Eros with Zu/DL103 Mk.II Cartridge?

[gregoryahunter]

HI all

I just finished and LOVE my SEX kit.  Im interested in the Eros Phone Preamp.  My cartridge is a Zu/DL103 Mk.II which, according to Zu's website has "The nominal output voltage of the Zu/DL-10 is about 0.3mV. The nominal internal impedance per channel is about 45 ohms."  Is this a good match for the Eros or will I need a step up transformer?  Any suggestions for a good step up transformer for this setup if needed?

Thanks

Greg

[Paul Birkeland]

You'll want a step-up transformer for this situation.  A 1:10 will do the job nicely.  The Sowter 9570 would be my #1 choice.

Cinemag, Jensen, and Lundahl all make units that will also get the job done nicely.

[Chris65]

Sowter 9570   http://www.sowter.co.uk/specs/9570.htm

[jjvornov]

I'm using a Budgie step up transformer between the Zu cartridge and Eros with great results. It's a cinemag based unit, but a quick look at the Parks Audio website looks like it's no longer available there. Bob's Devices https://www.bobsdevices.com/Moving-Coil-Step-Up-Transformers/ offers a similar unit that's higher priced.

James

[gregoryahunter]

Thanks everyone for the input.

I could use some advice regarding how to incorporate the Sowter 9570 into the EROS.  Im a numbskull in regards to electronics - but I can follow directions OK - hence the fact that my SEX kit works!

From the link to the Sowter site: "NOTE The cartridge should be connected to the White and Yellow leads. The amplifier should be connected to the Pink and Mauve leads. The Black (ground) lead is normally connected to the signal ground of the amplifier. You may need to experiment with different ground connection points to minimize hum."

So I'd need two of these Sowter step up transformers, correct?

And could I Simply build a box and put RCA connectors on it? and then connect what exactly to the white and yellow leads and what exactly to the Pink and mauve leads? And somehow connect the black leads from both Sowter transformers to ground somewhere?

Any and all help for the village idiot (me) greeeeeatly appreciated.

[Paul Birkeland]

So I'd need two of these Sowter step up transformers, correct?

Yes, one for each channel.

And could I Simply build a box and put RCA connectors on it?

This is a good idea.  It will let you move the transformers around a bit to find a good, quiet spot.

and then connect what exactly to the white and yellow leads and what exactly to the Pink and mauve leads?

From the link to the Sowter site: "NOTE The cartridge should be connected to the White and Yellow leads. The amplifier should be connected to the Pink and Mauve leads.

By "amplifier", they mean the Eros.

The Black (ground) lead is normally connected to the signal ground of the amplifier. You may need to experiment with different ground connection points to minimize hum."
 

If you use a metal box, you can add a ground post to it, then connect this ground post to the ground post on the Eros.

[gregoryahunter]

Thanks for the reply.

I have uploaded a drawing to make sure I understand. 

Am I correct in assuming that the white wire from the Sowter SUT would go to the central pin on the rca connector coming from the table, and the yellow cable would go to the solder tab. 

And the Pink cable from the SUT would go to the center pin on the output RCA connector, and the mauve to the solder tab? 

And the same on the other SowTER SUT for the other channel?

And ground wires (black) from both sides could be connected to the metal case and further connected to the ground of the Eros?

Thanks again

[gregoryahunter]

attachment

[Paul Birkeland]

On Sowter's transformers, if he doesn't specify which end should be grounded, it's not important.  Your drawing is correct, but I would move the ground post to the input side (where your tonearm grounding wire may be coming in with the interconnects).

The wiring does need to be consistent between channels.

I would suggest ordering the transformers with the threaded grommet option from Sowter.  That way you can leave the nut a little loose and turn them to get them optimally quiet once you have them setup in your system.

[Doc B.]

Positioning relative to the Eros is important too. Give yourself enough shelf space to move the transformer box around relative to the Eros. Distance always helps, but rotating the box can make a big difference too.

[gregoryahunter]

Awesome - thanks so much.

Just a couple more questions:

1---- am looking at the Sowter site to order the SUT and they mention something about OCC wire option for about 14 pounds extra.  Sowter seems to be convinced that this "super ultra high purity" wire may be audibly better, but they hedge their bets with "but it cant be tested so who knows".

Any advice if spending another 20ish bucks per SUT is worth it or a total waste.

2----If I use a metal case to house the SUT - and I move it around to minimize hum/background noise - there isnt any significant current/juice running through this thing?  I have read with some trepidation the multiple warnings to not stick my fingers into the workings of a plugged in piece of gear.  But since this thing Im making is completely passive - the worst I could get would be the 0.3 mV that my cartridge puts out- correct?

[Doc B.]

They may indeed sound better with the more expensive wire. Have not compared so I can't offer any useful opinion, but I have heard other transformers sound better in a version with "better" wire.  And if you hate them, the fancier ones will be easier to sell.

You are correct that the step up box will not generate any voltage on its own that is worth worrying about touching.

[Paul Birkeland]

Yeah, the step-up box is an extremely safe project. 

[Chris65]

Here's an example of an SUT I built using Cinemag transformers & a Hammond project box. These have the threaded bushing mount as recommended. Plenty of other examples to be found on the web.