Is my Dynaco Stereo 400 worth repairing for resale?

I still have 8 or 9 Dynaco pieces though I tend to grab the tube stuff. Have some solid states like the  PAT-4's & a Stereo 120 but I've never owned a 400. 

There are definitely people that are still interested in Dynaco's. If it's clean & in good working shape you can make a couple bucks on top of the repair costs but not much. With anything it depends on the buyer. What I would do is take your time renovating it for minimal costs but with quality parts. Do it for the enjoyment & keeping old audio alive. 

Then list it for a price you are comfortable with..with the expectations it might not sell right away. Enjoy it in the meantime or box it away. Eventually someone will come around that wants a solid working 400 to add to their collection. And won't mind paying a little extra for one that has been recently brought back up to spec. Fixing one up for a quick sale or needing your small investment money back right away might not end like you would want it to.

I was unable to see the exact one that you have but the 400's with VU meters still fetch a pretty penny. There was a really clean (exterior) 400 without meters on the Bay for like $320 plus shipping. So I'm guessing anywhere from $3 to $500 depending on some things. Although I'm looking at some right now as high as $950 no meters..$1800 with. How long have they been sitting for though. 

If you have the means & time to fix it up I say go for it. Keep your investment as minimal as possible. Or upgrade all the parts & keep it for yourself. 

Your Dynaco 400 might not need any immediate work. Put it on a variac to reform the power supply caps. Then use a multi-meter to check the DC voltage on the two speaker outputs. If those show only a few millivolts of DC try the amp with a pair of speakers. Not all old amps need parts replacement. My 40 year-old Sumo Andromeda - another Bongiorno design - has been in use 24/7 for seven years now without a hiccup! 

Under no circumstances should anyone buy "restoration" parts from Hi-Fi-Audio-Rocks on eBay.  He's notorious for send poor or wrong components and providing weak or nonexistent documentation.  There's a long thread mover at Audiokarma about this seller.

@curiousjim 

I get there is little room inside, however, all new caps of the same value will be much smaller. At times I have had to check the values again, they are less then 1/2 the old caps size for the same value. In fact have gone up in voltage on a lot of caps, they are sill much smaller. 

Point it, there should be a lot more room, after you swap out a few caps. 

Yes, do not purchase any "kits" get the service manual, it should have a parts list, with that, put together an order with mouser or digikey.

I built the Ampzilla in 1975. I paid for a rebuild 12 years ago after a 2 hour conversation with Mr. Bongiorno months before he died. I subsequently used it until I finally replaced it with a Spread Spectrum Analysis (SSA) Son of Ampzilla II amplifier, circuitry designed by Jim and finished in partnership with Jim by Wyred for Sound who physically built it and designed the beefy power supply.

A note about his name: I have only seen references to “James” Bongiorno in the last 25 years, with pictures of him usually wearing a wild colored suit with an extravagant shirt. When I met him as an 18 year old in late December 1984, he introduced himself to me as Jim and was wearing a white T shirt with a leather jacket, very biker like.

The original Ampzilla had a “dual-differential input” and had completely complimentary symmetry from input to output. I think the SWTP Tigersaurus had a complentary output stage with differential input. Others may know better, but the lineage of the Ampzilla runs through the Dyna400 to SAE 4 to Marantz 500 chain most directly. I think that the Marantz 500 was the first to use both high powered PNP and NPN transistors in its output stage.