Thanks Mihai
Another question, from what supply voltage on the drive i can check if it's working?
My bench supply is only ±25Vdc.
Another question, from what supply voltage on the drive i can check if it's working?
My bench supply is only ±25Vdc.
DRZ1 said:
Hi Denis,
I've checked in simulator and the bias points for the frontstage will remain unchanged. You could use +/- 25V for starting the amplifier 😀
Mihai
roender said:
Neither - right now. Build it up and test to make sure you can adjust to a position that doesn't introduce any noise from leakage. Toroid leakage is supposed to be mainly aligned with the center of the toroid, but also comes from gaps in the windings where the wires exit.
Sheldon
Niner,
It looks ok from electrically POV. Please cut or bend out the substrate pin (no. 4) from k389 dual jfet and connect directly under this pin the output of LTP current source to common JFETs source pins ( no. 3 & 5)
Mihai
It looks ok from electrically POV. Please cut or bend out the substrate pin (no. 4) from k389 dual jfet and connect directly under this pin the output of LTP current source to common JFETs source pins ( no. 3 & 5)
Mihai
Ideas for placing transformers
Hello,
I remember in DPA ( a.k.a. Upupa Epops here ) design the use of two transformers . Because It is your case too, I 'll propose you this solution. The example is in the following image.
http://www.hometheaterhifi.com/volume_6_4/images/feature-article-czech-republic-dp-amplifier.jpg
( If you're not to in to hurry maybe I can provide you somes picture during the week-end )
Hello,
I remember in DPA ( a.k.a. Upupa Epops here ) design the use of two transformers . Because It is your case too, I 'll propose you this solution. The example is in the following image.
http://www.hometheaterhifi.com/volume_6_4/images/feature-article-czech-republic-dp-amplifier.jpg
( If you're not to in to hurry maybe I can provide you somes picture during the week-end )
Hello,
I have another question about roender's design. In an earlier post you said that the takeoff point of the feedback network is critical. Why is that?
I have another question about roender's design. In an earlier post you said that the takeoff point of the feedback network is critical. Why is that?
Hi Roender
Regarding position for transformers:
Keep them horizontal and move to the front.
Regarding volume pot:
Mount the pot at the back and use a extension rod (like DRZ1).
Use the same mounting support, just rotate pot for 180º.
After this the pot will be "inside" mounting support.
================================================
Niner,
Good work!
P.S.
Is it problem to make board shorter and spread front end over the unused space. Left side seems to be overcrowded, with plenty of space around.
Regarding position for transformers:
Keep them horizontal and move to the front.
Regarding volume pot:
Mount the pot at the back and use a extension rod (like DRZ1).
Use the same mounting support, just rotate pot for 180º.
After this the pot will be "inside" mounting support.
================================================
Niner,
Good work!
P.S.
Is it problem to make board shorter and spread front end over the unused space. Left side seems to be overcrowded, with plenty of space around.
Mihai, it's up and running 😀
Look good at first attempt.
Offset < 2mv , Rise time > 30V uS , Square Wave at 10Khz = superb compensation look very good.
It just running at 25 V on the front end.
Now the Power Supply, I have a good Plitron 400VA 30-30 , is it to high For the PA ? I thing yes and i imagine that the front end must be raised to in the same order, what the limit ? so .....
Look good at first attempt.
Offset < 2mv , Rise time > 30V uS , Square Wave at 10Khz = superb compensation look very good.
It just running at 25 V on the front end.
Now the Power Supply, I have a good Plitron 400VA 30-30 , is it to high For the PA ? I thing yes and i imagine that the front end must be raised to in the same order, what the limit ? so .....
DRZ1 said:
Bravo Denis!
I'm glad that your amp is up and running.
Well, 42V DC seems to high for RMI-FC100 output stage, at least for 1W class A bias current but can be done if you have a big heatsink. There is enough SOA margin for 42V output voltage.
The front stage was tested for 38V only and if you want to increase the voltage you must add 5V over output stage voltage but I think it is to high (47V) and you need to add small heatsinks on cascode LTP transistors.
Please tell me how it sound?
Cheers,
Mihai
emanuel_hr said:
Emanuel,
Please send me PM with your e-mail address. I have a very good book for you.
Mihai
Re: Hi Roender
Max,
Thank you very much.
Hi Bob,
Plees see this post
http://www.diyaudio.com/forums/showthread.php?postid=1414883#post1414883
There is no point to mount the pot in the back of the case.
Cheers,
Mihai
MaxS said:
Max,
Thank you very much.
Bob03 said:
Hi Bob,
Plees see this post
http://www.diyaudio.com/forums/showthread.php?postid=1414883#post1414883
There is no point to mount the pot in the back of the case.
Cheers,
Mihai
Hi Mihai,
For the moment i only have one channel built. I must build the Power Supply first. Have problem to find 35-0-35 small Transfo. I think i will take two 17-0-17 in serie to feed the two channel frontend reg.
Fun , because i have copied all your stuff in Altium and redraw the PCB completly in Altium to. Seem to be 100% functionnal. I have respected your design integrity, just make some small change to accomodate components footprints (WIMA caps are really rare here! ) and managed area to use input cap if needed, if someone want it i can post it. It can be more adapted to friends this side of Ocean and our parts suppliers.
For the moment i only have one channel built. I must build the Power Supply first. Have problem to find 35-0-35 small Transfo. I think i will take two 17-0-17 in serie to feed the two channel frontend reg.
Fun , because i have copied all your stuff in Altium and redraw the PCB completly in Altium to. Seem to be 100% functionnal. I have respected your design integrity, just make some small change to accomodate components footprints (WIMA caps are really rare here! ) and managed area to use input cap if needed, if someone want it i can post it. It can be more adapted to friends this side of Ocean and our parts suppliers.
Attachments
Nice. Mihei, is there a significant advantage to dual front end supplies for this design? In other amps (limited sample to be sure), I'm finding that I often can't perceive a sonic difference.
Sheldon
Sheldon