My BoSoZ time for improvement

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I do NOT use safty-earth.

I have tried to make different connection to GND from -IN, also I tried to GND the -OUT, It doe's not make any difference. There is a small humming, in diskant and bass, and a little bit of 'hisssss' in the midrangespeaker.

It's the same 'level' howmatter where the volume is. (high or low)

How are you running it unbalanced (if you do) ?.
 
The difference, between my old BoSoZ and the X-Bsoz. as I see it.

Changes on X-Bsoz:

1 connection, from PSU, is at the other side of the R117/R116.
2 No Resistor after C101/C102 except R112/R111.
3 10uF -> 33uF Cap. (i use 10uF still). could this be problem ?
4 10K resistor in serie with +IN / -IN eg.. +IN from slider -----> 10KOhm --->

Maybe I have to connect, like the normal BoSoZ (made the PCB so it's possible). to see if the little problem is gone.

EDIT also the X-resisters :) R122/R123 is there.
 
Jesper, just in case its in the grounding scheme, you can compare your layout to this nice and clear drawing that JH6you made some time ago.
Its pretty good to have as a guideline.

Steen:)
 

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My solution, was to swap back to the old BoSoZ design, as I mentioned earlier.

I used the same ground connection's, just plugged out the 'X' resistor's the 10K series resistor, and placed a resistor 124Ohm(R15). The potmeter i moved to output. Input fixed with 10Kohm to gnd, and a R18, or in short, excatly the old design. R14 shorted to GND at -IN for unbalanced.

Suddently all hum and hiss was gone, as I expected. :D

I think the sonic is just the same for me, as the 'X'-et one. The better quality I noticed, when playing with x-bsoz, must have been my new steenoe-cap aka' RIFA phe426, cause i never tried with my old VISHAY's, in the 'X'et version.
Sorry about the confusion, but honestly, i am not very ear-trained listning to HIFI. through it get's better all the time!

The gain is slightly better now (~13.5dB) compared to my old BoSoZ (Don't know why) The more gain is something my LeachAmp really like's.

I will let the BoSoZ BURN in for the rest of the Easter, maybe the new part's sounding even better then....

Some of you, may wonder, why I even made a new PCB, for that the answer is, that i am construction a new chassis, something i ofcause will come back to here with one day...

My GOAL was to make improvement's to my BoSoZ. I ended up with a new PCB, for both a x-bsoz and bosoz version. A new ALPS 10K motorpot, 4 new
caps, and some new resistor's.

FINALLY, i would like to tell, that i now am perfectly happy with my BoSoZ.

Thank you all for helping.

:angel:
 
Thanx...

Well I think if everything work's, in next weekend, I will finish it, so that I could listen to it again ;-)
I then have to get, some new screw's for the front/rear - plate's, and some 'spikes' for the feet's.

Here is a picture, of how far I got until now.

I use 3mm 'blue' led's, to indicate the input-selection. My INPUT-1, goes through normally-closed relay, so that it's non-energized with this input. On the 3 remaining input's the relay's is ON.
 

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I took this old thread of mine, to ask a quistion about singleended input to balanced output.

I have been using my Unbalanced Bosoz, just with a short at the - IN, for my old (build 2001) LeachAmp. After finishing up my 2x F4 monoblock's today i descided to try my bosoz in balanced operation.
I have never tried this before, so i placed the 100K ohm's resistor at the - IN which was missing and shoot in 1vac 100hz sine wave...
The top picture shows the input at the bosoz, without any attenuator attached. I adjusted the scope so, that the sine was in the middle, and the V/div to 2V.
The middle picture shows output, either between GND and +Out or between GND and -Out, no difference.
The last picture shows the probe connected between +Out and -Out, swinging 10V

I never thought that it would double the swing, i think it could drive the F4 in balanced mode real good (not to clipping ofcause)...
---> How much will the F4 need to be feed before clipping 30V ? ~ 40V ? sving.

I have posted a larger picture at my web-site Go and click on the link BosoZ scope test. You can click on the picture on the website to make it even bigger!
 
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