Deluxe Memory Man... Swap out all 4558's?

[AC30Dirty]

hey guys, has anbody that owns a Deluxe Memory Man swapped out all the 4558 IC's for the TL072's? I did the one mod that aron suggested, but was wondering what would happen if i changed all of them? Whats the effect (for better or worse?)

[aron]

Check the archives. Someone already did it and claimed increased tone. I didn't bother with mine.... it sounds goooooood as is!

[LyleCaldwell]

If you mean me, I didn't say "increased tone."  I said "same tone, less noise".  The biggest improvement was putting a 1M pot in place of the 100K input resistor.

[Ben N]

It seems to me that there is a pretty significant difference in that IIRC the DMM has that input buffer in line all the time, whereas the DEM is an MXR-type bypass--leaving the effect input connected to the in jack, but switching the output jack between the effect output and the input.  That being the case, it is trivial to make the DEM true bypass (one of my two DEMs actually came from the factory with a Carling DPDT, utilizing only one half of the switch), in which case the input impedance is not very important.  FWIW, I switched the 4558 for a 5532, and I THINK I dedected a slight decrease in noise.  OTOH, the Memory Man switching is all post-input buffer, so switching to a jfet input should make a real difference.
JM2C,OC
Ben

[billings]

Changed out U1 for a TL072 today as per Aron's recommendation.  I didn't notice any decrease in noise, but I wasn't really looking for one, either.  The sound coming into the effect is a lot more clear, though.  I'm definitely going to leave it in.

For whatever reason I confused remarks here with remarks made in the archives.  So I guess this is stuff suggested in a thread somewhere else.

I also tried messing with caps around the feedback knob.  I started out with a 0.1uF across lugs 1 and 3, but then switched over to 0.4 uF with a A50K pot in series and started playing around with where to put them.  Putting this from wiper or third lugl to ground wasn't exciting at all.  It sucked.  Putting it across wiper and lug 3, however, was pretty interesting - although not even slightly subtle, which is what I think the intended effect was.  It's not unlike having a second feedback knob that skews towards higher frequencies.  I may drill another hole and see how useful it ends up being.

[alteredsounds]

I'd be very gratefull if someone could let me know what the transformer is meant to be putting out on the DMM.  I have 2, one has a transformer with 2 15v taps, the other has 2 28v taps!  Which is correct?  (If Either!)