Any C-65 Owners?

[39cross]

A few years ago I picked up a low-mileage C-65 preamp off of ebay for not much money. Of all the vintage equipment I own, this is the most pristine, not a mark on it, still looks new. I haven't done any recapping, nothing other than taking off the cover and visually inspecting the board and components. I didn't see any corrosive glue, so didn't see any need to rush into it.

This week I put it into action with a Realistic STA-2200 mosfet receiver I recapped. I really like the STA-2200, great sounding amp and tuner. The preamp section is not so hot. I'd been using it with another preamp.

The c-65 really surprised me, it sounds very good. According to the schematics it appears to share much of the design of the c-85. They are both loaded with op amps. Perhaps is some judicious upgrading that can be done, but as is, I am more impressed than I expected.

Anyone else using a C-65? Thoughts?

 

[39cross]

Looks like the C-65 fan club is a very small party. Second try in case anyone shows up.

 

[yamahafanatc]

For anyone interested(no affiliation)there is one on the bay right now.

 

[OMGCat!]

The C-80 is one of the most transparent Preamps I've heard. I tried A/Bing it vs. CD player going straight into the amp and could hear no difference. I ended up doing the test several times with a few different amps and still could never tell.
If the C-65 is that similar I don't think there is much to gain by swapping around parts. It likely could benefit from a deglue, some new caps and solder joint touch up however.

 

[Chorus1fan]

I've got a C-60 & LOVE it (& a M-60 powering it). So yours is probably even better !!!

 

[avionic]

C-60 is pretty much electronically identicle to a C-65. As is the M-60 identicle to the M-65. C-80/85 the same-- M-80/85 the same..

 

[Chorus1fan]

C-60 is pretty much identicle to a C-65. As is the M-60 identicle to the M-65. C-80/85 the same-- M-80/85 the same..

Do the 5's have a glue issue like the "rounded" number models in the series? (sent you a PM about working on mine)

 

[avionic]

Do the 5's have a glue issue like the "rounded" number models in the series? (sent you a PM about working on mine)

Of course they do..

 

[avionic]

If you compare the parts list of a C-60/65 , M-60/65 , C-80/85 and M-80/85. You will notice they are the same. Only difference in part numbers for all of them is the front and rear panel part numbers <----- Silkscreening is different. ie M/C- x0 or M/C-x5.

 

[Chris Brown]

As a C-80 user, it doesn't surprise me to see a C-60/C-65 fan club developing as they are so similar. It really is amazing to have a preamp with such a low output impedance that is so powerful. The main difference between the C-80/C-85 and the C-60/C-65 is the lack of inverted pre-outs on the C-60/C-65 though, and I use those for one thing or another for every single amp in my system. I could not live without them. I have a C-4 as my backup preamp, which doesn't have inverted pre-outs either, and if I had a chance to swap it for a C-60/C-65 I would seriously consider it. You would be hard to go wrong with a C-60/C-65.

 

[dondoucette]

I've got a C-65, no output, somebody has been in there before. I see some bulged caps, that nasty black glue around heatsinks, etc. Just trying to find some time to give it a look.

 

[mr.muddles]

I've got a C-65, no output, somebody has been in there before. I see some bulged caps, that nasty black glue around heatsinks, etc. Just trying to find some time to give it a look.

Take out the heat shielded transistors and clean up ALL of the glue carefully and remove the glue from nearby components if necessary. The solder joints underneath those transistors are probably broken. On my C-80 they were rocking back and forth and completely lifted from the foil side of the board. The no output could be due to dirty controls and switches but you'll want to replace those bulged caps at the very least, I think.

 

[dondoucette]

Take out the heat shielded transistors and clean up ALL of the glue carefully and remove the glue from nearby components if necessary. The solder joints underneath those transistors are probably broken. On my C-80 they were rocking back and forth and completely lifted from the foil side of the board. The no output could be due to dirty controls and switches but you'll want to replace those bulged caps at the very least, I think.

Yep to all of that.
TR149 and TR150 are loose as you have stated, I will clean the glue and probably just replace the resistors and any bad caps I find.
Any easy methods to remove the glue?

 

[mr.muddles]

If it's turned dark brown or black its going to be tought to get off without using a scraper. I used a very small flat head screw driver that had one side of the tip slightly bent so it was almost like a little shovel. I just very carefully scrapped everything away and blow it out or vacuumed it up and afterwards clean up with alcohol.

It's tedious and takes awhile but I'm not sure there is a better way.

 

[mr.muddles]

If you do a full recap which is what I did with mine, be mindful that there are a whole lot of bipolar caps. I missed all of them when I put in my initial order to Mouser because I was only looking at the parts list which was partially in Japanese and wasn't smart enough (at the time) to notice the BP and realize that mean't bipolar. I think I also found some bi polar caps that weren't listed as bipolar on the parts list but I need to go back and double check inside and compare to the schematic.

 

[mr.muddles]

Yep to all of that.
TR149 and TR150 are loose as you have stated, I will clean the glue and probably just replace the resistors and any bad caps I find.
Any easy methods to remove the glue?

make sure you clean all the old grease and put new grease on and don't use too much... just enough to lightly coat the back of the transistor.

 

[mr.muddles]

Yep to all of that.
TR149 and TR150 are loose as you have stated, I will clean the glue and probably just replace the resistors and any bad caps I find.
Any easy methods to remove the glue?

You can pull any suspect resistors and test them just make sure all the glue is off the body and legs of each resistor. I cleaned 2 in my C-80 and put them back in. My M-80 had many good components that had glue that I took out, cleaned, and put back in.

 

[avionic]

I cleaned 2 in my C-80

4.7KΩ 1/4 watt carbon film.

 

[dondoucette]

Just finished up, replaced the 2 4.7k resistors, replaced on obviously bad 100uf 16v cap with one I had in my parts stash, cleaned up all the old glue, reflowed several bad solder joints, tightened up the wobbly volume pot.
I powered it up slowly on my variac, everything seemed normal, gave it a signal and ta-da working again.
Now on to restoration. Didn't want to put much time or effort in unless I could get it working first.

Thank you for your assistance and comments gentlemen, much appreciated.

 

[vitorzoom]

I have a Yamaha c 65. Natural and balanced sound, noticeably more detailed than a NAD C352, which in comparison has a muffled sound and no middle. The bass (compared to the NAD yet) are more articulated while in the NAD it sounds more embolished.