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Kombo organ reverb, vol pedal shielding [message #3343] Tue, 16 December 2003 19:55 rodak Messages: 511 Registered: October 2001 Location: Georgia Senior Member Yeah, it's me again. My reverb has some pretty noticeable white noise in the background, that varies with the setting of the Depth control. What might be at fault there (or is it normal)? Also, I noticed that both wires to the reverb tank and to the volume pedal are unshielded - that doesn't seem right - seems like they ought to both be shielded, carrying line-level audio, right? I think that'll do me for now. Robert www.combo-organ.com Report message to a moderator

Re: Kombo organ reverb, vol pedal shielding [message #3345 is a reply to message #3343] Wed, 17 December 2003 08:01   stevem Messages: 4733 Registered: June 2004 Location: NY Senior Member HELLO.hiss or white noise is a good sign. It means that section of preamp has gain. If you unplug the output jack from the pan, and short the tip to amp ground the hiss should be killed.Only if you had a hum problem or where picking up stray radio or CB signals would I worry about the lack of shielding. Report message to a moderator

Re: Kombo organ reverb, vol pedal shielding [message #4440 is a reply to message #3345] Wed, 07 July 2004 19:07 rodak Messages: 511 Registered: October 2001 Location: Georgia Senior Member Finally got around to working on this some more (after I got everything else fixed!). I did as you suggested, disconnected the plug from the output side of the reverb unit and shorted it, and I got a steady bass tone out of the output(!). It wasn't one of the organ tones, so I presume it was 60hz leaking through somewhere (my tuner reported it as a very flat F2 - would that be 60hz (or 120, perhaps)? Seems like I recall the low E on a bass guitar is about 55hz, so that would make sense. Any ideas? www.combo-organ.com Report message to a moderator

Re: Kombo organ reverb, vol pedal shielding [message #4457 is a reply to message #3343] Fri, 09 July 2004 07:48   stevem Messages: 4733 Registered: June 2004 Location: NY Senior Member Hello, I would check to see if that reverb pan is the original hammond made pan. You may have a wrong impedance wise, replacemant pan. If not you may be having to turn up the depth control more than mormal, heres why! On all most all original pans that I have checked out, at least one of the small coils at each end of the double spring run can be moved on is iron core!THis is not good, that coil is used to induce sound vibrations into the springs, so if it doesnt fit tight it can not do that. To fix it I get some gap filling thick super glue from a hobbie shop, and pile it in, and on to retain it. Seing as it can be slid some if it is lose, it should be glued as close to the sping mount as you can get it. You can also use small bits of a thooth pick to fill the coil to iron gap some before you glue it. Do not use hot glue, it will absorb vibration. Epoxie would be good to. The super glue is fast, at the hobbie shop you can get spray on excelerant, to set the superglue in 2 seconds. Report message to a moderator

Re: Kombo organ reverb, vol pedal shielding [message #4508 is a reply to message #3343] Fri, 16 July 2004 07:33   stevem Messages: 4733 Registered: June 2004 Location: NY Senior Member Hi, I printed a mistake.If the white noise you are getting is cominmg from the return side preamp(the preamp the kicks up the signal from the out side of the pan)Than shorting the tip of the RCA plug to its case will kill all gain from that preamp, if it doesnt than you have problem in that curcuit.If that amp has ever got hit in the face, like on the reverb control you may have a open leg on that pot.You can also got to the the shack and get some component cooler spray, and heat up with a hair dryer than cool down the components around the RCA in and out jacks to see if it makes a differece. Dont set the parts on fire warm to the touch, no more than 130 degrees. Report message to a moderator

Re: Kombo organ reverb, vol pedal shielding [message #4509 is a reply to message #3343] Fri, 16 July 2004 07:36   stevem Messages: 4733 Registered: June 2004 Location: NY Senior Member P.S do not short the RCA tip to frame, short tip to RCA case. Report message to a moderator

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