upgrade a dual turntable

[ebijma]

hello

I have a dual ka12a turntable receiver.
The turntable is the 1224.
It has a cristal cardrige.
I want to put in a better cardrige, thinking about a mm.
So i do need a phonoamp to amplify the signal for the receiver.
But..................
The ria correction is already done by the receiver. ( i think )
Cristal cardrige needs ria too. ( i think )
So i need an phonoamp that has no ria correction.
Any one have an idea on how the build a simple chip amp?
And what chip to use?

[sreten]

Crystal cartridges do not need RIAA EQ.

This is because output is dependant on stylus deflection not velocity.

However they do work in a fashion into a MM input, due to the
loading causing falling treble output, giving something ~ flat.

Fit a low compliance Audio Technica.

sreten.

[ebijma]

Thanks for your reply, Sreten.

What's a low compliance Audio Technica, Sreten?
I know that Audio Technica makes cardriges but what's low compliance?

Sreten, your saying Crystal Cardriges do not need RIAA correction.
So i do need an Phono pre amp with this correction.

Do you know a simple circuit?

[sreten]

Compliance is the stiffness of the cantilever, compliance units.

The Audio Technica AT95E (6.5cu) from mantra audio is one choice.
http://www.mantra-audio.co.uk/mantraonline.htm


A simple series feedback RIAA using a NE5332 dual op-amp will
do the job well, plently of circuits on the net, the complications
are basically the supply arrangements, single or dual rails, it
could be included in the receiver and use its voltage rails -
regulated or RC filtered if need be.

See here for for RIAA EQ, fig 3 is the simplest -
http://sound.westhost.com/project25.htm

sreten.

[PsykoK]

Hi,
I have an old Dual 1214 TT and I have made some improvement to it.
The first step was to remove the original cartridge and replacing it with a brand new AT95E (I buy it via ebay.de for 26€ with all fee).
The Audio Technica AT95E is working very nice. This is a very good cartridge for less money.
The second step is to build a new enclosure and after that I will maybe replace the old monoplane motor (it makes some noise) with new one.

Recently I build a RIAA amp for my Dual TT. This preamp is easy to build and it's nice copy from a Grado PH1:
http://alexkachler.free.fr/riaa/

The only change between my version and the original Grado version is the AOP. I can't find some NJM4556, so I replace it with a nice APO2604.
Some pics:










The total cost of the PH1 like is less than 90€ for the RIAA preamp and the PSU.

So good luck for your improvement!

Alex

[ebijma]

Thanks allot PSYKOK.
Very nice looking phono pre amp.

Have to look into the circuit.
But seams very nice and simple.

Greetings