[RebellionElite]

Hey guys, been quite the off and on reader for Headfi whenever my interest drifted back towards headphones. Listen to a lot of Music on my PC and currently have an X-Fi Forte and Sennheiser HD598 I was wondering if changing out the OPAMP had any affect on the tonal quality of the headphone amplifier section of the sound card?
 
I read a post by Robscix in another thread that said that it changing out the OPAMP on the card only affected the Front Line Out on the 15 pin break out cable. Is this true? Otherwise I really don't understand the point of changing it out if you half decent headphones that need to be driven.
 
Anyone shed some light on this? Thank you!

 

[JRG1990]

It will impact the sound quality in a negative way if you use the wrong op-amp, if you don't know the properties of the circuit and what requirements it has for a op-amp using professional measuring and testing equipment your just gonna end up degrading the sound quality or if you do choose a suitable op-amp it will sound no different from the stock op-amp, op-amps aren't eq's or sound enchances there normally used as buffers or for voltage gain. You'd be wasting time and money messing about with the op-amp either affecting the sound quality in a negative way or gaining no real improvement at all.

 

[LeonvB]

From what I read on the Forte is that it still uses the opamp (which is logical), but the headphone out also utilises buffers. As changing opamps is a supported feature (Auzentech offers suitable opamps), I'd say swapping the opamp will definately change some of the sound signature of the headphone circuit.
Of course it's always a question if you will notice the difference, and what you think of it: it's not always an improvement.

 

[JRG1990]

A properly fuctioning op-amp adds and takes nothing away from the sound you don't even know it's there, if you switch out the op-amp and hear the difference then you are using the wrong op-amp and doing it wrong.
op-amps have loads of different properties each op-amp is optimized for different things input bias values, configurations, gains, feedback circuits, load impedances, quiescent currents, speeds/bandwidths, compensation values, operating voltages , unity gain , common mode rejection ratio , power supply rejection ratio. you can't just ignore all of these and hot swap them.
Maybe Auzentech has designed a cicuit where some these properties don't matter, or it's clever marketing trying to make there product appeal to more people as for some reason everyone likes swapping op-amps.

 

[Willakan]

Opamp swapping takes place due to the bizarre belief that the swapper knows better than the engineer, fed by another marginally less bizarre (but still BS) belief that if non-audiophile-magic-certified-opamps have been used, it is a cost-cutting measure and they will be audibly inferior. This is not helped by various popular companies making crap up to sell their "fully discrete" doorstops.
 
That said, the Auzentech was designed with the knowledge that a large chunk of their target market hold both beliefs, thus will probably not get too upset with different opamps.

 

[LeonvB]

Not too upset? They're selling them, ready to plug into the board... Compatibility matrix here: http://www.auzentech.com/site/products/opamp_intro.php
And hot swapping? You guys are incredible... Just turn the power off. ROFL
 
More serious now: while I do agree with some of the statements both of you make, I totally disagree with both of you on the technical part.
1. Auzentech makes the card, with a socket. This is to done specificly to allow op-amp swapping.
2. Auzentech gives you the matrix of compatible op-amps. Op-amps are fairly universal pieces of equipment, and some of them are easily interchangable.
3. Opamps add nothing? Do you even know what an opamp is? By definition an opamp modifies the input signal into the output, as it's a non-ideal AMPLIFIER. Being non-ideal means all introduce distortion. This will create small differences in the output.
 
Where I do agree with both of you on is the desirability of op-amp swapping: one can go look for the type of distortion you like best, but IMO the best way to spend your money is on a good DAC you really like. Then add a headphone amp you like. The Auzentech opamp prices are simply too high, and the possible benefit is too small. Your money is likely better spent elsewhere in the chain.

 

[JRG1990]

Hot swapping basically means swapping in and out, nothing to do with the temperature of anything.
 
Normally just because the op-amp fits in the socket doesn't mean it's compatable but as I said before Auzentech may have designed the circuit in such a way that it's not to reliant on the properties of the op-amps but if thats the case the op-amps they list as compatable should all sound the same so the differences relie purely on placebo.
Or there trying to appeal to a bigger market and don't care your using the wrong op-amps they won't harm the circuit but it will harm the sound quality and you may get negative effects such as ultrasonic artifacts that you may mistake for more detail.
 
While they do add disortion it's so low it's miles away from audiable 0.00003% and simlar figures i've seen on the datasheets theres no possible way you could hear disortion that low, if you miss use the op-amp and put it in an unsuitable circuit then you might be able to get the disortion so high its audiable.

 

[Head Injury]

Opamp rolling creates a strange dilemma. On one hand, if the circuit is designed specifically for opamp rolling, the differences should be far smaller than everyone claims. On the other, if opamp rolling does make a difference, then it's either making a difference for the worst or the manufacturer is ripping you off. All the options are rather worrying.

 

[Cotton]

 
Quote:

Hey guys, been quite the off and on reader for Headfi whenever my interest drifted back towards headphones. Listen to a lot of Music on my PC and currently have an X-Fi Forte and Sennheiser HD598 I was wondering if changing out the OPAMP had any affect on the tonal quality of the headphone amplifier section of the sound card?
 
I read a post by Robscix in another thread that said that it changing out the OPAMP on the card only affected the Front Line Out on the 15 pin break out cable. Is this true? Otherwise I really don't understand the point of changing it out if you half decent headphones that need to be driven.
 
Anyone shed some light on this? Thank you!

 
 
That is correct. The single LME amp is associated Analog I/O for your 5.1, ect. The headphone out's amplifier is an integrated circuit consisting of a smaller JRC amp as shown here;
 
http://www.auzentech.com/site/images/hthdtechnote/HTHDTechnote08209_html_m5fb9ecf1.jpg

 

[LeonvB]

Quote:

Hot swapping basically means swapping in and out, nothing to do with the temperature of anything.

Hot swapping does refer to the state of the device. It means you're swapping things while they are running. Google it or see: http://en.wikipedia.org/wiki/Hot_swapping
Obviously this is not required for the equipment at hand. You likely meant to say cold plugging or simply swapping.

NJM4580's distortion is 0.0005% actually, what you are referring to is the level of the LME49720 which is a possible replacement for it, and indeed more than 10 times better. And yes, you actually can hear that difference. Given the type and position of the 4580 opamp however I would strongly advice against replacing it. One could kill the card if the (de)soldering is not done right.

 

[Head Injury]

Quote:

Hot swapping does refer to the state of the device. It means you're swapping things while they are running. Google it or see: http://en.wikipedia.org/wiki/Hot_swapping
Obviously this is not required for the equipment at hand. You likely meant to say cold plugging or simply swapping.

NJM4580's distortion is 0.0005% actually, what you are referring to is the level of the LME49720 which is a possible replacement for it, and indeed more than 10 times better. And yes, you actually can hear that difference. Given the type and position of the 4580 opamp however I would strongly advice against replacing it. One could kill the card if the (de)soldering is not done right.

You can hear the difference between 0.0005% THD and 0.00003% THD? That's pretty revolutionary, you need to donate your ears to science.
 
Or maybe you're hearing increased distortion and coloration from the replacement chip because it's not optimal for the circuit, and it has nothing to do with the rated specs because the rated specs are for when the chip's used properly.

 

[LeonvB]

Quote:

You can hear the difference between 0.0005% THD and 0.00003% THD? That's pretty revolutionary, you need to donate your ears to science.

That's not so hard. It's a function of the buffer that's usually behind the op-amp. Problem isn't the THD of the op-amp, you don't listen to that but to the amplified version of it. 
The 4580 isn't a new chip, it's hardly state-of-the-art. If you want to try: your STX card has the better LM4562, order the DIP version of the 4580 and see how it sounds. It's a 0.80$ chip.
 

 

[Willakan]

 
Quote:

 And yes, you actually can hear that difference. 

BS. 
As for Auzentech selling opamp kits...they clearly know their target audience. Good business I suppose.

 

[JRG1990]

That's not so hard. It's a function of the buffer that's usually behind the op-amp. Problem isn't the THD of the op-amp, you don't listen to that but to the amplified version of it. 
The 4580 isn't a new chip, it's hardly state-of-the-art. If you want to try: your STX card has the better LM4562, order the DIP version of the 4580 and see how it sounds. It's a 0.80$ chip.

If you was to measure the intire thd of the whole sound card including op-amps from its low level line outs you'd find it measures in the 0.00*% range even the cheapy behringer uca202 does,this level of thd is just as inaudiable as the op-amps thd your worrying about the inaudiable and comparing the inaudiable against the inaudiable.
The thd has to get to 1% or around that to become audiable any properly fuctioning op-amp is miles and miles away from that kind of thd.

BS. 
As for Auzentech selling opamp kits...they clearly know their target audience. Good business I suppose.

Yep there marketing department know what there doing theres a 250 page thread here on op-amp rolling ,I've never read such rubbish and can't belive not 1 person even botherd to look up some facts about op-amps and how they work and why they sound different, just nearly 250 pages of subjective rubbish what a waste of the internet and bandwidth.

 

[leeperry]

 

Originally Posted by LeonvB /img/forum/go_quote.gif
 
your STX card has the better LM4562, order the DIP version of the 4580 and see how it sounds. It's a 0.80$ chip.
 

This whole thread is a troll bait, try to resist replying like I do

 
Besides I'll take 4580 over 4562 anytime of the day. I'm now unsubscribing from this thread.