New Fender "type" amp build suggestions

[Iain T]

Hopefully, you won't need to do any rework or have too many things connected at one point.

Rework - that's what the solder sucker is for, right?

My design has a few tight spots and one that could have 9 connections into it that's split into 2 currently - 5 in each as the link is an additional. Going to do a test on a piece of scrap to see how viable that is and, potentially, use larger eyelets in that spot. Using 3mm thick FR4 board so it's very solid even when eyelets are fairly close.

We'll see though - I did turret last build and liked some aspects of them and disliked others.

[JMPGuitars]

I did turret last build and liked some aspects of them and disliked others.

They take a little getting used to, but the most important part is to use good quality turrets. I have a list of stuff I like here: viewtopic.php?t=25173

I should probably update that too.

Thanks,
Josh

[foreverstrung]

Since I have built this one myself a few times I have dedicated docs for my use. I never build it with 2 channels.It's really a great amp with lots of OOOMPH!!! I use a Jupiter 12LC in this amp, or the newer M12C when you don't want the full volume of this beast. Here are my docs:

Do you happen to have any gut shots or front and back faceplate pics you'd be willing to share Bieworm?

[Bieworm]

Sure

[Bieworm]

Some more

[foreverstrung]

That is some good looking work Bieworm.
A Couple quick questions, (tho I'm sure there will be more )
I'm ordering Hammond transformers and choke. Can you confirm I've got them right please?
290DX PT
1760J OT
1750A Reverb
194A Choke
Thx
Dave

[Bieworm]

That is some good looking work Bieworm.
A Couple quick questions, (tho I'm sure there will be more )
I'm ordering Hammond transformers and choke. Can you confirm I've got them right please?
290DX PT
1760J OT
1750A Reverb
194A Choke
Thx
Dave

Thanks. I do my best to get nice work done.

The transformers are correct indeed

[foreverstrung]

Another question Bieworm.
On the "layout drawing" you posted, the electrolytic caps you have at nob A, B and C are 47uF and 3 at 15uF.
The schematic has all 4 at 16uF.
However the pics you sent of the guts have 2 at 22uF and 2 at 15uF. all 500v.
You definitely have way more experience than me at building these things, but I need to ask, which one is correct? Does it matter? Is it in part different considering your location in Belgium and me in the US? Regarding standard voltage I mean. (IDK if Belgium and the US differ or not or that if it did would that matter.)
I just want to make sure I get it right.
Thx
Dave

[Bieworm]

I have built this amp multiple times. In the 1st one I followed the schematic, but had to add an extra cap across the 1st to counter some hum issues on the B+. I drew a 47uf for that reason on the layout.
I think the picture of the actual build has 2x 22uf there because I ran out of 47uf500V caps while I started this build. So instead I added 2 subsequent 22uf caps. The build turned out great, so you’re fine doing the same.

[foreverstrung]

This jack in the layout drawing Bieworm, is it a “optional”Vibrato channel?
I do t see it in the gut shots though I can’t really see the rear plate

[Bieworm]

It’s the footswitch jack for the tremolo. In the pics that jack isn’t mounted yet. You can see the hole though. It’s on the other side because the jack would be in conflict with the speaker baffle.

[foreverstrung]

The schematic shows a bright switch. Did you just decide you didn't want that? I can see from your "gut shot" photos that there's 1 switch in the back besides power. I figured it was the NFB switch. Is that correct?
The NFB switch I'm thinking of putting on the front/faceplate rather then in back like you have it. I might add that bright switch too. in front.
As I'm sure you're aware the original 6G16's had the 2 input jacks and 2 vibrato jacks on the face. I'm thinking of keeping just the one input jack like you have it and the vibrato jack on the backplate for a foot pedal like you've designed.
I'm not experienced enough yet to start tweaking designs. I want to stick to yours as close as possible though I have no problem relocating.
Even though I'm using a Twin reverb cabinet and chassis, I think I'm going to use a doghouse for space. I'd like the PT fully clear of the turret board as the TR is only 1.75 inches thick.
Appreciate your thoughts on these things. Anything I've got wrong or am missing.
Dave

[Bieworm]

I never do bright switches.
The switch on the back is indeed the NFB switch.
My PT is not coming through the chassis. So there is no conflict with the turret board. I also try to keep each filter cap as close to its part of the circuit as possible. A doghouse implies longer DC leads an that’s exactly what I’m trying to avoid.

[Bieworm]

Why on earth would you add the NFB switch on the front panel? It is nothing you will use often, trust me.
My amp has a MV, so you can dial in dirtier sounds much sooner than they would on a non MV amp.
By the way, the twin chassis is so large that there is absolutely nothing to be worried about when it comes to topology for this amp. I use 10mm high stand off bolts and a 2mm thick turretboard. The filter caps of the preamp are short enough to put them up straight. You just need to select appropriate caps for that. I use JB's for that application.
Do you wanna see a cramped up amp build? It's a 5F6a bassman, with tremolo squeezed in an original 60's Gretsch chassis ( I believe it was 385 x 10 x 65mm)
That was ship in a bottle type of stuff. So don't worry with your twin chassis

[foreverstrung]

I never do bright switches.
The switch on the back is indeed the NFB switch.
My PT is not coming through the chassis. So there is no conflict with the turret board. I also try to keep each filter cap as close to its part of the circuit as possible. A doghouse implies longer DC leads an that’s exactly what I’m trying to avoid.

I get what your saying here. I figured you did something like this with your PT. However if I don't set the PT into the chassis, it will be mounted "proud" of the outside of the chassis, My PT bolts would be too short to anchor to the chassis this way. How did you anchor yours securely and proud without any of the PT base penetrating the chassis?

[Bieworm]

It’s a surface mount , so it’s intentionally designed for that way of mounting.

[foreverstrung]

IMG_7694.jpeg

IMG_7691.jpeg

IMG_7692.jpeg

Do you like a D24 or a D32 solder tip for turrets?

I’m attaching a couple pics of my turret board. Bought from mojotone. Turrets too. And drill bit

Also adding 2 pics. One of gut shot and one if layout drawing. The point I’ve circled, is this exclusively a grounding hub or is there something else here I’m missing.

Dave

[JMPGuitars]

I use 2.4mm tips for almost everything. You can use a 3.2mm if you want.

[Bieworm]

That is power amp ground.

[foreverstrung]

So I got the chassis together. I had to modify a bunch. I had a sign company locally build me faceplates and there way thick. Had to cut out and countersink. I’ll send pics later.
Question(s) as I start putting this together. In the picture of the layout I’ve attached, I’ve got an arrow indicating where I believe the OT’s red wire (center tap) is attached. At the 150R resistor. Is this correct? It’s like the “sag resistor” yes?
2nd, the purple wires coming up thru the dromet by the pilot light to the diodes (rectifier), is the 325v coming off the PT, yes?
Thx
Dave