hi,
the build is customized, I hope I have not done anything wrong, the scheme is respected.
JFET taken from Electro andijk, GR and BL grade.
Tested both without substantial differences, only adequate R21-R24 to adjust tensions.
R11 = 6K81
R12 = 909R
C10 = 0.01uF
C11 = 0.01uF
C12 = 0.1uF
C14 = 0.1uF
C16 = 0.1uF
C17 = 0.1uF
C18 = 0.1uF
C19 = 0.1uF
C20 = 0.033uF
Attachments
Well I got everything hooked up to the home stereo so after the B1 I am hooked up to QSC amp. At this time I do not have nearly the volume level I need.
When I was using the Cambridge Audio 640 I ran it to the B1 and to the same amp I am using now. Since that amp also is being used for everything else I would have to adjust the gain knob to one tick below full open. Now even if I go full open the volume is just not there.
Looks like I will be dropping R14 to a lower value. I am either going to drop it 100 ohm’s since I know I have those or I may check to see if I have a few pots I could use to adjust the value.
When I was using the Cambridge Audio 640 I ran it to the B1 and to the same amp I am using now. Since that amp also is being used for everything else I would have to adjust the gain knob to one tick below full open. Now even if I go full open the volume is just not there.
Looks like I will be dropping R14 to a lower value. I am either going to drop it 100 ohm’s since I know I have those or I may check to see if I have a few pots I could use to adjust the value.
Well according to the Pearl doc I can increase the gain by changing out a resistor (per board):
“The overall gain of the circuit as shown is 55 dB @ 1K Hz. Decreasing R14 from 1K to 300 Ohms gives 10 dB more gain when desired for lower output cartridges. R15 which normally would be shorted to 0 ohms can be replaced by a resistor to provide more gain as an alternative to reducing the value of R14. C15 has been placed on the board to allow for additional adjustment of equalization. In both cases these values are up to you.”
I am sure you have seen this a million times by now as much as you have helped people and worked on them.
“The overall gain of the circuit as shown is 55 dB @ 1K Hz. Decreasing R14 from 1K to 300 Ohms gives 10 dB more gain when desired for lower output cartridges. R15 which normally would be shorted to 0 ohms can be replaced by a resistor to provide more gain as an alternative to reducing the value of R14. C15 has been placed on the board to allow for additional adjustment of equalization. In both cases these values are up to you.”
I am sure you have seen this a million times by now as much as you have helped people and worked on them.
Is R14 at 300 ohms now?
I built a B1 and couldn't get my F5 up to even a normal listening level with classical music. 6L6 is right, you need a real preamp.
No it is not.
Not saying this in an a$$hole way, but check out what I have already posted. The B1 has worked with this amp successfully already.
All I need is 1.2Vrms to fully drive this amp.
I understand 6L6 is vastly more more experienced with the Pass line than I am but until I go back under the hood of this, I just cannot say I need a new anything.
Not saying this in an a$$hole way, but check out what I have already posted. The B1 has worked with this amp successfully already.
All I need is 1.2Vrms to fully drive this amp.
I understand 6L6 is vastly more more experienced with the Pass line than I am but until I go back under the hood of this, I just cannot say I need a new anything.
Mark,
I just tested this last night and just got downstairs today. Raine in those horses!
You probably move a lot faster than this old crippled guy
Once I do get things changed out I will report back.
James
My Pearl 2 with a low-output moving coil and R14 at 300 ohms overloads my headphone preamp. It's a huge amount of gain. I think you'll be happy with that setting in your rig. If it's still producing less gain than the Cambridge at 300 ohms, there may be a different issue.
If I use my B1 with Pearl 2 into BA3, I have plenty of gain. That is using a "high output" moving coil, 2.5 if I remember. With F5, it worked but so nearly so we'll. BA3 FE cured that nicely.
It isn't all about the gain, even at same over all volume it just sounded better to me. Try a BA3 FE, everyone needs an extra preamp around!
Russellc
