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Deep End DIY - My first speaker project

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What I love about modern valve amplifier builds is the possibility and benefits of mixing old and new technologies.  Lately, I've been sneaking an hour here and there to advance the electronics projects and have managed a few small milestones.  Have a look at the photo below...

 

1702757005_LCRFilter.jpg.48fb22151eefe5daf4c4cec8699d457d.jpg

 

That is the RIAA correction filter for one channel of my upcoming LCR phonostage.  Two handsome Slagle inductors on mumetal cores, some Jupiter copper foil caps and some custom cut TX2575 Z-foil resistors that should make a frequency response flat line out of the very wobbly riaa cut of the records.  It all sits on a 4mm thick aluminium plate that in turn sits inside an off-the-shelf EMI/RFI box which in turn will sit inside a 4mm thick steel sarcophagus in an effort to maintain a very low noise floor in the circuit.  It sits between a pentode first stage and triode second stage.

 

So, above is a nice example of the old-school purists method of sacrificing resources and real-estate with rats-nest wiring.

 

So the tubes have to be supplied 6.3vdc and I had alook through my pcb box to find a challenging build using paralleled LT3042 ultralow noise LDO's.  These things are tiny...0.5mm pitch MSOP.  I've never soldered them before so decided to order the parts and give the little psu a go.  See below, it worked...

 

606144485_DCPSU.jpg.9b2205bcec93e0cda6fb2edb737a62e7.jpg   

 

That green pcb has two 6.3V 1A power supplies including all rectifier diodes, filter caps and heat sinking (later two items under the board).  I hand-soldered the little bugger and it took a couple of hours but it worked first time!  Those big (haha) yellow 1205 caps make the LT3042 look tiny.  What is not shown is that little green pcb is going to be connected to two relatively huge EI filament transformers.

 

Anyway, that is my rather extreme example of modern and vintage electronics used in the same component, a RIAA phonocorrector.  Can't wait to get it finished.

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