|
Post by benttop (Steve) on Feb 23, 2011 21:43:32 GMT -7
I see this issue come by here all the time, and the trouble I have with it is that it seems even with a solution the problem remains a mystery to most folks here. I'd like to try to remedy that if at all possible. Most effects loops use a switching arrangement in the jacks, so that when there is nothing plugged in to them, the signal passes through the jacks and on down the line. When you plug in, the signal path is re-routed out the jack and through your external effect. In order to do this, the jack has to have a switch built in. It is this switch that causes the problems. Exhibit A: As you can see, there is a leaf next to the jack's "tip" contact that is making contact with the body of the tip "spring." This diagram illustrates the path of a signal using this jack without a plug inserted all the way: So as you can see, the signal flows into the jack, routes through the switching component, then flows right back into the amp. Now look what happens when you insert the plug: Oh ho! The element touching the tip body has deflected and the leaf is no longer in contact! What does that do to our signal flow diagram? AHA! now the signal flows into the jack, but not encountering the leaf, it flows right out the plug that was inserted. Obviously I've illustrated the send jack. The return jack operates exactly the same but in reverse. The point is, do you see that little dimple that is making contact with the "tip" contact there? THAT is where you need good connectivity. If that little dimple becomes corroded, the signal path is interrupted, but with no plug in the jack, it is terminally interrupted, as in NO SOUND. That is exactly why the problem is fixed by inserting a short cord in the send and return jacks - it gives the signal somewhere to flow. Go back and look at the first image - can you see a minor issue if you squirt something into the hole of the jack? Yeah, the contact is touching, which means none of the cleaner will get to it. That's why you have to squirt a good enough quantity in there, then insert and remove the plug numerous times so that the excess cleaner will flow into the spot where the dimple makes contact and hopefully clean it. Looking this over, it should be obvious that you can do a MUCH better job of cleaning this thing if you have access to it. I like to pull the chassis so that I can get right in there. Of course I can't recommend that without saying YOU COULD BE KILLED by doing that. Don't pull the chassis unless you know what you're doing. Anyway, I hope that helps just a bit. Sometimes a picture is worth a thousand words...
|
|
|
Post by Scott on Feb 23, 2011 21:51:11 GMT -7
Outstanding post! Thanks Steve...
|
|
Deleted
Deleted Member
Posts: 0
|
Post by Deleted on Feb 24, 2011 8:57:17 GMT -7
Hell ya great post!!! Recently bought some DeoxIT it really is great stuff to keep those jacks squeaky clean FWIW. Thanks again Steve...
|
|
Deleted
Deleted Member
Posts: 0
|
Post by Deleted on Feb 24, 2011 9:39:53 GMT -7
Thanks Steve. Great post.
|
|
|
Post by Phil (aka Phil) on Feb 24, 2011 10:05:27 GMT -7
GREAT post Steve! I guess my comment is that for years I've thought that the standard "Switchcraft" jack was kind of poorly designed. Just think, when it's in the "shunted" mode (no jack inserted) ALL your tone is going through that little dimple pressed up against the leaf. It's cost effective and works, but that's about it IMO. In my position at work I've seen a LOT of PQ (power quality) monitoring gear come and go. I evaluate them for not only their capabilities but also their build quality and field durability. The connections are always one of the weakest points. It kind of got turned me into an amateur "connection geek". That's the first thing I look at now. HDMI is a good example. Whoever designed that connector is a certified idiot. How many of you with HD gear has plugged in a HDMI cable only to move your Blu-ray player or Playstation 3 two inches and have the cable fall right out? It's got no lock or positive feedback that a connection has been made and not enough surface area to maintain a solid connection. And, the Neutrik speakON is a much better connector for speaker applications than that same Switchcraft jack used for instrument cables too. Now there's a decent connector. Rant over.
|
|
|
Post by benttop (Steve) on Feb 24, 2011 10:28:15 GMT -7
Phil, I couldn't agree more. I stopped using Switchcraft plugs for home-built guitar cords because they just don't hold up. The phenolic (or whatever they use for an insulator) shrinks and the whole thing comes apart after a year or so. The Chinese plastic insulator ones last longer. I hate being able to say that, but there it is. There are 1/4" phone jacks that have bronze contacts for the switching, but they are way more expensive, and frankly, they oxidize too (although not nearly as fast as the plain Jane models). If I was having this problem a lot (I'm not) I might consider replacing with the more expensive variety, but where I live we don't get enough oxidization to cause the problem.
|
|
Deleted
Deleted Member
Posts: 0
|
Post by Deleted on Feb 24, 2011 10:51:24 GMT -7
Love way you guys geek out on things.
|
|
|
Post by doctorice on Feb 24, 2011 11:11:44 GMT -7
Most informative, Steve. Thanks for the deep dive into the jack issues.
|
|
|
Post by benttop (Steve) on Feb 24, 2011 13:01:05 GMT -7
Love way you guys geek out on things. Well, yeah! In gear-geekdom, the saying goes: "Everything matters. Everything!"
|
|
Deleted
Deleted Member
Posts: 0
|
Post by Deleted on Feb 24, 2011 14:48:24 GMT -7
Love way you guys geek out on things. Well, yeah! In gear-geekdom, the saying goes: "Everything matters. Everything!" I freak people out sometimes with my gear speak my brother thinks I speak another language with that and computers. That's why I love this place. I feel fairly understood here. ;D
|
|
|
Post by benttop (Steve) on Feb 24, 2011 14:55:03 GMT -7
Yeah, it's fun hanging with fellow players who also obsess over gear. The wife sometimes wonders why I don't marry you all instead of her!!!
|
|
floyd
Full Member
Posts: 241
|
Post by floyd on Feb 24, 2011 15:30:12 GMT -7
That is priceless information! Thank you for taking the time for this explanation/tutorial Steve!! Have some more K
|
|
Deleted
Deleted Member
Posts: 0
|
Post by Deleted on Feb 24, 2011 15:46:18 GMT -7
Yeah, it's fun hanging with fellow players who also obsess over gear. The wife sometimes wonders why I don't marry you all instead of her!!! LOL!!! ;D
|
|
|
Post by mazmaster on Nov 22, 2011 14:06:52 GMT -7
This oxidation issue has occurred with my Maz 18 Jr NR (I've had the amp since 2002) and also recently with the same kind of jacks in my Glaswerks SOD II loops! In both cases, the fix was opening up the amp and inserting a feeler gauge coated with DeOxit between the dimple and it's contact point and rubbing it back-n-forth between the contacts to create some mechanical friction to enhance the chemical reaction.
I wouldn't recommend just spraying DeOxit into the hole because that doesn't really clean the dimple very thoroughly and squirting DeOxit all over the insode of the amp may have other consequences. As always, if you don't know how to work with the the high voltages that can sometimes remain in the amp after being turned off, then have a tech do this work for you.
|
|
|
Post by dixiechicken on Nov 27, 2011 3:29:54 GMT -7
DC here! Are you rich benttop? - if so - please marry me so I can quit work Great info on jacks Steve - and crappy components are abundant in lots of electronic gear btw. In our beloved amps as an example - carbon comp resistors are crap - they should not be allowed anywhere except in the junk yard. They are not stable over time, their values varies sometomes wildly from nominal and they are noisy. I had a Mesa Boogie MK-IIB for several years - suddenly it began sound very strange indeed - emit gargling noises and smell funny. Pulling the chassies out - I soon discovered why: The five watts carbon comp resistors in the power supply had dried out. When lightly tapping the resistors they turned into a fine powder - and I was left with two soldered wire stumps - in several places. And Mesa engineering prides themselves of building quality products - jeez. I replaced the resistors with 5 watts metallfilm resistors - they will likely outlast the next owners lifetime - Cheers Dixiechicken!
|
|
|
Post by benttop (Steve) on Nov 27, 2011 10:35:27 GMT -7
DC, I'm rich in the philosophical sense. Assets are another matter entirely.
|
|
|
Post by randalp3000 on Nov 27, 2011 12:58:01 GMT -7
Great post, I've thought many a time to take it out of my Stangray. I'll never use it and it's just one more thing that could cause a problem some day.
|
|
|
Post by Sean on Nov 27, 2011 14:37:08 GMT -7
That's four pics and four thousand words saved. THanks.
|
|
Deleted
Deleted Member
Posts: 0
|
Post by Deleted on Nov 29, 2011 23:54:06 GMT -7
Is this what all effects loop jacks look like? I see this issue come by here all the time, and the trouble I have with it is that it seems even with a solution the problem remains a mystery to most folks here. I'd like to try to remedy that if at all possible. Most effects loops use a switching arrangement in the jacks, so that when there is nothing plugged in to them, the signal passes through the jacks and on down the line. When you plug in, the signal path is re-routed out the jack and through your external effect. In order to do this, the jack has to have a switch built in. It is this switch that causes the problems. Exhibit A: As you can see, there is a leaf next to the jack's "tip" contact that is making contact with the body of the tip "spring." This diagram illustrates the path of a signal using this jack without a plug inserted all the way: So as you can see, the signal flows into the jack, routes through the switching component, then flows right back into the amp. Now look what happens when you insert the plug: Oh ho! The element touching the tip body has deflected and the leaf is no longer in contact! What does that do to our signal flow diagram? AHA! now the signal flows into the jack, but not encountering the leaf, it flows right out the plug that was inserted. Obviously I've illustrated the send jack. The return jack operates exactly the same but in reverse. The point is, do you see that little dimple that is making contact with the "tip" contact there? THAT is where you need good connectivity. If that little dimple becomes corroded, the signal path is interrupted, but with no plug in the jack, it is terminally interrupted, as in NO SOUND. That is exactly why the problem is fixed by inserting a short cord in the send and return jacks - it gives the signal somewhere to flow. Go back and look at the first image - can you see a minor issue if you squirt something into the hole of the jack? Yeah, the contact is touching, which means none of the cleaner will get to it. That's why you have to squirt a good enough quantity in there, then insert and remove the plug numerous times so that the excess cleaner will flow into the spot where the dimple makes contact and hopefully clean it. Looking this over, it should be obvious that you can do a MUCH better job of cleaning this thing if you have access to it. I like to pull the chassis so that I can get right in there. Of course I can't recommend that without saying YOU COULD BE KILLED by doing that. Don't pull the chassis unless you know what you're doing. Anyway, I hope that helps just a bit. Sometimes a picture is worth a thousand words...
|
|
|
Post by benttop (Steve) on Nov 30, 2011 13:02:31 GMT -7
Is this what all effects loop jacks look like? That would be a generalization, but most of them that switch your signal when you plug in do it in this way. There are always exceptions, but this is how the Z loops work.
|
|
Deleted
Deleted Member
Posts: 0
|
Post by Deleted on Nov 30, 2011 13:34:26 GMT -7
Is this what all effects loop jacks look like? That would be a generalization, but most of them that switch your signal when you plug in do it in this way. There are always exceptions, but this is how the Z loops work. Thank you. You just saved me from having to take my amp apart from shear curiosity.
|
|
|
Post by benttop (Steve) on Nov 30, 2011 14:50:36 GMT -7
That would be a generalization, but most of them that switch your signal when you plug in do it in this way. There are always exceptions, but this is how the Z loops work. Thank you. You just saved me from having to take my amp apart from shear curiosity. No need to do that: This is from Scott's "Getting to know the Maz Jr" thread in that section. You can clearly see the features I referenced above if you look at the jacks for the loop.
|
|
|
Post by Scott on Mar 12, 2012 18:03:29 GMT -7
I think I have to do this... After being an FX loop guy forever, I now am running everything up front. When I take my amp out of standby, loud static... Guitar in, or out. Makes no difference. I think I want to take my chassis out of my head. Is it just 4 screws? I think I can insure I don't go near the capacitors, and work with one had only... How many steps are there to pulling a chassis out of a head?
|
|
|
Post by benttop (Steve) on Mar 12, 2012 19:42:33 GMT -7
I think I have to do this... After being an FX loop guy forever, I now am running everything up front. When I take my amp out of standby, loud static... Guitar in, or out. Makes no difference. I think I want to take my chassis out of my head. Is it just 4 screws? I think I can insure I don't go near the capacitors, and work with one had only... How many steps are there to pulling a chassis out of a head? If no reverb, you pull the back off, unscrew the four chassis bolts on the bottom, and slide it out. Use the transformers as handles, because there isn't much else to grab. And keep in mind there is a foil shield stapled on to the cabinet under the chassis - if you lift as you pull back, you can avoid damaging it. Doesn't take much, but if you just grab and yank you might catch the edge of that shield and cause a problem for yourself. I usually use one hand to hang on to the chassis while I use the other to unscrew the chassis bolts. You're upside down after all. Then turn it over before pulling the chassis out. That's my way anyhoo. Reinstall in reverse order. Oh yeah, while it's out of the box, watch those tubes. They are easy to break if you're careless.
|
|
|
Post by Scott on Mar 12, 2012 20:01:26 GMT -7
Thanks Steve...
|
|
|
Post by benttop (Steve) on Mar 12, 2012 20:19:39 GMT -7
Thinking about this, I remember that I also used the "hangover" method - hang the end of the amp over the edge of the benchtop (just far enough to get to the screws) and unscrew from the bottom. Then swap ends to get the other two. That might actually work better with only two hands...
|
|
|
Post by Scott on Mar 12, 2012 20:44:01 GMT -7
Love the tips...
I will do just that.
|
|
|
Post by byrdland on Mar 13, 2012 4:50:33 GMT -7
This post has saved a lot of people a lot of grief. It will continue to do so if they use your advice. I took my Maz 18 chassis out yesterday, installed a NOS rectifier tube and re-cleaned my send and return jack with de-0xit. It took me a few minutes to re-align the 4 chassis bolts when re-installing the chassis but it was pretty easy. thanks again.
|
|
|
Post by Scott on Mar 13, 2012 13:50:08 GMT -7
Procedure successfully completed... Lifted the chassis out using the transformers, as suggested: The Foil Shield was unharmed... My FX loop Jacks before cleaning... Full shot of my Jr's guts: A small strip of a Deoxit soaked cotton T was used in the jack, for cleaning. Note that I put a plug in to open the gap a tad, then used a small paperclip to coax the material through, being careful not to bend anything. Worked it around pretty good before taking the material back out, then took the plug back out too, and wiped the entire jack down with another fresh shot of Deoxit. I did clean all jacks while was in there too.Hog Iron My Amp's secret info... I was also careful to lift the chassis back into it's normal resting place, insuring to protect the Foil Shield on the way back in. Procedure worked like a charm. My Maz Jr. is now back to it's normal outstanding self.
|
|
|
Post by benttop (Steve) on Mar 13, 2012 18:09:30 GMT -7
nice shots there! Now that's the way to clean jacks.
|
|