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Re: Edirol R-4

Subject: Re: Edirol R-4
From: "Rich Peet" <>
Date: Fri, 25 Mar 2005 17:13:36 -0000
For those wishing to trade time for money and have building experience.
The INA163 chip is under $3.00 and provides up to 60db gain.
Of course if you want flashy led's you would have to add to the basic
circuit given, but that is a single chip now too.

Using two 9 volt batteries would give a simple circuit if you do not
wish to play with P48 or wish to just build a no adjustment +60db
preamp for use with minidisc.

http://focus.ti.com/lit/ds/symlink/ina163.pdf

Rich

--- In  Lang Elliott <> wrote:
> Fo everyone interested in the Edirol R-4 issue, here is an e-mail I just
> received from Doug Oade, the engineer extraordinaire at Oade Brothers:
>
>
>
> HI!
> The stock unit sounds like it uses the same chips used in in the R1 and
> similar caps resulting in performance not much better than a stock UA5,
> M Audio DUO, etc. Low level signals are noisy and carry too much
> distortion, probably from low grade caps used to block the P48. We feel
> that a mod will be needed to bring it to the level a professional
> recordist that hopes to release the recordings would demand. If used
> simply to document the presence of birds or insects, or with an external
> HQ preamp (like the Grace V2), it is fine stock. A minimum of replacing
> the op amps and capacitors is needed to satisfy the professional market
> that expects HQ signal quality via the mic inputs for soft sounds. We
> hoped they would use the INA163, used by Grace and Apogee but they did
> not take it to that level of signal quality.
> Our MOD FR-2 is significantly more quiet than the stock unit and does
> use state of the art chips and parts to achieve the highest possible
> fidelity with that circuit topology.  We feel a preamp built on
> transconductance technology, like the Apogee or Grace design is best
> suited to very high gain applications like nature recording as current
> feedback devices do not suffer from the same limitations as voltage
> feedback designs do. An INA163 based mic preamp ( like the Grace V3,
> modified by Grace for higher gain)  used with high output mics like
> Schoeps or AKG C480, etc. produces excellent results. If you need the
> best for the lowest possible cost, our Pro MOD FR-2 is a great choice
> and cost 1600.00 for the FR-2 plus the MOD.
> I hope this helps.....>Doug
>
>
>
>
>
>
> [Non-text portions of this message have been removed]





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