I'm a bit challenged when it comes to grounding and I keep reading contradictory information on the best way to go about it.
My Selection Switch & Volume Control dont have ground inputs and I was hoping to get advice whether the grounding scheme below will work ok?
My Selection Switch & Volume Control dont have ground inputs and I was hoping to get advice whether the grounding scheme below will work ok?
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Turns out I'm impedance challenged as well 🙂
Many moons ago I replaced the Alps Blue pots I put in a couple of amps I built with pots made up using Russian NOS 12 position selection switches. I used good quality 0.1 % resistors and it made a world of difference to the sound, I assumed I got the setup right because they worked 🙂
I had 2 switches leftover and decided to use on for the pot in the KORG, most of the volume work will be done by the source, so no need for lots of positions.
I was hoping someone who is not impedance challenged could look at the diagram below to see if there are any fundamental errors in the pot layout.
This is going to sound stupid but I'm not sure what the 100k resistor between the ground and the output is all about. It was in my original design but for love nor money I cant workout what it was doing.
Many moons ago I replaced the Alps Blue pots I put in a couple of amps I built with pots made up using Russian NOS 12 position selection switches. I used good quality 0.1 % resistors and it made a world of difference to the sound, I assumed I got the setup right because they worked 🙂
I had 2 switches leftover and decided to use on for the pot in the KORG, most of the volume work will be done by the source, so no need for lots of positions.
I was hoping someone who is not impedance challenged could look at the diagram below to see if there are any fundamental errors in the pot layout.
This is going to sound stupid but I'm not sure what the 100k resistor between the ground and the output is all about. It was in my original design but for love nor money I cant workout what it was doing.
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Crossover for Sub in BIK?
I would like to have a Subwoofer output in my B1K. How best to facilitate this with the best sonic results is the question. I post options in order of complexity but if there are others, PLEASE chime in.
1) Just wye the output of the B1K sending full range to both the mains and the sub amp. I have Crown sub amps that will do low pass and also combine both channels into mono. But that sends full range to the mains and may not be optimal having lows coming from all over the room causing cancellation problems. The room works really well right now after lots of T&E and I don't want to re-invent the wheel... again.
2) Add a miniDSP 2x4 kit to the B1K output. But that sort of defeats my premise for my All Analog project. I already have a very high quality digital system. The miniDSP throws a AD and DA process to the signal chain. But, maybe others have a good experience with the miniDSP. I'm not totally adverse to the idea and could still go "pure analog" bypassing the miniDSP when I felt a purist analog need by having an additional full range output on the back.
3) Build the Pass Active Crossover kit and only use a piece of it for this. But this is more expensive, more work, ANOTHER large chassis to deal with. But may be the best sonic solution to stay in the Analog realm.
4) Other suggestions/solutions I may not be aware of? Maybe a two-way, two channel active analog passover that would fit in the B1K chassis? Other thoughts?
Thanks!!
I would like to have a Subwoofer output in my B1K. How best to facilitate this with the best sonic results is the question. I post options in order of complexity but if there are others, PLEASE chime in.
1) Just wye the output of the B1K sending full range to both the mains and the sub amp. I have Crown sub amps that will do low pass and also combine both channels into mono. But that sends full range to the mains and may not be optimal having lows coming from all over the room causing cancellation problems. The room works really well right now after lots of T&E and I don't want to re-invent the wheel... again.
2) Add a miniDSP 2x4 kit to the B1K output. But that sort of defeats my premise for my All Analog project. I already have a very high quality digital system. The miniDSP throws a AD and DA process to the signal chain. But, maybe others have a good experience with the miniDSP. I'm not totally adverse to the idea and could still go "pure analog" bypassing the miniDSP when I felt a purist analog need by having an additional full range output on the back.
3) Build the Pass Active Crossover kit and only use a piece of it for this. But this is more expensive, more work, ANOTHER large chassis to deal with. But may be the best sonic solution to stay in the Analog realm.
4) Other suggestions/solutions I may not be aware of? Maybe a two-way, two channel active analog passover that would fit in the B1K chassis? Other thoughts?
Thanks!!
I own several different miniDSP units and now use them only for design purposes in optimizing my preferred crossover points and slopes for implementation using Papa's ACN.
This all started with a miniDSP set up with Sigfried's official curves and connected to some stock LXmini loudspeakers. When I replaced the miniDSP with the ACN, there was a noticeable improvement. Quieter, more headroom, smoother yet detailed.
I then developed a 500Hz crossover design for the ACN to replace a miniDSP being used in a different biamplified system I own (ADS L980s). I used the Tube Cad Filter Designer software to determine R and C values for the ACN, then modeled and adjusted them using the LTSpice model of the ACN. Implementation did require some minor PCB hacks. Again, there was a noticeable improvement over the miniDSP. To my ears, there is no going back to DSP at this point, at least with a 500Hz crossover point.
I am in the process of adding some subwoofers to the LXmini loudspeaker system. My thought is to listen them both full range and then alternately high pass filtered and decide if the full range + sub is acceptable or if another ACN will be required.
Bottom line is a recommendation to get a miniDSP (not expensive) and experiment. Then implement with the ACN or cut down the ACN PCB to fit your chassis. You can use the B1K power supply and much of the value in buying the ACN from the DIY store lies in the set of matched JFETS included. But I'm guessing you will like LR24 as a config and that would use all the filter sections of the ACN. Or wait until Papa's new universal crossover hits the store.
Seems like great advice guru. I sort of always wanted to play with one of the mini devices anyway but tend to believe it won't be much more than a tool ultimately, as you found.
I searched a bit for the upcoming Universal Crossover you referred to. But didn't find anything. Could you point me to some information on it please?
I searched a bit for the upcoming Universal Crossover you referred to. But didn't find anything. Could you point me to some information on it please?
It is common practice to provide some guaranteed connection to ground
after a pot or switch if you are not certain that whatever follows has
one. This prevents possible open input circuits and the noise and offset
that might accompany them.
Hi Guys,
After reading the Pass Labs playground passively for about a decade, I'd like to show you my approach to the B1 Korg. A friend of mine, andreasw, has posted photos of his setup with my pcb's, he's always a bit faster than me, as I travel a lot.
The board has a lot of room for different capacitors, separate boards for input and Nutube. The PSU is a cloned S11, with filter, transformer, snubber and active rectifier.
This is my first serious project with Kicad after more than 20 years working with Eagle.
How does it sound? very good for the few parts that are installed.
After reading the Pass Labs playground passively for about a decade, I'd like to show you my approach to the B1 Korg. A friend of mine, andreasw, has posted photos of his setup with my pcb's, he's always a bit faster than me, as I travel a lot.
The board has a lot of room for different capacitors, separate boards for input and Nutube. The PSU is a cloned S11, with filter, transformer, snubber and active rectifier.
This is my first serious project with Kicad after more than 20 years working with Eagle.
How does it sound? very good for the few parts that are installed.
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In a post from Papa July 10 in the LXmini forum, he was just about to receive the new boards, reputed to be configurable for various slopes/xover points and to include input buffers. Many Greedy Boyz await this PCB. It took about 2 months to go from the Xmas Korg in December to the B1 Korg in the store. Maybe Papa or 6L6 can weigh in on ETA for the new ACN.
Could you abandon that star grounding method altogether? Meaning, can I just have signal wires directly routed to the ins/outs of board without star grounding everything together like shown in DQ828's schematic? In which case, it would just be the PCB grounding to case and nothing tied together except what occurs within PCB.
DQ828 also shows the potentiometer used as a variable resistor. Choosing between variable resistor and voltage divider... is there any reason for choosing one over the other?
Thanks
I'm finally getting close to blast off and have yet another question. I started building the Korg for myself but have since promised it to my son. I built a pair of Linkwitz LX521 and feed them the signal using the ASP.4. I have read that you need to invert the speaker leads but in this setup it's a bit of a pain to do that, especially since I will only be testing then hand it over with a bow on top.
Can I invert the signal going into the ASP and get the same outcome?
Can I invert the signal going into the ASP and get the same outcome?
You can do anything you like, but if you invert before the Korg, you might want to
set it for phase of 2nd harmonic on the other side. "Stock" setting is for the
2nd harmonic phase to be positive at the output of the Korg, and then it is flipped
to negative when you flip the polarity after Korg (in order to retain absolute polarity).
If you set the Korg for negative 2nd harmonic, then flipping the phase before the
Korg will give you negative 2nd at the speaker - except that routinely one of these
channels is inverted in the speaker wiring....
If possible I would try it both ways, - the sensitivity to 2nd harmonic phase is (I think)
mostly at the lower end of the audio band, below 2KHz or so.
set it for phase of 2nd harmonic on the other side. "Stock" setting is for the
2nd harmonic phase to be positive at the output of the Korg, and then it is flipped
to negative when you flip the polarity after Korg (in order to retain absolute polarity).
If you set the Korg for negative 2nd harmonic, then flipping the phase before the
Korg will give you negative 2nd at the speaker - except that routinely one of these
channels is inverted in the speaker wiring....
If possible I would try it both ways, - the sensitivity to 2nd harmonic phase is (I think)
mostly at the lower end of the audio band, below 2KHz or so.