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Author Topic: Headphone/Amp Rig  (Read 11888 times)

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stevetoney

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Headphone/Amp Rig
« on: January 23, 2014, 11:25:27 AM »
About a month ago, I asked whether at the show sound was possible through headphones.  That started a fairly detailed dialogue with OOK and Page.  (Thanks again guys).  I ended up with a rig I'm pretty happy with, but it's obvious at this point that I've dove headfirst into another money pit hobby, so this is the beginning of another tangential assault on the gear slut theme, no doubt about it.  Here's what I ended up with...

Headphones
Sennheiser HD600 (open back reference phones for general listening and audio mastering)
Beyerdynamic DT990 Pro (semi-open back bass heavy phones for fun listening to most of the types of music I like)
Audio Technica ATH-M50 (closed back phones for taking to the gig...I already owned these)
Shure SE-215 (IEMs for the office...I also already owned these)

DAC/Amp
Parasound ZDac

Semi-Portable Amp
Ray Samuels SR-71a 'The Blackbird'

As I upgrade, the Zdac will remain as my DAC, and the head amp on that sounds nice, but it's got an overly clean solid state sound to it.  I'm still getting used to it.  The Ray Samuels SR-71a amp just arrived so I don't even have an opinion on that one yet...bought it on the strength of reviews.   

On the wish list is a good stay at home tube amp to connect downstream of the ZDac, perhaps a Wu Audio WA-6 if I have the money or Little Dot MKIII if budget concerns prevail.  Then an upgrade to my IEMs...got my eye on Westone R4 right now, but this is probably gonna be awhile.
« Last Edit: January 23, 2014, 11:34:45 AM by tonedeaf »

Offline dyneq

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Re: Headphone/Amp Rig
« Reply #1 on: January 23, 2014, 01:02:32 PM »
Oh yeah, I'm in the same slutty place these days. I recently picked up an Objective2/ODAC to go with my Westone UM3X's at work. It's overkill for the Westones, but I'm still grinning ear to ear when I listen. They are for on-stage monitoring, so you have to like that sound profile, which i do.

I'm considering a pair of DT770 Pro's for monitoring duty. I currently use Grado SR225i's, which aren't the right tool for the job. They are nice for listening though.

stevetoney

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Re: Headphone/Amp Rig
« Reply #2 on: January 23, 2014, 02:06:26 PM »
I currently use Grado SR225i's, which aren't the right tool for the job. They are nice for listening though.

I tried a couple of mid-level Grado models...can't recall the specific models though.  I'm usually more focused on the sound than anything, but the ear cups on both of those that I auditioned weren't very comfortable.  Do all Grado's have the round profile that sits more on the ear than around them?

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Re: Headphone/Amp Rig
« Reply #3 on: January 23, 2014, 02:08:34 PM »
Forget about a dedicated headphone amp. If you have a decent stereo amp you can use it to drive your headphones by making your own break out box or buying a "Can Opener" from Vinylflat. They go for around $65.00.

I also find that the AKG 702's are a nicely balanced headset. I prefer them over the Grado RS2's I owned for 10 years. and.....they are super comfy.

Thank me later!
« Last Edit: January 23, 2014, 02:11:11 PM by raymonda »

stevetoney

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Re: Headphone/Amp Rig
« Reply #4 on: January 23, 2014, 02:21:05 PM »
Forget about a dedicated headphone amp. If you have a decent stereo amp you can use it to drive your headphones by making your own break out box or buying a "Can Opener" from Vinylflat. They go for around $65.00.

I also find that the AKG 702's are a nicely balanced headset. I prefer them over the Grado RS2's I owned for 10 years. and.....they are super comfy.

Thank me later!

I've read that the Can Opener is awesome, especially for the price.  Good advice for those that already have a good component-based system.  I don't have a good system, so at the advice of my two mentors, I'm building a computer-based system from the phones backwards to the 24/48 FLAC library that I've got saved and backed up on a 1tb passport drive that I can carry with me back and forth to work. 
« Last Edit: January 23, 2014, 02:28:56 PM by tonedeaf »

Offline dyneq

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Re: Headphone/Amp Rig
« Reply #5 on: January 23, 2014, 03:12:33 PM »
I currently use Grado SR225i's, which aren't the right tool for the job. They are nice for listening though.

I tried a couple of mid-level Grado models...can't recall the specific models though.  I'm usually more focused on the sound than anything, but the ear cups on both of those that I auditioned weren't very comfortable.  Do all Grado's have the round profile that sits more on the ear than around them?

AFAIK, they are all open back. They do have a reputation for being uncomfortable and I'd agree they are when compared to other offerings. When I first got mine, I wanted to take them off after about 30 mins. I judiciously bent them out a hair and now I feel like I've got a good compromise between clamping force and comfort and can wear them for about an hour (which is as long as I want to be sitting in one spot anyway). They lack deep bass, but what's there is tight and sweet.

And, regarding the necessity of an amp, just be careful to match the impedance of your phones to the application. There are some difficult to drive phones out there. I like that I can continue my sluttiness unabated going in to the future without limitations. Here is a good article about the subject by the guy who designed the O2/ODAC:

http://nwavguy.blogspot.com/2011/02/headphone-amp-impedance.html

BTW, my Creek integrated's headphone output has an impedance of 560 Ohms! So do your homework before you buy.

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Re: Headphone/Amp Rig
« Reply #6 on: January 23, 2014, 04:16:38 PM »
I currently use Grado SR225i's, which aren't the right tool for the job. They are nice for listening though.

I tried a couple of mid-level Grado models...can't recall the specific models though.  I'm usually more focused on the sound than anything, but the ear cups on both of those that I auditioned weren't very comfortable.  Do all Grado's have the round profile that sits more on the ear than around them?

All but the top end models. I recently upgraded my Grado SR80's with the Grado G Cushion ear pads. http://www.bhphotovideo.com/bnh/controller/home?O=&sku=544614&Q=&is=REG&A=details 

Much better than what they came with. A little pricey at 45 bucks for the pair but much more comfortable. Improved the sound a bit to.
Beyerdynamic CK930>Sound Devices MixPre 6

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Re: Headphone/Amp Rig
« Reply #7 on: January 23, 2014, 09:49:45 PM »
Let me first say how sorry I am to tonedeaf...  I personally feel responsible for your current new addiction, but misery loves company :-*

The list below is a pretty dam good one.  All are a great bang for the buck headphones and all have great reviews.

Headphones
Sennheiser HD600 (open back reference phones for general listening and audio mastering)
Beyerdynamic DT990 Pro (semi-open back bass heavy phones for fun listening to most of the types of music I like)
Audio Technica ATH-M50 (closed back phones for taking to the gig...I already owned these)
Shure SE-215 (IEMs for the office...I also already owned these)

If your looking for a pair of headphones made for monitoring/mastering you are better off getting the Beyer DT-880.

I'm considering a pair of DT770 Pro's for monitoring duty. I currently use Grado SR225i's, which aren't the right tool for the job. They are nice for listening though.

I haven't found a Grado I liked.  I can't put my finger on  it, I just don't like them.  And to answer the question they are all open back.  I did read somewhere a limited run closed back is in development, but I haven't read any reviews yet.

I tried a couple of mid-level Grado models...can't recall the specific models though.  I'm usually more focused on the sound than anything, but the ear cups on both of those that I auditioned weren't very comfortable.  Do all Grado's have the round profile that sits more on the ear than around them?

These are on my short list too, along with the Schitt Vahalla.  I have been reading though that Tube Amps don't play well in terms of noise when close to a computer.

On the wish list is a good stay at home tube amp to connect downstream of the ZDac, perhaps a Wu Audio WA-6 if I have the money or Little Dot MKIII if budget concerns prevail.
DPA/HEB 4060's > R09HR
MBHO648/KA100Lk/KA200/KA300/KA500 > SD702

stevetoney

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Re: Headphone/Amp Rig
« Reply #8 on: January 24, 2014, 08:10:24 AM »
Let me first say how sorry I am to tonedeaf...  I personally feel responsible for your current new addiction, but misery loves company :-*

No apologies necessary, that is unless you ever come face-to-face with my wife.   :P

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Re: Headphone/Amp Rig
« Reply #9 on: January 24, 2014, 10:57:17 AM »
I haven't found a Grado I liked.  I can't put my finger on  it, I just don't like them.

+1

They are amazing for electric rock guitars, but I don't listen to anything that is *just* electric rock guitars. I went through 2 pair, the Alesandro MS-1 and a pair of Grados and didn't like either. They need some seriously dark and warm/smooth tubes with a dash of sparkle on the top to really get it firing on all cylinders. I don't doubt that you can coax some excellent sound out of them, but I didn't want to frig with that at the time.

I have been reading though that Tube Amps don't play well in terms of noise when close to a computer.

In my experience they are environmentally sensitive. I had a Little Dot and it needed to be about 2' away from anything electrical (computers, power cables, cell phones, hard drives, etc).
"This is a common practice we have on the bus; debating facts that we could easily find through printed material. It's like, how far is it today? I think it's four hours, and someone else comes in at 11 hours, and well, then we'll... just... talk about it..." - Jeb Puryear

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stevetoney

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Re: Headphone/Amp Rig
« Reply #10 on: January 24, 2014, 11:06:56 AM »
I have been reading though that Tube Amps don't play well in terms of noise when close to a computer.

In my experience they are environmentally sensitive. I had a Little Dot and it needed to be about 2' away from anything electrical (computers, power cables, cell phones, hard drives, etc).
[/quote]

So the tubes buzz if they're too close?

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Re: Headphone/Amp Rig
« Reply #11 on: January 24, 2014, 11:20:54 AM »
Forget about a dedicated headphone amp. If you have a decent stereo amp you can use it to drive your headphones by making your own break out box or buying a "Can Opener" from Vinylflat. They go for around $65.00.

I also find that the AKG 702's are a nicely balanced headset. I prefer them over the Grado RS2's I owned for 10 years. and.....they are super comfy.

Thank me later!

I've read that the Can Opener is awesome, especially for the price.  Good advice for those that already have a good component-based system.  I don't have a good system, so at the advice of my two mentors, I'm building a computer-based system from the phones backwards to the 24/48 FLAC library that I've got saved and backed up on a 1tb passport drive that I can carry with me back and forth to work.

For what you would pay for a good headphone amp you can buy a good speaker based amp and add a break out box. You would most likely save money. too. There are plenty of great deals on 17-25 watt tube amps out there, that can be had. Couple that to a DA USB based pre-amp and your set. This way you have your headphone system taken care of and all you need to add is some decent speakers down the road and your (open air) playback system is up and running.

Really, I've gone your route.....with good results, too, I might add.....however, I've discovered, and learned, that there is a better way with less boxes and better sound.....that saves money. Sounds too good to be true but it is not. Unless, of course, you like lots of boxes and have a desire to stimulate our economy.

I would also add that many of the USB based AD's come with good headphone amps and usually allow for op amp rolling. Yulong and Matrix come to mind. These can easily be carried to and from work and you can use the headphone out section for pleasurable listening. I swapped out my op amps in my Matrix Mini i and have improved the headphone section. Not that the stock op amp was bad....just the new one improved it. Now I have a second headphone amp for late night listening  for more than I listener.

FYI, I bought a Jolida 102....did some mods too it and use this, along with my Can Opener for daily headphone listening. I also use the Jolida to drive my Klipsch Heresey (modded of course), as a second playback system. All very nice.... and with an added sub.....works well. Not my reference system but enjoyable none the less...and affordable.

So. I paid $65 for the break out box......$300 for the amp.......$300 for the Matrix for a total of $675.....and I have a great headphone system and a good second playback system. There are other options out there....this is just one example of how you can have your cake and eat it too.

Really, don't get stuck in a paradigm!
« Last Edit: January 24, 2014, 11:34:05 AM by raymonda »

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Re: Headphone/Amp Rig
« Reply #12 on: January 24, 2014, 11:32:54 AM »

I have been reading though that Tube Amps don't play well in terms of noise when close to a computer.

In my experience they are environmentally sensitive. I had a Little Dot and it needed to be about 2' away from anything electrical (computers, power cables, cell phones, hard drives, etc).

So the tubes buzz if they're too close?

buzz, chatter, all sorts of noise. Some of it's super noticeable, some of it's rather subtle.

It's not a vote against tubes, just a nuance you have to be careful about. I was able to get my tube amp to get really close to that inky black background that I covet, but it requires effort. Thats all.
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"Nostalgia ain't what it used to be." - Jim Williams

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Re: Headphone/Amp Rig
« Reply #13 on: January 24, 2014, 11:36:42 AM »

I have been reading though that Tube Amps don't play well in terms of noise when close to a computer.

In my experience they are environmentally sensitive. I had a Little Dot and it needed to be about 2' away from anything electrical (computers, power cables, cell phones, hard drives, etc).



So the tubes buzz if they're too close?

buzz, chatter, all sorts of noise. Some of it's super noticeable, some of it's rather subtle.

It's not a vote against tubes, just a nuance you have to be careful about. I was able to get my tube amp to get really close to that inky black background that I covet, but it requires effort. Thats all.


I run tons of electronics, digital and computer stuff and never once had any problems with interference with my Jolida.

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Re: Headphone/Amp Rig
« Reply #14 on: January 24, 2014, 12:11:21 PM »
As to the tube noise of a headphone amp, most headphone amps have exposed tubes, so I've got to believe shielding has alot to do with how much noise you'd get from nearby devices.

EDIT:  Jon beat me to the answer about shielded tubes.
« Last Edit: January 24, 2014, 01:35:31 PM by tonedeaf »

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Re: Headphone/Amp Rig
« Reply #15 on: January 24, 2014, 12:52:27 PM »
(Computer > USB-in/24bitSPDIF-out box) or (silver disc player's SPDIF out) > Mytek Stereo96 DAC / heaphone amp > Senn HD650

I'm happy with this for home headphone listening and detail checks when editing (although I prefer working primiarily on speakers when mixing/mastering).  I'd like to hear the Senn HD600s and the orthodynamic magna-planars but haven't had a chance.

I sometimes take the HD650s out with me to a session or on the road to listen to playback directly out of the recorders, and their headphone amps all drive them well enough if not as nicely as the Mytek.  Not suitable for monitoring as they are very open backed and keep meaning to pick up the ATM50's (holding out for a deal on the ones with the coiled cord) for that.

I have a pair of Etymotic 4S and an early-model Headroom Total Airhead I used to use for monitoring but I don't really monitor while recording much and haven't pulled those out in years.

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Re: Headphone/Amp Rig
« Reply #16 on: January 24, 2014, 01:10:12 PM »
I have been running a ZERO 24 BIT/192KHz DAC/Headphone Amp/Pre-Amp > AKG 702's for quite a while now and am very happy.  The open sound of the 702's is amazing and the Zero drives them smoothly!

http://www.head-fi.org/t/269458/review-zero-24-bit-192khz-dac-headphone-amp-pre-amp

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Re: Headphone/Amp Rig
« Reply #17 on: January 24, 2014, 01:20:50 PM »
I run the Audio-gd FUN Headphone amp/dac I think i paid like 300 or so for it.

USB 24/96 coax 24/192. Squeezebox > Audio-gd FUN > MusicHall Mambo > VR2's

extremely happy with this setup. I just got back my marantz sr880 and klipsch 1.5s and Energy sub. I tried driving the VR2s with the marantz and it did a decent job just didnt have the power of the mambo

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Little Bear tube Pre >Outlaw Audio 2200 Monoblocks > VR-2's

stevetoney

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Re: Headphone/Amp Rig
« Reply #18 on: January 24, 2014, 01:41:58 PM »

I have been reading though that Tube Amps don't play well in terms of noise when close to a computer.

In my experience they are environmentally sensitive. I had a Little Dot and it needed to be about 2' away from anything electrical (computers, power cables, cell phones, hard drives, etc).

So the tubes buzz if they're too close?

buzz, chatter, all sorts of noise. Some of it's super noticeable, some of it's rather subtle.

It's not a vote against tubes, just a nuance you have to be careful about. I was able to get my tube amp to get really close to that inky black background that I covet, but it requires effort. Thats all.

Right, I was just asking for knowledge's sake.  Puttin' in the noggin' for the future.

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Re: Headphone/Amp Rig
« Reply #19 on: January 24, 2014, 01:48:02 PM »
I keep coming back to Audio-GD too..  I woul like to try some of their gear.  Seems like really good quality for the price.
DPA/HEB 4060's > R09HR
MBHO648/KA100Lk/KA200/KA300/KA500 > SD702

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Re: Headphone/Amp Rig
« Reply #20 on: January 24, 2014, 02:05:19 PM »
As to the tube noise of a headphone amp, most headphone amps have exposed tubes, so I've got to believe shielding has alot to do with how much noise you'd get from nearby devices.

EDIT:  Jon beat me to the answer about shielded tubes.

Yeah, I can shield the amp and cut it out, but I found it easier to just move it a foot or two away. Amps are all designed different, some will be better than others. ymmv and all that.

I have been running a ZERO 24 BIT/192KHz DAC/Headphone Amp/Pre-Amp > AKG 702's for quite a while now and am very happy.  The open sound of the 702's is amazing and the Zero drives them smoothly!

The Zero was my first DAC/amp and for the price it was one of the best things to happen to personal audio, sorta like the UA-5 for taping; really helped bring the entrance fee (in terms of effort and price) for a quality headphone rig down.

I run the Audio-gd FUN Headphone amp/dac I think i paid like 300 or so for it.

I keep coming back to Audio-GD too..  I woul like to try some of their gear.  Seems like really good quality for the price.

If I was getting a cheap solid state amp, I'd totally pick up either something from Audio-GD or Schiit. The Audio-GD even has coloration control modules IIRC.
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Re: Headphone/Amp Rig
« Reply #21 on: January 24, 2014, 02:40:58 PM »
Red sports cars always appear to be faster.

Leveraging market percecptions, the savy business perspective is to give customer what they think they need and demand; whether it is truely necessary or not is a correct but more nuanced question. And if it causes no harm, the only downside for those who are truely in the know is some additional cost at no real benifit.

Big diameter wheels, big diameter power transformers. Both are more market perception driven than engineering driven for a vast majority of products, and of course have real applications where they really do matter as well.
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Re: Headphone/Amp Rig
« Reply #22 on: January 24, 2014, 02:42:58 PM »
So this is what a tinybox would look like if it was on steroids?
« Last Edit: January 24, 2014, 02:44:52 PM by tonedeaf »

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Re: Headphone/Amp Rig
« Reply #23 on: January 24, 2014, 06:00:04 PM »
Geek   ^^^^^^^^^    lol... :facepalm:
« Last Edit: January 24, 2014, 11:51:38 PM by OOK »
DPA/HEB 4060's > R09HR
MBHO648/KA100Lk/KA200/KA300/KA500 > SD702

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Re: Headphone/Amp Rig
« Reply #24 on: January 27, 2014, 09:33:46 AM »
No, very different design philosophies.  For example I'd never include a socketed opamp and encourage swapping; firstly, sockets degrade performance (which doesn't matter at AF, but it does at RF, and too often swaps are for very high speed chips that are thus not properly decoupled or their inputs snubbed; the result can be RF oscillation that will degrade AF performance), secondly, sorry but I don't trust customers' listening impressions over my measurement tools.  I pick the best parts for the job designed, you decide whether or not to buy it.

Anyway, the opamp is not even the output device here (which it shouldn't be, but many DIY headphone amp designs use opamps that are not suited for the job), so I'd expect little change in performance unless an inappropriate device was selected, which would only degrade performance of an optimized circuit.  Why would a manufacturer encourage that?

I would also not use a non-feedback discrete topology because I know that a design with large amounts of global feedback (such as an IC opamp) will outperform the discrete non-feedback solution using less space and current.  If I wanted a distortion/saturation feature, I would label it so and make it selectable.

This is not to say the Audio-GD isn't a good device; it looks well over-engineered (3.5W output!)  But it isn't something I would design.  I prefer to push the limits of very small case sizes and see how much I can extract from the resulting circuit.  tinybox, for example, doesn't need a power transformer because it uses a switching supply fed by DC which is about 85% efficient at 16V.

If the question is could I design a circuit that would output 3.5W/channel in a tinybox case?  The answer is yes, but battery life would be fairly terrible.  The problem is in order to output 3.5W into 25 ohm you need a 30V supply, but unless you do something like a class D or G design (tinybox is a pseudo-class G design), you get low efficiency at normal levels (say 100mW).  In order to drive 100mW into 60 ohm, you only need a 7V swing.  So if you have a 30V supply, you only have about 18% efficiency in a class AB amp.  You don't care about that in a wall-powered unit, but you sure do running on batteries.

This will probably show my ignorance more than anything but the FUN can also be used as a Pre-amp. I'm not sure if the design concepts you mention above would be any different taking that in to consideration.
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Re: Headphone/Amp Rig
« Reply #25 on: February 01, 2014, 04:55:32 PM »
 :police:  Is this unit actually UL Listed for the US?  It looks to me that this unit has diodes and resistor connecting the AC ground lug on the IEC to the chassis.  :facepalm:  That's not cool or safe should a line fault condition occur, the NEC prohibits the practice and it would be hard to believe they got this by the UL.



I run the Audio-gd FUN Headphone amp/dac I think i paid like 300 or so for it.

USB 24/96 coax 24/192. Squeezebox > Audio-gd FUN > MusicHall Mambo > VR2's

extremely happy with this setup. I just got back my marantz sr880 and klipsch 1.5s and Energy sub. I tried driving the VR2s with the marantz and it did a decent job just didnt have the power of the mambo


Mics: AKG CK91/CK94/CK98/SE300 D-330BT | DPA 4060 4061 4266 | Neumann TLM 103 | Senn ME66/K6/K6RD MKE2 MD421 MD431 | Shure VP88 SM7B SM63L SM58 Anniversary Cables: Gotham GAC-4/1 Quad w/Neutrik EMC | Gotham GAC-2pair w/AKG MK90/3 connectors | DigiGal AES>S/PDIF cable Preamp: SD MixPre-D Recorders: SD MixPre 6 | Marantz PMD 661 Edit: 2011 27" 3.4GHz Quad i7 iMac High Sierra | 2020 13" MBA Quad i7 Catalina | Wave Editor | xACT | Transmission | FCP X 

Offline cheshirecat

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Re: Headphone/Amp Rig
« Reply #26 on: February 04, 2014, 06:28:14 PM »
:police:  Is this unit actually UL Listed for the US?  It looks to me that this unit has diodes and resistor connecting the AC ground lug on the IEC to the chassis.  :facepalm:  That's not cool or safe should a line fault condition occur, the NEC prohibits the practice and it would be hard to believe they got this by the UL.



I run the Audio-gd FUN Headphone amp/dac I think i paid like 300 or so for it.

USB 24/96 coax 24/192. Squeezebox > Audio-gd FUN > MusicHall Mambo > VR2's

extremely happy with this setup. I just got back my marantz sr880 and klipsch 1.5s and Energy sub. I tried driving the VR2s with the marantz and it did a decent job just didnt have the power of the mambo



UL is an independent body and listing is only required if you live in a municipality that requires appliances to be certified.

At any rate, I would think the circuit in question is there to prevent ground loops, and would solve many more problems than it causes.  You would have to fry those devices to kill your chassis to earth ground connection

It sounds good go with it, if you're that concerned, lose the diode/resistor and replace it with a jumper and you're good to go... if you're constantly putting voltage on your chassis, rethink your hobbies.
SB2 / Rega P1 > Modified Dynaco PAS2 > Modified Dynaco MK-IV monoblocks> Axiom M22 v2

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Re: Headphone/Amp Rig
« Reply #27 on: February 04, 2014, 07:33:38 PM »
UL is an independent body and listing is only required if you live in a municipality that requires appliances to be certified.

At any rate, I would think the circuit in question is there to prevent ground loops, and would solve many more problems than it causes.  You would have to fry those devices to kill your chassis to earth ground connection

It sounds good go with it, if you're that concerned, lose the diode/resistor and replace it with a jumper and you're good to go... if you're constantly putting voltage on your chassis, rethink your hobbies.

Of course they did it to mask a ground loop problem, the point is it's not safe.

Do you think it would be able to survive a 100A fault for 2.5 seconds or a 1,000A fault for 2.5ms without opening up?  The UL determined these numbers represent a realistic range of short-circuit current and time taken for the circuit breaker to trip open. Safety grounding must return to NEUTRAL to provide shock/electrocution protection if a fault should develop. The practice is no safer than a ground lift plug during a fault condition.
« Last Edit: February 04, 2014, 07:50:40 PM by DigiGal »
Mics: AKG CK91/CK94/CK98/SE300 D-330BT | DPA 4060 4061 4266 | Neumann TLM 103 | Senn ME66/K6/K6RD MKE2 MD421 MD431 | Shure VP88 SM7B SM63L SM58 Anniversary Cables: Gotham GAC-4/1 Quad w/Neutrik EMC | Gotham GAC-2pair w/AKG MK90/3 connectors | DigiGal AES>S/PDIF cable Preamp: SD MixPre-D Recorders: SD MixPre 6 | Marantz PMD 661 Edit: 2011 27" 3.4GHz Quad i7 iMac High Sierra | 2020 13" MBA Quad i7 Catalina | Wave Editor | xACT | Transmission | FCP X 

Offline cheshirecat

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Re: Headphone/Amp Rig
« Reply #28 on: February 05, 2014, 12:29:28 PM »
The practice is no safer than a ground lift plug during a fault condition.

Exactly.
SB2 / Rega P1 > Modified Dynaco PAS2 > Modified Dynaco MK-IV monoblocks> Axiom M22 v2

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Re: Headphone/Amp Rig
« Reply #29 on: February 05, 2014, 09:15:45 PM »
I will say this for Audio-GD products...  Although I don't own any I have not seen any issues reported by anyone on HeadFi regarding the above concern.  That community is as crazied about their gear as we are here on the section.  If there were problems, even minimal ones they would show up in the online forums.  There must be something we either can't see or know what it is on the circuit boards to address the above concerns.  But hey what I know.  I know next to nothing about electricity except it hurt when you do something wrong.... :P  Hence I leave that stuff to others....

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Re: Headphone/Amp Rig
« Reply #30 on: February 06, 2014, 03:36:58 PM »
The danger is the devices frying, not the fried state. Put 120V across it and see what happens.  That's a lot of heat that has to go somewhere.  OOK, nobody will notice until they plug it into a miswired or faulty outlet.  Those are rare, and these units probably aren't common enough to have found a bad outlet yet.

Also, all of the RCAs appear to be isolated, so there's no reason to further isolate the chassis from safety ground.


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No, its status as also a preamp wouldn't change any of my design decisions.  There really isn't much difference between a headphone amp input stage and a mic amp input stage, except the mic input needs to be lower noise and higher gain*bandwidth.  That takes a small amount of additional current per channel--say, 3mA instead of 500uA.  Trivial compared with the required output power.

Thank you for the explanation. I will say that my previous living space was as bad as could be when it came to wiring so I either got lucky that the unit didnt cause any issues or the power conditioner in front of it is helping.

I can try and take a pic of my actual unit vs. the website pic used to see if there is any differences.
AKG c426, AKG414 XLS/ST, AKG ck61, ck22, >nBob colettes >PFA > V3, SD MixPre >  TCM-Mod Tascam HDP2, Sony M10
Little Bear tube Pre >Outlaw Audio 2200 Monoblocks > VR-2's

 

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