Balanced Cables and Sugden Masterclass

Why do we hi-fi buffs keep experementing?

I bought a Chord 64 in early December and have concluded that it stays

As it happens, I also use a Chord Phono Stage which I have used in balanced mode (turntable is AC Orbe + SME V + Lyra Dorian) feeding into a Sugden Masterclass Pre and a pair of Masterclass Monos. Result? :JPS:

So my problem? Well my former DAC had no balanced outputs, and I auditioned the DAC 64 in the same way. However, tonight I decided to use my balanced interconect (KIMBER KCAG) to link my DAC 64 to the pre amp. Result is jaw droppingly good. I am amazed at the improvement.

However, the Sugden Masterclass has only one balance input - and I can't sacrifice the vinyl front end. So what would you advise? Swap the cable every time I move from Vinyl to CD ? Go back to the phonos on the DAC 64? Would swapping the balanced cable all the time damage the outputs in the Chord Phono Stage and the DAC 64?

Help, please

 

Help - somebody!

 

Ask Sugden if they can convert one of your unbalanced inputs to balanced.

 

Would that be a big job?

 

possible alternative would be to find a clever technician, to make you some sort of adapter. It would consist of two xlr inputs, and only one xlr output, which would be linked by a pair of balanced cables to the XLR Pre In.

could be cheaper than going inside the preamp, but I cannot judge if it would be difficult technically.
it would have to be done with reasonable technical level, or else it would degrade sound.
Some companies make A, B, X boxes, to test impact of equipment change. If they exist with xlr input/output, you could use those.

 

A simple swiching unit with high grade switches or even relays could be built at a small cost. It should be easy to fit the four in coming xlr's and two out going sockets. This could be silver wired the two pairs of in coming signals being switched with a two pairs of double throw double pole relays for the plus minus signal. the grounds will all be common anyway. This could be powered by battery or a small 6v supply tucked away in the box or a nasty wall wart thingy. The extra set of connecting silver connductor xlrs could be built for a relatively small sum. off the top of my head £50 should cover the lot if you don't want an expensive case .

 

I've just taken a quick peek at the Sugden website. They say "virtual transformer coupling" is available for the balanced in- and outputs. I take that to mean that the internal signal path of the pre is not balanced. It seems what you are hearing is an effect of the DAC64's output stage, and possibly a cable or plug effect.

Ask Zanash or someone to make you a cable to connect the balanced out of your dac to the RCA in on your pre; only when that sounds less good than the same cable on a balanced input would I worry about the rest.

 

This is excellent advice.

 

I like my hi-fi but I'm no technophile so bear with me.

What you are stating is that the use of balanced cables is neither here or there within the Sugden because there is no balanced signal path within the pre? Therefore I'm hearing the benefit of the DAC64 output stage which could be retained without having an additional set of balanced inputs on the Sugden (not keen on that as it happens).

Is the above a fair summary? If yes, would Zanash care to comment and indicate willingness to run up a cable for me?

Much obliged for the advice

 

It really depends on just how Sugden have implemented that 'virtual transformer coupling'. On balance, I think the best way to deal with this must be to call Sugden and ask them.

Tell them about your dilemma and ask what would be the best way to deal with it, an adapter like Zanash proposes or converting an unbalanced input to balanced.

Sugden have a reputation for giving honest advice.

 

I had a quick search for stuff on the preamp.....

and found this quote

Those ‘virtual transformer circuits’ for the balanced input and output stages employ extremely fast hybrid op-amps with exceptionally low noise characteristics. The whole signal is carried in each half of the circuit and these are added together, due care ensuring that both halves of the circuit are balanced so that the load is shared equally. Matched resistors guarantee the absolute balance.


Now this seems to say that tranformers are best but we didn't use them as they cost too much. So instead we took some stock opamps and built a little curcuit and used matching resistors rather than different ones.

I would sugest that the input from the balacnced input needs to go through a number of stages to converted back to a line level signal for the pre to do its magic on it and then converted back for the balanced outputs. I'm of the keep things simple school and so I'd rather not mess with the incoming signal too much.

That said the alternative would be to use a pair of jensen transformers to convert the balanced signal from the 64 to line level and input through a normal set of connections.

http://www.jensen-transformers.com/as/as089.pdf

That would leave the balanced for the TT.

 

Contacted Sugden today and unfortunatley they would not recommend a second balanced input.

From my understanding of the conversation the path of the balanced input to the balanced output within the Sugden is balanced throughout - does this equate with some info gathered by ZeroGain members?

I was also told that the benefits of using the balanced input for the CD would be immediatley apparent (and description of benefits were exactly what I am hearing ) so it's not my imagination!

The advice of Sugden was to use the balanced input for the CD (my Chord DAC 64) and use the RCA input for my turntable. This is no good for me since I'm using a Chrod Phono Stage in balanced mode (having modified my SME V cable for the purpose).

So I'm back to square 1 . Any further ideas ?

 

Why not ask Zanash, ever so nicely, to make you up a two input/one output XLR router, as he outlined above?

 

I will do that and ask his opinion whether this is an acceptable compromise.