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Speaker amps for headphones - Page 26

post #376 of 2754
Quote:
Originally Posted by preproman View Post

 

potterma,

 

I think you hit the nail on the head with that one.  Although I do agree with Gary with the LCD-3 / Emo combo.  Sounds to muddy to me.  With a heavier load and the a-100 is pushed it tends to sound much better.  It even sounds pretty good with my Mad Dogs.  

I just ordered resistors to update my resistor box.  I want to try driving the Emo harder to see if it makes a difference with the HP-1's.

post #377 of 2754

Folks:

 

Has anybody determined if there is a "best" resistor for adapting speaker amps for headphones?  I saw some suggestions earlier in this thread, but wondered if anybody had done any experimenting like what Potterma is thinking of doing.  Jan Plummer didn't go out looking for special resistors to go in the box he made me (I think he said he used iron core resistors), but said that if I wanted a particular resistor used, he would build whatever I wanted.  I'm wondering in particular if I can reduce the noise level of the Millenia even further with a better magic box...

post #378 of 2754

The closest thing to research I've seen on the topic is the pdf linked here.

 

link to pdf:  http://www.duelundaudio.com/downloads/Resistorsvol5no3HIFICriticHiRes.pdf

 

I don't have much personal experience, so can't be of much help.  My first attempt was to use a 10 ohm thick metal film power resistor in parallel.  Prime objective was to provide a known load to the speaker amp and a convenient spot to make 'scope measurements.  What I found with the HE-6 and the Yamaha HP-1 is that it substantially collapsed the sound stage.  I didn't do much listening beyond that to try to figure out what else had been affected.

 

Not sure what an "iron core" resistor would be...  The Duelund resistors in the above pdf are carbon cast.  Expensive.  Worth it?  I have no idea.

 

I'm rolling the dice with some Vishay non-inductive wirewound.  More than an order of magnitude cheaper than the Duelunds.  We'll see if I can detect any difference.  I could send you my box and you can listen and give your impressions, too, if interested.  Resistors should be here later this week.  Wednesday, if I'm lucky.

post #379 of 2754

I've been researching resistors for the past hour or so, and those Duelands are pricey.  Have you tried Mills?  They are also about 1/10th the price of the Duelands. 

 

I'm interested because I'm still getting noise from the Millenia, more with the AC adapter, but some with the batteries as well.  I'm guessing the problem is in the magic box, and the extra power of the 24v adapter (which ups the amp's output) is just exacerbating the problem.  It isn't audible all the time, but when it is, it is irritating.  I'm probably going to hook the box to the Emo to see if I can duplicate the problem there.  If I can, I'm definitely going to send the resistor box back to TBI and get a better one built.  Even using Dueland resistors, the cost would be worth it if it really improves the clarity or at least eliminates the noise.  Of course I'd rather pay less, but I'm willing to do what it takes to fix this problem, otherwise I'm gonna have to send the Millenia back too, which would be a shame, because it is an outstanding amp. 

post #380 of 2754

It would be nice if somebody will do this, compare the different resistors. In John Curl's interview

(http://www.parasound.com/pdfs/JCinterview.pdf), he stated that there are sonic differences between resistors with magnetic and non-magnetics leads. Others are tolerance and temperature.

post #381 of 2754
I haven't tried the Mills. I'll look at placing an order tonight.

I'll take a close look and see if I can determine the lead type on the Vishays. Thanks for the John Curl reminder!
Edited by potterma - 7/9/13 at 6:25am
post #382 of 2754
Quote:
Originally Posted by Gary in MD View Post

 

 

I'm interested because I'm still getting noise from the Millenia, more with the AC adapter, but some with the batteries as well.  I'm guessing the problem is in the magic box, and the extra power of the 24v adapter (which ups the amp's output) is just exacerbating the problem.  It isn't audible all the time, but when it is, it is irritating.  I'm probably going to hook the box to the Emo to see if I can duplicate the problem there.  If I can, I'm definitely going to send the resistor box back to TBI and get a better one built.  Even using Dueland resistors, the cost would be worth it if it really improves the clarity or at least eliminates the noise.  Of course I'd rather pay less, but I'm willing to do what it takes to fix this problem, otherwise I'm gonna have to send the Millenia back too, which would be a shame, because it is an outstanding amp. 

 

Hey man,

just curious,

can you describe the noise to us?

thx

 

I'm probably off topic here, but when I plug headphones into the headphone jack on my Bryston 2B-LP power amp, I can hear a very faint ssshhhh,  This tells me the input transistors in that power amp were not selected for low noise!frown.gif

post #383 of 2754

Chris:

 

The noise is like static or very low-level buzz that follows the sound, garbling it.  It isn't a hiss or sshshsh.  In many cases it is very subtle, you really have to listen for it, but in others it is right there in front of you.  It also seems to be intermittent, making it even more irritating.  I can usually isolate problems if they are consistent, but this one isn't always there.  But when it is, it is really aggravating.

 

As I said in earlier posts, it is much less prominent with the batteries powering the amp, to the point where I had thought it was gone, but it isn't.

 

It is possible that it is in the recordings, but I only hear it with the Millenia, and I actually re-ripped some discs, thinking the problem was in the transfer.  It might still be, though I even polished the discs to get rid of scratches and try to improve the transfer.  I might try other ripping software to see if that fixes anything. 

 

One idea I had was to send some of you copies of the worst offenders, to see if you hear the noise.  If so, then I know it isn't related to the Millenia.  If anybody is interested, PM me.. 

 

By the way, I have finished my listening to the Adcom, and just need the time to write things up.  Then I'll do the formal analysis and write-up of the Millenia.  By now you probably know where this is headed: at least until the Cyclops shows up (still don't know when that will be), there isn't anything here that can come close to the sound quality of the Millenia when it isn't making that damned noise.

post #384 of 2754

One other thing I need to mention, the left negative output jack on the magic box does not tightly grip the banana jack on the speaker taps, and sometimes the banana jack slides out a small amount.  I was thinking that this could also be part of the problem, but how likely is that?

 

Let me know what you think,

 

Gary

post #385 of 2754
Quote:
Originally Posted by Gary in MD View Post

One other thing I need to mention, the left negative output jack on the magic box does not tightly grip the banana jack on the speaker taps, and sometimes the banana jack slides out a small amount.  I was thinking that this could also be part of the problem, but how likely is that?

 

Let me know what you think,

 

Gary

Loose connections.... ugh!  The very reason I detest banana plugs.  Can you open the springs on the plugs a bit?  The type that tighten into the jack are a good solution.  Short of that, spade lugs!

post #386 of 2754

Now that I'm not changing amps every few hours, I'll try going to spades... but that will have to wait until tonite!

post #387 of 2754

Gary, I am really enjoying your write-ups! I find them well thought out and written in terms understandable to me. Thank you for taking the time to put these up on the site!

post #388 of 2754
Quote:
Originally Posted by Gary in MD View Post

Chris:

 

The noise is like static or very low-level buzz that follows the sound, garbling it.  It isn't a hiss or sshshsh.  In many cases it is very subtle, you really have to listen for it, but in others it is right there in front of you.  It also seems to be intermittent, making it even more irritating.  I can usually isolate problems if they are consistent, but this one isn't always there.  But when it is, it is really aggravating.

 

As I said in earlier posts, it is much less prominent with the batteries powering the amp, to the point where I had thought it was gone, but it isn't.

 

It is possible that it is in the recordings, but I only hear it with the Millenia, and I actually re-ripped some discs, thinking the problem was in the transfer.  It might still be, though I even polished the discs to get rid of scratches and try to improve the transfer.  I might try other ripping software to see if that fixes anything. 

 

One idea I had was to send some of you copies of the worst offenders, to see if you hear the noise.  If so, then I know it isn't related to the Millenia.  If anybody is interested, PM me.. 

 

By the way, I have finished my listening to the Adcom, and just need the time to write things up.  Then I'll do the formal analysis and write-up of the Millenia.  By now you probably know where this is headed: at least until the Cyclops shows up (still don't know when that will be), there isn't anything here that can come close to the sound quality of the Millenia when it isn't making that damned noise.

 

Hi Gary, I think I'll fire off a PM, I wouldn't mind a listen to these offending files! Hopefully I have the software/hardware to listen to these files?! Noise sure can be hard to describe...................Question: How does this noise sound? Answer: really, really annoying! LOL! Here's one thing I try to do to give myself some peace of mind when I borrow equipment: I clean all the contacts to ensure I'm not listening thru some sludge somebody left on a connector! Chris
post #389 of 2754

What is this Magic Box?

 

Thanks

 

Jack

post #390 of 2754
Quote:
Originally Posted by jackiedh View Post

What is this Magic Box?

 

Thanks

 

Jack

 

I just searched for posts in this thread where Gary in MD used the word magic.

 

Mike

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