At least my open baffles seem to have the better overall sound with a current source amp with 5 -10 Ohm output impedance......
Mine too, but double the impedence, but have 15 Ohm drivers
tea-bag!Question to NP
In your official BA #2 push-pull output stage design recently posted with the BA3 front end, you have introduced 2 additional caps (C102/103) and 2 resistors (R129/130) in between the bias bord and the output stage.
The actual BA #2 bias board does not have space for such devices. Before I design an additional board, I would like to understand the reason for the introduction.
Thank you.
Gerd
In your official BA #2 push-pull output stage design recently posted with the BA3 front end, you have introduced 2 additional caps (C102/103) and 2 resistors (R129/130) in between the bias bord and the output stage.
The actual BA #2 bias board does not have space for such devices. Before I design an additional board, I would like to understand the reason for the introduction.
Thank you.
Gerd
Anyone interested in a Salas shunt reg of the BA-3 front end might be interested in my latest findings. http://www.diyaudio.com/forums/power-supplies/192625-sslv1-1-builds-fairytales-89.html#post2849148
Impedance of volume pot / attenuator
Hallo everybody!
I've a question regarding a BA-3(b) setup as a seperate preamp and the position and impedance value of a volume pot.
I'll use a stepped attenuator (R2R), its input impedance is always the same, say the chosen "volume pot value" (5k Ohm, 20k, 47k, ...).
First question is, what is the optimal impedance of this attenuator?
Second question is, can it be placed between pre (BA-3b) and amp (aleph jx, or F5, or...), as this should be better concerning noise, ... But, is there any reason not to do this? What speaks for putting it in front of the BA-3(b)?
Thanks for your help!
Matthias
Hallo everybody!
I've a question regarding a BA-3(b) setup as a seperate preamp and the position and impedance value of a volume pot.
I'll use a stepped attenuator (R2R), its input impedance is always the same, say the chosen "volume pot value" (5k Ohm, 20k, 47k, ...).
First question is, what is the optimal impedance of this attenuator?
Second question is, can it be placed between pre (BA-3b) and amp (aleph jx, or F5, or...), as this should be better concerning noise, ... But, is there any reason not to do this? What speaks for putting it in front of the BA-3(b)?
Thanks for your help!
Matthias
1. proper impedance is what make source (looking in/at pot ) happy , while maintaining as low possible impedance to keep capacitance of interconnects irrelevant
2.attenuator itself have its own output impedance ; place it where it will look at highest possible load impedance
combine reasons from #1 and #2 ........ and place it at input of BA FE ( with impedance set to ,say, 10K to 25K )
2.attenuator itself have its own output impedance ; place it where it will look at highest possible load impedance
combine reasons from #1 and #2 ........ and place it at input of BA FE ( with impedance set to ,say, 10K to 25K )
Reducing gain
Thank you Choky!
I read alot in this and the BA-3b thread, but as my knowledge is only slowly growing: How do I decrease the gain?
When I remember correctly, the gain (of the second gain stage) is mainly defined by R13/R10, so 332Ohm/22Ohm=15.1, times 2 (first gain stage) it is round about 30 (as the text says).
So if I would like to have a lower gain, do I have to lower R13? Or is it better to increase R10 or a combination of both?
Or does this conflict with the function of the circuit?
How is it best done? 15-20dB gain would be enough, this would be approximately 5-10 times.
Thx for help!
Thank you Choky!
I read alot in this and the BA-3b thread, but as my knowledge is only slowly growing: How do I decrease the gain?
When I remember correctly, the gain (of the second gain stage) is mainly defined by R13/R10, so 332Ohm/22Ohm=15.1, times 2 (first gain stage) it is round about 30 (as the text says).
So if I would like to have a lower gain, do I have to lower R13? Or is it better to increase R10 or a combination of both?
Or does this conflict with the function of the circuit?
How is it best done? 15-20dB gain would be enough, this would be approximately 5-10 times.
Thx for help!
I have played with this a bit and I think you will be fine with Nelsons original values. In practice the gain is about 8.5X so balanced you will get 17X or about 24dB. It also sounds better with Nelsons values. You could also reduce R13 and that will lower the gain also. I haven’t done any listening tests with a lower value R13 but it was fine on the spectrum analyzer.