Forum Replies Created
-
AuthorPosts
-
ScruffieMember
Ohhh, for the reissue 16 second, I thought you meant a vintage model. No, I don’t know what specific size it needs then.
ScruffieMemberNo, sorry, I’m not sure what you mean, if you send me a picture I might be able to help.
ScruffieMemberWhat’s wrong with these? http://smallbear-electronics.mybigcommerce.com/alpha-dpdt-slide/
Smallbear also carries these http://smallbear-electronics.mybigcommerce.com/potentiometer-cts-slide-for-old-micro-synth/ which should be suitable for the vintage 16 second, I’ve used them in other vintage EHX without problem.
ScruffieMemberVery likely a 2N4302, rare these days so try a 2SK30A.
ScruffieMemberI happen to have a V4 case with no circuit board, so yes, I would be.
ScruffieMemberIt could be any number of issues, replacing parts without following debugging procedures isn’t particularly effective and may be a waste of time and money but the electrolytic caps are less likely to be bad than vintage units simply because they’re not as old but they can still go bad.
Posting a full set of voltages for others to look at and audio probing through the circuit to find the source of distortion should help pin point the area of concern.
How strong are the pickups being used as well? BBD’s do have a limited headroom and don’t handle bass frequencies particularly well so with something like EMG’s the behaviour you experience could actually be normal. As the vintage units were not true bypass it was possible to drop the input level below unity gain and have the bypass match the level which isn’t possible on the reissues.
ScruffieMemberAn audio probe may sound like an expensive piece of equipment but it is incredibly simple and cheap to make, all that is required is a guitar lead and a capacitor, see this page https://www.diystompboxes.com/pedals/debug.html Debugging and biasing effectively without some way to check the effects of the trim pots within the circuit will be close to impossible.
It’s unlikely that the BBD’s are the issues themselves and they are fairly pricey if money is an issue.
ScruffieMemberThere is interactivity between the two bias trims (if one BBD is off, the other isn’t going to sound good) so just tweaking them doesn’t tell you much. Build an audio probe and trace through the circuit to find where the distortion occurs.
Taking voltages of everything and posting them is also recommended.
ScruffieMemberHave you checked the BBD bias’ on a scope? It’s probably just off a little bit. If you lack a scope you can audio probe the outputs and bias them that way.
ScruffieMemberThere is a second or two delay once stomped on but 5 seconds does seem excessive. It will do it every time as it’s not a powering issue but the FET taking a moment to change states.
It could very well be an aged cap, there’s a 47nF in the switching circuitry which may have drifted in value or a 1uF connected to the switching FET that could be leaky.
ScruffieMemberHoward Davis does paint touch ups on vintage EHX pedals but while I’m sure he does a good job I doubt it’ll ever look like new.
As there’s lacquer over the paint the repair would require buffing that off, touching up the paint and then re-lacquering it.
It’s probably best to embrace it as part of its history.
ScruffieMemberCould be a lot of things, but probably a microphonic or leaky cap or a bad foot switch.
You can test for microphonic parts by tapping around inside with a chopstick (if it’s a deluxe model with a transformer then be careful of the mains connections) and you can try cycling the foot switch on and off which might point to it being the problem but otherwise it might be best to send it to a tech.
ScruffieMember
The DC jack was what I was hoping to look at in the pictures, glad you got it sorted out in the end.ScruffieMemberOdd, can you post some pictures?
ScruffieMemberFirst off, did you check the polarity, voltage & mA of the router supply? And secondly do you have any experience with electronics at all? If so do you have a multimeter you can test the voltages with and if not it might be better to send it to someone for repair.
-
AuthorPosts
The DC jack was what I was hoping to look at in the pictures, glad you got it sorted out in the end.
