Thursday, November 10, 2016

Mark & Joe's Yamaha CA-2010 Integrated Restoration

Two Yamaha CA-2010 Integrated Amplifier's





Today were featuring two Yamaha CA-2010 Integrated Amplifier for two customers. The CA-2010 is considering one of the best integrated amplifiers from Yamaha. A step above its smaller CA-1010 brother the CA-2010 was manufactured during the late 70’s (1978-79) touting an impressive 120W/CH @ 0.005% THD with a switchable Class A operation with decreased output.






The CA-2010 used a high grade stepped, enclosed Alps potentiometer, dual controls, low noise RIAA EQ FET’s with a robust 22,000MFD filtering stage versus 18,000 for the 1010. The build quality is very good along with the original component selection, the RIAA is a bit over designed and the issue with Class A operation are discussed below.




Power Supply/Protection NA06878
The CA-2010 uses a special relay both for the audio muting inrush circuit and protection relay (12V DPDT 10A) device that was replaced with a new Panasonic HL2 type.  The Main filter capacitors for the coupled/rail stages were replaced with computer grade 22,000MFD 100V Cornell filter capacitors along with the associated relay and safety capacitors with X1Y2 Safety type.





The electrolytic capacitors with replaced with a higher operating voltage high temp (105C) Nichicon PW capacitors along with VP Nichicon’s for the Bi-Polar electrolytic’s. The two bypass .1MFD films were replaced with high grade polypropylene ECW Panasonic’s.  The heatsink mounted TO-220 devices exhibit a large amount of radiant heat evident on the PCB assembly. Both of these regulating devices were replaced with a more robust, heavy rating On-Semi TO-220 devices with new thermal compound along with the diode network to new Ultra-Fast UF400# type.


BEFORE



AFTER



Meter PCB NA06836 & LED Modification
The meter control allows for a accurate and reliable peak to peak indications due to the ultra-responsive circuit calibrating input (mv) decibels and output (Wattage.)  This assembly also uses a common JFET the 2SK30A  and a proprietary PM-02 control IC.



The electrolytic were replaced with two 47MFD low impedance high temp (105C) PW capacitors with an increase in operating voltages.



One of the major cosmetics upgrades for the CA series is LED meters, which give us a reliable, long term lighting solution with less current draw overall and almost no discernible heat. We’ve perfected the dispersion and flickering by adding an inline UF400# type diode with a 470MFD/35V filtering capacitor to reduce any flicker or surge. The LED’s turned our fantastic!
One of the units the customer had removed the blue filter, hence the white meters on one.







Tone Control NA06826-1
The tone control on the 2010 is hardwire as well the 45 degree mounted stepped Alps volume control.  One of my biggest concerns was the hardwired connections were used which greatly increased the risk of connections issues. The hardwired connection was removed and replaced with the x3 runs of silver wire (NOT CHEAP!) for a better long term solution. On this assembly the AF path film were upgraded to high grade MKP and ECW polypropylene film capacitors as well as the 47MFD electrolytic replaced with a audio grade Nichicon KT with an increase in operating voltages.





BEFORE



AFTER




Another thing we encountered now is the integrated of fussier type resistors, these have an average watt rating to fail as part of the fail safe. Im am not a fan of these components as they tend to drift substantially in rating and have poor audio characteristics.  Using an appropriate Ohms Law formula one can calculate the wattage and replaced with an appropriately rated carbon film type that still provide protection.  The formula consists of I(squared) X Resistors = P. This PCB used three each channel two 33OHM 85mA and a 47OHM 70mA; (0.0049)x47=.2303 W (1/4W resistors)




RIAA EQ NA06877
The CA-2010 features an adjustable input/impedance selection for either MM/MC setups.



 For the MC Amplifier front end audio grade KT and low impedance PW’s with a increased in voltages were installed replacing the original tantalums as well with a PW Nichicon (100MFD’s) for the standard RIAA EQ stage initial differential 2SK100 JFET are used.  As above mentioned the RIAA EQ stage uses an array of fusistor type resistors, again these were replaced with carbon film in the appropriate wattage (33OHM 85mA (.2384W), 390OHM 25mA (.2437W.) Input and coupling films were upgrading to a high grade polypropylene WIMA film capacitor’s.




RIAA Curve Response


Drivers NA06844
The driver stage of the CA-2010 features a unique option to operate in Class A SEPP operation rated at a lower distortion to 30Watts. After rebuilding dozens of CA’ units I have determine the distortion factors vs the cons are not worth operation. Using Class A operation runs the unit into uncontrollable heating issues stressing several stages of the design. I DO NOT RECOMMEND operating these in Class A operation simply due to the extremely excessive heat within the driver stage.

BEFORE



AFTER


Again like the AF boards so far the drivers feature an array of fusistors which were all replaced with appropriately rated carbon film KOA type with a noted increase to 1/2W for the 68OHM/85mA (.4913W) resistor.

FR301/302 (4.7/230mA) 4.7ohm 1/4W  (4.47 und 4.35) (.2486 W dissipation) 
FR303 (100/50mA)  100ohm 1/4W (100.91)  (.25 W dissipation) 
FR304 (68/85mA)    68ohm   1/2W (68)      (.4913)
FR305 (390/25mA)  390ohm 1/4W+ (393) (.2873 W dissipation) 
FR306 (47/70mA)  47ohm 1/4W  (47) (.2303 W dissipation) 



The CA2010 driver features x4 1/80V capacitors which were all replaced with a high temp(105C) Nichicon with an increase to 100V rating. The input 0.1 films were upgraded to a MKP polypropylene film capacitor’s.  All of the Bias/Class A bias/ offset potentiometers were replaced with a precision Bourns trimmers. The differential stage consisting of a NPN and JFET array, the NPN differentials were replaced with a 1% matched TO-92 low noise modern transistors along with the end stage driver compliments to a more rubust, heavy duty MJE On-Semi TO-220 device with new thermal compound applied along with the TO-3 output devices. 





Audio Notizen **Watch for the Class A Report Update 11/16
















1 comment:

  1. Nice work!, Wonderful attention to detail. Makes me want to find some CA 2010s for you to fix and me to own.

    ReplyDelete