Just scored a C-80 preamp!

RHafley

RHafley

Member
I just wanted to share it with the Yamaha lovers here. Right now I'm running a C-60 I found on ebay but it has acted ugly on me a couple of times so it will go into the closet for a backup or possibly off to one the Yamaha techs here for a redo.

The inverted pre out on the C-80 is interesting, according to the manual I can connect it to my stereo MX-630 amp with one channel normal and the other inverted with the speaker connections inverted as well. This is supposed to ease some of the stress on the amp power supply and possibly give better bass response. Has anyone tested this? If so what was the outcome? I should have the C-80 in a couple of days and I'll try it myself.
 
Agreed. I have a C-80 also. The inverted pre-outs are very nice, possibly the best thing about this preamp. I have a C-4 that is relegated to sitting on the shelf as a spare, even though the C-4 IMO has better build quality, all because I can't pass up the benefits of the inverted pre-outs on the C-80.

Your next step is to find another MX-630 and use the inverted pre-outs to run each one bridged :)
 
avionic said:
My NS-1000M's handle the B-6's nicely.
Click to expand...

Very nice! I would like to hear that setup. By the way avionic, back in the early 2000's I was in the wholesale lumber business and did some business with Mid-Continent Lumber in Fort Dodge. The guys name was Tom Sporrer I believe.
 
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RHafley said:
Very nice! I would like to hear that setup. By the way avionic, back in the early 2000's I was in the wholesale lumber business and did some business with Mid-Continent Lumber in Fort Dodge. The guys name was Tom Sporrer I believe.
Click to expand...

Never heard of him. Might have bought lumber from Mid Con a few years back. Don't buy much lumber. Buy a shitload of electronic parts though.Not from Mid-con--Mouser mostly.:D
 
The inverted preout option on the C-85 is wonderful but I have to keep reminding myself to wire one of the speakers out of phase every time I rotate different speaker into play.
 
tubed said:
The inverted preout option on the C-85 is wonderful but I have to keep reminding myself to wire one of the speakers out of phase every time I rotate different speaker into play.
Click to expand...

Why not just swap the wires on the amp end instead?
 
Just opened it up. I have a couple of loose solder joints to deal with and some of that crappy corrosive glue to remove.
IMG_0841


But what is this mod????
IMG_0845
 
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RHafley said:
Just opened it up. I have a couple of loose solder joints to deal with and some of that crappy corrosive glue to remove.
Click to expand...

Probably a 4.7KΩ 1/4 watt CF resistor corroded to the point of failure as well. Check the solder connection on those two heatsinked pass transistors. I'd reflow all those copper buss strips with a dab of fresh solder as well.

That film cap soldered to the bottom looks factory. Don't worry about it.
 
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Sorry I didn't see your first reply about the film cap avionic. I took the big transistors with heat sinks out and cleaned all the glue up and scraped the corrosion out, reflowed those solder joints you mentioned and got after it with some deoxit and faderlube. I have to say that the EQ on this unit is FAR more responsive to adjustment than the one on my C60. I may be just hearing things but the phono switch between 220pf and 330pf actually seems to make a small difference in the tone as well, I never heard a difference on my 60.
 
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