[sdiy] spring reverb.......

[harrybissell]

Memory serves you well... some reverb springs are fairly high impedance
on the drive side and would work well from an op-amp. Those in the National
book are not...

That National audio amp is not too easy to apply in real life... their bridge
mode
apps tend to oscillate ultrasonically if the power-up sequence is not JUST
right...

otoh they sell National chips so....

H^) harry

phillip m gallo wrote:

> Daryl,
>
> The old national databook depicted a bridge drive of reverb springs using
> (if memory serves) an LM1877 (couple of watt speaker amp).  The spring is a
> reactive load not typical of op-amp load characteristics especially TLO's.
> The pre-amp end was there microphone amp at (again if memory serve about 40
> dB.
>
> regards,
> p
>
> -----Original Message-----
> From: owner-synth-diy at dropmix.xs4all.nl
> [mailto:owner-synth-diy at dropmix.xs4all.nl]On Behalf Of daryl groetsch
> Sent: Wednesday, November 13, 2002 1:52 PM
> To: synth-diy at dropmix.xs4all.nl
> Subject: Re: [sdiy] spring reverb.......
>
> Thanks everyone for the great tips. I tried some
> different op-amps and temporarily used pots for the
> feedback resistors. If I can get it loud enough, then
> it's distorted. And when it's not distorted, it's very
> quiet! (when adjusting the feedback on the input
> and/or recovery circuit). Spring reverb is more tricky
> than i expected! I think i'll study this one some
> more:
> http://www.accutronicsreverb.com/drive1.pdf
>
> Thanks again,
> Daryl
>
> =====
> http://www.darylgroetsch.com
>
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