Quote:

monago said:

Interesting....
 
So instead of immediately ordering the new caps for my amp, I decided to look toward my source for the issue before coming to any conclusions. I said the amp sounded "harsh" in my initial post, but in fact, my source was the culprit. There was etch and grain in the treble, and I simply assumed 'this must be what neutral sounds like,' when in fact the warmer sound before cap modification was covering my poor source output. After some tinkering, the 'harshness' has completely disappeared, and I'm now hearing the clearest, most transparent sound I've heard in my entire life. It's incredible...
 
To be clear, I do not believe in cables, or any other 'snake oil' solutions for changing sound.
 
Edit: That said, I'd still like the sound to be ever-so-slightly warmer. I'll probably end up throwing in quality input caps relatively soon.

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Or replace the opamp power caps with Chemicon KZE for some slight warmth plus a bit more bass impact.  I suggest replacing the two red WIMAs in between them with ERO MKP 1837 caps.  The improvement is wonderful.

Quote:

purrin said:

If you have a DMM (if you don't, just pick up something cheap from a Home Depot), check DC voltage at headphone outputs. Just in case your source is putting out any DC. I don't want your headphones dying.
 
As far as cables, since you are now fully armed with a soldering iron, you can make your own $400 headphone cables. Watch the heat though when you solder wire on headphone drivers otherwise you will melt the voice coils. Get a cheap Weller soldering station where you can adjust temperature.
 
This is awesome. You are now one of the few people on the planet who has actually had first-hand experience and knowledge of what caps do to sound quality.
 

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I made a point of checking the potential for DC output on my source before performing the mod. I've more or less read this entire thread, and several times you've mentioned the dangers of removing input caps because of said DC output. My source came up with .5mV, which ends up being 5mV with 10 gain. I believe that's an acceptable amount.
 
As for cables, I don't believe in them (changing the sound), so as long as I have cables thick enough to deliver appropriate current, I don't feel the need to change anything. Even for something that's just more rugged, the cable on my HD650's seem sufficient.
 
And yes, I was honestly quite skeptical about the mod really changing as much as you claimed. Audiophile terminology seems to be thrown around like a cheap suit; the degree of noticeable change in a new component being highly subjective, the audible improvements almost always end up being exaggerated, so you end up with false expectations that generally go unfulfilled. This means disappointment/disillusionment with everything audiophile related - or so has been my experience, anyway. I'm extremely skeptical when it comes to audible change, and I legitimately heard a VERY big shift in sound from rather 'warm' to completely neutral. You could say that I'm now a 'believer' when it comes to capacitors. Quite an impressive change.
 
Quote:

mad max said:

Or replace the opamp power caps with Chemicon KZE for some slight warmth plus a bit more bass impact.  I suggest replacing the two red WIMAs in between them with ERO MKP 1837 caps.  The improvement is wonderful.

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As for these caps, I have the Lovely Cube (this thread was bigger/more traffic. Thought I'd post here instead). Looking at the caps I pulled from the input, they seem to be the same as the opamp power caps. Both are rated at .022uF. The ones you linked me are .01uF. Would this be a problem?
 
Edit: Oh, and would you mind linking me the Chemicon KZE caps you mentioned, as well? =)

Ok, so apparently I unknowingly had my EQ setting all out of wack. I completely forgot about them, but because of the sound before removing my input caps, I had the upper frequencies jacked up to +3.5db... uck. After pulling them down to +0.6db, I now have precisely the sound I was looking for. It's unbelievable! More transparency, air, detail, etc. It seems counterintuitive, but I'm hearing more micro-detail with less treble.
 
Anyway, I think I'm finished with audiophile stuff for a very long time. The sound I'm hearing is quite close to what I would consider 'perfect'.
 
Thanks to everyone in the forums for being so helpful! And especially thanks to purrin for contributing so much to this thread! I attribute much of what I'm hearing right now to his insights and ideas.

 
Quote:

monago said:

 
I made a point of checking the potential for DC output on my source before performing the mod. I've more or less read this entire thread, and several times you've mentioned the dangers of removing input caps because of said DC output. My source came up with .5mV, which ends up being 5mV with 10 gain. I believe that's an acceptable amount.

As for these caps, I have the Lovely Cube (this thread was bigger/more traffic. Thought I'd post here instead). Looking at the caps I pulled from the input, they seem to be the same as the opamp power caps. Both are rated at .022uF. The ones you linked me are .01uF. Would this be a problem?
 
Edit: Oh, and would you mind linking me the Chemicon KZE caps you mentioned, as well? =)

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10mv is not dangerous, but it will negate most of the improvement you should get from removing the DC blocking caps.
 
Nah, the difference in value won't be an issue.  It's the "speed" cap.  You could connect two MKP caps at a time to make 0.2uF of capacitance and see how it affects the sound.  I haven't bothered trying out two caps at a time, but those Vishays are pretty bulky already.
 
I buy circuit components from Digikey or Mouser, but since you're in Canada, you should probably google for a seller there; otherwise, Digikey and Mouser can ship internationally, but shipping won't be as cheap as it is for me here in the US.
 
Edit:  How can I check to see if the electrolytic + bypass decoupling caps for the opamp connect to floating ground or signal ground?

Quote:

mad max said:

 

10mv is not dangerous, but it will negate most of the improvement you should get from removing the DC blocking caps.
 
Nah, the difference in value won't be an issue.  It's the "speed" cap.  You could connect two MKP caps at a time to make 0.2uF of capacitance and see how it affects the sound.  I haven't bothered trying out two caps at a time, but those Vishays are pretty bulky already.
 
I buy circuit components from Digikey or Mouser, but since you're in Canada, you should probably google for a seller there; otherwise, Digikey and Mouser can ship internationally, but shipping won't be as cheap as it is for me here in the US.
 
Edit:  How can I check to see if the electrolytic + bypass decoupling caps for the opamp connect to floating ground or signal ground?

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I just rechecked my outputs. Source DC Offset is 0mV, as is amplifier headphone out. These were triple checked, so I'm quite certain of this. I'm not sure how I got my last readings, but I was quite tired at the time which can mean I did any number of things wrong. I'll check again tomorrow to be sure these are accurate, but from what I can tell, DC Offset shouldn't be affecting anything.
 
And cool, I'll probably pick up a few of those caps up sometime, then. Not sure when, though. I don't have any desire to mod my amp now. I've fixed my EQ settings, so everything sounds incredible; I can't imagine wanting a different sound... although I have a feeling that will change in several months =P.
 
Anyway, thanks for the recommendations Mad Max. Great help!

Your DC reading can be different when you check the amp after barely turning it on versus checking the amp after it has had warm-up time.
 
Vishay MKP 1837 are awesome and well worth it.  I will be avoiding WIMA's MKP for a long time for sure; too rounded, muddy, and artificial by comparison.

". . . the incredibly fast, detailed and transparent M-stage"
 
Anyone else think this is a bit off? 
 
I would say meduim paced, detailed, and somewhat colored. 
 
idk. 

Quote:

satellite_6 said:

". . . the incredibly fast, detailed and transparent M-stage"
 
Anyone else think this is a bit off? 
 
I would say meduim paced, detailed, and somewhat colored. 
 
idk. 

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With the input caps removed and using an opamp like the OPA2111AM, this amp becomes quite fast, detailed, transparent, etc; the biggest change being the removal of the input caps. It's an extremely dramatic shift in sound, as I mention above. But as an unmodified amplifier, yes, it's generally a bit slow and warm.
 

 
Quote:

satellite_6 said:

". . . the incredibly fast, detailed and transparent M-stage"
 
Anyone else think this is a bit off? 
 
I would say meduim paced, detailed, and somewhat colored. 
 
idk. 

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It's all relative. Ripping out the caps results in significant gains in speed, transparency, and treble extension. Jump up to another league of amp, and it's a whole other story. But in terms of those three aspects (and bass control), I'd put the modified version (meaning op-amp swap and shunting input caps) of this amp against those costing up to $700.

Hmmm, is removing the input caps easy to do? Where they at? (at the back I suppose)
 
I am very skeptical about switching opamps as NwAvGuy explained that it may actually degrade the sound depending on the on the design of the amp, but I may try the above. 

NwAvGuy? 
Funny guy.

Pfffft, engineers, what do they know. 

 
Quote:

satellite_6 said:

Hmmm, is removing the input caps easy to do? Where they at? (at the back I suppose)

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Remove the big blue cap (C22, C23) and the little red? (C21, C24) caps. Replace with wire.
 

 
Quote:

satellite_6 said:

 
I am very skeptical about switching opamps as NwAvGuy explained that it may actually degrade the sound depending on the on the design of the amp, but I may try the above. 

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Yes, NwAvGuy is the supreme authority of head-amp design. After almost 2000 posts, many of which were related to op-amp rolling, we have finally realized that he was right; and that we should have never touched the stock op-amp in the first place. All bow to NwAvGuy's vast knowledge and greatness!

Quote:

purrin said:

Yes, NwAvGuy is the supreme authority of head-amp design. After almost 2000 posts, many of which were related to op-amp rolling, we have finally realized that he was right; and that we should have never touched the stock op-amp in the first place. All bow to NwAvGuy's vast knowledge and greatness!

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How many of you are experts on amp design? Are you? I don't know much but the following have me worried: 
 
"As for the M-Stage, I'm not familiar with the internals of that amp. But most op amps in normal plastic packages (DIP, SOIC, etc.) are already a bit thermally challenged to drive headphones directly. Forcing them into Class-A will make them run much hotter and that could create other problems and/or seriously shorten their life. If an overheated op fails, it very likely will take the headphones with it as it will dump the full DC power supply voltage to the headphones."
 
-NwAvGuy, no link
 
"If you don’t put an input cap in your amp, you avoid these issues entirely. There’s no phase shift, no bass roll off, and no decrease in sonic clarity. Just realize that you risk damaging your headphones if you do this. A source that has a low DC offset today may develop a problem tomorrow."
 
Warren Young, whoever that is - first google result "input caps"
http://tangentsoft.net/audio/input-cap.html
 
Sorry but the more I read the more it seems like modding is a terrible idea - and now I seem like a troll - but I was genuinely interested.
Is there a significant risk here?
 
 

Yes, there is risk to removing the cap. I have made that perfectly clear many times and asked people to check their DC offset. There are quite a few amps on the market that are also direct coupled and will pass on DC. Most if not all CMOYs are like this.
 
The op-amp does not drive headphones directly in this amp. It drives a diamond buffer output stage. If you read some of the early posts regarding the class A mod, you would have realized there was quite a lot of discussion on thermal limits and how much current / what size resistor should be used for safe operation. If it's risky, why would the retailer coolfungadget, who would also be responsible for warranty service, incorporate this mod as an extra package for this amp.
 
And why is NwAvGuy now the supreme authority on everything now? And why is he commenting on an amp which he knows nothing about the internals about? And why are you parroting this nonsense? Are you one of this evil minions or groupies?