[sdiy] Buzzing reverb

[Steve Begin]

Forgive me for asking, but how would you measure these impedances?  if i 
have the spring tank unplugged and i measure across the rca connector i get 
200 ohms on both input and output.  Does this mean anything?
-steve


----- Original Message ----- 
From: "Bob Weigel" <sounddoctorin at imt.net>
To: <synth-diy at dropmix.xs4all.nl>
Sent: Friday, April 15, 2005 9:59 PM
Subject: Re: [sdiy] Buzzing reverb


>
> Yeah that's what I tried to say..not sure if my mail got through. Reverb 
> cans OFTEN have problems with coil connections to leads (they fail in 
> mexico to use strip-x or equiv to pull the enamel off the wires it 
> appears..and they just solder and say a prayer.)  check again the 
> impedences to the can. Input depending on can should be between almost 
> nothing and a couple hundred ohms.  Output 20 to maybe 800. Most common 
> ones I see in that kind of thing measure a DC impedence of 57 ohms on the 
> in and 200 or thereabouts on the out.  If no connect on output you'll be 
> amplifying an antenna. -Bob
> harrybissell wrote:
>
>>oooh... my bad
>>
>>I missed a clue.  If the Parametric EQ works without hum, but he reverb
>>DOES hum... its is very likely NOT a cap in the power supply !!!  Broken
>>wire, or EMI.  Or it could be a bad connection at, or insdie the reverb
>>tank itself. They usually use RCA connectors, famous for having corrosion
>>etc...
>>
>>H^) harry
>>
>>jays at aracnet.com wrote:
>>
>>
>>>You haven't moved it next to something that has a lot of EMI have you?
>>>
>>>Reverbs are great for picking up AC hum from computer monitors and other 
>>>units power supplies.
>>>
>>>Like Harry said, either bad caps or bad ground would be my guess after 
>>>EMI. Usually linear power supplies aren't that bad to deal with.
>>>
>>>Jay S.
>>>
>>>Steve Begin wrote:
>>>
>>>
>>>>I have an Intersound PRV-1 Spring Reverb / Parametric EQ, and when the 
>>>>reve=
>>>>rb section is switched on, there's a really loud buzzing sound added to 
>>>>the=
>>>> output.
>>>>It does this regardless of whether or not there's an input present, and 
>>>>the=
>>>> buzz would appear to be 60Hz.
>>>>
>>>>Would this mean it's likely one of the filter caps somewhere is dead? 
>>>>If s=
>>>>o is there anything anybody can tell me about how I should go about 
>>>>locatin=
>>>>g the offending capacitor?
>>>>
>>>>Thanks,
>>>>Steve=
>>>>
>>
>>
>>
>>
>