BOSOZ low output?

Brownlow · 9th October 2003, 07:56 PM

I've constructed the BOSOZ and the good news is that there is no smoke (I am always happy to get this far!). Anyway, I am using two Panasonic plastic pots at the output, valued at 10K. I chose not to match the transistors and at the moment I am using the amp as unbalanced.

The output seems very low, the volume pots work in that I can turn them all the way to the other end! However, these are the 4 pinned variety that I have not encountered. have I wired the pot wrongly? Also, the voltages on Drain is 31.4v and -4.3v on Source, Gate is grounded. R15 is 221 ohms, as I wanted to see how much gain we're playing with. Have I missed something?
Or is there a thread that someone could direct me to, as always advice is gratefully appreciated.

Cheers.

Brownlow

P.S. I got to start on the Aleph5 next...

Nelson Pass · 9th October 2003, 10:25 PM

Often a 4 pin pot means that there is a fixed tap on the resistor,
and grounding it gives more of an audio taper than a linear
pot. You are free to ignore it, if that's the case.

Kriss · 31st October 2003, 08:10 AM

Hallo
Few days ago I hooked up first time my BoSoZ. First impression was probably the same. It works, works fine but output signal was low. It was about twice lower than directly from CD ( CD with variable output so I could compare system with or without aditional preamp betwen CD and amp). I approach gain by decreasing R15 to 100 ohm. The output level now looks OK. Music play on the same volum like directly from CD.
This experience push me to omit input/output pots and adjusting only the gain.

Regards
Krzysztof

P.S. My next pre will be clone Aleph P 1.7 in P2P configuration.

wuffwaff · 31st October 2003, 11:26 AM

Hello Kriss,

normally gain should be between 10 and 20 dB (x3,16 and 10x) depending on R15 so something must be wrong.

william

9th October 2003, 07:56 PM	#1
Brownlow diyAudio Member Join Date: Apr 2001 Location: UK	BOSOZ low output? I've constructed the BOSOZ and the good news is that there is no smoke (I am always happy to get this far!). Anyway, I am using two Panasonic plastic pots at the output, valued at 10K. I chose not to match the transistors and at the moment I am using the amp as unbalanced. The output seems very low, the volume pots work in that I can turn them all the way to the other end! However, these are the 4 pinned variety that I have not encountered. have I wired the pot wrongly? Also, the voltages on Drain is 31.4v and -4.3v on Source, Gate is grounded. R15 is 221 ohms, as I wanted to see how much gain we're playing with. Have I missed something? Or is there a thread that someone could direct me to, as always advice is gratefully appreciated. Cheers. Brownlow P.S. I got to start on the Aleph5 next...

31st October 2003, 11:26 AM	#4
wuffwaff diyAudio Member Join Date: Aug 2001 Location: Ingolstadt Germany	Hello Kriss, normally gain should be between 10 and 20 dB (x3,16 and 10x) depending on R15 so something must be wrong. william __________________ een ooievaar is geen konijn want zijn oren zijn te klein!

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9th October 2003, 10:25 PM	#2
Nelson Pass The one and only Join Date: Mar 2001	Often a 4 pin pot means that there is a fixed tap on the resistor, and grounding it gives more of an audio taper than a linear pot. You are free to ignore it, if that's the case.

31st October 2003, 08:10 AM	#3
Kriss diyAudio Member Join Date: Oct 2003 Location: Warsaw	Hallo Few days ago I hooked up first time my BoSoZ. First impression was probably the same. It works, works fine but output signal was low. It was about twice lower than directly from CD ( CD with variable output so I could compare system with or without aditional preamp betwen CD and amp). I approach gain by decreasing R15 to 100 ohm. The output level now looks OK. Music play on the same volum like directly from CD. This experience push me to omit input/output pots and adjusting only the gain. Regards Krzysztof P.S. My next pre will be clone Aleph P 1.7 in P2P configuration.