upgrade amp in mini-system

[chuck55]

Looking to drop in an amp3 in my Denon UD-m31 mini-system. The chip amp is miounted to the heat sink and is connected to the circuit board right next to the heat sink. There are about 20 wires connected to the circuit board so wondering if it's more than just an amp board.
The preamp must be on a chip as there is a digital volume display and no conventional motorized pot. Which is too bad as it should be pretty cheap to fix the preamp too.
The main problems with the Denon:
1) bad H/F distortion or crosstalk makes it impossible to use with metal driver speakers.
2) Lack of adequate P/S so music lacks dynamic range. You can see the stock x-former in the photo.

The other possible option is to use the "pre-amp" output rca jacks on the back. Just not much room inside to add a second amp board.

I tried to attach a photo but it is too big.

 

[sam9]

Which chip is in the Denon to start with?

 

[sam9]

Oh yes. . . . have you tried substituting different speakers? It's possible that the worlds best amp won't help the sound as long as you use the standard speakers.

 

[chuck55]

Hi Sam9,
I can't get a look at the chip without taking half the Denon apart. But I figure the AMP 3 should be better. I ran a Creek 4330R in comparison and the Creek had better truth of tonality, detail, and so much more bass (do to better P-S) it was surprising.
I ditched the original speakers and use Tang-Band 871s. Soon to be upgraded to Tang-Band 1320S. If that is not good enough I will probably go with the FR-125. So I think I've got the speakers worked out.
Interesting thing with the speakers is I heard a lot more distortion with the Denon speakers. I don't know if this is because they are more revealing or it's just x-over distortion. Also there is up to 20dB boost in the bass due to an x-over equalization circuit. I think this because I drove the mid/woofer full range and bypassed the x-over.

The aboslute worst part of the Denon is the CD section. Not only is it lacking power and dynamics, but also cohesive focus (JA said in his Stereophile measurements it had 12 bit resolution). So I use my Marantz CDR-500 a lot of the time. It would be nice to drop in a Nixon DACkit but the power supply also needs an upgrade.

I also e-mailed Jan at 41hz but have not gotton a response. Problem with most of these kits is packaging. By the time I'm done I've got a bunch of boxes all over the place and doesn't look real classy.

 

[sam9]

I heard a lot more distortion with the Denon speakers. I don't know if this is because they are more revealing or . . .

In my experience it's because most mini-system speakers are . . . . uh, well . . . there really isn't a polite word for them. I had an experience with a Teac mini-system. Looked like toy but added a pair of M&K series 5 speakers and it was a completely new system.

 

[homer09]

is it worth the upgrade? i mean there is nothing you really like about the denon, so why keep it? if the amp section is lacking, the ps is crap and the cd section too, upgrading all that you basically have a new system.

start from scratch is what i say. and fund it buy selling the denon.

 

[chuck55]

It's really not that bad. Tonally very good. Meaning instruments sound like themselves. Good balance across the spectrum other than the H-F brightness. Eliminate the brightness and add some good dynamic range and it would be great.
Basically I like the idea of dropping the AMP3 into the Denon just hards to figure out how to do it - for me anyhow.
I like the idea of a 1-box stereo. I could get a much better stereo with seperates, but would like to stay with 1-box. I don't see the mods being all that difficult for someone like Nelson Pass.