or Connect
Head-Fi.org › Forums › Equipment Forums › Headphone Amps (full-size) › How do you compare 2 headphone amps?
New Posts  All Forums:Forum Nav:

How do you compare 2 headphone amps? - Page 2

post #16 of 60
Thread Starter 

When I think about it, it shall not be difficult to make my own basic device with few parts:

2x jacks for inputs, 1x jack for the headphone, everything wired correctly to a rotary switch!

Or am I missing something?

post #17 of 60
Quote:
Originally Posted by mrmagoo View Post
 


Hi, thanks for the link, it seems very interesting and the price is very good because it seems to include shipping, but it also seems that no one has used it and commented yet so we can't know for sure if it is good quality... and I would also prefer if it had 1/4" jacks. But for the price it's probably worth a try..

If there is no other solution, I think I will buy one..

I would prefer the Fiio (and it has a 1/4" for the hp jack), but unfortunately, it has a shipping cost nearly as expensive as the device! (I'm in Europe).

 

I was thinking about it and I think all you need is three stereo TRS jacks, a triple pole dual throw (TPDT) switch and an enclosure.

 

Middle position would be output to headphone R/L/NEG

Position 1 would be input from amp 1 R/L/NEG

Position 2 would be input from amp 2 R/L/NEG

 

I'm not sure how chassis grounding would work though between the enclosure and two different amps... or if its even necessary....?????  The DIY section gurus might have some ideas.

 

 


Edited by kramer5150 - 2/14/14 at 4:58pm
post #18 of 60
Thread Starter 
Quote:
Originally Posted by kramer5150 View Post
 

 

I was thinking about it and I think all you need is three stereo TRS jacks, a triple pole dual throw (TPDT) switch and an enclosure.

 

Middle position would be output to headphone R/L/NEG

Position 1 would be input from amp 1 R/L/NEG

Position 2 would be input from amp 2 R/L/NEG

 

I'm not sure how chassis grounding would work though between the enclosure and two different amps... or if its even necessary....?????  The DIY section gurus might have some ideas.

 

 

 

Thanks!

I tried to search for those parts online and unfortunately it would be very expensive to buy those few parts only because of the shipping costs (mouser quoted 20EUR of shipping costs for an order of less than 8EUR of parts !!!)

 

Someone in another thread about the Fiio hs2 gave this link: http://mfspdesigns.wordpress.com/a-b-switch-box-psb2-1/ and it seems it's a cheap and simple device doing exactly what I need and it seems to have high quality parts inside.

Curious to know if anyone already heard about that? (the site has some other interesting nice stuff though!)

 

Someone also in the same thread mentionned this one: http://www.sescom.com/product.asp?item=SES-IPOD-AB&utm_campaign=website&utm_source=sendgrid.com&utm_medium=email but it seems that they are some reviews about it on amazon complaining about noise/humming...

post #19 of 60
Quote:
Originally Posted by mrmagoo View Post
 

 

Thanks!

I tried to search for those parts online and unfortunately it would be very expensive to buy those few parts only because of the shipping costs (mouser quoted 20EUR of shipping costs for an order of less than 8EUR of parts !!!)

 

Someone in another thread about the Fiio hs2 gave this link: http://mfspdesigns.wordpress.com/a-b-switch-box-psb2-1/ and it seems it's a cheap and simple device doing exactly what I need and it seems to have high quality parts inside.

Curious to know if anyone already heard about that? (the site has some other interesting nice stuff though!)

 

Someone also in the same thread mentionned this one: http://www.sescom.com/product.asp?item=SES-IPOD-AB&utm_campaign=website&utm_source=sendgrid.com&utm_medium=email but it seems that they are some reviews about it on amazon complaining about noise/humming...

 

I would avoid that Sescom A/B box (the second one).  It uses a DPDT switch to toggle the positive signals from each amp into the single output.  But it ONLY toggles the + signals through the DPDT.  It relies on common grounding all the input and output negatives.  So what that means is you've got two amp input negatives connected to each other through the device.  Essentially the unused amp negative acting like a signal antenna receiving the ambient RFI noise environment.  Not sure the exact topography inside the box if its a star pattern or what-not, but at least a couple Amazon reviewers complain about ground loop noises.  In a plastic enclosure like that its not going to be chassis/common grounded, so ground path and wire layouts inside would have to be perfectly equal between all channels.  And even then, ground loop noise is tricky to debug because so much of it relies on the ambient noise environment of the user.  One amazon reviewer replaced the DPDT switch with this tripple pole dual throw and reported back positive results.  This is essentially the same device-design I recommended in my previous post.

 

Thinking about it further, I think (I am not positive on this mind you) a device like this with a 3PDT would need to be in a plastic enclosure.  If you mounted it in a metal box, it would end up common grounding all the sleeves together... and thus partially negate the third pole on the switch.

 

Not sure about that first one... I would inquire with them if they use a DPDT switch and common grounding all inputs/output or a triple pole switch and isolated negatives between the two amp inputs.

 

Oh one more thing... that blue push-button switch I show in my pic is more commonly called a "stomp switch".  Its designed for added robustness to be stepped / stomped on in a floor mounted device.  Think musicians on stage, heavy equipment operators...etc.  So its going to be more $$$ than a toggle flip switch.


Edited by kramer5150 - 2/16/14 at 9:03am
post #20 of 60
Thread Starter 
Quote:
Originally Posted by kramer5150 View Post
 

 

I would avoid that Sescom A/B box (the second one).  It uses a DPDT switch to toggle the positive signals from each amp into the single output.  But it ONLY toggles the + signals through the DPDT.  It relies on common grounding all the input and output negatives.  So what that means is you've got two amp input negatives connected to each other through the device.  Essentially the unused amp negative acting like a signal antenna receiving the ambient RFI noise environment.  Not sure the exact topography inside the box if its a star pattern or what-not, but at least a couple Amazon reviewers complain about ground loop noises.  In a plastic enclosure like that its not going to be chassis/common grounded, so ground path and wire layouts inside would have to be perfectly equal between all channels.  And even then, ground loop noise is tricky to debug because so much of it relies on the ambient noise environment of the user.  One amazon reviewer replaced the DPDT switch with this tripple pole dual throw and reported back positive results.  This is essentially the same device-design I recommended in my previous post.

 

Thinking about it further, I think (I am not positive on this mind you) a device like this with a 3PDT would need to be in a plastic enclosure.  If you mounted it in a metal box, it would end up common grounding all the sleeves together... and thus partially negate the third pole on the switch.

 

Not sure about that first one... I would inquire with them if they use a DPDT switch and common grounding all inputs/output or a triple pole switch and isolated negatives between the two amp inputs.

 

Oh one more thing... that blue push-button switch I show in my pic is more commonly called a "stomp switch".  Its designed for added robustness to be stepped / stomped on in a floor mounted device.  Think musicians on stage, heavy equipment operators...etc.  So its going to be more $$$ than a toggle flip switch.


Hi, thanks again for you advices kramer5150,

I've contacted the supplier of the first link I posted, and I'll report here when/if they reply...

In their site, it indicates a 3PDT toggle switch selector and an aluminum case, (and they have another model more expensive with rca connectors instead of 1/4" jacks, but that's not what I need for comparing 2 headphone amps.)

post #21 of 60
Quote:
Originally Posted by mrmagoo View Post
 


Hi, thanks again for you advices kramer5150,

I've contacted the supplier of the first link I posted, and I'll report here when/if they reply...

In their site, it indicates a 3PDT toggle switch selector and an aluminum case, (and they have another model more expensive with rca connectors instead of 1/4" jacks, but that's not what I need for comparing 2 headphone amps.)

Cool... thats the one to get I think.  Looking at the pics a second time it looks like they are using ground isolated TRS jacks, so they've done their homework.  But then again I think any amp maker who is selling open source design (for lack of a better term) amps like AMBs M^3, should have a deeper understanding of the circuits involved.


Edited by kramer5150 - 2/16/14 at 10:06am
post #22 of 60

One more thing you might want to inquire with them... Do they have completed products in stock ready to ship?   or you purchasing a contract  service to build the product?  Hard to tell from the www site which it is.  But if its the latter, it could be a long wait depending on what they have on order with other customers.

post #23 of 60
Quote:
Originally Posted by mrmagoo View Post

 

I've contacted the supplier of the first link I posted, and I'll report here when/if they reply...

 

Please do, I'm curious myself.

post #24 of 60
Thread Starter 
Quote:
Originally Posted by kramer5150 View Post
 

One more thing you might want to inquire with them... Do they have completed products in stock ready to ship?   or you purchasing a contract  service to build the product?  Hard to tell from the www site which it is.  But if its the latter, it could be a long wait depending on what they have on order with other customers.

 

Quote:
Originally Posted by jonbernard View Post
 

 

Please do, I'm curious myself.

 

This one seems interesting. I contacted them and they answered that they have a few units in stock at the moment and that their device (passive switch box psb2-1) uses high quality parts and that the inputs and output are 1/4inch TRS so no need of any adapter. They use silver plated contacts parts everywhere: in the three 1/4inch jacks which are Neutrik, and in the 3PDT toggle switch. Everything is isolated from the aluminum enclosure. They also use high quality shielded cable inside (cable used for professional microphone they say).

Seem professional and they told me that for comparing 2 headphone amps with this device, I will only need to add two cables ending with 1/4” male jacks , and they also sell some of high quality if I want.

So I will not need any adapters with their device.

Also the shipping cost for me is 6.90EUR so it seems correct.

 

Ah, and I asked them about any risk of noise with their device and they explain that if such a simple passive device induces noise, it's probably because the switch is a cheap one that doesn't switch the grounds which are probably all connected together permanently and it's not good... but it's not the case with their device because they use a switch that switches the grounds too...

I think I'll buy one.. but now I'm also interested in other very nice stuff they sell on their site, so I will probably need to wait and save more money... I think their amps and headphone stands are very beautiful, (but not cheap though)...

post #25 of 60
Quote:
Originally Posted by mrmagoo View Post
 

 

 

This one seems interesting. I contacted them and they answered that they have a few units in stock at the moment and that their device (passive switch box psb2-1) uses high quality parts and that the inputs and output are 1/4inch TRS so no need of any adapter. They use silver plated contacts parts everywhere: in the three 1/4inch jacks which are Neutrik, and in the 3PDT toggle switch. Everything is isolated from the aluminum enclosure. They also use high quality shielded cable inside (cable used for professional microphone they say).

Seem professional and they told me that for comparing 2 headphone amps with this device, I will only need to add two cables ending with 1/4” male jacks , and they also sell some of high quality if I want.

So I will not need any adapters with their device.

Also the shipping cost for me is 6.90EUR so it seems correct.

 

Ah, and I asked them about any risk of noise with their device and they explain that if such a simple passive device induces noise, it's probably because the switch is a cheap one that doesn't switch the grounds which are probably all connected together permanently and it's not good... but it's not the case with their device because they use a switch that switches the grounds too...

I think I'll buy one.. but now I'm also interested in other very nice stuff they sell on their site, so I will probably need to wait and save more money... I think their amps and headphone stands are very beautiful, (but not cheap though)...

Sounds good... they have a solid design, that pretty much matches what I would DIY build.  Neutrik TRS jacks are a really nice aded touch.

post #26 of 60
This device seems pretty similar to the Fiio HS2
http://dx.com/en/p/line5-a985-3-5mm-headphone-output-switcher-black-4-in-4-out-266636

anyone has any experience with this vendor? Is it legit?
post #27 of 60
Quote:
Originally Posted by Za Warudo View Post

This device seems pretty similar to the Fiio HS2
http://dx.com/en/p/line5-a985-3-5mm-headphone-output-switcher-black-4-in-4-out-266636

anyone has any experience with this vendor? Is it legit?

Looks like something similar.  Can't tell though if the inputs are isolated or common ground.  If its the latter there's risk of ground loops.  Looks like the outputs are in parallel.

post #28 of 60
Also, if you want to compare amps using the same source, wouldn't you need a 2nd such device to split the LO signal into the amps you are comparing?
post #29 of 60
Quote:
Originally Posted by Za Warudo View Post

Also, if you want to compare amps using the same source, wouldn't you need a 2nd such device to split the LO signal into the amps you are comparing?

Ugh... I was kind of hoping someone wasn't going to mention that, because I don't know why it works.  But the answer is no, you don't need to toggle-switch line-outs at the RCA level.  I have been using 1M2F "Y" adapters for decades and have never had a problem with ground loops/noises, or signal losses between multiple components.  This includes car audio installations that are a minefield of radiated EMI/RFI and ground loops galore.

 

I just got my adapter from radio hack, wasn't cheap but still $$ decently well spent. 

 

post #30 of 60
Thread Starter 

I've just bought one of these : http://mfspdesigns.wordpress.com/a-b-switch-box-psb2-1/ with 2 cables and it shall arrive within a few days. I'll report back once I receive it. :)

New Posts  All Forums:Forum Nav:
  Return Home
  Back to Forum: Headphone Amps (full-size)
Head-Fi.org › Forums › Equipment Forums › Headphone Amps (full-size) › How do you compare 2 headphone amps?