K2 sound will go toward a more tube sound or softer sound.
K3 will be more critical, sharp, edgy or emphasized sound.
Did I miss anything?
You want to bring down the 4-9 peaks. Although I'm unsure what would cause them. Card noise?
Unfortunately, you'll have adjust back and forth until you get what you want.
K3 will be more critical, sharp, edgy or emphasized sound.
Did I miss anything?
You want to bring down the 4-9 peaks. Although I'm unsure what would cause them. Card noise?
Unfortunately, you'll have adjust back and forth until you get what you want.
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too much respect vdi_nenna…..
friend Ittien makes good progress….and right channel looks in a way I like k2 about 10dB higher than k3.
But this is no general rule, only a recommendation. M2 with its k3 dominance sounds very good too, or let us take the Aleph P 1.7, normally k3 dominant, in my builds also sounds wonderful.
friend Ittien makes good progress….and right channel looks in a way I like k2 about 10dB higher than k3.
But this is no general rule, only a recommendation. M2 with its k3 dominance sounds very good too, or let us take the Aleph P 1.7, normally k3 dominant, in my builds also sounds wonderful.
BBA-3 with feedback
I showed it already in an earlier posting….
It is very easy to modify for fun the BBA-3 with no feedback but with the heavy (330R) load to
a) a pre with feedback gain 4 (12dB)
or
b) as a driver stage for a burning amp BBA-3 with feedback and a gain Nelson uses often, 26dB
Of course you have to omit the 330R loads at the output of BBA-3 and omit the four 1000uF caps as well to get enough open loop gain for the feedback.
In case b) you can change from local feedback including only the frontend to global feedback including the output stage also (Burning Amps or F4).
Simply trace the 4k7 from the speaker output to the input J-Fets.
Measure for security the offset in a) and b) with a DMM.
If you get a higher voltage around 20V at the outputs, the 4k7 went to the wrong side.
I assumed in Spice an output stage with an input impedance of 3k. Spice does not allow pots in my beginners level of handling it, so I simply took the 420R and 424R resistors instead of the 500R pots.
Forgot, a 100pF capacitor over the 4k7 feedback resistors could be useful against oscillation.
For me the feedback solution has a bit more punch and definition, the NFB is more romantic.
and helas I always get nervous when I make more complicated contributions like this…. so please check for possible faults…..
I showed it already in an earlier posting….
It is very easy to modify for fun the BBA-3 with no feedback but with the heavy (330R) load to
a) a pre with feedback gain 4 (12dB)
or
b) as a driver stage for a burning amp BBA-3 with feedback and a gain Nelson uses often, 26dB
Of course you have to omit the 330R loads at the output of BBA-3 and omit the four 1000uF caps as well to get enough open loop gain for the feedback.
In case b) you can change from local feedback including only the frontend to global feedback including the output stage also (Burning Amps or F4).
Simply trace the 4k7 from the speaker output to the input J-Fets.
Measure for security the offset in a) and b) with a DMM.
If you get a higher voltage around 20V at the outputs, the 4k7 went to the wrong side.
I assumed in Spice an output stage with an input impedance of 3k. Spice does not allow pots in my beginners level of handling it, so I simply took the 420R and 424R resistors instead of the 500R pots.
Forgot, a 100pF capacitor over the 4k7 feedback resistors could be useful against oscillation.
For me the feedback solution has a bit more punch and definition, the NFB is more romantic.
and helas I always get nervous when I make more complicated contributions like this…. so please check for possible faults…..
Attachments
Pot for adjustable gain?
Is there any reason one shouldn't use 3w pots in place of the R13s?
Found a Vishay PE30 pot that looks suitable. Comes in 470r (see pdf).
I was thinking that would give a nice feature alá Aleph P, with front panel adjustable gain for each channel, and also function as balance adjustment (so no need for seperate mono volume pots). Then I could easily adjust the gain on the fly, to match the given source voltage. This seems to in line with Mr. Pass philosophy, of not throwing away signal
Has anyone tried this with BA-3?
Is there any reason one shouldn't use 3w pots in place of the R13s?
Found a Vishay PE30 pot that looks suitable. Comes in 470r (see pdf).
I was thinking that would give a nice feature alá Aleph P, with front panel adjustable gain for each channel, and also function as balance adjustment (so no need for seperate mono volume pots). Then I could easily adjust the gain on the fly, to match the given source voltage. This seems to in line with Mr. Pass philosophy, of not throwing away signal
Has anyone tried this with BA-3?
Ok Will try it for sure then, but still just collecting parts for my BA-3, so will be a little while...
Thanks for tip about resistor for min. gain, that makes sense. I was more worried about max gain actually, with the 470r pot. Is there any real risk here you think? Or will it just run a little bit hotter at full gain?
Will try it for sure then, but still just collecting parts for my BA-3, so will be a little while...Thanks for tip about resistor for min. gain, that makes sense. I was more worried about max gain actually, with the 470r pot. Is there any real risk here you think?
Or will it just run a little bit hotter at full gain?
