CA3080A or CA3080E? yet another noisey ross compressor

[mitzrecords]

Hi, so I built this a couple of days ago but it is quite noisey. I searched here and found a couple of suggestions and tried replaced resistors, look for cold solder joints. etc.

Im about to order CA3080 but should I get CA3080A instead of E? right now, I have CA3080E from smallbear. or any other not noisey ones you recommend?

also, I have 2N3904 trannies. Should I try to get 2N5088?

thanx!

[Mark Hammer]

1) Just about ALL compressors are hissy when you stop playing.  That's because when the input signal goes low, the gain gets cranked, and when the input signal gets hotter, the gain gets reduced.

2) Differences between types of CA3080 chips will make negligible difference, if any at all.  More likely candidates would be the first transistor the signal encounters before the 3080.  That should be a low-noise type if possible, and so should the one after the 3080.  The 3 other transistors are not part of the audio path, so their noise specs are generally moot.

[ZiggyZipgun]

Just about ALL compressors are hissy when you stop playing.

+1 - Looks like your next project should be a nice noise gate, which would take care of that even at minimal settings.  With a little luck you could fit 'em in the same enclosure.

[mitzrecords]

thanx guys!

i will swap trannies and see how it goes.

thanx!

[mitzrecords]

actually it might be from my power adaptor. it gets radio signal too. voltage regulator fixed this same problem when i made valvecaster so im gonna try to to put L7809 on my ross comp.

thanx

[mitzrecords]

78L09 100mA is enough right with a 100uf electro cap?

same method as i used with valvecaster except L7812 was used for valvecaster.

is this ok?

just need a confirmation.

thanx!

[mitzrecords]

anyone? please confirm. thanx!

[mitzrecords]

?

[oskar]

100 mA is plenty of e- for this circuit...       it's a go!
Edit! That only answer your latest question. If you're having trouble with the unit picking up radio signals too and have had problems with this in other builds, then I can't answer if this is a good fix for it.
The radio thing sounds more like a thing from the input/guitar and the cure is somewhere around GEOFEX... a small cap from input to ground. The noise issue have been answered previously in this thread. It doesn't sound like a problem with the power to me.

[JDoyle]

actually it might be from my power adaptor. it gets radio signal too. voltage regulator fixed this same problem when i made valvecaster so im gonna try to to put L7809 on my ross comp.

thanx

It may be just me, but if this is a pattern then it may be more cost effective to fix your power supply rather than attached a regulator to each pedal you build...

regards,

Jay Doyle

[george]

yeah - get a regulated 9V adapter.  it's allready got the 78L09 in it.

I built a zombie chorus once and I was using an unregulated regulator.  It had a rhythmic sort of noise like a washing machine or clothes dryer then I used a regulated PS and the noise disappeared.