62-0-62 volt power transformer: options?

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ostripper

ostripper

Member
Joined 2008
soldersmoker said:
OS, you make a compelling case. I'll give it a shot with the old transformer. I can always swap it out if it doesn't cut the mustard. Great idea about using the other secondary too. Thanks!
Click to expand...

It will "cut the mustard" - as well as the original amp , at least. Might sound
far clearer ( 30 years of semi improvements).

(below) is what you can do for the secondaries -
a zener- free shunt regulator/cap multiplier hooked to the "R" pads of the "Badger" CRC.
Use reverse wiring (MJE 350 + diode reversed) for the negative rail .

67V with < 2mv ripple for the LTP/VAS of the badger.
(simulated 86V unreg. secondary rails).
Your high current supply would be 60V for the output stage.

Besides the heat of the EI trafo , it is in a steel case (lower radiated field). You
might be quieter than a modern toroid build with greater PSSR (second supply).

OS
 

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AndrewT

R.I.P.
Joined 2004
Krisfr said:
Has anyone ever made a chart that spells out the ac output of a transformer and what rail voltage it produces and aligned that with amplifier output into 4 or 8 ohm and then the needed VA of that combination. The chart in Bob Cordell's book on pages 10 and 11 would be a great start IMHO.
Click to expand...
use the standard formulae.
P = I²R = IV = V²/R

or use Bensen's spreadsheet, or the many other guides/calculators on the Forum.
 
TonyTecson

TonyTecson

Member
Joined 2003
soldersmoker said:
I have a rescued Yamaha M4 power transformer that has three secondaries: 62, 45, and 15 volts. The Yamaha circuit shows that the 62 volt secondaries were rectified to +/-80 volts. Is there a good amp design out there that I can cobble together so I can reuse this transformer? I've looked, and it seems that voltage is a bit high for most designs, and way too high for class A (my preference). A good class AB design would be nice. 50-100 wpc or so . . .

Thanks!

9pu9jym.jpg
Click to expand...



the 45-0-45 volt winding is actually used to power the output stage,
the 62-0-62 volt winding is used to power the front-end stage and is low power..
the reason the front-end used +-80 rails is because the front end is voltage regulated..
this is a common practice with japanese amps of the era...
so a honey badger is good to use with this traffo...

you can confirm what i say by measuring dc resistance of the windings and then posting them here...
 
TonyTecson

TonyTecson

Member
Joined 2003
jwilhelm said:
The Yamaha would have likely been an AB amplifier. They aren't known to have overly robust power supplies but if you build an amplifier around the same power range at 8 ohms it should work out. If the finished product makes it into a chassis, it might be a good idea to leave some space to upgrade the transformer later if you find it's not up to the task.
Click to expand...

it is an AB indeed...
 
TonyTecson

TonyTecson

Member
Joined 2003
Krisfr said:
Has anyone ever made a chart that spells out the ac output of a transformer and what rail voltage it produces and aligned that with amplifier output into 4 or 8 ohm and then the needed VA of that combination. The chart in Bob Cordell's book on pages 10 and 11 would be a great start IMHO.
Click to expand...


yes, a look at the specs of this amp, gives you the power ratings...Yamaha M-4 Manual - Stereo Power Amplifier - HiFi Engine
 
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