I only have the folded on breadboard right now. You should measure your builds too to see about deviations. A test record and a DMM on AC are enough. Probe the 2nd stage's input and output and you calculate gain by the out/in division.
Ok fellas, first channel fired up. Something not right. 35V rail. 8.1V at base of bc560. 5.9v at top of Jfet. 8.1through 3.9r sorce resistors of jfets. Nothing at collector of bc. I am leaning towards bad bc560.
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Recheck the BC its a PNP and its correct orientation first. All the circuitry realization around first stage for that matter. You should get 8.1V plus Vbe on top of the input Jfet(s) and 25-30mV across each Rs.
I am in the bermuda triangle here.
Top of BF245 12V
Base and emitter of BF245 - 8.1V
Used pot to get emitter of bc560 to 8.1V
Nothing on collector.
Jfets have 31mV acorss 3.9R source resistor.
Output gain fet has 4.7V across drain. Same thing at output, as the cap and pull down resistor are not added yet.
16V at top of the buffer.
R5/6 sitting at 6.71K
This thing should be working.
Gonna try the other channel. Just does not make sense.
Top of BF245 12V
Base and emitter of BF245 - 8.1V
Used pot to get emitter of bc560 to 8.1V
Nothing on collector.
Jfets have 31mV acorss 3.9R source resistor.
Output gain fet has 4.7V across drain. Same thing at output, as the cap and pull down resistor are not added yet.
16V at top of the buffer.
R5/6 sitting at 6.71K
This thing should be working.
Gonna try the other channel. Just does not make sense.
Yes. You should have half the BC560's emitter to ground voltage on its collector to ground after trimming, ~10V across second stage's Jfet drain to ground, for 35V to ground B+. Also the BF245 looks like drawing much. Either isn't an A type (lower IDSS rank) or its a short.
I have bf245b🙁. I have 4ma of current on Jfet gain stage after 43R degeneration. Both channels exactly the same. In terms of general settings and measurement. Is it the bf245b?
Check its legs in its datasheet, its not like Toshiba pin order in case you did not, also take them down to 5mA with a resistor on their gate to source, feeding the leds from gate. See from there on by measuring again.
Are you saying insert a degeneration resistor into current layout. The led's are just a Vref for the bjt, being fed by bf845 current source, correct.
Correct. Or use a K117GR if there is no space for a resistor. Only be sure about orientation. If its wrong or type is changed, do the Irish dancer leads with a pliers.
when you use obbligato premium gold as a coupling which end Is recommended to be In and which out for signal
do you recommend bypass of obbligato premium gold 4.7 uF - If you do which bypass and value - teflon ft-1 ft-2 ft-3
do you recommend bypass of obbligato premium gold 4.7 uF - If you do which bypass and value - teflon ft-1 ft-2 ft-3
I normally use the cap orientated as per it´s casing lettering.
input -------[Obbligato]-------- output
I would start without any bypass. Let the caps settle and see if you like the sound. I once bypassed one of those with a smaller obbligato (0.47u) with good results.
