preamp question

[flux01]

I'm designing a preamp with the following configuration:
MPC509A -> INA2134 -> BUF634 -> PGA2310 -> DRV134
I have two questions which are in regards to the input resistance and the connections between the ICs.
For the input resistance I was planning on putting 10K resistors in series with the inputs of the MPC509A. Is anything else needed? I've running the MPC509A off +/-15V rails so the variation in Ron is quite small.
As for the connections between the ICs, I've search diyaudio, googled schematics online and gone through datasheets, and I think I can just connect these just up. Is this right? I don't need any caps or resistors between them, do I?
Thanks for any help.
Cheers,
Dave

[w00t1985]

I'm also very interested in building a preamp to use with my future gainclones. I'd like it to be high quality, and definately worth the time and effort used to build it. Just curious on a few things...

What is the MPC509A for? I looked up the data sheet, but was a little lost...is that like a digitally controlled input selector?

What is the INA2134 used for?

What do you use for the PGA2310 controller? Do you need to have anything programmed to use it?

Also, is the purpose of the DRV134 to make balanced outputs from the preamp?

Thanks for the help, I'm still fairly new to most of this stuff, and don't quite know of all these different parts. I know op amps, and that's about it

[cwteoh]

Try this intergration...
OPA627 + BUF634 you will find SOMETHING.... I have not yet biuld one... I implemented to my friend this opamp who very impress with him OPA134AP before... After he build he preamp with the above, here is his reply...

a) OPA134 - more detail/refine than those common opamp but a bit "cold"
b) OPA604 - less detail than OPA134 (but still better than normal opamps)
but very warm and natural sounding.
c) OPA627 - this chip has very high resolution and very natural sounding (at
least few more levels higher than (a) and (b)). with this opamp, i can hear
clearly every word that comes out form the singer and the emotion too, while
very detail/clear movement from note to note on the instruments. Once you
listen to this opamp, it is not easy to switch back to option (a) and (b)
because you have known what info that you have lost with (a) and (b). This
is not a fair comparison because (c) cost about 5 times than (a) and (b) but
if cost is not a major issue, (c) will be the best choice.

The above comparison is done from (a) to (c), without testing the (b), i did
not realise (a) is so cold even others have mentioned it in other forums.
And, without listen to (c), i will not know (a) is not detail enough and (b)
is not natural enough.

No measurement data, no proven record, and just some finding after listening
to them.

While for the burn in time of 627, I am glad that I will get more good
things from this 627 even though I am already very happy with the "before
burn in" performance.

[Nuuk]

I'm designing a preamp with the following configuration:
MPC509A -> INA2134 -> BUF634 -> PGA2310 -> DRV134

Or why not take the KISS approach and build this!



More details here .

I guarantee that it won't sound any worse, and you'll save time and money!

[flux01]

OK, I'll do my best to clarify here.

Originally posted by w00t1985
What is the MPC509A for? I looked up the data sheet, but was a little lost...is that like a digitally controlled input selector?

What is the INA2134 used for?

What do you use for the PGA2310 controller? Do you need to have anything programmed to use it?

Also, is the purpose of the DRV134 to make balanced outputs from the preamp?

The MPC509A is a 4-channel differential mux. It will be used to select an input, and will be controlled by a PIC micro. The INA2134 converts the differential output of the mux to single-ended (as the PGA2310 works as a single-ended system). The PGA2310 will be controlled by the PIC also. And yes, the DRV134 creates balanced outputs and acts as a driver.

Originally posted by Nuuk
Or why not take the KISS approach and build this!

http://www.decdun.fsnet.co.uk/gc/ls.buffer.gif

More details here .

I guarantee that it won't sound any worse, and you'll save time and money!

I realize there are about a bazillion ways to implement a pre-amp, however I want to have it controlled via a remote control, I want to work with the PIC, and so I've chosen the components I've chosen and I'm going to stick with them. I know other opamps may be better, and relays are better than a digitally controlled mux, but I'm interested in getting this system to work.

So... anyone have any inputs on the input resistance question? I know how to do a good input network going into an opamp, but I don't know how to do it for the digital mux. Any thoughts would be welcome! Also any thoughts on how to properly connect the different ICs.

Thanks,
Dave

[psychosteve]

im not trying 2 hijack this thread but im looking for a mic. pre amp for anouncements through a p.a. sytem, what do you recomend for transistors and res values on the circuit u posted, if i run +12v -12v and the impedance of the mic is between 400 and 600 ohms?

[psychosteve]

p.s.
to clarify, the output of the pre amp is about 500 ohms, and the buffer is coz it distibutes to 8 active speakers. steve.. ..

[flux01]

Has anyone designed a preamp with an analog mux as the selection circuit? Any insight would be greatly appreciated.
Thanks,
Dave