New to WD

[LesleyEA]

Well hello everybody I understand the form is to introduce myself here first before asking for help. I have just become a very grateful owner of a Pre4 having been lucky enough to win it in the recent Hi-Fi World competition. I've just been installing it in my system where it's replacing an ancient but very loved McCormack TLD-1and feeds a McCormack 125 power amp.

The Pre4 was pre-built by World Audio and I was surprised to find that there are no +/-, left/right indications for connections to the rear panel and the manual that came with the amp is also silent on this matter. There are also 2 sets of outputs, one being recessed and I'm wondering the significance of this are they different tappings for loudspeaker impedance? Again no info in manual.
There is also a chassis earth on both preamp and PSU but no advice as to if this is optional or essential.
I have connected up and all sounds good with right & +ve on bottom and connected earths but would be delighted if someone could advise if this is correct and the reasoning for no markings.
Any help would be very gratefully received.
Many thanks, Lesley

[BOONDI]

Welcome to the forum Lesley.

First question.... The inputs are not colour coded or marked left and right, nor marked +/-.
Some people say that left is top and right is lower. Others the opposite. The best way to sort out is with a test CD or LP. Play the track with left ad right audio channels. If the channels are wrong swap leads and you will know which is which. Failing that, simply connect one side of your source to either top or bottom and see which side has music playing through it. As long as you stick to using the same with all the inputs then you should have no problems. A small red dot on the white insulation will give you a reminder once you sort it out.
Maybee someone who has one will chime in and be able to better answer this one....

The recessed outputs are for balanced outputs. If your amp has balanced inputs you can use these for better signal transfer and higher interference rejection. It also means you can drive much longer signal cables from the pre to power amps. Some people use very long cables because they have the amps sat as close to the speakers as possible so as to get very short speaker cables, and preserve the signal/music.
If you are connecting your pre to "professional" audio equipment such as a mixer or recorder then you will probably be better off using these as they are about 6db or so louder.

With regards to the earth post, if you have some residual hum from say a phono stage, the post will hopefully ground it out. I have a pre3 but don't need mine. It's really a suck it and see option. Some swear by them and others are not fussed either way....

Congrats on the win btw...

HTH....

[bob orbell]

Just to add to Derik's post, all the phono output and input sockets will have a black ring and red ring, black is left and red is right channel, centre pin + outer -, the two small three pin sockets are not marked but as Derik has explained. Bob

[Richard]

Welcome Lesley,

Yes, Red/right/+ is the lower line of inputs. Strange how they're not marked or coloured, perhaps the original design work was done using coloured sockets.

Circling round the white centres of those sockets with a red sharpie pen may help.

I would expect the output sockets also to be that way around but plug and play the inputs and see if L/R is correct when playing a test record or known piece of music.

Or, drop Matthew an email, sales@world-designs.co.uk

[LesleyEA]

Thanks very much for the help. I also emailed Mathew and he asked me to phone in the week. So will get it sorted.

[bikerhifinut]

If its working to your satisfaction then all fine.
If like me you find its got way too much gain for real world Power amps, and my homebrew EL34 job is deliberately designed to have a 1V sensitivity for full output meaning I do need a bit of gain on most normal sources, then I've had a play with my Pre4 based preamp and theres a tweak you can do that allows you to remove the potentiometer attenuator between stages.
It also means you don't need large value and therefore expensive interstage coupling capacitors to preserve the LF response.
I've postted a thread to this mod elsewhere.
John C may well have something to say, i had a good chat with him at the tonbridge audiojumble yesterday and this was mentioned.

Andy