Re: [Harp-L] Kinder Anti-Feedback+ modification

[Garry <harp@xxxxxxxxxxx>]

BluzeHarp@xxxxxxx wrote:
> I'm going to install a power input jack and am looking for some  advice.  
> Is it ok to power both the 9v inputs in a simple parallel  circuit from a 
> single clean 9v source?  Or, does it require  seperate discreet 9v power 
> supplies due to the internal  configuration?  Anything else I need to be aware of?
if you find a good solution to this, please share it with the list.
this is my major problem with this device, and a big impediment
for me in using it.  i did try using a single source power supply
(visual sound's 1-spot).  but it didn't work, generated large
amounts of heat, and when i asked john kinder about it, he said
i was lucky i hadn't fried my afb.  others have suggested using
multiple radio shack units, but i never found anything there
that seemed right.

in case it helps, here's what john had to tell me.  it is doubtless
good information, but i'm pretty useless when it comes to things electrical.
if you can decipher it and come up with a workable solution, that'd be
really great.

> I'm sorry to hear you are having problems in trying to adapt an external
> power supply for your AFB+ device.  There is a special reason why the 
AFB+
> does not feature an external power supply connector.  The AFB+ 
requires a
> ripple free bi-polar power supply (+/- 9V DC) as its operation relies on
> "DC" coupled circuits.  This is not the usual type found in outboard
> supplies of today, consequently it does not have an adapter for an 
external
> supply.  
...
> I noticed
> he had adapted "two" small (white) Radio Shack 9V power supplies 
featuring
> battery snaps to mate with the existing battery snaps in the AFB+.
> According to my tests, the adapters provided proper power to the AFB+ 
with
> no artifacts being introduced.  He had "successfully" emulated a true 
+/-
> bi-polar power supply by using two independent adapters - very 
resourceful!
> If you do the same thing, you should experience the same results with 
your
> AFB+.  Please note that if you are using a "single polarity" 9V DC 
adapter
> featuring two battery snaps to mate with the two battery snaps in 
your AFB+,
> the circuit arrangement within the AFB+ will provide, via its 
internal PCB
> runs, close to a zero Ohm path load, effectively shorting out this power
> supply.  CAUTION! The "one-spot" 9V adapter features a high enough 
current
> capability to possibly overheat the PCB runs in your AFB+, causing 
permanent
> damage to the board.

he later wrote:

> Here is a link to a 9V adapter that specifies that "The end 
termination is
> suitable for all 9V battery snap type connections."  Of course you 
will need
> two of them for your AFB+.
>
>http://www.samash.com/webapp/wcs/stores/servlet/product_PR9009%20AC%20Adapter%20for%20Pocket%20Rockit%20Series_-1_10052_10002_-49961555_cmCategorySA-10001

but that device doesn't have the right kind of connector at the end.

--
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but we make a life from what we give.
- Kathy Moser