sorenb

http://www.ti.com/lit/ds/symlink/cd4093b.pdf

zeners? ...really?

one might do one/two unregluated PSU's, and feed it to each channel through some pairs of C5200/A1943 being controlled by one GRLV, like Kevin is doing in the Über

...and does that also apply to second edition of the output board? ...wouldn't the sources be at -12V until the HV900 is applied?

@kevin gilmore would applying -15V gradually from 0V, make it easier for the opto´s to balance the bridge?

is the OpAmp postive input grounded? - as I recall I shorted the trimmer

https://www.youtube.com/watch?v=jGdiE-Ssfx4

did you ever listen to a Stax SRD7 ? that will probably provide you a similar enjoyment

you can probably always do better. Building a Carbon using a KGBH PSU will still give you a good Carbon.

Yes People have different opinion in this regard. No problem in replacing with a GR later. You might consider using the BH PSU rather - it's simpler and a lot cheaper in comparison to the GRHV.

Sorry, I haven't noticed that you have mentioned that the "recipe" didn't work ... Anyways, I had a look at my notes from back then, and it seems I forgot to add a few things I did in addition to get it working; I've edit the post accordingly.

I believe you need to reconsider your approach a bit. consider having the FB local on the driver rather - makes things less complicated make the servo working at the driver (Kevin mentioned this a few posts back) - having the driver in balance with the servo working is key check the opto's on the output boards whether the emitters are pulled towards ground when the current in the bridge is rising (from your description it sounds like one or both isn't working).

from your posts I am not sure exactly what you are doing, or how you have connected the various parts. do you have ~zero out of the driver? and -15V present at the output board?

lower the current or the tail resistor ...

not sure what you are up to, as far as I remember the silk value for the tail resistor wasn't far off. 10mA or 8mA isn't day or night anyways.

you probably need to lower the tail resistor for the driver output ...or dial down the current ....anyways, you need 0 offset at output (Kevin recommends ~8mA)

remove the house from headband assembly, be careful not to bend the plastic as it is kind of brittle. there are four small Philips-screws, located in each corner beneath the pad - you don't have to remove the pad, just push/lift it a bit in the corners and loosen up the four screws. Afterwards you can remove the pad + baffle inlucing driver from the housing.

you might add to the beauty, by slicing the lemmon like this:

Don't see why it should be any different, and not sure your listening experience can be explained by adding the diode as you suggest.

how? Isn't the plate always positive in rgrds to the screen. Have you tried to increase the resistor value x2 to see if you got the same change in sound?

DC Yes: Gate - Drain - Source Can't remember ... look at PCB and you'll figure it out; the black (negative) probe goes to the tail of the CCS The @MLA suggestion is a good advice BTW

Original post

seems like a badly done write-up of what Spritzer has stated about the Carbon for the past two years or so, blended with the usual Katz-magic: a touch of EQ ... wonder if Katz is aware of what ever is being written in his corner ...

Thanks. Digital printing from ModuShop (Text and Graphics in 600dpi)