DIY Sakuma-Schade 6V6 Amp

[Opa1]

I have most of the amp finished. Still needing a few things. @paul_b , The C4S has three connections per board half. OA/1A-OB/1B and B. What goes where?

 

[paul_b]

The "I" terminals are input, which go to the high voltage power supply. B is ground. The "O" terminals are outputs and go to the plate of the driver tube.

 

[Opa1]

Thanks! Wrote it down on the schematics.

 

[Opa1]

I decided to wire up the rest of the circuit today. It took a while to make it look somewhat symmetrical. All that's left to do is mount the transformer covers, build a base and the IEC plug.
My 65 yr. old eyes are blurry and I'm full of solder fumes. I'll stop for now.

 

[StevenZ]

I decided to wire up the rest of the circuit today. It took a while to make it look somewhat symmetrical. All that's left to do is mount the transformer covers, build a base and the IEC plug.
My 65 yr. old eyes are blurry and I'm full of solder fumes. I'll stop for now.

View attachment 53387

Excellent work Mark!

 

[marantzfan]

Coming right along, nice and tidy! Looks awesome!

Fingers crossed my parts get here this weekend sometime so you don’t lap me. 😂

 

[MrEd]

Looks great.

 

[MikeyFresh]

I'm full of solder fumes.

Builds character, good for the soul.

 

[Opa1]

Thanks everyone.

Builds character, good for the soul.

I don't know about that but, My eyes burn and I have a headache. LOL

 

[Audionut]

Thanks everyone.

I don't know about that but, My eyes burn and I have a headache. LOL

Take care of yourself.
If I get to soldering more, I’ll likely invest in a solder fume extractor. Though I’ve been using lead free solder as of late. (Yes leaded solder is easier to work with than none).
Lovely build by the way, very tidy too!

 

[MikeyFresh]

Take care of yourself.
If I get to soldering more, I’ll likely invest in a solder fume extractor. Though I’ve been using lead free solder as of late. (Yes leaded solder is easier to work with than none).
Lovely build by the way, very tidy too!

It's actually the huffing of burning flux that is of major concern. Lead only vaporizes at a much higher temperature than a soldering iron could ever approach. Flux is fairly nasty shit however.

 

[MrEd]

Thanks everyone.

I don't know about that but, My eyes burn and I have a headache. LOL

I have had the same issue before, I am more conscious of it now and try to mitigate by work position and some air flow.
There's better stuff to huff you know 🤣

 

[Opa1]

Here's the top half.

 

[Opa1]

Today's progress. Built a base. I'm not sure what the wood type is. It was a gift from @StevenZ . Top plate fit right in.

 

[StevenZ]

Today's progress. Built a base. I'm not sure what the wood type is. It was a gift from @StevenZ . Top plate fit right in.

View attachment 53487

Tree wood.

 

[Opa1]

Tree wood.

Those were the planks wrapped in plastic.

 

[maxddnj]

This is what I would build as a 6V6 amp intended to get some decent juice and have decent damping:
View attachment 49940
You should get about 4W out at less than 10% THD. The damping factor should end up being 3-4, and gain about 13-14dB (so full power from about 1.3V or so at the input jacks). The B+ can be fine tuned by switching between the 115 and 125V taps on the power transformer (go down to the 115V tap to increase B+). You could also change from the C-7X to a lower or higher DCR choke to trim out the B+ a little bit. The 5AR4 was chosen here for slow warm up and would be my recommendation based on that.

The current source loading the plate of the 6V6 is presumed to be our C4S circuit, which you can build on a prototype board, or you can order the SEX 3.0 C4S upgrade and cut the board in half with a pair of tin snips. I have provided the R1 and R2 values that go on the board, and the rest of the parts provided could be the same. The "I" terminal wires to B+, the "O" terminal to the plate of the first stage 6V6, and the "G" terminal to ground of the circuit. A small heatsink on the MJE5731A would be a nice idea, perhaps this one: Digikey clip on heatsink

@paul_b would this work using the Sony TC500A iron (pt and opt)?

 

[StevenZ]

Those were the planks wrapped in plastic.

Ah, must have been the white oak I had from the FlexiRack

 

[marantzfan]

Wow, that really came out nice! Great work all around on this one.

Can’t wait for the dimly lit photo with tubes in and turned on while your enjoying it.

 

[Opa1]

Wow, that really came out nice! Great work all around on this one.

Can’t wait for the dimly lit photo with tubes in and turned on while your enjoying it.

Thanks, should be firing it up soon.