Preamplifier, worth modifying? Pics attached

[gil1]

Just got a Pyle PYP-X1 preamp for next to nothing, solid build, looks good but the sound could be a lot better.

Dont really want to spend a lot of cash squeezing juice out of a rock but what do you think guys, is it worth changing a few caps, upping the power supply caps, etc? Im open for suggestions other than using it as a door stop.

Gil

[Tekko]

Replace those useless opamps with some OPA2134's or similar.

[gil1]

Originally Posted by Tekko

Replace those useless opamps with some OPA2134's or similar.

Would that be a pin by pin replacement or do I need to change anything else?

[Tekko]

Yes most dual opamps are pin compatible.

[gil1]

Originally Posted by Tekko

Yes most dual opamps are pin compatible.

The ones in the pre are BA4558. And that would be a direct replacement with nothing to alter?

[Tekko]

As far as i know yes.

[Nrik]

Yes I agree with Tekko. OPA2134's are good and cheap, and are pin compatible with your 4558's. I have done this in many amps and CD-players and the sound improvement is enormous!
It should work fine without extra components, but if you want to be super-safe, you could add a small cap of 100pF between pin 1 and 2, another 100pF between pin 6 and 7, and a film-cap (MKT, MKP or similar) of 10nF between pin 4 and 8 (power supply pins), on each of the OPA2134.

Another modification that improves sound quality quite a bunch is to parallel all those electrolytic capcacitors with film-caps of 10% of the value (100nF - 1uF). This goes for both those that are in the power supply and those that carries the actual audio-signal. The easiest is to solder these caps to the pins of the original caps on the underside of the board.

Have fun, and on't forget to reply with images and your listening impresions

[gil1]

Originally Posted by Nrik

Yes I agree with Tekko. OPA2134's are good and cheap, and are pin compatible with your 4558's. I have done this in many amps and CD-players and the sound improvement is enormous!
It should work fine without extra components, but if you want to be super-safe, you could add a small cap of 100pF between pin 1 and 2, another 100pF between pin 6 and 7, and a film-cap (MKT, MKP or similar) of 10nF between pin 4 and 8 (power supply pins), on each of the OPA2134.

Another modification that improves sound quality quite a bunch is to parallel all those electrolytic capcacitors with film-caps of 10% of the value (100nF - 1uF). This goes for both those that are in the power supply and those that carries the actual audio-signal. The easiest is to solder these caps to the pins of the original caps on the underside of the board.

Have fun, and on't forget to reply with images and your listening impresions

So by-pass the electrolytics rather than changing them?

BTW thanks to all for the input

[Nrik]

Originally Posted by gil1

So by-pass the electrolytics rather than changing them?

Bypass them for the sake of sound quality.
Replace them if they are malfunctioning.

...some might say you should replace them anyway, but in my opinion it would be a bit too much. Your call.

[jaycee]

I dont know if I'd immediately recommend OPA2134, i'd want to see what kind of local decoupling there is. 100nF on pins 4 and 8 to ground close to the chip is pretty much mandatory for OPA2134. NE5532 would be a good start.