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DIY Meier Crossfeed Questions

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MorningDew

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Your welcome! I find it great when somebody wants to build his devices instead of buying them - it's become relatively rare today, that attitude.


Here are better pics on a second article on Rock Grotto - they also deal with the question of the "220nf" instead of the "difficult-to-get" 200nf. The 220nf work well for me.
http://www.rock-grotto.co.uk/crossproject2.htm

You may want to try out the "high"-version, too. Then substitute: 47nf by 22nf; 2K by 4,4K; 200/220nf by 100nf; 330 Ohm remain the same; 2,2K remain the same.
Excellent, thank you! I'll get enough parts for both versions (and extra because I'm sure mistakes will be made). More questions to follow, thanks for your help.
 

tomchr

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My apologies for the game of 20 questions. The ingredients call for a 200 nanofared capacitor but it apperas that the closest WIMA makes is a 220 nanofared. Is this suitable or should I look elsewhere? Thanks!
Just put two 100 nF in parallel. That'll give you 200 nF total. The Wima MKP or FKP is what you want.

+1 for metal film resistors. 0.25 W. Any brand.

Tom
 
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MorningDew

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I'd like to implement a bypass switch into the crossfeed. The tutorial I'm following states "Don't use a DPDT switch to bypass the crossfeed as it won't fully bypass the circuit but will give you two different levels of crossfeed instead. Instead use a 4 pole "on off on" switch". So, I'm looking on Mouser at the numerous options. Is there a current or voltage rating I should consider? Also, NKK mentions "Low-, medium-, and high-capacity models" of their switches. What should I be choosing for an audio application? I'm assuming low, correct? Thanks!
 

MRC01

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It's a line level unbalanced audio signal in between your source (output) & amp (input), so you're looking at a max of around 2 V, say 4 V to be safe. Minimal current and power pass through this circuit due to the amp's high input impedance.

The switch should be wired like this. I drew green lines to show what's connected when the switch is in bypass mode, white lines showing what's connected when the switch is engaged. So the switch has 2 positions, and controls 4 contacts: thus on/off 4 pole. I recommend "make before break" so when you flick the switch you don't get a pop/snap/spike. Because in this case if both are engaged it doesn't short, so if that happens for a brief moment as you flick the switch, it won't hurt anything.

Note: when the site says "on off on", he may be referring to a "break before make" switch. I don't see why he'd recommend that, since it will briefly disconnect the circuit which could cause the amp to pop/snap/spike when you flick the switch.

Switches can build up corrosion and get intermittent or sticky contacts over time and usage. And top quality switches don't really cost that much, so I'd go for a top quality switch.

1611336650608.png
 
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tomchr

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If the output impedance of your preamp/headphone amp (whatever drives the cross-feed circuit) is low, you should be able to get away with a DPDT switch on the output. However, "low" is a relative term and "should" is not the same as "will", so taking the circuit out completely with a 4PDT switch is probably a pretty good idea. You do not need an ON-OFF-ON switch, however. A regular ON-ON switch will work just as well.

You'll want a switch with gold contacts for switching small signals. The C&K 7401-series, such as the 7401SYZBE (DigiKey: CKN10609-ND), would be a good option. The NKK switches are good also.

Tom
 
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MorningDew

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It's a line level unbalanced audio signal in between your source (output) & amp (input), so you're looking at a max of around 2 V, say 4 V to be safe. Minimal current and power pass through this circuit due to the amp's high input impedance.

The switch should be wired like this. I drew green lines to show what's connected when the switch is in bypass mode, white lines showing what's connected when the switch is engaged. So the switch has 2 positions, and controls 4 contacts: thus on/off 4 pole. I recommend "make before break" so when you flick the switch you don't get a pop/snap/spike. Because in this case if both are engaged it doesn't short, so if that happens for a brief moment as you flick the switch, it won't hurt anything.

Note: when the site says "on off on", he may be referring to a "break before make" switch. I don't see why he'd recommend that, since it will briefly disconnect the circuit which could cause the amp to pop/snap/spike when you flick the switch.

Switches can build up corrosion and get intermittent or sticky contacts over time and usage. And top quality switches don't really cost that much, so I'd go for a top quality switch.

View attachment 107794
The idea of "make before break" is new to me so thanks for sharing - that makes sense. Also, thanks for the annotations to the image, I'm sure that will be helpful in understanding the switch. Are C&K or NKK considered "top notch" for this application or is there something in the audio world that I should consider without this getting too expensive?
 
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MorningDew

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If the output impedance of your preamp/headphone amp (whatever drives the cross-feed circuit) is low, you should be able to get away with a DPDT switch on the output. However, "low" is a relative term and "should" is not the same as "will", so taking the circuit out completely with a 4PDT switch is probably a pretty good idea. You do not need an ON-OFF-ON switch, however. A regular ON-ON switch will work just as well.

You'll want a switch with gold contacts for switching small signals. The C&K 7401-series, such as the 7401SYZBE (DigiKey: CKN10609-ND), would be a good option. The NKK switches are good also.

Tom
Ah, interesting - thanks so much for the item number...I'm new to the DIY game so specifics like that are very helpful!
 

tomchr

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Are C&K or NKK considered "top notch" for this application or is there something in the audio world that I should consider without this getting too expensive?

C&K and NKK are available from common electronic component distributors, so I'm sure they're not blessed by the audiophile community. After all, they were not hand carved from a solid block of rhodium plated unobtanium by certified organic vegan virgins. They work well for switching audio signals, though. :)

Seriously. What matters for switching small signals is the contact plating. You want gold there. You also want a switch that lasts. The C&K and NKK will do that. If you also want a switch with the right feel, you may want to look at using a SPDT or SPST switch and having it control some relays for the actual switching. This will allow you to accomplish the switching without having to drag the audio signals to the front panel of the chassis. It'll also open up the options for a wide range of relays. It may even be less expensive. 4-pole switches are pretty expensive.

If you also want to satisfy the audiophiles, Elma might be a good brand to pursue.

Ah, interesting - thanks so much for the item number...I'm new to the DIY game so specifics like that are very helpful!

It's easier when you know the part numbering system. I always seem to end up with the C&K switches, so I know their part numbers pretty well. 7x01 is an 'x' pole, double-throw switch. The rest of the alphabet soup refers to the type of bushing, length and type of the bat, contact materials, terminations, etc. You can see the numerology in the data sheet.

Tom
 
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MorningDew

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C&K and NKK are available from common electronic component distributors, so I'm sure they're not blessed by the audiophile community. After all, they were not hand carved from a solid block of rhodium plated unobtanium by certified organic vegan virgins. They work well for switching audio signals, though. :)

Seriously. What matters for switching small signals is the contact plating. You want gold there. You also want a switch that lasts. The C&K and NKK will do that. If you also want a switch with the right feel, you may want to look at using a SPDT or SPST switch and having it control some relays for the actual switching. This will allow you to accomplish the switching without having to drag the audio signals to the front panel of the chassis. It'll also open up the options for a wide range of relays. It may even be less expensive. 4-pole switches are pretty expensive.

If you also want to satisfy the audiophiles, Elma might be a good brand to pursue.



It's easier when you know the part numbering system. I always seem to end up with the C&K switches, so I know their part numbers pretty well. 7x01 is an 'x' pole, double-throw switch. The rest of the alphabet soup refers to the type of bushing, length and type of the bat, contact materials, terminations, etc. You can see the numerology in the data sheet.

Tom
No unobtainium?!?! I'm out! Really though, I'll just be happy if this thing works when I'm done! Interesting point about the signal going through the front panel, I had not thought of that. Thanks for the data sheet - coincidently was just looking at that. I'll get the C&K 7401SYZBE. Just saw the Neurochrome link in your info. Something I'll keep in mind after I graduate from this build. This DIY thing started with a few cables but I can see it headed to an amp rather quickly. Thanks again!
 

Bob-23

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This DIY thing started with a few cables but I can see it headed to an amp rather quickly. Thanks again!
Great!

The switch, by the way, is a good exercise, and as such useful, but, in my experience, you'll never need it if you like crossfeed at all - 'medium' crossfeed can be applied to any recording (for some recordings, mainly the older ones, it's not sufficient, and you need 'high' crossfeed, had to apply it yesterday with even a relatively new recording of Esbjörn Svenson Trio's).

Nontheless, for the purpose of demonstration of the crossfeed effect the switch may be justified.
 
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MorningDew

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Great!

The switch, by the way, is a good exercise, and as such useful, but, in my experience, you'll never need it if you like crossfeed at all - 'medium' crossfeed can be applied to any recording (for some recordings, mainly the older ones, it's not sufficient, and you need 'high' crossfeed, had to apply it yesterday with even a relatively new recording of Esbjörn Svenson Trio's).

Nontheless, for the purpose of demonstration of the crossfeed effect the switch may be justified.
Hmmm...that's a very good and practical point. I guess I assumed I wouldn't want crossfeed with modern recording but it sounds like if I'm bothered by the ones that I think require it then it's probably a good "all the time" idea. Thanks!
 

MRC01

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... The switch, by the way, is a good exercise, and as such useful, but, in my experience, you'll never need it if you like crossfeed at all - ...
This is a personal thing and my experience differs. I prefer not to use crossfeed except for recordings that need it or benefit from it. Like, having instruments/tracks panned hard L or R, or unnaturally wide separation (as in some of Pierre Sprey's Mapleshade recordings). In short, I find that most recordings don't need crossfeed. And you'll also need to be able to turn it off to listen to binaural recordings. So while crossfeed is great, I recommend having a switch to disable it.
 
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MorningDew

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This is a personal thing and my experience differs. I prefer not to use crossfeed except for recordings that need it or benefit from it. Like, having instruments/tracks panned hard L or R, or unnaturally wide separation (as in some of Pierre Sprey's Mapleshade recordings). In short, I find that most recordings don't need crossfeed. And you'll also need to be able to turn it off to listen to binaural recordings. So while crossfeed is great, I recommend having a switch to disable it.
Thanks for your input and I plan to check out those recordings. I think for now I’ll simplify things by going without the switch and since this is DIY in nature I could always add it later. I guess the personalization of it all is part of what makes this so enjoyable - we get to choose every part of the audio chain and most importantly the music! Thanks again.
 

Lbstyling

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I’ll look into the PC based ones, thanks. I’ve not heard Meier’s before and was tempted by one of the amps reviews here that has it but performance of the amp in general seemed sub-par. I think with the lack of live music taking place right now anything that makes headphones sound more natural and put you “in the room” sounds very appealing.

JRiver has this built in the software. You can vary the level, crossover threshold point (of you choose to cross-fade a frequency range rather than the whole band, you can choose steepness of the crossover for it etc, infinite variability.

You can even go the other way and add width to the sound in various ways also. If you stick to 2 channel, there is a headphone setting option that allows this.
 
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MRC01

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... for now I’ll simplify things by going without the switch and since this is DIY in nature I could always add it later. I guess the personalization of it all is part of what makes this so enjoyable ...
Did you finish the project? If so, how do you like it?
I'm about to build a little EQ kit and was thinking about adding this crossfeed to it.
 
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MorningDew

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Did you finish the project? If so, how do you like it?
I'm about to build a little EQ kit and was thinking about adding this crossfeed to it.
I'm ashamed to say that I have not. I incidentally ended up with the Monoprice amp that includes their "Dirac" feature which accomplishes something similar. For the time being it's met my need for reducing the dramatic R/L channel effect of some recordings. I'm keeping the parts though in hopes of getting around to it sometime this summer.
 
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