Hi,
only a little thought- could it be that we missed a pad from Q6,7- or different, to LTP Q2 backward, like VLatVet is Q3- there also 180° rotate?
Sorry if not right.
only a little thought- could it be that we missed a pad from Q6,7- or different, to LTP Q2 backward, like VLatVet is Q3- there also 180° rotate?
Sorry if not right.
Then you would love my builds. They never work the first time. 😛
Those few times when it works on the first attempt, I feel a little empty inside. Takes all the joy out of it.
I will put the vhex on my to-do list. 🙂
Sons of Vhex
I have double check for dry joint,wrong orientation and wrongly placed parts but nothing.
I have double check for dry joint,wrong orientation and wrongly placed parts but nothing.
Thank you Thimios.
I think I know what the problem is.
This design is rather sensitive to the rails voltage.
You've got some +/-36V instead of +/-50V it's initially calculated for.
Attached is the version, adjusted for +/-35V rails - I did it earlier for one of the members. Can you please try these values (marked by red frames).
Cheers,
Valery
I think I know what the problem is.
This design is rather sensitive to the rails voltage.
You've got some +/-36V instead of +/-50V it's initially calculated for.
Attached is the version, adjusted for +/-35V rails - I did it earlier for one of the members. Can you please try these values (marked by red frames).
Cheers,
Valery
Attachments
Yes,i have power it using +/-50v but with 18R in serial of each rail INSTEAD OF FUSES AND a lamp in series with the transformer primary.
I have measure 4v on 18R.Voltage on amplifier board is +/-36v and the lamp isn't full dark.
I had tried it without primary lamp but without success too.
I have measure 4v on 18R.Voltage on amplifier board is +/-36v and the lamp isn't full dark.
I had tried it without primary lamp but without success too.
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I can't get to it right now, but my rails were 47v. Give me a couple hours and I will take measurements on my boards.
You can try this PSU config with adjusted values.
Or - the other way - try the front-end without the spreader, drivers and output transistors, connecting NFB to the VAS output, but with full +/-50V rails.
Some other designs tolerate the rails increase/decrease easily, but this one is rather sensitive to the rails voltage - it's getting imbalanced with the lowered rails.
OK, no problem. It would be also interesting to know the offset at the output (no load so far, until we balance it out).
Offset is.......29-35v
Or - the other way - try the front-end without the spreader, drivers and output transistors, connecting NFB to the VAS output, but with full +/-50V rails.
Can you post a schematic diagram?
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Here we go!
You can remove 22R resistors at the rails and connect the rails directly to the front-end (although it would be good if you can add the diodes and 22R in series for having the voltage equal to the real situation).
Attachments
