Re: My 5F2A project... *IT! ARE! DONE!*

Re: My 5F2A project... IT! ARE! DONE!

rikus

The first parts for my project arrived today (from tubesandmore), so I thought it's a good time to start a thread detailing my little project.

So without further adieu, the parts:

The tweed and grill cloth:

The handle:

And now for the back-story...
It all started with the great Laney Cub incident of December '09 when people were snapping up the little cubs for great prices. Long story short, an initial bout of GAS for a Laney Cub 8 turned in a project to put together a kief looking 5 watt amp which turned into a project putting together a vintage looking 5 watt amp.

The amp is going to be doing duty as an amp for my harmonica playing as well as guitar playing. I was referred to Karel Mars by Dave Ferguson, a Cape Town harp player who's used Karel quite a bit. After some discussions with Karel (who was super helpful and is a helluva nice guy) we settled on a 5F2A circuit. I spoke to Karel end of last week and it seems I won’t have to wait too much longer.

After lots of reading a sample and whatnot I settled on a Jensen C8R 8", which should have been here already, but I’m expecting in a week or two.

I'll be building the cab and, despite lots of warnings, covering it with tweed myself.

I’m super excited and I can’t wait to get stuck into the project properly.

I'll keep you folks apprised of the progress.

R.

TomCat

Nice to see another amp build on the go.......Best of luck with the project and I look forward to seeing the results.

BTW.......Please let us know how you plan to stick the Tweed to the cabinet. I'm about to start another amp build and I am possibly looking at the Tweed option.....(Although I still have Tolex and Cloth left over from the last build)

MikeM

Nice ? I'd recommend you implement a better tonesuck - ala fender 3 knob and just make it switchable.

Perhaps look for my thread on designing my single ended amp for some ideas.

rikus

Thanks TomCat!

I'm planning on using normal cold/wood glue. It'll allows ample time to position the tweed and won't discolour the tweed. This is based on what I've read only, but I'll be test gluing a small piece just to be sure.

I'll have a look at your thread Mike, but this stuff mostly goes over my head, which is why I've got Karel doing the technical stuff! ?

MikeM

Oh misunderstood you! My bad ? I thought you'd still be building the amp..

Keen to see this project

Karel-Mars

Hey... I just supply the components ? Rikus will have to warm up the iron ?

MikeM

? Well if that's the case... I'd suggest the biggest improvement that can be made to the amp IMO is the filtering. I'd suggest using a pi-filter, something like 20uf - 4h 40uf. Reduces hum DRASTICALLY. Even the increased 44uF (instead of the 32uF on the stock 5f2a schematic) I used produces a really large voltage swing in the B+. Otherwise a RC filter will work fine if the voltage is high.

rikus

I got a surprise visit from the courier today...

The speaker is here! ?

(excuse the crappy cell pics again)

TomCat

Super Uber.....exciting stuff man.......... ? ?

I know Matta is a big Jensen man.......Classic Fender tone......

rikus

TomCat wrote: Super Uber.....exciting stuff man.......... ? ?

I know Matta is a big Jensen man.......Classic Fender tone......

? ? I can't wait to get everything to get stuck in properly!

Ps. almost forgot, I was also pleasantly surprised to find a shirt tucked into the box! ?

rikus

Right, so the amp is done! I'm very excited! I can now start putting things together! ???

I picked it up this afternoon from Karel (thanks Karel!). He deviated slightly from the original plan, in that instead of winding his own power and output tranny he decided to use a vintage set that he had salvaged, and add a choke. It's a 250-0-250 Power transformer, a Parmeko Neptune series Choke and a Audax 7000 Ohm output transformer. While this stuff largely still goes over my head Karel assured me that the components are more than up to the task and I am more than willing to trust his expertise (Karel, please feel free to add some more info on these parts). He had it wired up to a speaker when I got there and it sounded promising! Looking forward to hearing the end result.

Enough text, time for pictures!

From left to right: power switch, pilot light hole, Tone knob, Tone stack switch (turns it into a 5f1 circuit by cutting out the tone stack), volume knob, negative feedback switch, input jack, spare holes x 2 (as this amp will probably be tinkered with its whole life).

From the top.

The insides.

Gearhead

Looks like a cover on the solder side of that power transformer might not be out of place - good place to get shocked ?
Maybe Karel should tell his chassis supplier to put some cloth on the bending press die. That will eliminate those hideous marks about 12mm each side from the bends...

Have fun with the cab ?

nick

Where did you source the tweed and how much if I may ask? If my Greenback ever arrives I plan to put the Peavey Blue Marvel in a cab as an extension for my Classic 30 8)

inflames

Looks great! Well done!

TomCat

Looking good....I love the simplicity of these Champ amplifiers.

Gotta build me one soon...... :-\

rikus

Gearhead wrote: Looks like a cover on the solder side of that power transformer might not be out of place - good place to get shocked ?
Maybe Karel should tell his chassis supplier to put some cloth on the bending press die. That will eliminate those hideous marks about 12mm each side from the bends...

Have fun with the cab ?

Thanks Gearhead! I'm looking forward to building the cab (I'm still a bit apprehensive about the tweed, but I'm sure a bit of planning will prevent any problems). I'm basing the cabinet on some really nice 5e3 plans I found on the interwebs, scaled down slightly.

Not really phased about the marks on the chassis. The cabinet and the fascia thingies at the back will conceal all of the marks.

nick wrote: Where did you source the tweed and how much if I may ask? If my Greenback ever arrives I plan to put the Peavey Blue Marvel in a cab as an extension for my Classic 30 8)

Hey Nick,

I bought the Tweed (Clicky) and grill cloth at Tubesandmore.com.

The tweed was $31.95 (1 yard). Shipping came to $39.45. I think the shipping would be similar for just the tweed, as the grill cloth doesn't weigh much. They ship it in a tall box, so I'm assuming that the shipping cost is due to the size of the box.

Thanks inflames and TC! ? I agree, they're *simply* beautiful amps (see what I did there? ? )!

rikus

Why do I never have a camera handy when I need to snap a picture? Here is another dodgy cell phone picture of the front of the cab.

So the basic cab has been built. It's a scaled down 5e3 cabinet. We've figured out how we want to mount the chassis. Next up routing the corners and making the baffle, back pieces and cleats.

makepeace

cool man ?

what did you do to join the top and bottom to the sides?

most of the expensive cabs are fingerjointed, but that seems like a serious mission without factory tools.. how did you go about it?

rikus

makepeace wrote: cool man ?

what did you do to join the top and bottom to the sides?

most of the expensive cabs are fingerjointed, but that seems like a serious mission without factory tools.. how did you go about it?

We glued it up with Biscuit joints.

rikus

We finally made some good progress this weekend on the amp.

Saturday was spent mocking the whole thing up. We had to come up with a few very creative solutions to get everything to fit (and we were very lucky here a there with a couple of things, where huge potential problems were avoided by bare millimetres thanks to blind luck ??? ). With everything squeezed into such a small cabinet there really aren't big tolerance in making everything fit nicely, but at the end of Saturday the amp was fully mocked up. I plugged it in and it sounds great (It’s friggen loud!)!

Sunday we tackled applying the tweed. This is the part we stressed about the most. We spent the whole morning looking at pictures online, measuring, remeasuring and checking the direction of the tweed before we cut the tweed. We also tried a couple of different types of glue on some test pieces. Contact glue is a big no-no. It causes serious discoloration on the tweed when wet, which doesn't totally go away when dry. Normal cold wood glue works the best, it does not cause any discoloration. You just apply it with a brush to the wood. The standard one takes very long to dry though and it has almost no adhesion/tack while still wet, so you really have to be patient.

After one panel of using the normal stuff we tried fast set wood glue, and this turned out the be the winner! It leaves you enough time reposition tweed if necessary and it dries very quickly compared to normal wood glue and has more tack while still wet.

The tweed process is now about halfway. We've applied to side panels to the cab, done all the small details like the cleats at the back and pinched the corners. We also finished one corner just to see how it turns out and I'm really pleased.

I had a bit of brainfade with regards to taking pictures. I was just so excited to get going we just jumped in!

I'm hoping to finish it on Tuesday, but we'll see. I'll post some pics of where it is at the moment if I get the chance!