This weekend I will mostly be making.....

A phono preamp. Im using a simple schematic thats on diyaudio, got all the bits to make everything except the actual psu. Slight problem, I dont actually have a TT but I do know people who are willing to be victims er, I mean enthusiasts. If it all works and sounds good I'll make a high-spec version with decent parts. Should keep me out fo trouble for a few hours!

 

Good work, your wallet will thank you

 

Keep us informed, I was just about to buy a seccond hand TT when I sold the nu-vista, the quad doesn't have a phono stage so didn't bother. If one could be had for a few ££'s I might still buy it, I just can't afford much after splashing out on the II40's.

 

Actually a phono preamp might be trickier than it sounds, for a simple project. It has a lot of gain and will therefore be very fussy about board layout and power supply. Every '0v/earth reference' must have it's own wire or track - all joining at one place on the board and only to there.
This called star earthing and is just what you need in this appplication, different for other types of systems such as vhf. The earth connection to the psu must also meet at this point. You need a star earth for each channel. Twist the cartridge input wires together from the back of the phono socket to the board to reject hum...good luck

 

Thanks for the advice. Ive got two schematics to work of, one is a simple dual op-amp design and the other uses single op-amps. Ive just got the second one and the designer has been kind enough to draw a suitable layout on his software. The design uses one earthing rail straight down the centre, all components use this rail and like you say meets the psu earth at one point.

I'll have a go, if it doesnt read right I'll just recycle the parts for something else, the psu will always come in handy if nothing else. At this stage Ive bought el cheapo components to het it going. I'll keep you informed and post some pics.

 

Well, the phono made its maiden voyage last night and would you adam and eve it it sounded pretty dam fine. Ive got very little hum indeed, in fact I only get a hum when the dials gets past 2 o'clock which is way too loud for most people. The signs are very promising indeed, more to come.

 

now then fella - whilst your efforts are certainly to be applauded (last time i picked up a soldering iron i burnt my hand ) i feel you and your soldering iron are getting too well aquainted .............i fear it could be a slippery slope - you'll be listening to different grades of solder before you know it

 

The silver solder fumes is highly addictive! Im afraid Im way down the slope, too far gone, no hope, I admit it Im a hi-fi diy annorak.

 

Of course Ive still got the slight problem of not actually having a TT! I cant keep going round to my mates everytime I adjust something, Im going to have a go el cheapo and see what I can find!

 

phono pre-amp build prior to owning a TT???

in Chorley i guess they call that 'reverse engineering'

enjoy your weekend!

 

Yes, its typical of us chorley folk! There is abit of method in my madness, I could have a bought a TT and not have been able to use it, which would have drove me mad and as I got itchy fingers for making something I choose this