Hi Terry ,what your opinion about this INP after 1st modification?
I mean listening test
Thimios.
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Good news!Well I have just finished the first pass of the PCB design for this mod like 1 minute ago. I just need to check it to make sure that all is well, then I will probably give it a go.
Having just altered my preliminary CFA-XH design into the CFA-XHmod2 from BV, I can say that it does change a reasonable amount. Not so much as to be impossible to mod, but you are going to end up with a fair few cut traces and the like.
Troubleshooting
Hello,
When I fried the ips cascode resistors, I connected the IPS as floating without the G2 connection on the OPS board.
I wonder what else has been fried? Most likely the cascode transistors which I do not have anymore. I could throw in BC546/bc556 for the cascodes for testing purposes but cannot install those face to face...
As mentioned somewhere earlier I have made my own pcb.
Help would be appriciated a lot
J
Hello,
When I fried the ips cascode resistors, I connected the IPS as floating without the G2 connection on the OPS board.
I wonder what else has been fried? Most likely the cascode transistors which I do not have anymore. I could throw in BC546/bc556 for the cascodes for testing purposes but cannot install those face to face...
As mentioned somewhere earlier I have made my own pcb.
Help would be appriciated a lot
J
Attachments
Sorry, I spent what little time I had today working on the latest version. I didn't get a chance to listen to it. As soon as I get the new one working I will give the first one a listen. I looks really good on the scope. More tomorrow.
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When you hooked it up floating did you tie PD and ND to the NFB with some 470R resistors? Without that it will put out like half the rail on the output
Hi Still4given
No I did not. I just hooked the IPS on the connectors, on the main OPS but the G connection was not there.
It seems that all passive components are fine except those 150r.
J
No I did not. I just hooked the IPS on the connectors, on the main OPS but the G connection was not there.
It seems that all passive components are fine except those 150r.
J
Hi,
What I meant with floating was that IPS ground was not connected, or better yet It was connected to Cap multiplier base which were also floating.
I tried to simulate the situation in Spice but I could not create condition where those resistors would fry with the installed components.
Also the pcb is fine, no solder bridges or anything.
J
What I meant with floating was that IPS ground was not connected, or better yet It was connected to Cap multiplier base which were also floating.
I tried to simulate the situation in Spice but I could not create condition where those resistors would fry with the installed components.
Also the pcb is fine, no solder bridges or anything.
J
May be CCS (Q6 and Q8) current is too high. Please disconnect R9, R10, R11, and R12. Connect collector Q6 and Q8 to ground. Tell me the voltage of R16 and R17.
2 Terry
In schematic are some changes (i hope last..) to improve behavior during clipping and at fast transients (to limit all internal currents to safe levels and avoid saturation under those conditions). Enjoy..But it is not "cook book"!
I attempt to trim DC ofset another way (IMO more comfortable) , look at attachments. Here is trimpot P1 added, to trim output DC ofset. Open potentiometer.zip file, put symbol file into LTC lib/sym/.. folder, and library file into LTC lib/sub/.. folder
In schematic are some changes (i hope last..) to improve behavior during clipping and at fast transients (to limit all internal currents to safe levels and avoid saturation under those conditions). Enjoy..But it is not "cook book"!
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As expected
Hi,
IPs hooked to OPS, plays music nicely but my driver heatsink getting hot!
I quess the drivers or bias circuit is oscillating. I need to add the extra caps recommended somewhere.
My drivers are 2sa1837 / 2SC4793. Predrivers are bf471 / BF472. The bias transistors are superfast 2sc3953 that I had in my junkbox.
Would it be beneficial to change predrivers / bias circuit to slower devices?
J
Hi,
IPs hooked to OPS, plays music nicely but my driver heatsink getting hot!
I quess the drivers or bias circuit is oscillating. I need to add the extra caps recommended somewhere.
My drivers are 2sa1837 / 2SC4793. Predrivers are bf471 / BF472. The bias transistors are superfast 2sc3953 that I had in my junkbox.
Would it be beneficial to change predrivers / bias circuit to slower devices?
J
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