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Speaker amps for headphones - Page 95

post #1411 of 2717
Quote:
Originally Posted by Hutnicks View Post


I think we more or less have to thank the various "safety" organizations for that. There are some places where you cannot sell a two pin solution. We pay now for bad design's sold decades ago.

What places are those?

se
post #1412 of 2717
Quote:
Originally Posted by Steve Eddy View Post


What places are those?

se


Ontario is a fairly good example. You would find it very difficult to get approval for a two pin solution here.

post #1413 of 2717
Quote:
Originally Posted by Hutnicks View Post


Ontario is a fairly good example. You would find it very difficult to get approval for a two pin solution here.

So even all the cheap A/V receivers sold there have three pin plugs?

I'll have to give my business partner a call. He's in Mississauga.

se
post #1414 of 2717
Quote:
Originally Posted by Steve Eddy View Post


So even all the cheap A/V receivers sold there have three pin plugs?

I'll have to give my business partner a call. He's in Mississauga.

se

 

No there are lots of two prong items here. It's a matter of conflicting agencies. CSA is universally accepted, however if you manufactured locally and went to the local authority, they have been known to fail things CSA would pass. It's why in most cases you pay the outrageous fees for the CSA approval. If you were small volume you might find it to your benefit to use the local approval system, it's far cheaper. This is a unique case in that the province is regulated by an Act that goes back to the days of Adam Beck.

post #1415 of 2717
Quote:
Originally Posted by Hutnicks View Post

No there are lots of two prong items here. It's a matter of conflicting agencies. CSA is universally accepted, however if you manufactured locally and went to the local authority, they have been known to fail things CSA would pass. It's why in most cases you pay the outrageous fees for the CSA approval. If you were small volume you might find it to your benefit to use the local approval system, it's far cheaper. This is a unique case in that the province is regulated by an Act that goes back to the days of Adam Beck.

Ok, I'm confused. You originally said there are some places where it would be hard to find two prong solutions. I asked you where for example. You said Ontario. Now you say there are lots of two prong items there.

What am I missing here?

se
post #1416 of 2717
Quote:
Originally Posted by Steve Eddy View Post

Ok, I'm confused. You originally said there are some places where it would be hard to find two prong solutions. I asked you where for example. You said Ontario. Now you say there are lots of two prong items there.

What am I missing here?

se

Two pin items are common as dirt in Ontario.......toasters, drills, wall warts, etc.
To be specific, 2 pin audio devices are common as dirt in Ontario.

I place the blame on the companies who can't get their act together and work within the code when designing equipment.

Look at Bryston.
They figured it out.
For some magical reason they have figured out how to make a hum free 3 pin amp with safety ground tied to "signal ground" or "signal common" by loosely coupling the two " grounds" together.
Which is good practice anyway.

There was another company operating in Ontario who Sold approved equipment that hummed like a banshee.
The manufacturer claimed the solution was to cut the bonding pin off the 3 pin AC power cable.
They didn't have their internal grounding scheme together.
Edited by Chris J - 11/19/13 at 9:06am
post #1417 of 2717
Quote:
Originally Posted by Steve Eddy View Post

And the sad thing is, the so-called "high end" can't seem to figure out how to make double insulated chassis. And even if a chassis could qualify as double insulated, they still burden people with the three pin power cable. In fact, if a piece of double insulated gear had only a two pin cable, people would take it less seriously, as if giving people the most common cause of ground loop and other noise is some kind of "high end" virtue.

se

I think that sums it up quite nicely.

Audiophiles appear to have bought into the "3 pins good, 2 pins bad!" philosophy.
Right up there with something poorly understood and called "balanced" is good, and something called "single ended" is bad.

I've had stuff CSA approved, UL approved, CE mark. It's not rocket science.

The so-called "high end" needs to read the applicable code book, then seek regulatory approval.

Odd how it's only "high-end" stuff that has hum issues..........................rolleyes.gif
Edited by Chris J - 11/13/13 at 2:05pm
post #1418 of 2717

@potterma I bought the software chip upgrade for my LDR pre. It was only $32 shipped, not too shabby! I'll keep you updated on the results :D Coolest part about it is I get to A/B the old and new.


Edited by brunk - 11/13/13 at 9:05pm
post #1419 of 2717
Quote:
Originally Posted by brunk View Post

@potterma
 I bought the software chip upgrade for my LDR pre. It was only $32 shipped, not too shabby! I'll keep you updated on the results biggrin.gif  Coolest part about it is I get to A/B the old and new.
Very cool. Look forward to hearing your impressions.
post #1420 of 2717

Hello, I made this post in the Emotiva thread, but nobody answered. It seems like there are engineering types here, so maybe one of you can help me.  I'm trying to calculate the power I'm getting into my HE-400 with the Emotiva Mini-x amp. 

Using the relationship P_2 = P_1 * (R_1 / R_2), I have P_1 =  50 W and R_1 = 8 ohms for the Emotiva, and R_2 = 35 ohms for the HE-400, so P_2 = 50 * (8/35) = 11.4 W.

With 300 ohm serial resistors, I have R_2 = 300+35, so P_2 = 50 * (8/335) = 1.2 W. About the same as what a Magni would deliver with no resistors in the chain, yes? Interesting. 

But does it actually work this way? The Emotiva doesn't have 100 W into 4 ohms, so it seems like this linear model isn't quite right? Is this a good approximation?

post #1421 of 2717

Power, I or V can be the amp's limiting "drive" value depending on load impedance

 

for series R calculation you may want to go back to V based calculations - a 50 W into 8 Ohm amp only puts out 20 Vrms, apply that V to the 35/(300+35) voltage division ratio and you only get ~120 mW from ~2 Vrms into 35 Oms

 

series R really shouldn't have much effect on Ortho "sound" - they have very flat, near pure R impedance themselves

post #1422 of 2717
Quote:
Originally Posted by jcx View Post
 

Power, I or V can be the amp's limiting "drive" value depending on load impedance

 

for series R calculation you may want to go back to V based calculations - a 50 W into 8 Ohm amp only puts out 20 Vrms, apply that V to the 35/(300+35) voltage division ratio and you only get ~120 mW from ~2 Vrms into 35 Oms

 

series R really shouldn't have much effect on Ortho "sound" - they have very flat, near pure R impedance themselves

Thanks! That helps. I think I understand the voltage divider concept. I'd probably need a multimeter to really know what power I'm getting, since I don't have any specs for the amp other than the published 50W @ 8 and 80W @ 4.  

There is one thing though -- the amp I had before the Emotiva (Little Dot Mk3) had 100mw into 32 ohms, and it clipped with the HE-400 on the low gain setting (gain =3). The Emotiva doesn't clip at any volume I can stand to listen to. Is this more of a gain issue than a power issue? I could also get the Little Dot to clip at high gain (10) when I used the resistors -- the Little Dot is rated at 350mW into 300/600 ohms. I don't really understand how the Little Dot was clipping if it has just as much or more power than the Emotiva with the series resistors. I imagine I'm missing something here. 

post #1423 of 2717
Quote:
Originally Posted by manbear View Post
 

Thanks! That helps. I think I understand the voltage divider concept. I'd probably need a multimeter to really know what power I'm getting, since I don't have any specs for the amp other than the published 50W @ 8 and 80W @ 4.  

There is one thing though -- the amp I had before the Emotiva (Little Dot Mk3) had 100mw into 32 ohms, and it clipped with the HE-400 on the low gain setting (gain =3). The Emotiva doesn't clip at any volume I can stand to listen to. Is this more of a gain issue than a power issue? I could also get the Little Dot to clip at high gain (10) when I used the resistors -- the Little Dot is rated at 350mW into 300/600 ohms. I don't really understand how the Little Dot was clipping if it has just as much or more power than the Emotiva with the series resistors. I imagine I'm missing something here. 

Its likely that the Little Dot was running into either the voltage or current limits of one or more amplifier stages.

post #1424 of 2717

I was worried about hurting my speaker tube amp, a Yaqin MC-13S (push-pull 4x6CA7, 2x40w into 8 ohms), with headphones but after reading this thread I decided to give it a try. I started with a direct balanced cable connected to the speaker outputs and all three of the headsets used in this test have been modified with balanced cables. I used a raspberry pi (far right in pic) as the music source -> USB -> Aune T1 as DAC only -> Amp.

 

I listened with Modified Fostex T50RP and AKG K240 Studio cans and both sounded great. I had absolutely no issues with this setup. Max volume was around 9:30 with most music. The AKGs needed a little less volume compared to the T50RPs of course.

 

I then built an interface box so I could add a resistor network to match up the amp and headphone impedances. I started by only installing a 10 ohm 12 watt Mills wire wound non-inductive resistor across both speaker terminals (one resistor across each + and - terminal). I plan to add a 2 series + 2 parallel resistor network later. With this loading resistor setup the max volume on the knob didn't seem to change but the T50RPs sound incredible. I would have to say they sound better than when used with my Schiit Mjolnir. It's just a warm, wonderful sound. I was running late for an appointment but had trouble taking off the headphones to get out the door. The AKGs sound really good too but the sound quality seems comparable to the Mjolnir and Aune T1 headphone amps. The HE-500 did not like the tube amp with just the loading resistors. The tone was noticeably weak and hollow. Of the three headsets tried the T50RPs get the most out of this tube speaker amp.

 

I apologize for not giving a more detailed description of the sound quality but I just don't feel qualified to do so.

 

I love the Yaqin amp by the way. I replaced the Chinese preamp and phase-splitter tubes with Mullards but the original power tubes sound great. It's also quite a looker with beautiful chrome chassis to highlight the 8 tubes.

 


Edited by robrob - 11/22/13 at 3:01pm
post #1425 of 2717
Great looking amp.

Al D
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