BoZ- Listening fatigueness

Plydsen · 8th November 2004, 06:36 AM

Hi out there!

I wonder if anyone of you out there can help me out with a problem….

I am the happy owner of a Bride of Zen. I based it on a pcb from AudioXpress, and fitted it out with premium components. Basically It sounds great…. But I have a problem with an ”non-audible” noise or distortion that gives a very annoing listening fatigueness.
Some facts that might be usefull:
The torroidal - housed separately - is somewhat smaller than recommended: 28-0-28V/80VA giving the circuit some 64V AC.
The Rectifiers (D1-D4) are 25BYV79E-200.
Coupling capacitors (C103 & C104) are Auricaps.
The amp drives my headphones – Grado SR-80 – directly, accept for a 1Kohm resistor between C103 and the headphone outlet.

A big thank you in advance….

Plydsen

Cobra2 · 8th November 2004, 07:27 AM

Trafos are ok, I guess
Try different caps!

Arne K

Taco · 8th November 2004, 09:30 AM

With a standard line-level source (like CD) my BOZ also distorted. I have put a extra series resistor on the input (I used a 5K output attenuator).

Nelson suggests using 2 pots, one to set the level on the input and one as output volume control. Also some people have changed the gain of the circuit.

Do a search on this board, there a couple of threads about the subject.

wuffwaff · 8th November 2004, 09:47 AM

Plydsen.

how big are those output caps? When you are driving a low impedance they should be big enough otherwise you´ll have a nice highpass. You could try a combination of 220uF / 50V Panasonic FC plus 10nF as recomended by Klaus.

William

Stabist · 8th November 2004, 12:33 PM

Hi!

I had same problem with my BoZ ... I've tried with different input resistors - no help ... The solution was to lower CDP's output (it has variable output - but it lowers also the resoulution...)
So - as someone said - you can use another pot at input ...

Mine solution was an AlephL ... No probelms whatsoever since I use it ...

Nelson Pass · 8th November 2004, 03:09 PM

It's very common for the input to the preamp to be overloaded
by the source. Try attenuating it with a pot of resistive divider.

Plydsen · 8th November 2004, 08:06 PM

Heureca….

My signal is pure as newfallen snow…..

This afternoon I changed my couplingcaps without getting rid of the problem. Then I put 2x 2K2 Ohm cermet trimmerpots at the pcb entrance - adjustet it to 1K5 Ohm and the problem was gone.

May I express my gratitude Arne K, WuffWaff, Taco, Stabist and Mr. Pass – with guys like you its easy to be a D.I.Y. newbee…

Regards,

Plydsen

8th November 2004, 06:36 AM	#1
Plydsen diyAudio Member Join Date: Oct 2003 Location: Aarhus, Denmark	BoZ- Listening fatigueness Hi out there! I wonder if anyone of you out there can help me out with a problem…. I am the happy owner of a Bride of Zen. I based it on a pcb from AudioXpress, and fitted it out with premium components. Basically It sounds great…. But I have a problem with an ”non-audible” noise or distortion that gives a very annoing listening fatigueness. Some facts that might be usefull: The torroidal - housed separately - is somewhat smaller than recommended: 28-0-28V/80VA giving the circuit some 64V AC. The Rectifiers (D1-D4) are 25BYV79E-200. Coupling capacitors (C103 & C104) are Auricaps. The amp drives my headphones – Grado SR-80 – directly, accept for a 1Kohm resistor between C103 and the headphone outlet. A big thank you in advance…. Plydsen

8th November 2004, 07:27 AM	#2
Cobra2 DIY ! diyAudio Member Join Date: Apr 2002 Location: Stavanger, Norway	BoZ Trafos are ok, I guess Try different caps! Arne K __________________ Ars longa, vita brevis

8th November 2004, 09:47 AM	#4
wuffwaff diyAudio Member Join Date: Aug 2001 Location: Ingolstadt Germany	Plydsen. how big are those output caps? When you are driving a low impedance they should be big enough otherwise you´ll have a nice highpass. You could try a combination of 220uF / 50V Panasonic FC plus 10nF as recomended by Klaus. William __________________ een ooievaar is geen konijn want zijn oren zijn te klein!

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8th November 2004, 09:30 AM	#3
Taco diyAudio Member Join Date: Nov 2002 Location: Place in the Netherlands	With a standard line-level source (like CD) my BOZ also distorted. I have put a extra series resistor on the input (I used a 5K output attenuator). Nelson suggests using 2 pots, one to set the level on the input and one as output volume control. Also some people have changed the gain of the circuit. Do a search on this board, there a couple of threads about the subject.

8th November 2004, 12:33 PM	#5
Stabist diyAudio Member Join Date: Sep 2002 Location: Slovenia	Hi! I had same problem with my BoZ ... I've tried with different input resistors - no help ... The solution was to lower CDP's output (it has variable output - but it lowers also the resoulution...) So - as someone said - you can use another pot at input ... Mine solution was an AlephL ... No probelms whatsoever since I use it ...

8th November 2004, 03:09 PM	#6
Nelson Pass The one and only Join Date: Mar 2001	It's very common for the input to the preamp to be overloaded by the source. Try attenuating it with a pot of resistive divider.

8th November 2004, 08:06 PM	#7
Plydsen diyAudio Member Join Date: Oct 2003 Location: Aarhus, Denmark	Heureca…. My signal is pure as newfallen snow….. This afternoon I changed my couplingcaps without getting rid of the problem. Then I put 2x 2K2 Ohm cermet trimmerpots at the pcb entrance - adjustet it to 1K5 Ohm and the problem was gone. May I express my gratitude Arne K, WuffWaff, Taco, Stabist and Mr. Pass – with guys like you its easy to be a D.I.Y. newbee… Regards, Plydsen

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