Bill
If you refer to my KX2, thank you very much. It still have some details remaining, will place some photos in the KX2-thread when completed.
I am eager to build the X-Altra preamp to complement the power amplifier. Mr. Bonsais work is indeed serious and the instructions are clear and easy to follow for a beginner like me.
Now its just to wait and keep fingers crossed that the parts on the coming BOM will be available at the time of release🙂.
If you refer to my KX2, thank you very much. It still have some details remaining, will place some photos in the KX2-thread when completed.
I am eager to build the X-Altra preamp to complement the power amplifier. Mr. Bonsais work is indeed serious and the instructions are clear and easy to follow for a beginner like me.
Now its just to wait and keep fingers crossed that the parts on the coming BOM will be available at the time of release🙂.
Yep Bonsais build manuals are first class, having come from building beta kits for Heathkit and reviewing their manuals I wish everyone were as thorough.
X-Altra Mini II is finished - I've updated the 1st post in this thread to reflect that. Feel free to ask any questions etc.
🙂
🙂
I wonder if TIs JFE2140 could be an alternative to the LSK389? On the pictures it looks like the PCB is "SOIC-ready"
I've updated the main presentation and put the PCB price lists up on the webpage here https://hifisonix.com/x-altra-mini-ii-line-preamplifier/
I've grouped the PCB's in sets to cover configurations A-F, but you are of course free to order any of the boards on their own if you like.
If you have any questions, feel free to email or PM me.
🙂
I've grouped the PCB's in sets to cover configurations A-F, but you are of course free to order any of the boards on their own if you like.
If you have any questions, feel free to email or PM me.
🙂
I downloaded the data sheet and took a look. The TI SOIC package has the same pinout as the LSK389 SOIC device. The TI device noise specs look superb and in line with the LSK device - the DC offset voltage match is also very tight. Since the X-Altra Mini II discrete line stage can take either the SOIC or the TO71-6L package, I will order some samples and try it out.
I've done some preliminary tests using a PSU I've lashed up on the workbench and a second build of the X-Altra Discrete Line stage fitted with the TI JFE2140's.
The distortion results are the same as for the LSK389B - ie below 10ppm at 5 V RMS output. For this test I loaded the output at 600 Ohms (the tests on build #1 were with 2k Load for 9V RMS output at 10ppm distortion). I'll do some more tests with 1k and 2k load in the next few days but so far I'd say the device looks superb. The noise floor is the same as the LSK389B in this application ie better -130 dBV. My guess is will also work well with the X-Altra MC/MM phono pre as well.
The distortion results are the same as for the LSK389B - ie below 10ppm at 5 V RMS output. For this test I loaded the output at 600 Ohms (the tests on build #1 were with 2k Load for 9V RMS output at 10ppm distortion). I'll do some more tests with 1k and 2k load in the next few days but so far I'd say the device looks superb. The noise floor is the same as the LSK389B in this application ie better -130 dBV. My guess is will also work well with the X-Altra MC/MM phono pre as well.
Hi Bonsai,
Very nice preamp. I was wondering what type of board to board wire interconnect are being used? Is direct soldering preferable in this particular setup?
Best Regards
Farooq
Very nice preamp. I was wondering what type of board to board wire interconnect are being used? Is direct soldering preferable in this particular setup?
Best Regards
Farooq
Hello Farooq, I’m using 20 AWG silicone insulated wire I got off Amazon. Very nice to work with.
For signal interconnects, I’m using single and twin core 3mm diameter screened cable from RS Components.
