BPA300 Round 2 - Page 110

toufu · 16th November 2009, 11:38 PM

Hi guys, what's the best way to bias the BPA150? Is the goal to have all three chips output 0? If I change one, the others change as well. Short of having three multimeters, how could one do it easily?

By the way, the sound is awesome, I am not missing the F5 that it's replacing at all. It's got way more bass and just more powerful sounding without losing the clarity and detailness.

udailey · 17th November 2009, 02:42 AM

Toufu,
What speakers are you driving? Not missing the F5 is a pretty big statement! Did you change sources or preamps between the F5 and the BPA?
Uriah

TjongKristian · 17th November 2009, 03:20 AM

Peranders,
I saw your website and I am interested in your chassis. How much are they and how heavy ? Thanks.

toufu · 17th November 2009, 03:23 AM

I am driving them using the same preamp to a pair of Zu Druids.

udailey · 17th November 2009, 04:50 AM

Man, I cant get into this conversation. If you convince me to build one of these I am going to go broke in a pile of amps

Uriah

peranders · 17th November 2009, 06:18 AM

Quote:

Originally Posted by TjongKristian

Peranders,
I saw your website and I am interested in your chassis. How much are they and how heavy ? Thanks.

I think your are mistaken here. Did you really go to _my_ homepage? I'll guess you'll have to ask Alex about this.

TjongKristian · 17th November 2009, 06:33 AM

My bad, sorry.

AlanElsdon · 17th November 2009, 08:52 AM

Quote:

Originally Posted by udailey

Man, I cant get into this conversation. If you convince me to build one of these I am going to go broke in a pile of amps

Uriah

Uriah,

At the moment I am thinking about a 20 channel system, I have enough amplifiers (built and still in kit form) - just need a couple more speakers!

Alan

shmulik · 19th November 2009, 01:28 PM

has anyone completed a set and connected signal generator on one end and a oscilloscope on the other (besides Alex)? I did and have not managed to both get a square wave without ringing and constant gain well over 20KHz. I can reduce ringing by enlarging the feedback capacitor but this hampers on the frequency response. I must have a systematic error on all boards or some other error in the devices around (PS? what can go wrong with a transformer diode bridge and a pair of capacitors?).
To emphasize, I test an insulated board with signal generator directly connected to its input and a scope on its output - no bridge configuration. the square wave is in low frequencies.
the result of having a decay in gain towards 20KHz is a "slow" and somewhat fuzzy amplifier.

toufu · 20th November 2009, 08:34 PM

Quote:

Originally Posted by shmulik

has anyone completed a set and connected signal generator on one end and a oscilloscope on the other (besides Alex)? I did and have not managed to both get a square wave without ringing and constant gain well over 20KHz. I can reduce ringing by enlarging the feedback capacitor but this hampers on the frequency response. I must have a systematic error on all boards or some other error in the devices around (PS? what can go wrong with a transformer diode bridge and a pair of capacitors?).
To emphasize, I test an insulated board with signal generator directly connected to its input and a scope on its output - no bridge configuration. the square wave is in low frequencies.
the result of having a decay in gain towards 20KHz is a "slow" and somewhat fuzzy amplifier.

I completed mine, and I am getting a little high frequency hiss and noise, is that what you are talking about?

17th November 2009, 02:42 AM	#1092
udailey Passive Aggressive diyAudio Member Join Date: Mar 2008 Location: Houston, TX	Toufu, What speakers are you driving? Not missing the F5 is a pretty big statement! Did you change sources or preamps between the F5 and the BPA? Uriah __________________ NEW GROUP BUY for MYREF_C with Ultimate BOM post interest there and enter info here in Google Document You can purchase LDRs anytime to build a Lightspeed or to build my new LDR Attenuator "A Lighter Note". Email me. diyldr@gmail.com

17th November 2009, 04:50 AM	#1095
udailey Passive Aggressive diyAudio Member Join Date: Mar 2008 Location: Houston, TX	Man, I cant get into this conversation. If you convince me to build one of these I am going to go broke in a pile of amps Uriah __________________ NEW GROUP BUY for MYREF_C with Ultimate BOM post interest there and enter info here in Google Document You can purchase LDRs anytime to build a Lightspeed or to build my new LDR Attenuator "A Lighter Note". Email me. diyldr@gmail.com

19th November 2009, 01:28 PM	#1099
shmulik diyAudio Member Join Date: Aug 2004 Location: country side	measuring the PA150 has anyone completed a set and connected signal generator on one end and a oscilloscope on the other (besides Alex)? I did and have not managed to both get a square wave without ringing and constant gain well over 20KHz. I can reduce ringing by enlarging the feedback capacitor but this hampers on the frequency response. I must have a systematic error on all boards or some other error in the devices around (PS? what can go wrong with a transformer diode bridge and a pair of capacitors?). To emphasize, I test an insulated board with signal generator directly connected to its input and a scope on its output - no bridge configuration. the square wave is in low frequencies. the result of having a decay in gain towards 20KHz is a "slow" and somewhat fuzzy amplifier.

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16th November 2009, 11:38 PM	#1091
toufu diyAudio Member Join Date: Jun 2008 Location: San Francisco	Hi guys, what's the best way to bias the BPA150? Is the goal to have all three chips output 0? If I change one, the others change as well. Short of having three multimeters, how could one do it easily? By the way, the sound is awesome, I am not missing the F5 that it's replacing at all. It's got way more bass and just more powerful sounding without losing the clarity and detailness.

17th November 2009, 03:20 AM	#1093
TjongKristian diyAudio Member Join Date: Aug 2002 Location: Jakarta, INDONESIA	Peranders, I saw your website and I am interested in your chassis. How much are they and how heavy ? Thanks.

17th November 2009, 03:23 AM	#1094
toufu diyAudio Member Join Date: Jun 2008 Location: San Francisco	I am driving them using the same preamp to a pair of Zu Druids.

17th November 2009, 06:33 AM	#1097
TjongKristian diyAudio Member Join Date: Aug 2002 Location: Jakarta, INDONESIA	My bad, sorry.

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