My SSS 001 As Built, Corrected Schematics

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David Root
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Re: My SSS 001 As Built, Corrected Schematics

Post by David Root »

Thanx mh! It's not been cranked yet, see my note above about preserving vintage Celestions. But it is very clean, but not at all sterile, nicely harmonic, and did I say LOUD?
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M Fowler
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Re: My SSS 001 As Built, Corrected Schematics

Post by M Fowler »

David I ended up using my Heyboer PT screw-up in a Marshall Plexi 4 tube monster. Nice looking build David.
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David Root
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Re: My SSS 001 As Built, Corrected Schematics

Post by David Root »

Thanx Mark, don't look too closely there are a lot of redundant holes in the chassis and the backplate as this was built on a recycled chassis.

It looks better with its headbox on, which is also recycled, and hacked in the back to get the big transformers in, and hacked on the top to put a vent in as the headbox is a tad small for four 6L6GC. It was designed for a 50W tubes upright build.
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M Fowler
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Re: My SSS 001 As Built, Corrected Schematics

Post by M Fowler »

My rjguitar SSS chassis was the same way front and back panels drilled for tubes up and tubes down, lot of holes but plates covered that. :)
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David Root
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Tube Count

Post by David Root »

Final minutiae: tubes.

V1 '58 Mullard
V2 '50s Amperex Bugle Boy (someone told me these are indestructible for CF)
PI '50 Telefunken Ribbed
Driver '60s Tung-Sol 12BZ7 (also have used a '58 Hytron, no difference noted)
Power 4xNOS Mesa 415-STR (Sylvania heavy duty 6L6GC)
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mcinku
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Re: My SSS 001 As Built, Corrected Schematics

Post by mcinku »

This is going to be my next project but before I do it, I though it would be good to have a layout in front of me... so here it is.
I still have to do the power board part but the preamp is done.... I think.
My intention was to use 8 tube ODS chassis, so I added a bright, deep and Jazz/Rock switch.... I also added "presence" pot. I would appreciate if somebody would take a look at this, I'm sure I missed a thing or two in there. :oops:

:wink:
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David Root
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Re: My SSS 001 As Built, Corrected Schematics

Post by David Root »

I took a quick look. May have missed something but as far as it goes it looks OK to me. Put the raw bias supply and the driver grids bias supply in and I'll take a look at those.

Please note that if you're using a 12AX7 driver, HAD used 100K "dropping" resistors. I used 51K because I used a 12BZ7 driver which should draw twice as much current as the -X7. Just to be safe the 100K should be 1W IMO. I used 3W 51K which turned out to be overkill.
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Structo
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Re: My SSS 001 As Built, Corrected Schematics

Post by Structo »

Nice layout!

Just a minor thing but if you orient your preamp tubes with the gap towards the rear of the amp, it is easier to wire the grid stoppers as well as the other components to the sockets.
Tom

Don't let that smoke out!
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mcinku
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Re: My SSS 001 As Built, Corrected Schematics

Post by mcinku »

David Root wrote:I took a quick look. May have missed something but as far as it goes it looks OK to me. Put the raw bias supply and the driver grids bias supply in and I'll take a look at those.

Please note that if you're using a 12AX7 driver, HAD used 100K "dropping" resistors. I used 51K because I used a 12BZ7 driver which should draw twice as much current as the -X7. Just to be safe the 100K should be 1W IMO. I used 3W 51K which turned out to be overkill.
I have to admit this bias network is not entirely clear to me but anyhow I replaced the original layout, so please take a look.
I also replaced 51k resistors with 100k.
:wink:
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mcinku
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Re: My SSS 001 As Built, Corrected Schematics

Post by mcinku »

Structo wrote:Nice layout!

Just a minor thing but if you orient your preamp tubes with the gap towards the rear of the amp, it is easier to wire the grid stoppers as well as the other components to the sockets.
Yes I am aware of that... the reason for this is cause I have some sockets on stock with this orientation and I intend to use it.
:wink:
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David Root
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Re: My SSS 001 As Built, Corrected Schematics

Post by David Root »

mcinku, what is your raw bias DC voltage? For the CF driver cathode bias you will need at least 130VDC. I used 175VDC and that works fine.

There needs to be about 1.5V or so difference between the CF driver cathode voltage and the CF driver grids. Grids of course more negative than cathodes. Typically these voltages will be about -50 and -52V. That is based on about 350V on the driver plates.
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mcinku
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Re: My SSS 001 As Built, Corrected Schematics

Post by mcinku »

David Root wrote:mcinku, what is your raw bias DC voltage? For the CF driver cathode bias you will need at least 130VDC. I used 175VDC and that works fine.

There needs to be about 1.5V or so difference between the CF driver cathode voltage and the CF driver grids. Grids of course more negative than cathodes. Typically these voltages will be about -50 and -52V. That is based on about 350V on the driver plates.
Well before I know what voltages I have I have to build this thing... at the moment I'm not even sure which PT I will get for this.
:oops:

...but anyway thanks for the tips.


BTW I found one error..... on that 6 lug solder strip, I put 0.005pF cap instead of 0.005uF cap.
:wink:
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mcinku
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Re: My SSS 001 As Built, Corrected Schematics

Post by mcinku »

This is where I am at the moment...
[img:1280:960]http://shrani.si/f/N/8c/35OnOZ3W/sss.jpg[/img]

I spotted some errors on my layout. After I finish the amp, I will fix the layout accordingly.
I just hope I will find all the errors before I'm ready to power on this amp.
:?
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David Root
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Re: My SSS 001 As Built, Corrected Schematics

Post by David Root »

Just put cheap tubes in it and cross your fingers! If you're really worried put a 750mA fast blow fuse on the OT CT.

Where did you get that chassis? Doesn't look like a CE chassis.
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mcinku
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Re: My SSS 001 As Built, Corrected Schematics

Post by mcinku »

I have a variac in my shop so I will go slow on this one. :roll:

This chassis is my own design... a local company builds these for me.
:wink:
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