Mr. Yamaha
Not so much Yamaha lately...
I had some spare time and recently acquired these units for setting up an office system.
The CA-810 is pretty straight forward and I used the guide as found here: http://www.stereo.net.au/forums/topic/37009-led-replacements-for-incandescent-lamps-in-vintage-gear/
The difference is I used warm white (2700k) LED's with a wide angle of 140 degrees. Also I used two 5 Watt 1.8 K Ohm resistors to replace the original resistors in order to feed the LEDs 25 mA.
The LEDs I use for all my conversion projects do nearly produce the same light warmth and color of the original bulbs. And while in the picture it seems very green and bright, in real life it's that very light green / yellow it should be. Not sure why it always looks so different in the pics.
The CT-600 and the CT-810 were a different story. I know some guys are using the AC voltage to power the LEDs, but I wanted to do it 'right'. So no flickering LEDs and a longer lifespan for the LEDs.
I used a small bridge rectifier and a 100 uF / 50V to smoothen the rectified +. I used this bridge rectifier, but most will do the job: http://uk.rs-online.com/web/p/bridge-rectifiers/2965353/ The Nichicon Muse cap was just laying around.
I tried to make it as good looking as possible with nice shrink sleeves (is that even a word?) and some good soldering. Both the CT-600 and the CT-810 had nice pins to solder the rectifiers on. Pretty solid. Those are the pins where originally the wire leads of the bulbs are soldered on.
First I removed all bulb leads. I cut the 2 AC input legs of the rectifier to the right height (same as the pins they were soldered on). I bent the DC output legs forward in order to solder the cap leads on them. I tied the cap to the rectifier with tie wrap and bent the leads of the cap in line with the leads of the rectifier. NOTE: watch + and - ! Covered the legs with sleeves and soldered the the leads to to each other (cap and rectifier) Some pics:
After that I soldered the AC input leads on the AC leads of the CT's. The CT-600 had 12V AC and the CT-810 had 14V AC. When installed I measured the DC voltages the rectifiers put out. It was 21V for the CT-810 and around 18V for the CT-600. You can calculate the needed resistors here: http://led.linear1.org/1led.wiz. I chose again 25 mA to meet the CA-810 and my LEDs had a forward voltage of 3.2V.
After that I soldered the needed resistor in every + lead. At the CT-600 I chose to solder the resistor just before the LED and in the 810 at the start of the + lead, just after the cap. Why? I was trying which was best, but both has pros and cons.
I used the original rubber meter bulb holders (cut in half) just behind the LED in order to fix the LED properly in the original socket without light bleeding. The soldered the leads on them and some sleeves.
Some pics:
And the results:
The CA-810 is pretty straight forward and I used the guide as found here: http://www.stereo.net.au/forums/topic/37009-led-replacements-for-incandescent-lamps-in-vintage-gear/
The difference is I used warm white (2700k) LED's with a wide angle of 140 degrees. Also I used two 5 Watt 1.8 K Ohm resistors to replace the original resistors in order to feed the LEDs 25 mA.
The LEDs I use for all my conversion projects do nearly produce the same light warmth and color of the original bulbs. And while in the picture it seems very green and bright, in real life it's that very light green / yellow it should be. Not sure why it always looks so different in the pics.
The CT-600 and the CT-810 were a different story. I know some guys are using the AC voltage to power the LEDs, but I wanted to do it 'right'. So no flickering LEDs and a longer lifespan for the LEDs.
I used a small bridge rectifier and a 100 uF / 50V to smoothen the rectified +. I used this bridge rectifier, but most will do the job: http://uk.rs-online.com/web/p/bridge-rectifiers/2965353/ The Nichicon Muse cap was just laying around.
I tried to make it as good looking as possible with nice shrink sleeves (is that even a word?) and some good soldering. Both the CT-600 and the CT-810 had nice pins to solder the rectifiers on. Pretty solid. Those are the pins where originally the wire leads of the bulbs are soldered on.
First I removed all bulb leads. I cut the 2 AC input legs of the rectifier to the right height (same as the pins they were soldered on). I bent the DC output legs forward in order to solder the cap leads on them. I tied the cap to the rectifier with tie wrap and bent the leads of the cap in line with the leads of the rectifier. NOTE: watch + and - ! Covered the legs with sleeves and soldered the the leads to to each other (cap and rectifier) Some pics:
After that I soldered the AC input leads on the AC leads of the CT's. The CT-600 had 12V AC and the CT-810 had 14V AC. When installed I measured the DC voltages the rectifiers put out. It was 21V for the CT-810 and around 18V for the CT-600. You can calculate the needed resistors here: http://led.linear1.org/1led.wiz. I chose again 25 mA to meet the CA-810 and my LEDs had a forward voltage of 3.2V.
After that I soldered the needed resistor in every + lead. At the CT-600 I chose to solder the resistor just before the LED and in the 810 at the start of the + lead, just after the cap. Why? I was trying which was best, but both has pros and cons.
I used the original rubber meter bulb holders (cut in half) just behind the LED in order to fix the LED properly in the original socket without light bleeding. The soldered the leads on them and some sleeves.
Some pics:
And the results: