[sdiy] Buzzing reverb

[Steve Begin]

It seems like if i move the tank somewhere else or even turn it around 
inside the enclosure the buzzing is reduced drastically.
I got it really cheap but it's been buzzy right from the start, and it would 
seem kind of crazy if it was just built this way.
Is there anything that could cause a spring reverb to become more sensitive 
to noise from the power transformer?  (it looks like it's probably over 20 
years old)
If I can't find any other solution I'll probably just mount the tank 
externally, but I'm curious as to how it got this way.
steve

----- Original Message ----- 
From: "Bob Weigel" <sounddoctorin at imt.net>
To: "Steve Begin" <trypannon at hotmail.com>
Sent: Saturday, April 16, 2005 7:52 PM
Subject: Re: [sdiy] Buzzing reverb


> sure.  That means the tank is probably ok..barring any broken springs 
> inside. Possibly then the problem is in the amp that picks up the signal 
> from it. -Bob
>
> Steve Begin wrote:
>
>> 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=
>>>>>>
>>>>
>>>>
>>>>
>>>>
>>>
>>
>>
>