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Installing a Presence control to STA200

Posted: Sun Feb 09, 2014 6:33 pm
by Philrob1
Hiya folks

I would like to install the Presence control to my newly acquired STA200

I have been studying the diagrams on MHuss's fantastic Hiwatt site and this is what I have deduced.

The is similar to the DR103 - post MV.

From this, could I pin out from Pin 6 on V3 to a separate turret board dedicated to the Presence control, then connect the back end of this to the Turret upon which 8k2 resistor prior to the 16 ohm tap is soldered to?

If this wouldn't work, could anyone suggest a way it could be done?

Much thanks :D

Re: Installing a Presence control to STA200

Posted: Tue Feb 11, 2014 3:30 am
by mhuss
Well, it's a little trickier, since there's already NFB going to the input stage cathode. You'd have to remove that, then add in the complete presence circuit from a standard DR preamp, from pin 6 of the input stage to the top of the 2k2 in the PI.

--mark

Re: Installing a Presence control to STA200

Posted: Wed Feb 12, 2014 10:07 pm
by Philrob1
mhuss wrote:Well, it's a little trickier, since there's already NFB going to the input stage cathode. You'd have to remove that, then add in the complete presence circuit from a standard DR preamp, from pin 6 of the input stage to the top of the 2k2 in the PI.

--mark

Hi Mark

Thanks for your help. I have given it to the professionals at Chandlers Guitar Experience in London to do. Very highly recommended and at the cost of £25.