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Old 8th February 2013, 11:22 AM   #1201
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arranged the grounding, finish the hum.
rob vs Boz 1-0 !
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Old 8th February 2013, 12:03 PM   #1202
tinitus is offline tinitus  Europe
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arranged the grounding, finish the hum.
rob vs Boz 1-0 !


mine works very well too although a different 2-stage mono version with 2-channel split, for my bass guitar
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Old 9th February 2013, 06:13 AM   #1203
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power supply:

Click the image to open in full size.

Click the image to open in full size.

rob vs BoZ 2 - 0
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Last edited by robertor; 9th February 2013 at 06:17 AM.
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Old 9th February 2013, 07:18 AM   #1204
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the big question:
waiting to build a DAC which is based on the TDA1541, the Boz will be connected to the output of the PC.
I would not use the potentiometer as the volume would be controlled by the PC.
I must to replace the potentiometer 20k of Boz with some component (resistor, capacitor, resistor and capacitor)?

the question comes for not using two potentiometers.
unnecessary in this case.

thanx
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Old 9th February 2013, 07:27 AM   #1205
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I must to replace the potentiometer 20k of Boz with some component (resistor, capacitor, resistor and capacitor)?
no, you have 1k in series, and 1M to ground

unless you have too high output from DAC, and is overdriving your jfet Boz
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Old 9th February 2013, 11:53 AM   #1206
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THANKS for answer.
The PC output "saturate" the Boz.
In fact I do not have a large volume control.
1 step and already sounds, second step and it sounds too strong.
to prevent this, or use an 20k input pot or what?
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Old 9th February 2013, 11:56 AM   #1207
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try mount resistor from wiper to ground
and you can mount a resistor in series with signal, on pot input

what is your pot impedance ?
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Old 9th February 2013, 12:13 PM   #1208
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mine works very well too although a different 2-stage mono version with 2-channel split, for my bass guitar
Sorry, might be a fault thought from my side, but if you turn the 10k pot up for full volume, the JBOZ in the first stage will only see 660 R to ground. This is a little low, I think it will give you "real Distortion".

My intention is always to try that the stuff I built works with every setting of the knobs - I often tend forget the boundary conditions by the time...

Just my 2ct.

Best regards

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Old 9th February 2013, 12:58 PM   #1209
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@tinitus: i don't know the impedance of the pot of the PC.
sorry
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Old 9th February 2013, 01:21 PM   #1210
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... first stage will only see 660 R to ground.
maybe close, but maybe you forgot the 330ohm in series to ground ?

yes, there is a little distortion at full volume
but the gain so excessive I have to use a buffer with further attenuation
anyway, I have tried other resistor combination on the pot
all sound differnt
this one is so far the best

also because this special resistor 'curcuit' seems to interact better with the following balance pot, making it work more

but no, its far from ideal, and just a proto to see how it works
most are random components I found
but it works, and I havent been able to kill it yet
tough little amp
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