AudioCircle

Audio/Video Gear and Systems => Headphone Mania => Topic started by: macdane on 3 May 2018, 09:23 pm

Title: Amps with Crossfeed circuit?
Post by: macdane on 3 May 2018, 09:23 pm
In the hopes that someone here tracks such things, I'd really be interested in a list of headphone amps offering a crossfeed circuit. I have a Meier Corda Prehead as part of my main rig and I personally find a small amount of crossfeed indispensable for headphone listening. I understand there's a cost involved in adding a feature like this, but I'm baffled to see so few amps that include it.

Specifically what I'm looking for is something portable. Having a good DAC built-in would be a plus but not absolutely necessary. Having a good crossed option, however, is a must. Meier and Headroom both had such devices once upon a time, but who does it now?

Thanks,
Dane
Title: Re: Amps with Crossfeed circuit?
Post by: FullRangeMan on 3 May 2018, 09:46 pm
In the hopes that someone here tracks such things, I'd really be interested in a list of headphone amps offering a crossfeed circuit. I have a Meier Corda Prehead as part of my main rig and I personally find a small amount of crossfeed indispensable for headphone listening. I understand there's a cost involved in adding a feature like this, but I'm baffled to see so few amps that include it.

Specifically what I'm looking for is something portable. Having a good DAC built-in would be a plus but not absolutely necessary. Having a good crossed option, however, is a must. Meier and Headroom both had such devices once upon a time, but who does it now?

Thanks,
Dane
What exactly is crossfeed circuit?
Do you mean say Negative Feedback?
Title: Re: Amps with Crossfeed circuit?
Post by: macdane on 3 May 2018, 10:02 pm
No. In simple terms, a crossfeed circuit modified the signal fed to headphones in a much more realistic way. In a nutshell, a bit of the right channel signal is slightly delayed and then added to the left, and vice-versa. This mimics the way we hear sounds in the real world and leads to a much less artificial, contrived sound. It also greatly extends my listening time.

Dane
Title: Re: Amps with Crossfeed circuit?
Post by: FullRangeMan on 3 May 2018, 10:12 pm
No. In simple terms, a crossfeed circuit modified the signal fed to headphones in a much more realistic way. In a nutshell, a bit of the right channel signal is slightly delayed and then added to the left, and vice-versa. This mimics the way we hear sounds in the real world and leads to a much less artificial, contrived sound. It also greatly extends my listening time.

Dane
By the little I know I never see a HP amp w/this circuit,
I would welcome a circuit to enlarge the soundstage without tone controls or loudness.
Title: Re: Amps with Crossfeed circuit?
Post by: macdane on 3 May 2018, 10:36 pm
By the little I know I never see a HP amp w/this circuit,
I would welcome a circuit to enlarge the soundstage without tone controls or loudness.

Oh, I'd definitely recommend giving this a try if you listen to headphones. It's not so much a matter of soundstage size — which is a very problematic concept with headphones — but certainly makes the whole experience sound much more natural. There's nothing remotely natural about each ear hearing the signal from only one channel. A well-implemented crossfeed circuit remedies that, and it can also be managed digitally by software if you happen to be attached to an amp that doesn't do this. Here's a bit of info and some samples that were recorded using this technique ...

http://www.meier-audio.homepage.t-online.de/crossfeed.htm

Dane
Title: Re: Amps with Crossfeed circuit?
Post by: gefski on 3 May 2018, 10:41 pm
No. In simple terms, a crossfeed circuit modified the signal fed to headphones in a much more realistic way. In a nutshell, a bit of the right channel signal is slightly delayed and then added to the left, and vice-versa. This mimics the way we hear sounds in the real world and leads to a much less artificial, contrived sound. It also greatly extends my listening time.

Dane

Check out SPL Phonitor

https://spl.audio/professional-fidelity/phonitor-x/?lang=en

Supposed to be superb amps at a couple price points. Never had my ears on one though.

Title: Re: Amps with Crossfeed circuit?
Post by: FullRangeMan on 3 May 2018, 10:55 pm
Oh, I'd definitely recommend giving this a try if you listen to headphones. It's not so much a matter of soundstage size — which is a very problematic concept with headphones — but certainly makes the whole experience sound much more natural. There's nothing remotely natural about each ear hearing the signal from only one channel. A well-implemented crossfeed circuit remedies that, and it can also be managed digitally by software if you happen to be attached to an amp that doesn't do this. Here's a bit of info and some samples that were recorded using this technique ...

http://www.meier-audio.homepage.t-online.de/crossfeed.htm

Dane
I like the small music details HPs presents in the music, but I dont like the small sound stage size my HE400 presents, however w/balanced connection the soundstage is larger than banana plug at a low cost.

The SPL Phonitor works changing the music signal phase which have an efect most in the bass freqs imo.

OBS.: the Phonitor have a knob to adjust the phase angle, a variable adjusting is always useful, the crossfeed seems a fixed option.
Title: Re: Amps with Crossfeed circuit?
Post by: Mark Korda on 3 May 2018, 11:30 pm
Hi Macdane,
   I built a Corda from Meier Audio around 2003. When you explained crossfeed to Fullrangeman I think you got a tiny bit wrong. I am almost positive there is no time delay. My Dynaco Quadapter uses a time delay for the back wave of a concert hall.
  The way Jan Meier put it; When you listen to stereo you hear whats coming from the left and right speaker. The same thing with ear phones but, when you have ear phones on those 2 channels are isolated. Crossfeed lets you hear a little of the right channel in the left ear phone cup and vise versa......just as you would when you were sitting in front of a pair of speakers.
   As Dane said without it head phone listeners were getting a listeners fatigue and thats why he came up with it.
    I'd like to talk to someone else who has a Corda....I got some funny stories....Mark Korda
Title: Re: Amps with Crossfeed circuit?
Post by: macdane on 4 May 2018, 02:58 am
Check out SPL Phonitor

https://spl.audio/professional-fidelity/phonitor-x/?lang=en

Supposed to be superb amps at a couple price points. Never had my ears on one though.

Looks like pretty cool stuff and indeed includes a crossfeed option, but I didn't see anything portable. Thanks for the tip though!

Dane
Title: Re: Amps with Crossfeed circuit?
Post by: hayden on 4 May 2018, 02:59 am
The meier amps are great.  You should also checkout Leckerton audio.
Title: Re: Amps with Crossfeed circuit?
Post by: macdane on 4 May 2018, 03:01 am
I built a Corda from Meier Audio around 2003. When you explained crossfeed to Fullrangeman I think you got a tiny bit wrong. I am almost positive there is no time delay.

Hi Mark ... if you check out Jan Meier's page about crossfeed info, you'll see that there is indeed a time-delay component:

http://www.meier-audio.homepage.t-online.de/crossfeed.htm

Dane
Title: Re: Amps with Crossfeed circuit?
Post by: macdane on 4 May 2018, 03:01 am
The meier amps are great.  You should also checkout Leckerton audio.

Will do ... thanks!
Title: Re: Amps with Crossfeed circuit?
Post by: ryno on 4 May 2018, 03:51 am
Decware’s portable has crossfeed.
Title: Re: Amps with Crossfeed circuit?
Post by: dB Cooper on 4 May 2018, 04:03 am
Most if not all of the HeadRoom amps, desktop and portable, had switchable crossfeed; in fact, it was their 'calling card'. There were (are? haven't looked lately) a variety of them.
Headroom's status seems uncertain;  awhile back they got out of the headphone biz (they sold almost everything out there) to concentrate on a new line of amps, which don't seem to be available yet. But their amps should be plentiful on the used market.

What are your sources? My listening is almost 100% from computer, do I do crossfeed in software. (I use a Mac so the following may not be helpful to you, but...) The Fidelia audio player has an (unfortunately overpriced) version of CanOpener, and the previous release of the Vox player (before it went to a subscription model) has excellent crossfeed with your choice of both Meier and Chu Moy parameters (I prefer the Meier). There is a VST/Audio Unit plugin called Canz3D which may work depending on the computer and OS (it's 32-bit so it may go away unless the developer gets around to updating it to 64-bit.) I mention all this because IMHO crossfeed is much easier to implement and control in the digital domain. Canz 3Dt, it too is Mac-only. I haven't owned a Windows box in a long time, but I had something called 'Dolby Headphone' which was a software-based crossfeed.

Hope this helps. If it were me, I think the best value hardware-based option is a used HeadRoom amp.
Title: Re: Amps with Crossfeed circuit?
Post by: dB Cooper on 4 May 2018, 04:13 am
Wow, the Leckerton amps are very reasonably priced (starting at $219 for a portable DAC/amp?!?  :o  )
That might take the HeadRoom used amps out of contention unless the price is really right. Thanks hayden.
Title: Re: Amps with Crossfeed circuit?
Post by: JohnR on 4 May 2018, 04:58 am
I believe some of the iFi portable gear has something called 3D which they say is better than crossfeed eg. https://ifi-audio.com/portfolio-view/micro-idsd/, https://ifi-audio.com/portfolio-view/nano-ican/

On the non-portable front, RME ADI-2 Pro and ADI-2 DAC have crossfeed.
Title: Re: Amps with Crossfeed circuit?
Post by: wagnju on 4 May 2018, 10:53 am
I know these two with integrated crossfeed + more 
I own both of them  8)
the minidsp HA-DSP for travelling
https://www.minidsp.com/products/dsp-headphone-amp/ha-dsp

and as JohnR also mentioned the RME ADI-2 DAC for home (around $1000)
http://www.rme-audio.de/en/products/adi_2-dac.php
best regards
Juergen
Title: Re: Amps with Crossfeed circuit?
Post by: rif on 4 May 2018, 12:34 pm
Years ago, I had a portable headroom amp and can verify the crossfeed made a huge positive difference.  It had a switch to turn it on/off.  IIRC it was around $100.

I now own one of their desktop amps which is more versatile in crossfeed control.  Wouldn't think about listening without it.

Maybe it's not seen frequently,  did they have a patent?
Title: Re: Amps with Crossfeed circuit?
Post by: Letitroll98 on 4 May 2018, 12:53 pm
I just listened to the Meier crossfeed samples provided in the link, when I got thru the tutorial samples and got to the music sample I listened all the way to the end, excellent solution to the problems of headphone listening, not at all subtle.
Title: Re: Amps with Crossfeed circuit?
Post by: Mark Korda on 4 May 2018, 01:13 pm
Hi Dane,
  thanks for looking that up. I stand corrected. Sorry about that.
One test I'd like to try is the Corda vs. the Schitt Vali (3?). or the smaller amp with 1 tube.
I built my Corda from a kit. Jan Meier did not include a build manual and  took in fact you were on his level. Until his headphone business he was a trained nuclear scientist. Every night I had a question and he answered every one by e-mail from Germany. I even sent him a Dynaco manual and a manual from Frank Van AlStine to show him how to simplify the build and  lessen his future headaches from dopes like me. If he dropped the kit option I was probably the biggest reason.
    I did finally get it going and it sounds great! I use Grado 80's for headphones....thanks Dane...Mark Korda
Title: Re: Amps with Crossfeed circuit?
Post by: dB Cooper on 4 May 2018, 01:43 pm
BTW, Tyll Hertsens of Innerfidelity just did a report on  something called the 'Smyth Realizer' (https://www.innerfidelity.com/content/canjam-socal-2018-smyth-research-realiser-a16-headphone-surround-system) which is probably the state-of the-art in headphone spatial presentation. He raved about it. It's a hybrid DSP/hardware solution, apparently. Downsides are high cost and possibly separate costly calibrations required for each headphone (not for 'headphone rolling') (the article isn't clear on this but IIRC it was mentioned by Mark Waldrep in one of his blog posts.)

Video mentioned in the article, describing the 'Smyth Realizer' system (https://www.youtube.com/watch?v=HYQDJMvmLCs)

In the meantime, until there is a cost breakthrough in this technology, I'll continue to use crossfeed most if not all of the time. It's not perfect, but it usually does improve the 'headstage'.

By the way, if you watched the video... One of the many parameters controllable in the Canz3D plugin is head circumference. Since HRTF is critical to the presentation, and everybody's will be different, having someone measure your noggin and plugging in the result may be very helpful to the presentation. This is a perfect example of something that would be difficult to impossible to implement in the analog domain.
Title: Re: Amps with Crossfeed circuit?
Post by: adydula on 4 May 2018, 04:48 pm
I built this amp severl months ago:

http://www.diyaudio.com/forums/headphone-systems/304684-ampcasq-opa1622-integrated-headamp-project.html

Here is Chris's intro....I was interested in the new specifically designed OPA 1622 TO chip the was designed for Headphone amps..
Chris wanted to experiment with crossfeed, so I got to build it and try this implementation of crossfeed for myself.

If you go to the link there is a link to the actual Xen Audio cross feed circuit and design as well as a description of how it works.
It definitely added to the cost with the switching stuff....

"Hi All,
Like some of you I followed with great interest the thread 'New Audio Op Amp - OPA1622' by TI’s Johnnc124. I wasn’t initially specifically interested by headamps but as the OPA1622 was simple to implement and was supposed to provide good results I decided to setup a project with it. More than building an headamp this project was aimed to confirm I could achieve designing a PCB with a CAD software and also soldering SMD devices, including ones in DFN or QFN package.

I’have finally been through all steps, I’m happy with the result (OPA1622 sounds very good !) and I’m now confident to move to projects that will require complicated PCB and good soldering capabilities.
Now, I have to finish assembly and testing of a Salas DGC3 in order to do some comparisons!

The main requirements for AmpCasq where :
It should stand in a small aluminum box, in order to sit on desk
It should be powered by an AC adapter I had, which provided 17VDC
It should have a volume control
It should have RCA and jack 3.5 inputs
It should have jack 3.5 & 6.35 outputs
It should allow me to experiment crossfeed
Final price should stay under control

About the schematics:
Regulators:
Ampcasq was designed in September 2016, at this time LM27762 was announced but not available. So, I did stay with LM27761 for -5V and LP38798 for +5V; LP5907 was a bit short on current. The 7805 lifted by R17/R12 was added to limit LM27761 input voltage to 5.5V, its max value. 7805 allow Ampcasq to be powered by any DC source from 10V to 35V, 300mA max.
Power Input:
D1 to protect against bad connection.
D2, R23, R10, R11, C24 to manage the Enable pin of the OPA. Objective was to avoid noise in the can at power up/down. This partly works: mute the output when enable Low (<~0.8V) but can’t avoid noise in can when power supply capacitors are discharching and OPA1622's supply getting out of tolerance. On power off with SW1, OPA1622 is muted as C24 is quickly discharged through R23, D2 and SW1. D2 is a Schottky, not for speed but for low drop (Vf close to 0.3V).
Crossfeed:
It is based on an Xen-Audio (EUVL) paper: Xen Audio cross feed.
There’re three positions for the switch: Low Xfeed – No Xfeed – High Xfeed. Low Xfeed is Ok, High is exaggerate: there’s too much bass boost. After some listening sessions I finally do not use the Xfeed.
Gain + out
Not much to say."

So I built the amp and have a thread here on the circle with the build and listening results.

The net of it was the crossfeed had three settings, high, med and low.
I heard no real world difference in any of the positions with my set of headphones.

It was very subltle if any changes auduble etc...I then removed it and used the space on the pc board to build three selectable gain settings instead.

YMMV...
Alex


https://www.audiocircle.com/index.php?topic=150546.msg1610824#msg1610824
Title: Re: Amps with Crossfeed circuit?
Post by: macdane on 4 May 2018, 05:38 pm
Most if not all of the HeadRoom amps, desktop and portable, had switchable crossfeed; in fact, it was their 'calling card'. There were (are? haven't looked lately) a variety of them.

I think part of the reason I'm surprised at the relative lack of crossfeed options is that both Headroom and Meier were major players in the market last time I went through this process. At the time, I ended up buying the Meier Cord Prehead and I'm still enjoying it immensely.

What are your sources? My listening is almost 100% from computer, do I do crossfeed in software. (I use a Mac so the following may not be helpful to you, but...)

My primary source at home is a MacBook Air with a Meridian DAC, but headphone duties there are under control thanks to the Prehead. What I'm looking for now is a good portable solution. A local coffee shop serves as my "office" and I like to listen in my own world while working there. To that end, I have a pair of Opposite PM-3s with the Opportunity HA-2SE DAC/amp and I've also played with a friend's Dragonfly Red. In both cases, my most significant complaint is the lack of a crossfeed option. In this setting, I sometimes use my MacBook Pro as a source and sometimes my iPhone, so I think an amp with crossfeed makes the most sense.

Thanks,
Dane
Title: Re: Amps with Crossfeed circuit?
Post by: macdane on 4 May 2018, 05:40 pm
Wow, the Leckerton amps are very reasonably priced (starting at $219 for a portable DAC/amp?!?  :o  )
That might take the HeadRoom used amps out of contention unless the price is really right. Thanks hayden.

Agreed ... these look like a real possibility.
Title: Re: Amps with Crossfeed circuit?
Post by: maty on 4 May 2018, 05:54 pm
Some soft players have crossfeed or you can add it with plugin. JRiver, foobar2000 for example.

https://www.foobar2000.org/components/view/foo_dsp_meiercf

https://www.foobar2000.org/components/view/foo_headphone_eq

https://www.head-fi.org/threads/natural-crossfeed-on-headphones-earphones-for-foobar2000-v2-1-major-update-made-public.811837/

https://www.112db.com/plugins/redline/monitor/

or something like Dolby headphone or...
Title: Re: Amps with Crossfeed circuit?
Post by: macdane on 4 May 2018, 06:03 pm
I believe some of the iFi portable gear has something called 3D which they say is better than crossfeed eg. https://ifi-audio.com/portfolio-view/micro-idsd/, https://ifi-audio.com/portfolio-view/nano-ican/

I've seen these but, frankly, I don't find their claims very persuasive. They offer essentially no explanation of what they're doing other than that it's not just a rehash of the techniques used by Bauer and Linkwitz. Since the Meier circuit works really well for me, I'm leery of trying something different that's described so vaguely.

Dane
Title: Re: Amps with Crossfeed circuit?
Post by: macdane on 4 May 2018, 06:14 pm
I know these two with integrated crossfeed + more 
I own both of them  8)
the minidsp HA-DSP for travelling
https://www.minidsp.com/products/dsp-headphone-amp/ha-dsp

Thanks Juergen. Is the HA-DSP as complicated as the manual makes it seem? While I appreciate the array of options offered by an approach like this, I'm not looking for a new hobby. I'm starting to wonder if my best bet will be to look for one of Meier's old portable amps with crossfeed ... I'm not sure, but I think he had some at one point.

Dane
Title: Re: Amps with Crossfeed circuit?
Post by: wagnju on 5 May 2018, 06:09 am
Hi Dane
The HA-DSP is not a easy plug and play unit. It sounds very good but I have to admit that you need some patience to set-up the huge amount of options . I have the unit since 4 months now and I'm still playing with different setups .
So I wouldn't say the unit is complicated but it is challenging to find the right setup that fits your taste . Just too many choices for setup , maybe a little bit too much for me , maybe heaven for somebody else  8)
Title: Re: Amps with Crossfeed circuit?
Post by: FullRangeMan on 5 May 2018, 06:29 am
The owner manual dont suggest settings?
Title: Re: Amps with Crossfeed circuit?
Post by: adydula on 5 May 2018, 03:16 pm
I went to the HA DASP site and read the 40 page manual.

This device is a DSP for sure with many, many variables, settings and adjustments....your going to have to be a rocket scientist to really understand its complex design and settings....IMO this is not an easy device to use by folks that just want tp press some buttons to change the sound.

It looks like it can be a really nice tool in the hands of someone that really understand audio processing, recording etc...

There is a simple plug and play mode...but the power of the DSP IMOP cant be unleashed unless you read and understand the various setups and interactions.

My guess most people would become confused and most likely screw up stuff and get frustrated...so again IMO if you buy this device understand what your getting into and what you want to do...and will this device allow you to accomplish that??

Alex
Title: Re: Amps with Crossfeed circuit?
Post by: EkW on 8 May 2018, 04:12 am
I too read through the long manual but could not find a single mention of crossfeed in it. The Leckerton units look nice but they provide no info on how they implement the crossfeed. I have an old Meier Porta-Corda amp and really like the crossfeed. Not sure why Meier doesn't make a portable unit any more.
Many years ago I rigged up a potentiometer to reduce the channel separation. It kinda worked; using a good audio taper pot would have helped. My old Apt-Holman preamp had knob that provided L+R when turned clockwise and L-R when turned CCW.
I wonder if it would be possible to implement a passive crossfeed circuit inline with the headphone cable?
Title: Re: Amps with Crossfeed circuit?
Post by: macdane on 8 May 2018, 05:25 am
I too read through the long manual but could not find a single mention of crossfeed in it.

It's in there ... sorta. There are several pages on FIR filtering, of which I think crossfeed is a part, but no specific mention of it or instructions regarding *how* to do it. For someone who wants to do a lot of fiddling, I can see where this would be a good tool. Personally, I want zero fiddling.

The meier crossfeed just plain works for me and it's a simple matter of turning it on. Well, ok, my Prehead offers a choice of off/low/medium/high crossfeed, so it's slightly more complicated than just turning it on, but barely. And virtually 100% of the time, *any* level of crossfeed is better than "off."

If I didn't know it'd end in certain disaster, I'd buy the Porta Corda kit from the Meier site; I'm envious that you have one!
Title: Re: Amps with Crossfeed circuit?
Post by: adydula on 8 May 2018, 05:04 pm
I mucked with the XEN Audio implementation in several ways and never found it to be worth it or that it really made a whole lot of difference.
I find that finding well recorded (mic'd) material hjas a more pronounced affect of the listening experience.

So if you indeed find a crosfeed circuit implemetation that you like..it may work you with some material and be even worse on other material.

Audio source material is so different across the board, I constantly look for recordings that are done well up front....I have several recordings of
a particular song, some sound like CRAP and others sound awesome....

YMMV
Alex
Title: Re: Amps with Crossfeed circuit?
Post by: macdane on 8 May 2018, 05:33 pm
I mucked with the XEN Audio implementation in several ways and never found it to be worth it or that it really made a whole lot of difference.
I find that finding well recorded (mic'd) material hjas a more pronounced affect of the listening experience.

I'm not familiar with XEN, but I think one lesson here is that preferences and priorities vary from listener to listener ... otherwise there'd be no need for the vast array of options in the marketplace.

I think it's a given that well recorded material is a plus, but sometimes that's not an option. There are certainly some recordings that I only have because of their sound quality; most often, though, my priority is on the music.

So if you indeed find a crosfeed circuit implemetation that you like..it may work you with some material and be even worse on other material.

The reason I said "virtually 100% of the time" is that I necessarily have a large handful of mono recordings — perhaps 5% or so of my library? — and for those I switch the crossfeed circuit off. Other than that exception, I'd have a hard time pinning down a stereo recording that in *my* experience doesn't benefit from the Meier crossfeed.

As I said earlier, I'm leaning more and more toward looking for an old Meier portable amp as the solution to my particular issue, since I know their crossfeed implementation works for me.

Dane
Title: Re: Amps with Crossfeed circuit?
Post by: adydula on 8 May 2018, 09:55 pm
Dane,

What headphones do yoiu use?

Alex
Title: Re: Amps with Crossfeed circuit?
Post by: macdane on 8 May 2018, 10:43 pm
Dane,

What headphones do yoiu use?

Alex

At home (with the Meier Prehead) I alternate between DT-880s and K-501s, with the AKGs getting perhaps 70% of the time on my head. Well, 70% of the relatively little time I spend listening to headphones, since I'm primarily a 2-channel speaker guy. I like certain things about each of those but have never been super happy with either, and to that end I'm considering adding ... something to the mix.

Most of my headphone listening is done at a local coffee shop that serves as my office most days. So here I need a closed-back set and the best balance of price-sonics-mobility I've found is the Oppo PM-3. My source is ALAC files served by either my laptop or my phone, and then fed into the Oppo HA-2SE DAC/amp.

I've had two gripes with that mobile rig. First, my ears get really hot when listening to the Oppos. Second, the HA-2SE doesn't have crossfeed ... which is why I'm here!

Dane
Title: Re: Amps with Crossfeed circuit?
Post by: maty on 9 May 2018, 09:41 am
https://headfonics.com/2018/04/rme-adi-2-dac-review/2/

Quote
Crossfeed

I love crossfeed. I use it all the time. My first serious head-amp was the Meier Corda Jazz because it had crossfeed. Usually, recordings are mixed for speakers in a stereo setup. This results in strong channel separation that can cause fatigue when listening over headphones.

RME gives you 5 options to remedy this. The 2nd option is actually based on Jan Meier and thus is a DSP emulation of the hardware crossfeed found on Corda amps. The 4th option is supposed to emulate a stereo speaker placement in 30 degrees at a 3m distance.

The experience is definitely not as strong as some gimmicky head tracking or surround emulations, but for that, they stay clean and precise. Except for the 5th option, I haven’t noticed any mud or lack of resolution introduced. As I often see false information: These are not equalizer settings! Crossfeed considers the time domain and treble adjustments of the opposite channel. Also, crossfeed is not the same as crosstalk. The latter is information with the wrong polarity, effectively damaging the signal.
Title: Re: Amps with Crossfeed circuit?
Post by: adydula on 9 May 2018, 01:09 pm
I read the headphonics link just posted and it was interesting and helpful in understanding what the design and engineering side of this subject is.

If the article is correct in that most cd's music etc are made (recoreded/mic'd) for 2 cha stereo systems then IMO your going to need a seperate set of crossfeeed settngs or circuits for potentially each cd you have.

In my thousands of cd's they are all over the place in quality and recording and how they were mic'd..

So many of us look for heeadphones that have large soundstages, differing frew response curves etc..and many varing types of dace, amps, cables, tubes , opamps etc....and now your adding a crossfeed variable...

Seems like this had gotten to a point where things hae become very complex......???

I have always tried to keep all but the minimum "stuff" between the source and the transducer....a system that can discern a good recording from a mediocre one...and I am at that point.

These IMO "magic" boxes that tinker with crossfeed are indeed intriguing but seem to require a bit of tinkering....I guess that maybe a few settings might be used with a majority of your cds or material....just dont know.

In a perfect world it would be nice to have a intelligent processor in these crossfeed boxes that would detect how to set up the materail based on how its recorded to emulate a 2 ch stereo system iin your headphones...

But headphones are not speakers and this may not ever be totally possible, but its neat stuff for sure...

Alex
Title: Re: Amps with Crossfeed circuit?
Post by: macdane on 9 May 2018, 02:37 pm
https://headfonics.com/2018/04/rme-adi-2-dac-review/2/

That's cool, but looks like another way-too-complicated solution for my needs. And among RME's dizzying array of products, I haven't yet found anything that looks portable. Thanks for the info, though.

Dane
Title: Re: Amps with Crossfeed circuit?
Post by: maty on 9 May 2018, 02:48 pm
It is desktop DAC I have selected to buy if someday I find an amplifier that satisfies me.

Review and Measurements of RME ADI-2 DAC

https://audiosciencereview.com/forum/index.php?threads/review-and-measurements-of-rme-adi-2-dac.2582/

These measurements do not detract from those that appear in the manual, highly recommended reading.

And it has a very important characteristic to me: it uses super low noise regulators -> very clean power to the circuits. With the own external SMPS -> it does not problem with DC at mains (I have a lot).

By the way, DC at mains is problematic with the phono too and not only with big amplifiers. Well, if you want to listen very good records or to make very good vinyl rips.
Title: Re: Amps with Crossfeed circuit?
Post by: macdane on 9 May 2018, 02:53 pm
IMO your going to need a seperate set of crossfeeed settngs or circuits for potentially each cd you have ... In my thousands of cd's they are all over the place in quality and recording and how they were mic'd ... These IMO "magic" boxes that tinker with crossfeed are indeed intriguing but seem to require a bit of tinkering

Alex,

A couple of these recent examples (RME and minidsp) are indeed complex and appear to require a lot of tinkering. Looking at it from the other direction, they *allow* a lot of tinkering and customization. But that's not what I'm personally looking for. My reality is that the low/medium/high crossfeed settings are even more flexibility than necessary; a simple on/off switch applying a predetermined amount of crossfeed would be sufficient, at least in the Meier implementation.

Like you, I have CDs and hi-res digital files that span a broad spectrum of recording quality and micing techniques, but I feel no need to tweak the amount of crossfeed from recording to recording. I simply set it to one of the "on" settings and leave it. Which particular setting I use is almost immaterial, as any one of them is better than "off" across the board.

I think you'd be doing yourself a favor by seeking out an amp with this feature to give it a listen for yourself. Nothing about it comes across as gimmicky or artificial or magic ... there's no sense that extra unnecessary stuff has come between me and the music. Granted, I'm coming at this as a long-time 2-channel speaker guy and I recognize that some (particularly younger) people have only ever experienced hifi sound through headphones. Even in those cases, everything else you hear in normal life has this crossfeed phenomenon built-in, and I have a hard time understanding how anyone would *not* find this a more natural way to experience music.

Dane
Title: Re: Amps with Crossfeed circuit?
Post by: ajzepp on 15 May 2018, 01:44 am
I told Jan Meier a while ago he should really have a stand alone crossfeed unit. He said he did used to have one, but it wasn't popular because nobody really understood what it did. I've been using his gear for about six years and love it. I much prefer it to the alternative (i.e. being without it). He's coming out with a new flagship unit with DSP and crossfeed, and I think he's toying with the idea of another standalone option.
Title: Re: Amps with Crossfeed circuit?
Post by: macdane on 15 May 2018, 06:04 am
I told Jan Meier a while ago he should really have a stand alone crossfeed unit. He said he did used to have one, but it wasn't popular because nobody really understood what it did. I've been using his gear for about six years and love it. I much prefer it to the alternative (i.e. being without it). He's coming out with a new flagship unit with DSP and crossfeed, and I think he's toying with the idea of another standalone option.

That would be terrific, and I'd also like to see him resurrect the portable amp — with crossfeed, of course. From what I've seen of the Soul project, it should be pretty cool, although I can't imagine my Prehead is going anywhere for quite awhile.
Title: Re: Amps with Crossfeed circuit?
Post by: adydula on 15 May 2018, 12:48 pm
Dane.....

I will take a look at this again and if I can find a unit I will definitely give a listen...

But the unit I buit with the three crossfeed settings didnt impress me much at all....maybe its the circuit design? But it has a white paper on it describibg the postive merits etc....

If this idea is so great I would think most of the audiophile folks would have one...but most dont? So is it really that much more "better", more "life-like"? etc.

Also the comment about it wasnt popular because nobody understood what it does is a bit lame to me? To sell something  IMO I have to hear the difference and if its a small subtle difference and adds to the cost, its most likely doomed for retail failure...

I wonder if there are any of these stand alone Meier units around?  I will serach but if you know what the model # is please let me know...

Thanks
Alex

Title: Re: Amps with Crossfeed circuit?
Post by: macdane on 15 May 2018, 01:41 pm
But the unit I buit with the three crossfeed settings didnt impress me much at all....maybe its the circuit design? But it has a white paper on it describibg the postive merits etc....

Like I said previously, I'm not familiar with the ZEN approach to crossfeed. It may be that there are significant differences between the many approaches that have been taken over the years. All I know for sure is that the Meier implementation works for me.

If this idea is so great I would think most of the audiophile folks would have one...but most dont? So is it really that much more "better", more "life-like"? etc. Also the comment about it wasnt popular because nobody understood what it does is a bit lame to me? To sell something  IMO I have to hear the difference and if its a small subtle difference and adds to the cost, its most likely doomed for retail failure...

Hmm. Maybe. The thing is, I hear it as a subtle difference rather than the hyperbolic "night and day" difference. Sometimes it's the huge, immediately noticeable differences that get the market's attention. Decades ago, during my college days, I'd spend weekends with friends swapping components and cables, listening for differences and trying to get a handle on whether those differences were improvements or merely changes. As I've aged, I'm less (i.e., not at all) inclined to do that. Instead, on the rare occasions I make a change to my system, I now listen for at least several hours if not several days before swapping back to the original state. I feel that to be a more reliable way to gauge organic changes in presentation, and certainly helps me pick up on subtle differences — as they say, the devil's in the details.

So while I might agree that crossfeed is better or more life-like, I'd have a hard time quantifying the improvement as "that much more" anything. I'd say the effect is subtle but undeniably desirable. Beyond that, I struggle to describe it. Listening to headphones without crossfeed, I'm almost always aware that something is "wrong." It's a poor substitute for the experience I get with my "real" speaker-based system, and I find that an hour of listening seems like a looong time. With crossfeed, a decent amp/headphones can be a very believable way to listen, and I can easily go for hours. All because the crossfeed, while subtle, more closely mimics the way I hear everything in real life. I think.

I wonder if there are any of these stand alone Meier units around?  I will serach but if you know what the model # is please let me know...

I wish I could tell you, but I don't know. If I run into it, I'll let you know ... please do the same!

Dane
Title: Re: Amps with Crossfeed circuit?
Post by: macdane on 15 May 2018, 01:44 pm
Also, Alex, I'll repost the link to the crossfeed page on the Meier site:

http://www.meier-audio.homepage.t-online.de/crossfeed.htm

Because of everything I just said about preferring to rely on longer-term evaluation of any changes to my system, I'm reluctant to recommend short audio clips like the samples on that page. But you should give them a listen and see what you think.

Dane
Title: Re: Amps with Crossfeed circuit?
Post by: dB Cooper on 16 May 2018, 01:34 pm
I'd say the effect is subtle but undeniably desirable. Beyond that, I struggle to describe it. Listening to headphones without crossfeed, I'm almost always aware that something is "wrong." It's a poor substitute for the experience I get with my "real" speaker-based system, and I find that an hour of listening seems like a looong time. With crossfeed, a decent amp/headphones can be a very believable way to listen, and I can easily go for hours. All because the crossfeed, while subtle, more closely mimics the way I hear everything in real life. I think.

Dane

Pretty good description of  it IMO. Not perfect but it helps. 'Smyth Realizer' is apparently the breakthrough product in the world of headphone spatial presentation. Early stage product right now so subject to the early adopter tax (also requires calibrating your cans, ears and head.) Read Ty'lls piece on innerfi; he was blown away.)
Title: Re: Amps with Crossfeed circuit?
Post by: adydula on 16 May 2018, 02:06 pm
Here are the circuits for the Meir, Xen and AmpCasq passive crossfeed circuits:



(https://www.audiocircle.com/image.php?id=180138)


(https://www.audiocircle.com/image.php?id=180139)
Title: Re: Amps with Crossfeed circuit?
Post by: ajzepp on 29 May 2018, 01:11 pm
Dane.....

I will take a look at this again and if I can find a unit I will definitely give a listen...

But the unit I buit with the three crossfeed settings didnt impress me much at all....maybe its the circuit design? But it has a white paper on it describibg the postive merits etc....

If this idea is so great I would think most of the audiophile folks would have one...but most dont? So is it really that much more "better", more "life-like"? etc.

Also the comment about it wasnt popular because nobody understood what it does is a bit lame to me? To sell something  IMO I have to hear the difference and if its a small subtle difference and adds to the cost, its most likely doomed for retail failure...

I wonder if there are any of these stand alone Meier units around?  I will serach but if you know what the model # is please let me know...

Thanks
Alex

I actually notice it more when Im without it. Part of the reason it’s subtle is because to those of us who like it, it’s more natural. So something that presents as more realistic/natural to our ears/brain is likely not going to stand out the way other changes to the presentation might. I find that I generally avoid listening fatigue when Im using Jan’s amp vs when Im using my oppo portable. It may not be anything that appeals to you, but I love it. Jan is a legit genius and he’s a pleasure to deal with. He even went out of his way once to help me locate the town my family is from in Germany. Just a really good dude who sincerely cares about the end-user experience. And on top of that, builds some damn nice gear.
Title: Re: Amps with Crossfeed circuit?
Post by: Yun66 on 29 May 2018, 04:45 pm
I have a SPL Phonitor 2. I like its appearance, many switches, knobs and 2 VU meters. I turn on crossfeed only for music with fewer instruments, like solos or certain vocals. For orchestra, the soundstage will become narrower and doesn't sound good. Most times I leave it off. I think it's not for everyone and not for every types of music. You have to experiment with it to see if the music sounds more natural to your ears. YMMV is very true here.
Title: Re: Amps with Crossfeed circuit?
Post by: dB Cooper on 29 May 2018, 09:42 pm
For sure, and it's a recording-by-recording YMMV situation too. When I used to use Canz3D, I'd insert the plugin using Audio Hijack and adjust the 'wet/dry' slider to get the 'best' soundstage I could. Something else you really can't do in hardware (maybe in the Phonitor but that's, like, three grand).