Tweakers' Asylum: Re: Building a DIY battery phono stage by Thorsten

Hi,

> 1. For the Analog Addict 'El Cheapo' phono stage, where does one
> find a 10H 30ohm DCR inductor?

www.steinmusic.de - that is where I get mine from. BTW, if you don't need the MC Stepup stage you don't need the inductor.

> 2. Which battery chargers are people using

If you do a search, I discussed my own take on that a while back, these chargers have a minimum sonic impact if charging when playing, most chargers do offer that.

> I found a source for Yuasa NP 2-12 batteries, but would like reqs
> on chargers for parallel charging.

I (obviously) used one charger circuit per battery, nothing parallel.

> 3. What's the difference between the OPA637AP and OPA637BP?

Non that I'd consider very relevant.

> I looked at the TI/BB site and there is little mentioned. Are
> these different grades of the same chip?

Yes.

> 5. What are the maximum MM input voltages for clipping?

Depends upon a lot of factors. The "El Cheapo" has a gain of around 120 @ 1KHz and will clip when fed from 12V batteries at around 6V RMS. Thus up to 50mV RMS can be applied. The active RIAA does not waste any headroom like all passive EQ designs do, thus high gain for level parity with CD and excellent overload behaviour can be BOTH achieved.

Ciao T