Philharmonic tone control.

[jonathan dollimore]

As I understand it, on the Philharmonic, the tone control is part of the sensitivity control.  And since the latter is switched out when on phono, it means there’s no facility for a treble cut on phono. I am wondering about the design philosophy of this arrangement since, with some 1950's 78 records I would quite like a little treble cut.

[jonathan dollimore]

Well, between you, your erudition is now confusing me almost as much as my freely confessed ignorance…..

[Norman S Braithwaite]

The sensitivity control adjusts the sensitivity of the receiver and in the minimum sensitivity position switches to phono input.  When phono is selected, the signal from the radio is excluded.  The sensitivity control does not affect tone.

The selectivity control has three operations, adjustment of IF trimmers to adjust IF bandpass, adjustment of bias to compensate for change in gain (potentiometer), and treble control for both radio and phonograph reproduction (switch with low pass filter capacitors).

Norman

[Scott Seickel]

David, I don't know what you are speaking of.  I currently have about 10 Philharmonics and have had at least 6 to 8 that I previously owned and have sold. 

Dial pointers that I have had, or still have currently include KK-71, KK-86, KK-88, and KK-104.   Weird thing is of all the KK series I have in my list, only one is not a dial pointer. I have also had 2 very early sets with the smaller tag on the rear.  I believe these were single number prefixes. 

Anyway, there is no treble pot on these sets as I pointed out, just the 5 mica caps on the selectivity control.  The 9 knob version of this set introduced a treble pot. 

David C. Poland said:

Scott - interesting. You have a real early production example? maybe with 83V rectifier?

Mine is early 1938 with double KK prefix set #. has VR tube behind the tuning cap. has the treble control as I described

[David C. Poland]

Hmmm. Scott, that is a lot of Philly's. Mine is KK-237.

Been some years since I had my pointer Philly on the bench. I just looked at my 1937 diagram. I see the 5 caps composing the stepped treble control just after the bass tone reactor. - noted as the "HF control". Guess I was thinking of the apparent action of the selectivity/fidelity control on my pointer Philly ... and partly thinking of the 1941 BOL Philly remote control model I restored more recently with its separately mounted treble control.

Nonetheless, the treble control is electrically located after the expander tubes in the audio circuitry, ahead of the 3rd AF. Although mechanically, it is mounted on the selectivity control, so as to work in conjunction with it to reduce high frequency response.

Sorry for adding confusion on the type of control- Dave