So you're using 220 ohm resistors for R13? I saw where someone else had used 180 ohm resistors.
My concern here is too much gain with the BA-3 since I typically only use a buffer between my sources and power amp.
24+\- dual supplies.
It's not so much the detail because they sound similar in that respect.
It now sounds like there's more weight to the music. But this might be due to the B1 trying to drive the amp or lack of gain. The pairing I have may not be optimal. The B1 is a thorough preamp. It's not leaving my house.
A better comparison will be with the boz-j.
Vince
Vince thanks for the answers.
For source i have an old CDplayer Technics SL 520 with output 2V p-p with db attenuator -12db .
My B1 buffer with 0.012V dc offset match perfect with my GOLMUND clone 9.2 and my VSSA without cap input i dont have any problem lack of gain due CDplayer Technics SL 520.
Very VERY detail my B1 with two amps
http://www.diyaudio.com/forums/vend...lateral-mosfet-amplifier-231.html#post3616830
http://www.diyaudio.com/forums/soli...lifier-i-have-ever-heard-189.html#post2893894.
For source i have an old CDplayer Technics SL 520 with output 2V p-p with db attenuator -12db .
My B1 buffer with 0.012V dc offset match perfect with my GOLMUND clone 9.2 and my VSSA without cap input i dont have any problem lack of gain due CDplayer Technics SL 520.
Very VERY detail my B1 with two amps
http://www.diyaudio.com/forums/vend...lateral-mosfet-amplifier-231.html#post3616830
http://www.diyaudio.com/forums/soli...lifier-i-have-ever-heard-189.html#post2893894.
25K seems to be a odd value. Most pots I'm seeing for sell are either 20K or 50K, so I assume 20K is close enough.
I don't think I have the patience or money for a good DIY attenuator.
With this one, you can make any value you want and with resolutions up to 256 steps:
The δ1 Relay-based R-2R Stereo Attenuator
Or you could buy a kit from TentLabs:
Volume control
Best regards
Arthur.
The δ1 Relay-based R-2R Stereo Attenuator
Or you could buy a kit from TentLabs:
Volume control
Best regards
Arthur.
25K seems to be a odd value. Most pots I'm seeing for sell are either 20K or 50K, so I assume 20K is close enough.
I don't think I have the patience or money for a good DIY attenuator.
HI guys, I have a few questions please. ON diyaudio ba3 board which I am stuffing now, can I use 1500 uf instead of 1000 uf on c1 and c2. Will it make a difference, as I do not have any 1000 uf.
Second point, do I use r2 or not, I see some people suggest not using, and some put it on the attentuator instead, or between the attenuator and the input if I understand correctly. I am going to use a John Broskie 20K attenuator. Should I install this r2 or not?
Thanks, John
T
Second point, do I use r2 or not, I see some people suggest not using, and some put it on the attentuator instead, or between the attenuator and the input if I understand correctly. I am going to use a John Broskie 20K attenuator. Should I install this r2 or not?
Thanks, John
T
John,
I think 1500 is OK, but look at the article. I think its OK, but it does have a specific job, not just filtering.
"Coming off the Drain of Q1 is the loading network of R6, C1 and P1, and there is a comparable network of R7, C2, and P2 attached to the Drain of Q2. R6 clearly sets the AC load for Q1, but the DC requirements to bias up Mosfet Q3 are higher than that, so P1 in parallel with C1 provides a higher resistance value below about 0.5 Hz, and gives the approximately 3 volt DC drop required to bias the Mosfets."
ZM said it helps with protection at the input in case of pot failure. I didn't use it, but you might feel you need it.
Have someone smarter than me chime in.
I think 1500 is OK, but look at the article. I think its OK, but it does have a specific job, not just filtering.
"Coming off the Drain of Q1 is the loading network of R6, C1 and P1, and there is a comparable network of R7, C2, and P2 attached to the Drain of Q2. R6 clearly sets the AC load for Q1, but the DC requirements to bias up Mosfet Q3 are higher than that, so P1 in parallel with C1 provides a higher resistance value below about 0.5 Hz, and gives the approximately 3 volt DC drop required to bias the Mosfets."
ZM said it helps with protection at the input in case of pot failure. I didn't use it, but you might feel you need it.
Have someone smarter than me chime in.
while we all are waiting someone really smart to chime in , I can tell that 1500uF can be freely used instead of 1000uF for C1,C2 positions , ref to attached schm
R1 and R2 are having their own function , helping that usually disoriented (when laying in drawer) small Jfet certainly knows it's own orientation in Universe and broader ...... so not having particular connection with attenuator issues
R1 and R2 are having their own function , helping that usually disoriented (when laying in drawer) small Jfet certainly knows it's own orientation in Universe and broader ...... so not having particular connection with attenuator issues
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R1 and R2 are having their own function , helping that usually disoriented (when laying in drawer) small Jfet certainly knows it's own orientation in Universe and broader ...... so not having particular connection with attenuator issues
So I assume this means "yes" we should use both R1 and R2 along with the volume control?
After listening to the BA3-pre for some time, I can say that the B1, BOZ-J and the BA3-pre are all very similar in that they are all very transparent. The BA3-pre adds a bit more force to the sound. I think a limiting factor is the source equipment, not the preamps, especially not the BA3-pre. Only adjusting/changing the ASIO driver in my digital setup revealed sounds missing before. Incredible highs from the BA3-pre!
Reference: Brubeck's- Time Out! 176Khz hi-res tracks. Some well recorded voice are in the room and big. DSD tracks: no harshness in vocals at all and sound very "vinyl record" like. Sound stage wraps around in a semi circle in front of seating area.
all sounds appear to start 1 foot behind the speakers (Slotted Open Baffles).
have not played with P3 adjusmtment yet. That would mean removing the pre from the rack.
Don't be afraid to build this preamp! It's great!
My build:
Dual power supplies with LT1033/1085 regulators
Shunt stepped 25k attenuator (DIY)
20v+20v Antek shielded toroid transformer.
Par-Metals amp case
Mundorf M-cap
Vishay/Dale, Xircon (?) metal-film resistors.
~10db gain
Parts Connexion Connex selector switch. (I'd look around for another switch. )
Pin 2 is output on both poles. The rest are 1-6 input pins. Need continuity tester to figure it out.
Getting decal sheets soon. Will label ins and outs and post a few pics.
Hope this helps someone.
Vince
ps. There is a difference in spiking and isolating the preamp. Spiking adds more focus. Isolating gel feet rendered the sound more smooth, but more stable than just using the chassis feet.
Reference: Brubeck's- Time Out! 176Khz hi-res tracks. Some well recorded voice are in the room and big. DSD tracks: no harshness in vocals at all and sound very "vinyl record" like. Sound stage wraps around in a semi circle in front of seating area.
all sounds appear to start 1 foot behind the speakers (Slotted Open Baffles).
have not played with P3 adjusmtment yet. That would mean removing the pre from the rack.
Don't be afraid to build this preamp! It's great!
My build:
Dual power supplies with LT1033/1085 regulators
Shunt stepped 25k attenuator (DIY)
20v+20v Antek shielded toroid transformer.
Par-Metals amp case
Mundorf M-cap
Vishay/Dale, Xircon (?) metal-film resistors.
~10db gain
Parts Connexion Connex selector switch. (I'd look around for another switch.
)Pin 2 is output on both poles. The rest are 1-6 input pins. Need continuity tester to figure it out.
Getting decal sheets soon. Will label ins and outs and post a few pics.
Hope this helps someone.
Vince
ps. There is a difference in spiking and isolating the preamp. Spiking adds more focus. Isolating gel feet rendered the sound more smooth, but more stable than just using the chassis feet.
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