RCA Calypso

[fullrangeSR]

I got this console in non-working condition (bad caps). The attachment is an approximation of the circuit ( I omitted the balance, tone and loudness). Any thoughts on the schematic?

 

[DigitalJunkie]

Other than the plate-to-plate feedback,it looks pretty standard to me. Should make a handful of watts.

 

[azazello]

Sorry, but where is the grid resistor /to ground/ of 6BQ5?

 

[fullrangeSR]

Sorry, but where is the grid resistor /to ground/ of 6BQ5?

There wasn't one...

 

[azazello]

OK....I'm sure that RCA is right!

 

[fullrangeSR]

OK....I'm sure that RCA is right!

It didn't seem anybody messed with the original circuit... The fact that the resistor is not grounded was the main reason for my starting this thread: while I'm not totally new to 'toobs', I'm still light years away from being able to understand all the nuances (doing the math, etc.)...

 

[DigitalJunkie]

Hum,I didn't catch that on my first glance.
It seems for sure that there should be a grid-leak resistor to ground,or else the bias point will drift at the least,or go into runaway at worst. Strange.

 

[fullrangeSR]

'Mystery' solved - thank you guys. You persuaded me to double-check the (complete) circuit, which I did and... The grid resistor IS grounded - through the balance pot... Oh well, another lesson learned...