Hi reedcat,
Using the schematic in post 1800, your feedback resistors are R5 (820R) and R6 (27K). R5 is very sensitive as far as your circuit gain goes. It wouldn't hurt to use a higher wattage resistor for R6, or two to make up the 27K value. That will reduce temperature change as your output power changes.
-Chris
Using the schematic in post 1800, your feedback resistors are R5 (820R) and R6 (27K). R5 is very sensitive as far as your circuit gain goes. It wouldn't hurt to use a higher wattage resistor for R6, or two to make up the 27K value. That will reduce temperature change as your output power changes.
-Chris
Is the build guide still not updated!? I "complained" about this a long time ago, but... ouch. Maybe the build guide PDF should be replaced by the Wiki page, which is easier to keep up-to-date.
The other sch has changed the transistors from Q7 & 8 to Q9 & 10
Sorry for the wrong data.
I believe it was updated in the 2012 Version of the build guide?
On the 8th page of the build guide (available from the DIYA Store), under the section "Ideas and Alternatives", subsection "Cascode/ Current Mirror".
I believe this is the "Baker Clamp" modification if I understand it correctly. It is presented as one of three different methods of cascode reference.
Cheers,
Tim
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a 3pin inline VR can be inserted in either direction.
As a variable resistor, it still operates the same. But the direction of rotation of the adjuster will either increase, or decrease the resistance.
You need to decide what effect you want when you turn in one particular direction and insert the VR to achieve that.
My preference is for the effect to increase when I turn in a clockwise direction.
eg. when I want to increase the output bias voltage, I want the resistance to decrease. I look at the PCB traces and find which two leads are shorted and find which orientation gives a decrease in resistance for a clockwise rotation.
That way I get an increase in output bias with clockwise rotation. But, That is a personal preference.
I know from looking at many Member designed layouts that most Members here don't care and some boards even have different rotation on the same PCB !!!
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Looking closely at the build guide and the schematic, r23 and r27 seem to carry just under 9mA at their rated resistance. Power is I*I*R so only milliwatts across those resistors. Verified by a search in the build thread where the designer ostripper confirmed it (26 July 2013, post 384))
In fact ostripper's comment at the time was that most resistors can be 0.125W with no issues.
hi I'm fine !! as soon as the pcb will be available in the store, then the store ... and I'll take both the transformers .. I'm completing the big Ekta and 4ohm speakers ... that require many W .. thanks
HoneyBadger and Ekta, yummy!hi I'm fine !! as soon as the pcb will be available in the store, then the store ... and I'll take both the transformers .. I'm completing the big Ekta and 4ohm speakers ... that require many W .. thanks
excellent .. buy !! thanks now I have 2 questions on the PSU; I'm going to use my 2 toroidal transformers from 600w 2x37 and do a dual mono, a friend had passed me a x psu dual mono x f5 turbo v2 that uses a transformer from only 2x24, I can use this psu (mur3020w, cap from 15000uf 63v, ..) , x dual mono I have to use houses from 5u x 400 ?? or x dissipate the heat can be enough 5u x 300 ???? thank you
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I advise to build a few amps before this reason is your questions, this is not choose build guide and solder plug&play.excellent .. buy !! thanks now I have 2 questions on the PSU; I'm going to use my 2 toroidal transformers from 600w 2x37 and do a dual mono, a friend had passed me a x psu dual mono x f5 turbo v2 that uses a transformer from only 2x24, I can use this psu (mur3020w, cap from 15000uf 63v, ..) , x dual mono I have to use houses from 5u x 400 ?? or x dissipate the heat can be enough 5u x 300 ???? thank you
Even the designer said that his ef3 is more stable than this ef2.
You need knowledge, like do it yourself amp.
Or ask questions, get answers.
As mentioned before, the DC voltage will end up at about 55 V with your transformers (or maybe a bit lower). The 63 V rating should do it, although some may say that more margin would be better. But with this PSU already available I would just give it a try.