Opamps and Modding thread.

I know ,I'm working on replacing the speakers (this month)and getting a receiver
I have a pair of sennheiser ht558 HP and a Antlion 4 mic
but I was wondering which ones to replace and the locations of them
thanks

 

Good choice on replacing the speakers and using a receiver. It will open up a new world for ya.

OK, if you look at the main card, you have 3 opamps. 2 of those are matched, they are your current to voltage converters (I/V) They always need to be matched in this case. Those 2 opamps feed into the LPF/Buffer opamp. You can change any of these opamps, make sure the I/V are the same. The opamps and sockets are keyed to indicate proper orientation when inserting. The opamps usually have a dot, this shows pin 1. the sockets have a notch in the one end. The first pin, counter clockwise is pin 1. You put the opamp pin 1 in towards the socket pin 1 and that's all there is to it.
Be carful of the pins they are easily bent, try and pull the opamp straight out if you can.

If you are still unsure, wait and I will see if I can post some pics to better illustrate the procedure.

Note, when using the headphone output, only the I/V opamps are used. The LPF/buffer opamp is switched out and the headphone amp chip is swapped in.

 

ok,I understand,but why did the kit only give me 1"muse" and 2 "NA" opamps
is the muse opamps for the headphone socket ?
thanks

 

Beats me....those are the ones they sent.

There is no "headphone socket"....the line outs and headphone outs use the same opamps.
Except, the headphones only use the 2 matched LPF/buffer opamps and the head amp chip (not swappable)

 

ok,I see
so that means that the 2 matching NA opamps and the 1 muse opamp
go in there respective sockets
thanks

 

Well, you can use either opamp in the LPF/buffer socket, but that only works during speaker output.

 

To note, above I said the 2 matched LPF/Buffers....I meant to say the 2 matched I/V opamps.

Quickly, DAC's are current output devices. So they need a conversion section, this is where the two I/V opamps come in.
Some DAC's do not require these chips, only because they are already built in.
This setup is superior to the built in option.

 

thank you

 

I opened the main card cover and all 3 opamps are muse 8920 already
so that eliminates the "Muse" situation
but I see what you were describing,thank you

 

Sure, once it is explained, it is pretty easy to see what is what.

You see the DAC chip, there are the two I/V right after it. This circuit is a differential input current to voltage conversion section.
they feed into the LPF/Buffer chip. This amp filters giving us just the audio band and sets the levels for proper line level output.

The daughter card also uses the same system. The one issue, in my opinion is the sub and center use the same dual channel opamp. I build adapters that split this into two single channel chips. This way you can use a separate opamps for the center signal and for the subwoofer signal.
This also allows you to tune the center to match the fronts better and use a good opamp for the sub output.

Most of the modern cards are sporting this type of opamp system because they are using higher end DAC's. The ZXR takes it a step further and splits the buffer chip for the front channel into 2 single channel chips.

Two single channel chips are preferred over a dual channel chip. Keeps better channel separation, lower distortion..etc.

 

Thank u ROBSCIX for your help in this matter, it helped me a lot, I changed my sound blaster zxr opamps as u did in your review and I very impressed with the results, but now I want to go further and I want to add dual mono modules for each I/V section to clean up the signals as u mentioned in your review but taking into consideration Im a newbie on this I not sure which are the I/V sections for this card, kindly could u please guide me on this to add dual modules in my card, there is a seller in ebay of this modules ready with adapter but I not sure how many should I buy or where to place them in the card


your help is much appreciated

 

The JRC2114D's are your I/V converters. You might run into an issue with spacing putting in dual mono opamp adapters. I have some adapters and that card in the reference collection so I will see what I can whip up and help you....stay tuned.

 

thank u so much, I'll be waiting for it

 

Hi ROBSCIX, any update on this? :cry:

 

ROBSCIX?????? **Crickets**

 

with tears in my eyes please rob

 

The Gustard H10 that I waiting on from massdrop have op-amp sockets, so it look like I might be coming back to the whole op-amp swapping game that i swore I never do again.

The sad thing is I don't have my notes any more of op-amps i rolled when i originally mess with op-amps.So I only remember a few good models. I know the Gustard H10 has two Dual op-amp sockets one for Left and Right RCA I think and then two Single op-amp sockets for Left and Right when Balanced connections of used, or I may had forgot the setup as might be different then I remember.

 

Any one compared the LME49990 to AD79BRZ's planning on replacing the ne5532's using Two dual to single adapters. As I found out my gustard H10 uses ne5532 for the two I/V's and 2 single OPA134 for the buffers.

 

what about the muses02 on the i/v converters on the sound blaster zxr?

 

ok guys this is my new mod as promised, I cant believe how good it sounds now, powerful bass but not as bloated as before Im really happy with my card now, double drum bass from metal music are so defined, cymbals incredible
rob was right, signals are so clear with this setup