RPS,

Thanks for the detailed information on parts and their part numbers. This will help me greatly as I decide how to proceed with the updates. After 42 years, I think a refresh is in order.

I'm humbled by your very generous offer to provide me with some great music to evaluate with the C9 in my system and room. This sounds like a great opportunity!
I'd be more than willing to review the music/sound and post the results here. I'm not exactly the best reviewer or writer but I think it would be fun and hopefully provide some insight to others who may be curious about the C9.
I will reach out after the holidays for sure. Thanks much!

Even though I can't set up my listening environment as the manual describes, I agree with you that one needs to try all the options on the C9 to hear what is best for their situation. With a reasonable amount of room treatment and a little work to tweak what you can with the room setup, I was able to achieve a really nice expansive soundstage that sounds very natural. It took the Decware sound to the next level. On some tracks it's a small improvement, but on others it's very obvious and very realistic. It just takes time to set the switches, listen for a while (hours/days/etc.) and then change the settings and rinse and repeat. It will be obvious at some point.

I'm also with you in the fact that it didn't take me long to hear the difference the C9 made. It was pretty much immediate, just like in your case. Maybe it's the treatment or the work I had already put in to get the speakers just right, but whatever it was, it was pretty obvious from the get-go. I'm just glad I was able to get a very big improvement even though my speaker placement couldn't be changed. (I wasn't expecting that since the manual stated multiple times 'to follow the speaker setup and listening seat exactly'.) Granted, I'm not getting the true 3D spatial sound, but I'm very, very pleased with the sound I'm getting.

Thanks for the link to the Carver video. It was humorous, cheesy, and insightful at the same time.

I too will be interested to see where this journey leads for you, JB, and I as well as any others who choose to hear what the C9 can do for their listening enjoyment.

JB,

Thanks for the pictures of the inside of your particular unit. Very interesting to see the differences in the layout.


Here's wishing you, JB, all the Decware family as well as the forumites a very Merry Christmas, New Year, and holiday season. Enjoy it y'all.

 It occurred to me that I could add a bit more information about the rebuild. Specifically, what drew me into this whole idea were the original RCA jacks used for the unit. Since they are recessed, it can be difficult to use just any interconnects. They must have skinny barrels or else they don't fit into the RCA jack. I didn't like that at all, and looked inside to see what could be done. It took a lot of experimentation to find RCA jacks that mount to the chassis and not the circuit board  itself. I ended up using Manley Labs RCA jacks and have done it that way for years. Well, since we are now inside the unit, it is a good time to take a look at the electrolytic capacitors seeing how they are 30+ years old. There are a total of 10, and it doesn't cost that much to just replace them with new and probably better caps. Of course that led to other stuff, namely the power supply. I realize that it is only needs to be tiny, but I was into replacing two of the 4136 chips with military models which happen to draw more current. FWIW, the 4136 Texas Instrument chips (there are 5) used in this unit have an unusual pinout, making the use of an adapter for other chips such as the 2134 which is a more modern version of quad amp. Yup, tried this out, with the help of a 'Brown Dog' adapter with pre-mounted with SMD chips from yes, the company named Brown Dog. This will set you back about $35 per chip replacement. Is it worth it? Not so much in my opinion, so I went with trying to find a better 4136 chip, and that is when I discovered the metal jacketed military chip that usually runs about $20 per chip if you can find them. I only have two left at this time. They sound slightly better than the originals, but hell, we are racing cars here so every little bit helps.
I have replaced numerous other components, but will tell you that each one in its own is not likely to make any difference either. From what I have gathered, replacing those two transistors is of little value since they don't amplify but just pass the signal through upon turn on just to eliminate the turn on thump.
I have tried just about anything that you can imagine, including using a battery power supply to using a separate power supply, to well, name it. Really. In the end this is where I have ended up. Like I said in the first post a rebuild of an existing unit sent to me runs around $125, and if I get the right price on eBay for a used unit, $250 is the selling price. As expected these units have become popular, and for a while people out there were selling them as reworked/tested/rebuilt/improved. This usually meant that the little red light cam on when plugged in and nothing more. If they did show the inside, I was immediately able to tell if they were ever taken apart or not. Maybe I will give up that secret later, depending on the interest of these units, and yes, they are truly worth having in a system. Many other brands have attempted in various ways to replicate this audio illusion and I have listened to a number of them. This unit by far and away the best.