[Iron_Dreamer]

Quote:

Originally posted by Zemo Keep in mind I need dual channel opamps....the LT1122 looks promising, but I'd need a browndog adapter....got a dual equivalent?

I think the LT1126 is the dual version of the 1122, but I'm not completely sure, their website doesn't exactly make it clear.

 

[Edwood]

That's what the adapter is for. You use two single channel OPamps. So you need them in pairs.

-Ed

 

[Edwood]

You'd still need an adapter if you want to use a DIP socket.

-Ed

 

[Glassman]

Quote:

Originally posted by Iron_Dreamer I think the LT1126 is the dual version of the 1122, but I'm not completely sure, their website doesn't exactly make it clear.

no, it isn't dual LT1122.. completely different chip..

I'm happy to hear you enjoy Class A bias

another opamps to roll should be AD817 (or AD826 dual) and AD825

Zemo, your MIA has AK4524/8 DAC, which seems to be little on the dark side, on the contrary AD1852 used on RME is slightly brighter, so I think you should look for less darker sounding chip.. with two OPA627AU on BrownDog you can't go wrong.. especially biased into Class A..

definitely try LT1122 also.. it sells almost free

 

[Edwood]

Yeah, compared to the 627, the LT1122 is butt cheap!

Can't wait to hear what the 627 in Class A sounds!

BTW, how much hotter are the OPamps running now in comparison? Anything to worry about?

 

[Iron_Dreamer]

Quote:

Originally posted by Edwood Yeah, compared to the 627, the LT1122 is butt cheap! Can't wait to hear what the 627 in Class A sounds! BTW, how much hotter are the OPamps running now in comparison? Anything to worry about?

They feel slightly warm, less than the PSU of my Gilmore, nothing too bad. I don't think it shoudl be a problem.

 

[Edwood]

OK, now that we are pretty close to maxing out the OPamp mod, what's next?

What else can be modded?

Power regulation somehow?

-Ed

 

[Glassman]

yes definitely.. I need really detailed pictures of the card to tell you what to do with power supplies.. the opamps are powered with +/-12V right?

 

[Edwood]

I'm hoping my better digicam holds long enough to take good pics.

-Ed

 

[Iron_Dreamer]

One thing to note about the class-A bias is that the resistors add ~1/2" to the height of the opamp adapter assembly, making it impossible to use another PCI card in the slot below an RME card so equipped, much like an AGP video card

 

[Edwood]

What? so that means I won't be able to fit four RME PAD's in one computer?

-Ed

 

[Edwood]

Oh yeah, remind me to bring my DMM so I an measure the continuity of the ground in your Gilmore. I'm curious to see if it's really grounded properly or not.


(My Grace is. My Little More Power is not.)
-Ed

 

[Glassman]

those two caps under the DAC are unnecessary.. they are in the way of OUTL+ and OUTL-, there should be another pair of simillar caps in the way of OUTR+ and OUTR-, but I can't see them from the pictures.. those should be removed and bridged.. also, if the output circuitry is more or less taken from AD1852 datasheet, it is three pole Bessel filter.. I would change it to just two pole filter, becouse you can then remove one cap from the output and also replace 200R output resistor with ten times smaller one, so that you significantly lower the output impedance.. this could also help things..

 

[Iron_Dreamer]

Quote:

Originally posted by Glassman those two caps under the DAC are unnecessary.. they are in the way of OUTL+ and OUTL-, there should be another pair of simillar caps in the way of OUTR+ and OUTR-, but I can't see them from the pictures.. those should be removed and bridged.. also, if the output circuitry is more or less taken from AD1852 datasheet, it is three pole Bessel filter.. I would change it to just two pole filter, becouse you can then remove one cap from the output and also replace 200R output resistor with ten times smaller one, so that you significantly lower the output impedance.. this could also help things..

Could you please highlight the specific parts you are talking about removing/replacing?

 

[Glassman]

I can't unless I can see the traces on pcb.. I was judging from the AD1852 datasheet.. the caps I was talking about are the ones that were different on some Steinberg cards and that you tried replacing for Black Gates I think..