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Hello! I was getting together a parts list for a this Brown Deluxe amp (6G3) and I came across some funny cap labeling (new to me at least). Any help would be appreciated. Are these all electrolytic?

Also, the diode I've circled near the bottom isn't labeled, what would work there?

25uF rated for 25V (25-25)

25uF rated for 50V (25-50)

One of the things you've circled is a diode

Yes, but no specifics on the diode?

So I guess it's safe to assume all other cap values are in micro-farads as well? Such as the .0005 near the volume pot? that's .0005 uF?

Disclaimer: I'm no expert But yes, all cap values in microfarads. As for the diode, it's acting as a half wave rectifier to provide the negative bias voltage. I'd say a 1N4007 should be OK (1000V, 1A) given the low bias current requirements and the voltage coming off the PT secondary. 1N4007 diodes for bias circuit mentioned here: http://music-electronics-forum.com/t9988/#post78831

Just curious, what made you decide to go with the 6G3? I'm considering another build but I'm not sure what I'd like to tackle next.

Thanks mysticwhiskey. As for the decision to build 6G3, it came down to the tube bias tremolo and the heavier-than-blackface breakup the brown/tweed amps bring to the table. It's also simple enough for me to build it and learn from it. Plus enough room to always modify. It's a cool amp. Check out the Ampeg J-20 if you're interested, it's a pretty close clone, though also out of production .

6G3 well FWIW,
If you are chasing different breakup charicteristic then play around with the *Screen Drop R vaule*.
A lot of those Deluxe kinda circuits are much the same, cept for the Screen Drop.

It never gets much mention as having any mojo value by the "Experts" but it is one of the simplest ways to make major changes to the way the power stage responds.

Try 1k but even up to 2k7,, past that you start to loose a fair bit of useable clean wattage.
Some early Deluxe circuits use a 10k Screen drop but I found that did little except loose volume.
Phil.

Finally getting back to this, sorry to revive an old thread. So the only caps that are electrolytic are the caps to ground?

Looking at the schematic, all electro caps go to ground, and also three non-electros: The two off the tone pots, and one off the tremolo intensity pot. Also note that the bias filter cap has its positive end going to ground since the bias DC voltage is negative.