I finally placed an order for a ZROCK earlier this week, and I'm greatly looking forward to putting it in my system.  

My main intention is to place it into my vinyl chain.  My turntable has an MC cart, and is currently connected to an Ortofon ST80 MC transformer.  This is then currently connected to the MM phono input on my amplifier.  

I am not certain where to place the ZROCK, and would appreciate some advice.  My plan is to insert the ZROCK after the Ortofon SUT.  Is that the best choice?  

If so, with the ZROCK in place would I then connect it to the MM amplifier input (as the Ortofon SUT currently is), or to an AUX input?

I don't know whether the Ortofon has a higher output voltage than the voltage produced by the MC cart.  All I know (from the Ortofon website) is that the ST80 has 27 dB of gain.  

The ZROCK manual implies that its output voltage is four times higher than the input voltage.  But I don't know whether this would be enough for the ZROCK to drive the amp through an AUX input.  

Any thoughts?  

Of course I can experiment with it when it arrives, but it would save some time if anyone has advice on this.  

Many thanks.

Yes, you're correct: at the moment I'm using an integrated amp.  However in the next few weeks I'll be switching over to a separate pre / power amp combination (vintage Sansui C2301L + B2301L).  

The ZROCK manual simply says 'Install the Z-ROCK between your source and preamp/amplifier'.  I've been exchanging messages with Lon about this.  To summarise briefly: the signal from the SUT needs to go into a phono stage next in the chain, for the RIAA correction to be applied.  Also, my understanding is that the ZROCK is designed to work with line level signals.  

So I THINK my options are as follows:

1) Connect the SUT to the MM phono input on my new separate preamp.  Then connect the preamp to the ZROCK and the ZROCK to the power amp.  The advantage of this would be that I could apply the EQ of the ZROCK on both my vinyl source, and my digital music files / DAC source.

2) Buy a separate outboard phono stage, and connect the SUT to that.  Then connect the new phono stage to the line level input of the new preamp.  Two disadvantages to this: firstly, I'll have to spend money on the new phono stage.  Secondly, the ZROCK EQ will only work on my vinyl source, not my DAC source.  

Further comments are welcome.  In the meantime I'll drop Steve and email.  

Yes, though there is one slightly fly in the ointment.  The Sansui C2301 / B2301 pre / power amp combination I'll be using has fully balanced architecture.  So I was aiming to connect the C2301 to the B2301 using XLR cables.

Putting the ZROCK between the C2301 and B2301 will remove that as an option.  

I am not particularly convinced of the case for the balanced approach when it comes to home audio amplification, but the designers at Sansui made a conscious choice to design these two amps in this way.  So I don't know what I'd be losing by not having a balanced connection, in terms of sound quality.  

Both Sansui amps are being overhauled (e.g. re-capped where appropriate) by a chap who knows Sansui inside out.  I'll ask him whether he thinks I'll be losing much by not directly linking the C2301 and B2301 via their XLR outputs / inputs.

I've had a reply from Steve on this, which I'll post here in case others need the information in the future.  

It is correct that the ZROCK cannot be inserted in the vinyl chain after the SUT and before the phono stage of the preamp.  The ZROCK must be used with line level signals.

The solution is to connect the SUT to the MM phono input on my Sansui separate preamp.  Then connect the preamp to the ZROCK and the ZROCK to the power amp.

Separately the Sansui tech has confirmed that I am unlikely to see much (if any) benefit using the balanced connections on the C2301 / B2301 in a home audio setting.  

So this has worked out very well from my perspective.  It means that I'll be able to apply the EQ of the ZROCK on both my vinyl source, and my digital music files / DAC source.