Lichstarck
Val, can you please help with resistor values when running the ip stage on 65Vdc. I suppose the the OP vertical mosfet stage is OK with 65Vdc ?🙂
Thanks
Jan
Val, can you please help with resistor values when running the ip stage on 65Vdc. I suppose the the OP vertical mosfet stage is OK with 65Vdc ?🙂
Thanks
Jan
Lichtstark-X is up and running nicely. I posted some initial testing results in the Sons of VHex thread. http://www.diyaudio.com/forums/solid-state/294632-sons-vhex-45.html#post5089933 I settled on 15k values for R12 & R13 and replaced the bias pot with 200R. Bias was still flowing slightly with the pot maxed out. It's a very well behaved stable amp so far. It clips nicely too. I've attached the "As Built" schematic.
Hi Jan,
For +/-65V DC rails the optimal values are:
R4, R5 = 24K
R12, R13 = 20K
R18, R19 = 30K
Schematic is attached to make sure we use the same reference numbers.
Cheers,
Valery
Attachments
Mile, that C9 amplifier will come close to .0005% distortion with the 100 Rf changed to 220.
I've been using a similar setup for many years
my amp also uses 2 feedback loops, 1 current and 1 voltage loop both from output
My amp does not require the mosfet drivers
the original op amp was an LF353 which is almost as nice as opa2134
I have this amp now in the SX3700, Lichtstark is going into the sx780
I've been using a similar setup for many years
my amp also uses 2 feedback loops, 1 current and 1 voltage loop both from output
My amp does not require the mosfet drivers
the original op amp was an LF353 which is almost as nice as opa2134
I have this amp now in the SX3700, Lichtstark is going into the sx780
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is C10 15pF or 1p5F?
Edit, I have blown it up to enormous and can now see it is 1p5F.
Valery, for +- 47v rails can R12 and R13 still be 20k or changed to 18k
I was going to use R12,13 = 20k and R18,19 = 27k
I was going to use R12,13 = 20k and R18,19 = 27k
I ended up with 15k there for 48V rails. This puts VAS current around 6.5mA.
Right, live test, performed by Jeff, showed R12, R13 = 15K is the optimal value for this rail voltage.
Evening guy's.
I see that the Vhex OP stage does not have a zobel cap and resistor on the output. Is that correct ? Then I have just wondered if anybody just maybe have put a BOM together for the Lichtstark IP and Vhex OP stage !😀
I see that the Vhex OP stage does not have a zobel cap and resistor on the output. Is that correct ? Then I have just wondered if anybody just maybe have put a BOM together for the Lichtstark IP and Vhex OP stage !😀
Hi Jan,
VHex OPS runs fine with no Zobel, although Thiele network (inductor + resistor) is required anyway for isolating capacitive loads at HF.
BOMs - not yet. OK - I will generate ones during the next few days.
Cheers,
Valery
If you are talking from file i posted previously yes i have BOM related to those.
Marc