DRV134
I am thinking to use the DRV134 to drive a stereo F5 kit per channel, did anyone tried this layout ?
If I am not wrong, this will give an extra 6dB gain and each channel will be fully balanced! (it could improve the distortion)
Do you guys think this will work with the F5 ?
PS: I am just afraid that in high volumes it could clip...
I am thinking to use the DRV134 to drive a stereo F5 kit per channel, did anyone tried this layout ?
If I am not wrong, this will give an extra 6dB gain and each channel will be fully balanced! (it could improve the distortion)
Do you guys think this will work with the F5 ?
PS: I am just afraid that in high volumes it could clip...
I have removed Q5 R17 19 21 Q6 R18 20 22. It behaves same.Nelson Pass said:Take the bipolar current limiters out and see if you get a difference,
if not then take R3 and R4 out altogether and report back.
Watch your current!
Then removed R3 and 4. Behaves same. The voltage across P2 increases faster earlier on, since R4 is removed, but won't go above 3.3V.... What should I try now?
That's interesting! Although I also have a large DC over Output to ground (1.4V) and it doesn't seem to change much over P! and P2 value at least when voltage across R3 and R4 is small. How was yours like? Did you use your own layout or others?umut1001 said:i remember that i had same problem.my gate to source was not over 3,7volts.so i removed IRFPs and reduce the trimpots and make 2,7volts for toshibas..i am using toshiba 2sk1530/j201 nowit plays well
Any other idea as to find out what's wrong?
I wonder whether this is caused by JFET somehow, It seems problem is for only N type side. My Noobie mind cannot comprehend why the voltage won't go over 3+a V....
Babowana said:If the P2 has the correct value but the maximim voltage is 3.3V across it, then it must be that too small current is flowing through the P2. If so, we might have a problem with Q2 or R2 . . .
Hope you will find the problem soon.
Cheers,
Thanks. I've already replaced Q2 3 times now, devices from 2 different sources. With DVM I'm measuring D to ground 40 ohm and source to ground 10 ohm, which seems right but, I guess DVM voltage may be too small compared to circuit operation voltage.
Actually I tried to measure Idss of J74 to check whether it is functioning using circuit shown here. http://www.diamondstar.de/transistor_matching_jfet.html
Except I put 330 ohm resistor in to the circuit to imit the current. With one polarity of 9V battery, I was seeing 26mA, as what resisotr dictates and in other polarity it was 9.9ma, So I thogut IDss is 9.9mA. Did I do fry JFET by reversely flowing 26mA?
Babowana said:If the P2 has the correct value but the maximim voltage is 3.3V across it, then it must be that too small current is flowing through the P2. If so, we might have a problem with Q2 or R2 . . .
Hope you will find the problem soon.
Cheers,
Babo-In your build thread you noted use of 2K P2.. Is that your current value??
sandyhooker said:
Babo-In your build thread you noted use of 2K P2.. Is that your current value??
Yes, my current value is 2K.
In addition, my current values are 2.4K for R4 and R16, and 5K for TH2. With these values I can have resistances min 0 to max 950 ohms between the rail and the drain of Q2. So, if I have about 6mA from Q2, I could have max voltage across P2 about 5.7V. Therefore, P2 of 2K is still useful.
Season's Greetings,
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2SJ103 / 2SK246 input
Happy holidays to F5 builders !
Just discovered: 2SJ103 / 2SK246 both have Vgs max = 50V.
Roughly - J103 has 1/7 junction capacitances of J74 and K246 has 1/3 capacitances of K170. Unfortunately they have much lower transconductance.
The big question is: can we keep high perfomance of F5 using paralleled 2SJ103/2SK246 ?
Can we compensate jfets lower transconductance with paralleling output mosfets ?
Happy holidays to F5 builders !
Just discovered: 2SJ103 / 2SK246 both have Vgs max = 50V.
Roughly - J103 has 1/7 junction capacitances of J74 and K246 has 1/3 capacitances of K170. Unfortunately they have much lower transconductance.
The big question is: can we keep high perfomance of F5 using paralleled 2SJ103/2SK246 ?
Can we compensate jfets lower transconductance with paralleling output mosfets ?
sorry i meant crc filter i bought four pieces of rifa 35volts 18000uf caps today..i think theyre enough for one channel..but someone says paralleling many little caps is more effecient than only using 2 big caps for getting high ripple.because esr becomes lower.why nelson doesnt do that?.what do you think about this subject ?
i bought four pieces of rifa 35volts 18000uf caps today..i think theyre enough for one channel..but someone says paralleling many little caps is more effecient than only using 2 big caps for getting high ripple.because esr becomes lower.why nelson doesnt do that?.what do you think about this subject ?
Re: 2SJ103 / 2SK246 input
If you're going to parallel devices, match them up -- the Fairchild and Vishay parts aren't that expensive.
When you parallel devices the noise goes down as well.
Jack
estman said:Happy holidays to F5 builders !
Just discovered: 2SJ103 / 2SK246 both have Vgs max = 50V.
Roughly - J103 has 1/7 junction capacitances of J74 and K246 has 1/3 capacitances of K170. Unfortunately they have much lower transconductance.
The big question is: can we keep high perfomance of F5 using paralleled 2SJ103/2SK246 ?
Can we compensate jfets lower transconductance with paralleling output mosfets ?
If you're going to parallel devices, match them up -- the Fairchild and Vishay parts aren't that expensive.
When you parallel devices the noise goes down as well.
Jack
umut1001 said:sorry i meant crc filter
You will be Ok using 4 per channel, dont bother about paralleling small caps for lower ESR or inductance, that may bring other troubles too. So I would suggest you go ahead with those 18mf caps @ 35V.
Havent read all your postings but how far are you with the circuit itself?