Get Axel to re-tip it - the SP12 is the one to have.

Hi,

I can confirm this, my Beocenter 3500 has a re-tipped SP12 and it does sound fantastic. My rectifier also had two bad diodes! The SP14 is not as good. The treble thing: don't forget that most radio stations will have a tweaked frequency response to raise treble, typically for car use. I even find differences in sound quality with different transmitters for the same stations!

Ok, it seems the major problem is that the speed of the plate is too low instead of a worn-out pick up. I've tested the stroboscope sign: it isn't "stopping", and compared a track from a record with an mp3, and the record was notably slower, thus lower pitch.

The question is now how to set the right speed? The +/- signed knob does nothing just engage/release the drive mechanics, the belt is in ok condition.

Any help will be appreciated.

Problem solved... Accidentally I got a sony home theater receiver for testing and I hooked up it's phono input with my bc3500's turntable, and the difference was very-very notable. So I digged myself into the BC's phono preamp and found the way to make it better. I replaced the resitor 347, 385 to 33kOhm and capacitor 348, 384 to 2nF (2*1nF in parallel, but probably a single 2,2nF will do the job too) 

Hi,

That's weird.

I haven't modified the RIAA filter circuit in my BC3500 and the phono has plenty of treble.

I just followed

I was also amazed by the sony receiver, but it sounded just as it should instead of my BC3500. Also I had a BM3000-2 which sounded ok with a cheap TESLA turntable, but this BC doesn't impressed me with the same record, so probably the problem is unique to this specimen. I measured all parts in the phono preamp, but only found 3 resistors which were slightly out of specs (but they doesn't affected the equalization -in theory at least)

For the RIAA curve: I found that the real problem (in my case) is that there is too much bass coming from the BC (instead of lack of highs), and the mid area isn't flat enough, so this mod I did only flattens a bit more the mid area (200-5000Hz).

I did a computer simulation for the circuits, the reference was the REVOX A78's RIAA, and the theoretic RIAA curve.

Great job then! 🙂