Scott indeed built a beautiful pre! congrats! envy!
I'm going to try myself on it, what PSU are recommended? (besides the Glass-Ware Bipolar LV 6L6 recommends?) Would Salas' ultrabib fit, or is it totally a different beast?
thank you for insights...
david
Mark Johnsons VRDN PSU will also be a great fit, i am planning on using it.
VRDN: bipolar regulator PCB for line level ckts: ±11V to ±20V @ 1.5A with "De-Noiser"
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Dennis, myleftear and 6L6:
Thank you! A version of this project has been rattling around in my head for a while, and I'm pleased by how it all came together. The preamp is still burning in (there has been a subtle but clear improvement after running my FryBaby2 through the BA2018 overnight) and I trust that by next weekend it will be sounding as good as it ever will.
myleftear:
I'm not sure about the value of my guidance on BA2018 power supplies. I considered the John Broskie bipolar supply but once I committed to three supplies, size considerations made that a difficult choice. It certainly would have been less expensive. I coincidentally just finished a Salas Ultra FSP preamp as well and appreciate how the Ultra BiB 1.3s supplies work, but I have no regrets in choosing the Pete Millett boards -- they are very compact and I like the design. Honestly, I doubt there's a bad choice amongst any of your options.
Regards,
Scott
Thank you! A version of this project has been rattling around in my head for a while, and I'm pleased by how it all came together. The preamp is still burning in (there has been a subtle but clear improvement after running my FryBaby2 through the BA2018 overnight) and I trust that by next weekend it will be sounding as good as it ever will.
myleftear:
I'm not sure about the value of my guidance on BA2018 power supplies. I considered the John Broskie bipolar supply but once I committed to three supplies, size considerations made that a difficult choice. It certainly would have been less expensive. I coincidentally just finished a Salas Ultra FSP preamp as well and appreciate how the Ultra BiB 1.3s supplies work, but I have no regrets in choosing the Pete Millett boards -- they are very compact and I like the design. Honestly, I doubt there's a bad choice amongst any of your options.
Regards,
Scott
Wow, ba 2018 works with f4? That’s good news, I always thought there weren’t many capable of this!
Will still have to evaluate (big word [emoji3166]) Mark‘s solution above...
Thank you, Scott!
Even though you‘re not ranking, I appreciate this above quote a lot—being in a solder-happy mood again, this makes me wanting to build them all. It quite probably won’t be so, as there are other projects that I somehow „must“ do... f4, ba 3, pumpkin, Salas’s njfet riaa, Td-125 and and and...
But I’m comforted that any psu will be really good.
The truth is, VRDN was designed as a special favor for one of our Moderators, who wanted a regulated PSU (a) to power his Wayne's Linestage, and (b) to have plenty of flexibility to use with other line level projects that might emerge in the future. He provided me a list of requirements + wishes-but-not-requirements and boom, VRDN was born. If you were curious why the write-up includes a final section named "Features and Mis-Features".
Bear in mind he has Cinemags pinned on to the outputs giving an additional 6 dB. Without, you will not drive F4 to full output. You may be fine depending on speaker efficiency and listening habits.
Russellc
I made a quick video of how I do SMD soldering by hand. Typically, I prefer to use hot air and solder paste, but since most of y'all seem to do it by hand, that's how I did it in the video. I personally find this method easier than using the tape method.
YouTube
I have shaky hands, and it's usually much easier when I don't have a camera blocking my view. I promise it's easier than setting up the ability to record that!
YouTube
I have shaky hands, and it's usually much easier when I don't have a camera blocking my view. I promise it's easier than setting up the ability to record that!
Ya, it's situation dependent. If I had a higher gain linestage, I would just be dialing in more digital attenuation (at my DAC) at the level that I listen at. So 18 dB works well for me. I prefer not to throw away signal if possible. But if driving F4 to full capability is an absolute requirement, then you will want more gain / drive.
I mention it here: https://www.diyaudio.com/forums/pass-labs/97540-f4-power-amplifier-460.html#post6202567
Not ideal for sure. Nearfield setup in a hobby room. Speakers are NHT XDS's with a custom passive crossover that went through lots of tweaking.
Not ideal for sure. Nearfield setup in a hobby room. Speakers are NHT XDS's with a custom passive crossover that went through lots of tweaking.
I need some help troubleshooting my build. I'm using the board from the store and powering it using a ultraBIB psu set at +/- 20 vdc @ 200 mA. When I power up the LEDs do not light and Q8 and Q20 get very hot.
I installed the leds so that the cathode(short leg) was towards the flat side on the silkscreen.
It is configured as a line stage using the digikey BOM in this thread (KSC1845, KSA992, 2SK209BL) I have double checked all the transistors to make sure the correct ones are in the right spots, they are.
I double checked all of the resistors and they are the correct values shown on the silkscreen with the exception of R6 and R36 which read 894R and 929R respectively instead of 1.5K, but since they are in parallel with P1 that should be OK.
I have cleaned the board and checked it for shorts and cold joints under magnification and found nothing.
I have attached pics of my build so that hopefully someone can see what I'm missing and point me in the right direction.
Thanks,
Paul
I installed the leds so that the cathode(short leg) was towards the flat side on the silkscreen.
It is configured as a line stage using the digikey BOM in this thread (KSC1845, KSA992, 2SK209BL) I have double checked all the transistors to make sure the correct ones are in the right spots, they are.
I double checked all of the resistors and they are the correct values shown on the silkscreen with the exception of R6 and R36 which read 894R and 929R respectively instead of 1.5K, but since they are in parallel with P1 that should be OK.
I have cleaned the board and checked it for shorts and cold joints under magnification and found nothing.
I have attached pics of my build so that hopefully someone can see what I'm missing and point me in the right direction.
Thanks,
Paul
