nice done to both!
at berlusconi:
would be nice if you have time for the post 30, 31.
thx
chris
at berlusconi:
would be nice if you have time for the post 30, 31.
thx
chris
I'm not sure whwat's you have proposed in posts #30 and #31. Could you please draw the proposed changes on the image below.
Hi
the caps in the red frame should be changed.
1 the frame with 100pF should be change to 220pF these are the input filter - before opamp.
test-measurement
2 the frame at the 10pF should be changed after test 1 with also 220pF - these are the filtering after the opamp.
thx
the caps in the red frame should be changed.
1 the frame with 100pF should be change to 220pF these are the input filter - before opamp.
test-measurement
2 the frame at the 10pF should be changed after test 1 with also 220pF - these are the filtering after the opamp.
thx
Attachments
You could start with changing at one channel and then compare.
Its on you.
Thx
Chris
Its on you.
Thx
Chris
well, if the price was already unbelievable, new price drop, the reason, for me inexplicable, but it's good for many people in the forum to try, and have a decent preamp to experiment with.
Apart from this from the beginning I have said that it had good measurements, pro above some recognized brands, but I also said that for me, it was too neutral, so I will try to bring it to my taste (when I have time), the other day I tried replacing the ceramic capacitors for other values and copper, and it sounds a little better quite imperceptible, but I notice it, and the best thing is that I did not have to buy the capacitors, I made them, and I will put as and measures.
if they continue like this they will soon give you direno because you ask for it.😀
Apart from this from the beginning I have said that it had good measurements, pro above some recognized brands, but I also said that for me, it was too neutral, so I will try to bring it to my taste (when I have time), the other day I tried replacing the ceramic capacitors for other values and copper, and it sounds a little better quite imperceptible, but I notice it, and the best thing is that I did not have to buy the capacitors, I made them, and I will put as and measures.
if they continue like this they will soon give you direno because you ask for it.😀
I was a little bit busy too...built in the C3850 in an old housing. Tomorrow i will make the first hearing test. I dont like the ceramic capacitors, will see what is in stock...
My first change was to change the 100 µf capacitors at the ic into 100 µf bipolar. I had in stock 🙂
BTW the 5 volt SNT is only for backlight led behind the pot knob....
Greets
Peter
My first change was to change the 100 µf capacitors at the ic into 100 µf bipolar. I had in stock 🙂
BTW the 5 volt SNT is only for backlight led behind the pot knob....
Greets
Peter
Attachments
yes the ceramic caps should be changed in a adequate film cap - its also written in FH9 by XRK.
peter?: blue colored bipolar? Panasonic?
if yes i would try the green nichicon muse (UES serie)
chris
peter?: blue colored bipolar? Panasonic?
if yes i would try the green nichicon muse (UES serie)
chris
@Chris
Yep, Panasonic bipolar. Muse 100 µf 25 volt a little to big i found. I will see when the film capacitors arrived. If there is space enough then i can change quickly.
Yep, Panasonic bipolar. Muse 100 µf 25 volt a little to big i found. I will see when the film capacitors arrived. If there is space enough then i can change quickly.
First hearing session....sounds very good... 🙂 I have tested with my AKG 712. No hiss, no hum, deadly silence if foobar is paused.
I have done 3 changes of components. Feedback capacitor 100 µf is a bipolar type now, the gain is lowerd to ~ 5x with two 560 (556) ohm resistors. The 100pf capacitors parallel to 1M near output are glimmer capacitors.
I have to wait for more components (220 pF and more). I have ordered but it takes time...if i find time tomorrow i change the input ic.
With KiCad I have made a new schematic with values.
I have done 3 changes of components. Feedback capacitor 100 µf is a bipolar type now, the gain is lowerd to ~ 5x with two 560 (556) ohm resistors. The 100pf capacitors parallel to 1M near output are glimmer capacitors.
I have to wait for more components (220 pF and more). I have ordered but it takes time...if i find time tomorrow i change the input ic.
With KiCad I have made a new schematic with values.
Attachments
good to hera that the sound is fine. Do you have another preamp for compare?
my components are on the way...
wow...thanks Peter for the KICAD schematic!
chris
my components are on the way...
wow...thanks Peter for the KICAD schematic!
chris
Hi Chris,
yes, i have 3 preamps more. But in the first time i will use my headphones. Later i will hear with only one amp and change the preamps.
P30ZF, a JC2 Clone and one preamp with LM49740. The last one was designed by a forum user 2pi, oliver, at diy-hifi-forum. I need sometimes because of its balanced outputs.
Thanks to oliver..because i am the only owner of an headphoneamp with timing belt. Photo ? 🙂🙂🙂
Greets
Peter
yes, i have 3 preamps more. But in the first time i will use my headphones. Later i will hear with only one amp and change the preamps.
P30ZF, a JC2 Clone and one preamp with LM49740. The last one was designed by a forum user 2pi, oliver, at diy-hifi-forum. I need sometimes because of its balanced outputs.
Thanks to oliver..because i am the only owner of an headphoneamp with timing belt. Photo ? 🙂🙂🙂
Greets
Peter
Attachments
@Kleinhorn please check your schematic. Both the website and Beeny schematics show a connection from the 470R in the feedback circuit to the output of the Class A stage between the two 22R emitter resistors, which then continues on to the point between the 100R resistor and 100uF cap. Circled in red in the Beeny schematic below.
I had a misstatement earlier that the schematics from the website and Beeny are different. I think they are the same.
I had a misstatement earlier that the schematics from the website and Beeny are different. I think they are the same.
Thank you very much....i overlooked that connection. Tomorrow i will correct that mistake, a little thing. I upload the new schematic then...
Greets
Peter
Greets
Peter
my pcb is partly done...mouser delivered faster.🙂
gain is set with 680R --> 4.61dB
i need:
transistors - have BC557/BC550 - BC337/327 - decision not done.
transformer 30VA 2x15V
47k resistor
and time😉
ooops...i see...i was too fast...some resistors are not good soldered...have to check...
gain is set with 680R --> 4.61dB
i need:
transistors - have BC557/BC550 - BC337/327 - decision not done.
transformer 30VA 2x15V
47k resistor
and time😉
ooops...i see...i was too fast...some resistors are not good soldered...have to check...
