[sdiy] [AH] Arp Solina with excessive chorus noise

[Oren Leavitt]

I have an early model from 1974 that does not have the chorus bypass 
switch on the right side. It is very quiet when idle.
The chorus circuits in this model use these obscure BBDs in 6 pin cans 
marked "ORB-33", the later ones use TCA350 BBDs.
Makes me wonder if the noise is an issue with the later design?

If Harry were here, there would surely be a tirade about BBDs H^)

On 1/31/16 2:14 PM, Terje Winther wrote:
> Use a noise-gate. That is more or less the only thing able to handle 
> this. You can do tons of service and adjustments and improvements, but 
> in the end you will still fell that it is noisy, because:
> a. the acceptable noisefloor was way different in the 1970s
> b. more or less all the components have drifted since the 1970s, and 
> you really do not want to swap them all out
> c. a chorus is usually noisy because of the technique involved
>
> So, yes: it is noisy with the chorus. I have one, and mine is noisy 
> too. Still sounds great.
>
>>>> I recently picked up a 70's Arp Solina String Ensemble. It has the 
>>>> button on the right cheek block to turn the chorus on/off and it is 
>>>> not the later version with LEDs.
>>>>
>>>> It's in pretty good condition, every function works and it sounds 
>>>> great, but there is, in my opinion, excessive noise and 'swooshing' 
>>>> when the chorus/modulation circuit is engaged.  It is dead silent 
>>>> with the chorus turned off.  Not a big deal when you are playing 
>>>> notes or chords, but enough to be annoying when it's idling.
>
>
> Terje Winther
> terje.winther at wintherstormer.no <mailto:terje.winther at wintherstormer.no>
> http://wintherstormer.no/
>
>
>
>
>
>
>
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