2 PT-2 power transformers on 1 chassis--SR45 amp

[howardnair]

i am done for the evening-so running through my head as you and paul talk paramour-it seems  much more logical  to do just that-paramours -forget the sr45--i  have softstart bd, -5670-,-456 b+--the exo 45 is a 5k load-mmmhhh

[Paul Birkeland]

and will change whatever is suggested

Build the basic Paramour II circuit.  A 47K resistor will work as a plate load instead of the C4S, just to get you going. 

[howardnair]

Paul-thank you--I don't have a schematic labeled paramour II- i have the sr 45 paramour schematic-a simple enough change everything is in place -i will lift the zener string from the circuit-and the grid to ground for v2-that leaves one question -the value of the v1 cathode resistor-ie; pin3--the circuit for the sr45 shows a 5.5k resistor and a 2490 resistor in series-intercepted by a 431 sr- a+b simple enough but how much does the 431 figure into this

[2wo]

Disconnect pin 1 and the zener string, that should isolate the regulator.

On the C4S connected to pin 6, I would remove the 10000uf cap and 33k resistor. Now see if the LEDs light and check the voltage at pin 3. Try adjusting the pot to see if you can get ~3-8v or so at pin 3...John

[braubeat]

Hello

The 2490 ohm resister in series with the 5.5K resister sets the operating point of the shunt regulator. The 431 chip has a voltage reference of 2.5 volts. So the 2490 ohm resister forms a voltage divider with the 5.5K resister so the 431 chip holds the regulator at 550 volts in this case.  I would guess this is more voltage than you want for a 45 amp. And of course if your power supply won't produce at least 550 volts the shunt regulator will not work at all. 
One more thing I learned the hard way, the anode of the 431 chip must go to ground. Not the cathode as you would think if you did not read the data sheet carefully enough.

Michael

[Paul Birkeland]

Hello

The 2490 ohm resister in series with the 5.5K resister sets the operating point of the shunt regulator. The 431 chip has a voltage reference of 2.5 volts. So the 2490 ohm resister forms a voltage divider with the 5.5K resister so the 431 chip holds the regulator at 550 volts in this case.

2.5V across 2.5K -> 8V across 8K.

[howardnair]

john -rt side pin 3  0v  pin 6 381v   pin 3 at the 45 0v
   left side pin 3 4v    pin 6 85v        pin 3 at the 45 0v
left side driver tube lights up the right side does not

no leds light up--either side-moving the bias resistor  on the left side has very little effect

michael -i realized that after i walked away from my post--so i have been going through the sections of morgan jones book on voltage dividers and cathode resistors-the reading is a little more involving when you can apply it to a situation at hand

[2wo]

On the left side 4v is reasonable, 85v is not, sure its not 185?. But is should play. Might be time to try the 47k resistor ( at least 1W) pin 6 to B+, disconnecting the C4S.

If the right tube is not lighting up there is something wrong with the heater voltage pins 4,5 

[howardnair]

Do I disconnect or connect anything else

[howardnair]

WE HAVE MUSIC-direct from b+ via the 47k -on pin3 both sides i have 5.9v-
left side pin 6 185
right side pin 6 177
the rt side 6.3  heaters were not getting voltage--cold joint at transformer-
thank you--john
thank you -paul 
now that the amp is viable what will be the next step/s   again- thanks -your help was much appreciated
howie

[2wo]

Next would be to get the C4S for the driver working. The SS is set for 4.3ma, which is probably OK for now. Refer to the SR-45 schematic you can connect a 160k from bD to ground and remove the 300k RLd.

Now, from previous testing it look like the C4S was passing all the B+. This does not bode well for the active components. you can test the LEDs with your meter or a battery, if they light they're OK.

You can test the C4S. leave the 47K in series, Connected from pin 6 to OB and restore the B+ to IB.
If the C4S is working the voltage ACROSS the 47k will only be be a couple of volts. if not replace the transistors and LEDs and try again...John   
 
edit, check the voltage across the 47K before you make changes, so you know were you start

[Paul Birkeland]

If the C4S is working the voltage ACROSS the 47k will only be be a couple of volts. if not replace the transistors and LEDs and try again...John   
 

A working CCS feeing 3-4mA of current across a 47K resistor will make more than a few volts.

[howardnair]

john and paul--i will implement the changes and ck the voltages maybe tonite-monday evening i was force fed some nice bourbon from the local distillery--there was some fallout from this-ie; late evening, inebriation-the next day--howie

[Grainger49]

Oooooo... I need to be force fed some Bourbon. 

I had one last drink from my Woodford Reserve before working on the Crack I am trying to get well this evening.

[2wo]

Have fun, Paul is right about the voltage across that 47k. As usual I got the decimal wrong...John