fuzzbunny wrote:R1 & R2 are both 100k? Is that verified?
Thx.
Manfred wrote:fuzzbunny wrote:R1 & R2 are both 100k? Is that verified?
Thx.
I ran a simulation of this circuit and found the collector voltages as follows:
Using R2 = 100kOhms : 1.8 Volts DC
Using R2 = 10kOhms: 7.7 Volts DC
A collector voltage of about 7 Volts is common in the known Rangemaster circuits.
IMO the Value of R2 must be 10kOhms.
I did a quick breadboard with Apollo's schematic values but subbed a 10K in the R1 position.
I used a variable resistor in the R3 position ( collector) and biased by ear.
The circuit sounded best with approx. 4.5v on the Collector, R3 around 50k.
Don't get me wrong, Don't get me wrong, I appreciate the great contributions Apollo makes to the forum! I just wanted to pass,on my findings for others to build on..! I just wanted to pass,on my findings for others to build on..
Manfred wrote:The symbol of the DC jack is wrong in the schematic, sleeve and tip have been mixed up.
Manfred wrote:http://www.tubeampdoctor.com/en/shop_TAD_Equipment_Other_TAD_equipment/RangeKing_Power_Booster_667
In the Specifications of the TAD Rangeking you can find;
- jack for external 9VDC power supply (tip: ground, sleeve: 9VDC)
In your schematic the sleeve is connected to ground and the tip to +9VDC
rs wrote:From looking at the photos, R1 looks like 4M7 to me (yellow-violet-black-yellow-brown) but i could be wrong.
Manfred wrote:rs wrote:From looking at the photos, R1 looks like 4M7 to me (yellow-violet-black-yellow-brown) but i could be wrong.
Indeed, I measured R1 with 470k an R2 with 2M2.
I ran a simulation with the new values which confirm the read voltage values.
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