An multi-part Ono clone

[GUILHERME]

Hi,

Bellow are a few pics of my implementation of the Ono phono preamplifier. I've decided to put the MC gain stage right bellow the tonearm and the PSU on a separate box, so it's a three part implementation. I've been listening to it for a couple of days now, and I like it a lot; cartridge is DL-304 loaded with 100 Ohms.

J.Guilherme

The MC gain stage that sits bellow the arm:


Same, but fitted and finished:


The circuits that will go into the main box (reg+riaa x2+mute):


PSU closed:


PSU open:


Trial run at main rack:

[Ren]

GUILHERME --

Is the separate MC gain stage based on experience with the typical practice of putting MM & MC together in one chassis? I.E. Do you think this gives better noise performance in practice?

Are you using balanced or unbalanced outputs?

Any more details about your successful build?

Thanks!

Ren

[h_a]

I'm not sure that I fully understand your question, but if you mean that putting the MC-headamp close to the cartridge - i.e. into the turntable - is noise wise better than in a box a bit away, then the answer is: not really.

Avoiding 1 m of cabling does not bring real benefit, especially in the case of MC-cartridges which are not susceptible to cable capacitance.

On the other hand so close to the turntable you can have problems with the magnetic field of the turntable motor, it can couple into the MC-headamp, increasing noise.

Have fun, Hannes

[GUILHERME]

I didn't make the experiment of putting everything inside the same box and compare both options for a given schematic, so I really can't say if this design works better. However, when I compare what I have now to the one-box I had before, there's a world of diference. Putting the volume of the amp at full, I could hear mobile interference, hum, ocasional ticks, and that phono didn't even had the same high gain as the Ono. On this setup, when the riaa stages are inside shielded boxes, I hear nada.

I think that the chances of the MC gain stage picking up hum from the motor sitting on the other side of the plinth are much less than picking hum from near by transformers sitting on other electronics on the rack. In fact, in that regard I think that this stage, being the most sensitive, is in the best possible place.

Yes, an MC has less inductance than an MM, so it will be less influenced by the capacitance of the cable.


I'm using unbalanced outputs (in fact, I didn't even implemented the 'balanced' part of the Ono).


J.Guilherme

[h_a]

Glad to hear yours is working well!!

Have fun, Hannes