about the dresser, but I hope to do a little more tolex tonight. I have to wait for the rest to get here from Mojotone anyway.

[Jimmy Rocket]

tolex is tedious, but it's coming along nicely.







I'm waiting for tolex reinforcements to finish the bottom and one of the back panels, but I bolted the speaker to the baffle in the mean time, and as soon as this tolex is set up I'm going to assemble it and hook it up to another amp head to see how it sounds in the cabinet.

Oh yeah, and then there's this huge freakin' OT: