Latest recap and Upgrade amp - Yamaha M-70
- Thread starter brutal
- Start date
"ItsTooLoud"
Metal Mind
Is that a piece of beveled plexi the binding posts are mounted to? Looks slick.
It's Home Depot "Acrylic", the Lexan was too much but may have held up better.
All done with simple handtools and by hand. Six varying grades of sandpaper finishing with 1500 and plastic polish to get that beveled edge. Mostly did it that way because it chipped a tiny bit on the tablesaw without a proper plywood blade. Delrin used for the backing on both the BP and RCA connectors.The half-dogbone cutout on the Vampire backing plate to clear the screws was the toughest part and didn't come out as well as I had hoped.
It's Home Depot "Acrylic", the Lexan was too much but may have held up better.
The half-dogbone cutout on the Vampire backing plate to clear the screws was the toughest part and didn't come out as well as I had hoped.
Looks great..
Time will tell as it breaks in. Bass seems a tad tighter and the damping more in control but that could simply be first impressions. I tried to give it some serious listening time before the recap, but time has a way of changing one's perceptions and it took a little while to finish it all up. Except for Yamaha's poor choice of binding posts, the build quality on this model is pretty great.
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Know what you mean about time. Unless there is something obviously wrong with a piece of gear it can be somewhat difficult to tell if a recap made a difference or not unless you've had extended listening time with it prior to the recap. I'll be watching this thread to find out your impressions after break-in. :yes:
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Wonderful!
The M-70 is a sweet sounding amplifier, but those speaker connectors are f 'ed up. I have to make sure one wire is "pushed-in" snugly. Visually speaking, no glue problem here, yet
The DSBG is on the front vertically mounted power circuit board where you can't easily spot the issue. You should also have the .22uf X2 cap on the Control 1 power supply board looked after.
I'm still trying to decide if the M-70 or M-80 has the worst binding posts ever...
It's a shame as they are all such nice sounding amps.pradigmshift
Active Member
That looks really good!
Did you replace the rca input jacks or did you clean the original jacks? And with what? I can't seem to find the yamaha style input jacks.
Did you replace the rca input jacks or did you clean the original jacks? And with what? I can't seem to find the yamaha style input jacks.
Replaced with new Vampire RCA. These were mounted on the panel and easily replaced unlike pre-amp jacks. They had been replaced by a previous owner, but they were low grade knock-offs and on a cheesy metal plate. I use Delrin backing plates for everything. If I do clean RCA jacks, I use a clipped off cheapo rca cable end chucked up in a drill with a thin pad and soaked in DeoxIT.
ouimetnick
Hafler Fan!
Where and what is that Black glue that you used to hold in the capacitors?
Black RTV
Specifically,
http://www.permatex.com/products/Au...ermatex_Black_Silicone_Adhesive_Sealant_b.htm
As much as I dislike silicone based products, it's something I had and found works well.
The problem with silicone is that nothing else, including fresh silicone sticks to it once cured. Evil stuff that must be mechanically removed from anything it touched to be reliably re-bonded. I normally avoid the use anywhere that's ever going to require a redo in my lifetime.
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sonavor
Active Member
Beautiful work. My first separate power amplifier was an M-70 and I still have it (and use it).
What thickness of Delrin did you use? Did you just order it from a plastic supply house?
On the recap, did you replace all of the electrolytic capacitors in the M-70?
Thanks,
Sonavor
What thickness of Delrin did you use? Did you just order it from a plastic supply house?
On the recap, did you replace all of the electrolytic capacitors in the M-70?
Thanks,
Sonavor
Spectrum77
Super Member
Looks great!
Thanks,
1/4" I ordered a 12x12 piece a while back some place online and still have a bit left for two or three more amps depending on size.
Yes, I replaced all the 'lytic caps in the M-70 and the troublesome X2 power input safety caps as well.
