Dumble SSS with Eyelet Boards

[desertmouth90]

I have aquired two sets of Hoffman eyelet boards of his Steel String Slinger set but just looking at the layout and in some places it looks different... for example I have to drill out the holes for the valve sockets clearance.

I am intending to use some 70s Fender Twin transformers for the build (Hopefully have enough mA for each valves, not sure how to test for this yet but im working on it.)

So far ive collecting parts for it. Not sure wether to go for parts close to the originals for more contemporary ones.

The Chassis is made from aluminium, I intend to get a silkscreen instead of a faceplate. not sure where to go in the UK for this but push comes to shove ill get faceplates custom made.

Any advice before I go down this particular rabbit hole?

[martin manning]

Silkscreening a single chassis would not make economic sense. I'd go with laser engraved faceplates.

Your Twin PT should have enough current, but it looks like it has been hot based on the varnish oozing out of it.

The Hoffman rectifier board does not have the bipolar power supply shown in the layout. I recommend replacing that.

BTW, who made that modified layout?

[desertmouth90]

My mistake, Ill be following this one more.

Okay I can do the faceplates. I have to cut the chassis myself

[desertmouth90]

Silkscreening a single chassis would not make economic sense. I'd go with laser engraved faceplates.

Your Twin PT should have enough current, but it looks like it has been hot based on the varnish oozing out of it.

The Hoffman rectifier board does not have the bipolar power supply shown in the layout. I recommend replacing that.

BTW, who made that modified layout?

Now I look silly, I just posted your layout!

Not sure who edited it, But ill be following your original layout.

thanks,

Clive

[martin manning]

Colgan did the original version. I would go with the edited one you posted. It has the modifications I have suggested on this forum (bipolar driver supply, bias pot connection, and revised step filters). I would replace the 300mH inductor with a jumper, though. It has no significant effect in the audio range.

[desertmouth90]

Colgan did the original version. I would go with the edited one you posted. It has the modifications I have suggested on this forum (bipolar driver supply, bias pot connection, and revised step filters). I would replace the 300mH inductor with a jumper, though. It has no significant effect in the audio range.

Yeah I think ive heard about this inductor not doing much from a friend who built this with Erwins PCBs.

I was going to aquire those but it out of my budget slightly at the time.

Does the Bias pot need to be B25k?

[martin manning]

Yeah I think ive heard about this inductor not doing much from a friend who built this with Erwins PCBs.

I was going to aquire those but it out of my budget slightly at the time.

Don't waste your money.

Does the Bias pot need to be B25k?

No. See the bipolar bias supply .pdf document here: https://ampgarage.com/forum/viewtopic.p ... 08#p365408

[rccolgan]

Assuming you're following my layout since your boards match, you can do B25k or B20K. I use the 2W wire wound in my build for additional degree of accuracy and a little beefier than a standard carbon. It was my way to take a fixed bias and make it variable without changing too much and will fall back to fixed bias if the pot fails instead of red plating the tubes. If you're going with Martin's suggestion of a bipolar bias supply, follow that layout and disregard my suggestions

[desertmouth90]

Assuming you're following my layout since your boards match, you can do B25k or B20K. I use the 2W wire wound in my build for additional degree of accuracy and a little beefier than a standard carbon. It was my way to take a fixed bias and make it variable without changing too much and will fall back to fixed bias if the pot fails instead of red plating the tubes. If you're going with Martin's suggestion of a bipolar bias supply, follow that layout and disregard my suggestions

Straight from the horses mouth! Both of you have helped me get into this hobby the most out of everyone haha.

I might try both ways. I have to retrofit an old evil twin that I’ve gutted. Needs to be a proper amp again!

[rccolgan]

I merely scratch the surface compared to Martin's contributions. Looking forward to your progress!

[martin manning]

Don't sell yourself short- Sorting out the SSS002 circuit was epic!

[desertmouth90]

I merely scratch the surface compared to Martin's contributions. Looking forward to your progress!

I work as an Architect at my day job and my tutor at uni used to say - 'A picture paints a thousand words'.

You are the trailblazer

[desertmouth90]

Marking out the chassis ready for drilling!

[desertmouth90]

First mockup! Almost got the chassis ready!

Not sure I can get faceplates sorted in the U.K. for it, also would be a shame to cover this nice aluminium finish don’t you think?

Any ideas on getting a vinyl or waterslide or something?

[desertmouth90]

Progress!