EH Memory Man (orig) noise issue

[yeeshkul]

I have an original vintage MM Solid State Echo/Chorus (the type with black and blue print all over the top panel - neither the Deluxe nor the stereo model).



Unfortunately it produces quite a lot of background noise - even if the guitar is not plugged in. The noise very much depends on the "Blend" knob.
Here is a mini-soundsample: http://www.hoho.cz/osobni/memoryman.mp3.
Would please anyone tell me if the spacey hum really should be there or where may be the problem? Thank you very much. There is no noise in chorus mode.

[Jonathon Stevens]

replace the old electrolytic capacitors. Mine was the same way until i opened it up and did this, now it's much quieter.

[yeeshkul]

thanks man!

[yeeshkul]

I was looking around internet and the noise seems to be the generel issue. Is your MM the same type as mine? Do you think i can also help it by a better rectifier? Mine is just 2 diodes. I am just making sure before i start changing all the caps

[StephenGiles]

They were always going to be noisy because there was no compander - don't waste your time changing capacitors.

[Jonathon Stevens]

mine is similar to yours, just doesn't have the blue paint and has boost input. Mine was really noisey so I opened it and noticed that the 3 large capacitors (sorry i forget their values) had leaked. Replacing them resulted in much lower noise, although it is still noisey.

[yeeshkul]

Jonathon how did you recognise they were leaky? Can i measure it somehow? By the way i have the blue model "Solid State Echo/Chorus" with the "boost in". There is so many of them . I am afraid the "boost in" is a bit weak anyway and i play humbuckers. It is about unity gain when you turn blend towards the dry sound but weak in the middle position - especially the bass strings sound weak.

I believe that the electro caps go bad much faster in these EH models because people let them plugged to the power over night and so. It is 30years old model after all and the electro caps usually work fine for less 5000 hours.

Also, i noticed i can suppress the noise with one of the trimmers inside - the one that is on the PCB side of the board and has a little handle for hand adjustment (i am not gonna change the other 2) although you loose the crazy feedback sounds this way.

[Jonathon Stevens]

The caps in mine were physically falling apart so it was pretty obvious which needed to be replaced. Replacing them improved the amount of noise but it's still far from great with longer delay settings. I'm mostly using it for slapback delay so it's not too noisy.

As Stephen said, these things are noisy. If the noise makes you unhappy sell it on ebay and get something a little more modern? Ibanez adl/cd10 seem to sell for resonable prices on ebay and are quieter.