Denon DL-103 -- Was it a mistake?

Well, first, add mass to the arm. Second, the 640P was a bad match with the 103 in my system. The brightness at the top of the Denon's midrange not matching well with the upper midrange brightness of the 640P. But in a darker toned system, it may be heaven. You will know the answer to that one soon enough though. The 100 ohm load impedance is a little low for the 103, as well, matching the lower internal impedance of the 103R a bit better.

Well I guess I'll find out when the 640P arrives. I never heard anyone say that it was bright before, after reading several reviews. I wish I would have known that beforehand, because my system is definitely not dark. I'd say that it's fairly neutral as is. It may be possible to mod the 640P to change the loading on the MC section. I'm not afraid to use a soldering iron, I just need to know which caps/resistors to change.

I could also try moving the TT around, because it is fairly close to the speaker. I never noticed a feedback problem before, but that was with a higher output MM cart. Maybe it is more sensitive now with a low output MC.

My experience....

I currently own six DL 103 series carts ( 2 stock DL-103, 1 stock DL-103R, 1x Dl-103R SS retipped, 2x DL103 with wood body).

All I can say is that the arm needs at least 14-16 gms minimum effective mass in order to hear what the 103 series are really made of excluding the headshell weight. On the stock 103's currently installed in my system, I found the Orsonic AV101-S (16 gms) and Yamamoto (10.4 gms) to sound the best loaded at around 40 to 100 ohms in 26 dB SUT gain (1:20) with VTA a tad high (tail up a bit). As you can see, using the two headshells results in an effective mass in the range of 24-30 gms effective mass.

I tried unipivot arms in the 14 gms and less tonearm mass before and I was not pleased at the results even if I add weights on the headshell.

On the two wood body carts I have, I found that it sounds good even on the SME 3009 S2 Improved arm (9.5 Eff. Mass not including the original SME headshell which is about 6~7 gms)but really sound much better using a heavier headshell (Orsonic or Yamamoto).

So, in summary, try using an arm with a total effective mass of 23 gms. and above and I assure you from my experience, that you will hear a new sound on your DL103 compared to what you have now.

Yes, you need to get all of it broken in and settled before making any types of changes, so that you can have a baseline; you might just fall in love right off. I did not say that the Denon is bright, but that there is a brightness in the upper midrange/lower treble, which makes up for a lack of resolution in this area, this is matched by a bit of conceit in the midbass and low bass that makes the whole affair sound quite balanced, with good weight and snap. The Denon is far from being neutral, but in the right rig it will sing like few others.

Also do not forget the Denon arms! You can find these relatively inexpensive arms and if you put the 103 on it...you got it!