Remember, I'm not the one who spec'd 25V for C1 & C2. I'm just wondering where everyone else was, including N.P. with this. I would not really expect to see more than 6V on the 100 and the pot||cap together. You need about 1V on the source R, 2Volts Vgs add some signal and mabe thats 2 more volts, and a little more for when the drive gets tough. But it's a pre. So a 6.3V might work but I'm not goin there. A 10V at min and I think thats doable. My 16V caps are 12.5mm and they fit but my 25V caps are all 18mm!
I used the 1000uF, 25V Silmic II and you are quite right, they don't fit. Doesn't look good but they sound just fine.
I had the same problem with the Silmics on the BA-2 board.
I'm getting used to my boards looking like Stone Henge.
I had the same problem with the Silmics on the BA-2 board.
I'm getting used to my boards looking like Stone Henge.
Hey guys, I'm at a point where I need more gain in my system, especially for the digital front end. So, I'm thinking of adding the BA-3 at the output of the DCB1 (the current pre). My question is, can the BA-3 be used this way? From what I can tell, its output impedance is about 300 ohms and should be fine as a standalone preamp into amps other than the BA series.
Yeah, but I'm thinking of just stuffing it in the same chassis... you know how much work a new chassis is.
I think I'll keep the DCB1.. it allows many inputs and does a good job of buffering the sources... Planning to put a switch to flip the BA-3 in and out of the system. I really don't need the gain for the analogue source (Pearl II).
I think I'll keep the DCB1.. it allows many inputs and does a good job of buffering the sources... Planning to put a switch to flip the BA-3 in and out of the system. I really don't need the gain for the analogue source (Pearl II).
Beyond its output impedance, it has su stantoal drive current, having no problem driving the BA output with an input Z of about 7500, if I remener correctly.
What would be cool, is if Salas came up with a hot rodded BA3 front end with one of his power supplies.
Then put the output stage in separate case with its own supply (eg CRC).
Then put the output stage in separate case with its own supply (eg CRC).
Little bit above my head, TBO. Interested though. Got to many pokers in the fire anyway. In about 2 months, it will be time to finalize my system, that will be on the agenda .
Well just compare BA3 front end with BA2 output stage vs BA1 output stage.
Then think BA1 output with more grunt is what you will get with BA2/current source. It is a bit of a compromise for difficult/reactive loads.
If you don't need the grunt, then BA1 output or Aleph output is all you need.
With or without these tweaks the amp will sound sensational.
Then think BA1 output with more grunt is what you will get with BA2/current source. It is a bit of a compromise for difficult/reactive loads.
If you don't need the grunt, then BA1 output or Aleph output is all you need.
With or without these tweaks the amp will sound sensational.
Last edited:
I watch in earnest. No feedback naked F4/Ba output has a sweet sound to it. MOre musical than F5 for me. I havent messed with P3 on F5t yet. That will come when i get soundcard up and running. Too little time!
Hi buzzforb,
We were talking about thermal drift on the BA-3 but I don't think we decided how much heatsink was enough. I was getting a variable dc offset, certainly not rock solid, using the same heatsink as in Nellson's picture in his build plans except mine had two more prongs.
Did you end up using something more substantial? Technical details or a picture would be appreciated.
Chris
We were talking about thermal drift on the BA-3 but I don't think we decided how much heatsink was enough. I was getting a variable dc offset, certainly not rock solid, using the same heatsink as in Nellson's picture in his build plans except mine had two more prongs.
Did you end up using something more substantial? Technical details or a picture would be appreciated.
Chris
If you are still getting drift and your fets are cool or at least warm to the touch, it is probably more circuit related than the heat related. I believe this is the primary reason for such a large cap. Mine is torn down right now, as I am in the midst of the F5T, but will be reinstalled on the sinks when I am done testing.
Hi,
is there any issue in decreasing R10/R11 to 10Ohms, to double voltage gain? Are there Problems with oscillations?
Bias Point will be adjusted to 70mA per Device and R13 an 12W type will be used...
Best regards, Felix
is there any issue in decreasing R10/R11 to 10Ohms, to double voltage gain? Are there Problems with oscillations?
Bias Point will be adjusted to 70mA per Device and R13 an 12W type will be used...
Best regards, Felix
Panasonic FR
Has anyone used panasonic FR caps? They look significantly better than panasonic FC. I am looking at ordering some for C1 and C2. However I have noticed 2 different part numbers for the same cap, but can't see what the difference is.
Has anyone used panasonic FR caps? They look significantly better than panasonic FC. I am looking at ordering some for C1 and C2. However I have noticed 2 different part numbers for the same cap, but can't see what the difference is.
Last edited: