Crate Vintage 30 problem

[butterblum]

I have a Made in the USA Crate Vintage 30 that I just bought used about a month ago. Today, I discovered a problem. My amp works fine when my guitar is the only thing plugged into the input jack. I also plug a loop pedal into to FX loop input on the back. When the guitar isn't plugged in, the loop pedal works flawlessly as well. But when both of these are plugged in, the loop pedal is loud and clear while the guitar is very faint with a lot of reverb. Does anyone know what this could be? There may have been a faint crackling coming from the amp last week... Thanks.

[newey]

butterblum-

Hello and Welcome to G-Nutz2!

We've had a long-running thread here about problems with the Crate "Vintage Club 30". I'm not familiar enough with the Crate lineup to know whether that amp is similar to your "Vintage 30" or not, so the thread itself may not be much help. Here it is:

guitarnuts2.proboards.com/index.cgi?board=Amps&action=display&thread=2833

But one of the posters in that thread (I believe it was yacaman) noted that problems with a faulty jack in the effects loop were causing him grief. And, based on that and on your description of your problems, it sure sounds to me like that would be the place to start looking.

The way these work, at least one of the jacks for the loop is not just a regular output jack, but is switched. Plugging into the jack opens the switch contacts, directing the current into the barrel and tip of the plug. With no plug inserted, the contacts stay closed and the current bypasses the effects loop.

So, a faulty switched jack there would explain why it's OK with nothing plugged into the effects loop, but wonky when the jack is occupied. Switch contacts mean moving parts, and moving parts imply a potential node of failure.

But sumgai is our resident amp guru, let's let him weigh in before you start tearing into anything. It may be a few days before he sees your post, however.

And there are certainly others who may weigh in with more knowledge than I have.

[sumgai]

buttery,

Hi, and welcome to the NutzHouse! ;D

Don't wait for me, newey has it correct. In fact, the problem lays exactly with the Effects (FX) Return jack. Replace that, and you're golden. ;D

(Sometimes I just swap that jack with one of the other jacks on the board, one that is rarely or never used. All of them are the same jack type, it was easier for the manufacturer to buy all the same kind of jack, instead of a bunch of different ones.)

HTH




sumgai

[butterblum]

Weird. It worked the other day after I let it warm up, but it's not working again today. I already use all of the other jacks on the amp, so where would I go to order a new jack? How easy of an installation is it? Thanks!

[butterblum]

Also, just for curiosity's sake, could you guys explain how the input jacks physically work? I know the contacts open when something is plugged in, but what would be wrong with my jack that actually keeps it from working? Are the contacts still touching even when something is plugged in? Thanks!

[sumgai]

buttery,

Jan 26, 2013 11:55:12 GMT -5 butterblum said:

Weird. It worked the other day after I let it warm up, but it's not working again today.

Not an unusual occurence. Explanation below

I already use all of the other jacks on the amp, so where would I go to order a new jack?

This style of jack can be found at lots of places around the web, or possibly even your local guitar/amp shop, if it's pretty large. But, and here's the big "but" part.... Shops that cater to guitar players charge much more for the same thing than an electronics company, whether it's a brick-and-morter or an on-line outfit. Around the NutzHouse, we usually recommend DigiKey or Mouser as a first place to look. After that, there are other companies that sell to the everyday hobbyist, though they're smaller, and there are also several places that are guitar-oriented, but finding the best price can be a headache. Sometimes you just want to scream, and then you say to Hell with it, and just buy it from a known reputable store, no matter what the cost. I suggest that you wait a day or two to see who else responds with suggestions on this part of your quest.

How easy of an installation is it?

Well, that depends. On your skill level, on your comfort level, and possibly on how fat your wallet is.

In other words, there's a trade-off - if you feel you can do the job, then you'll save some money. Otherwise, you'll spend it on a technician to do the job for you. But of course, in that case, you have someone to blame, should the problem remain. ;D

But here's an "interesting" thought. I said earlier that I usually just swap the problem child with another jack from the same board. You said that's not gonna work because there are no "spare" jacks - you use 'em all. Fine. Don't buy another one of the same flimsy, crappy jacks. Instead, go out and spend 8 or 10 dollars (US) on a Switchcraft quality jack. (I think the part number you want is 1204, but I could be wrong, I haven't looked for some time at a Switchcraft catalog.*) This is not a direct substitution, you'll now be running wires from the circuit board to the jack.... the jack will stay in the mounting hole permanently, with wires running to the circuit board that are long enough to let the board be removed without needing to take the jack out too.

When doing that kind of job, sheilded wiring is not normally needed - the chassis itself is metal, and grounded, so there should be no noticible hum added to your signal. Nonetheless, you do want to use quality wire, and again, long enough to do the job without stressing anything, as you remove/replace the circuit board.

Also, just for curiosity's sake, could you guys explain how the input jacks physically work?

Well, it's a metal-to-metal contact, which is usually a good way to conduct electrical current from Point A to Point B.... emphasis on the "usually". Sometimes cheapness gets in the way of proper engineering, and we consumers end up with the short end of the stick. By that I mean, the metal used in the jack contacts is not really a good conductor in the first place, and becomes unreliable over time (as it gets used). Eventually, poor quality jacks become unable to make a good, firm contact with the plug - even though you and I think it feels solid, it's not, electrically speaking. And therein lays the rub - the problem is not obvious to our physical senses, so we tend to not place the blame where we should, the jack's poor quality.

(See many other posts/threads on this Forum for diatribes about jack quality, both from myself and others. Let's not go any further on that, in this thread. )

I know the contacts open when something is plugged in, but what would be wrong with my jack that actually keeps it from working? Are the contacts still touching even when something is plugged in? Thanks!

Now you're speaking of "switching" jacks, the kind you have in your amp. In point of fact, they aren't necessary except in the one place where we want to interrupt the signal path, and that's the FX loop. However, as I said earlier, it's easier for the manufacturer to stock only one kind of jack, and the wholesale cost to that company for each kind (switching versus non-switching) is only a penny or two at the most.

So, in the end, while I can't be absolutely certain that in your case it's the FX Return jack that's at fault, I can tell you that experience sure leads me in that direction. (I'm an EE, and fixing amps was a good 'retirement hobby'.) There are other parts in your particular amp that may also cause problems, but they're:
a) harder to get to for replacement;
b) more expensive; and
c) not as likely to be the culprit, from your description.

Try the jack first, and if that doesn't work, then no harm done - it would've needed replacing anyway, eventually.

HTH



sumgai

* Now that I think about it, why don't you do a bit of research, and if you decide to buy a jack to do the job yourself, then post a link here pointing to your intended purchase. One of us will vet the link/part for you, to make sure you don't end up with an unusable part.

[gumbo]

Some Caig's De-Oxit down the hole, and plug and re-plug the thing sometimes can make things work for a while..

..not really a 'fix', but sure proves a point about where the problem lies...then one can go and BUY / REPLACE a jack with relative confidence that the cause of the problem has been unearthed...

2 Oz c worth.. (about 2.08 of yours) ;D

[butterblum]

Sorry, I'm kind of crunched for time right now and haven't been able to open the amp up, but how do you remove the jack? Is it soldered onto the circuit board or what? Are there more durable direct replacements available that wouldn't require soldering elsewhere on the circuit board?

[sumgai]

buttery,

Jan 27, 2013 12:04:02 GMT -5 butterblum said:

Are there more durable direct replacements available that wouldn't require soldering elsewhere on the circuit board?

Yes, you take the chassis out of the cabinet, and there you'll see the circuit board(s), ready for disassembly. But you'll need to:

a) remove all knobs;

b) remove all nuts from around any jacks; and

c) remove (of course) all mounting screws.

Once you've done this, the circuit boards are exposed, and you can begin work. But sadly, soldering skills and equipment are required, there's no getting around that.

As for a direct substitution, no, there'll still be some soldering going on - can't get away from it, sorry.

I have to mention that on some Crate models, the board is "upside down", meaning that the controls and jacks are not plainly visible when you view the circuit board(s) mounted in the chassis. Other models, the controls and such are visible. But in either case, the boards must be dismounted before you can effect any repairs/replacements, it's just the nature of the beast.

If all of this is making you queasy, don't worry - you aren't alone! Techs (or former techs, like me) are around just for that reason - to do the work that you can't, whether it be for lack of time or lack of skills, or whatever. If that's the case, just do some judicious shopping for a tech - references from other musicians are your best bet.

HTH





sumgai

[butterblum]

Do you know what the part number of a replacement switchcraft jack would be? I'm going to take it in to a technician, and he said he normally puts the brand of jack that came with the amp back into it when he repairs it. From the sound of it, it's not a very high quality jack, so I would like to tell him to replace it with a switchcraft jack if he can. Thanks.

[sumgai]

buttery,

Switchcraft doesn't make an exact, drop-in replacement for these pieces of crap. In fact, that's exactly why the BrandX companies started making these things, so that they could take some of the business (market share) away from Switchcraft. They knew, and still know, that there is a price-point for everything, and they saw that Switchcraft was not serving the "low price, even if low quality" segment of the market.

Switchcraft still refuses, after all these decades, to stoop to their level. For Switchcraft, it's all about quality, and everything else comes second. For that reason, I'm sorry to say that you, or your tech, must resort to either duplicating the original part, or else one of you must invest some time and labor to do what we call a "jury rig" - the new Switchcraft jack is installed just like it was (and still is) in amplifiers of bygone days - you mount the thing into the chassis hole, then solder wires between the jack and the circuit board. Somewhat more work, and not nearly as 'clean and neat', but oh so much more reliable in the long run.

But to address to your point about which jack to use..... I just did a Google and came up with the proper part number - you want a Switchcraft 14B, not a 12 as I had earlier suggested. For a wonder, there is an outfit that's clearing them out right now, and you can snap up one of these babies for a mere 5 bananas! (Well, the shipping is allegeldy free, but there is a $6 "processing" fee.) Still, $11 or $12 is a steal, compared to DigiKey or Mouser (nearly 6 bucks apiece, and shipping ain't free for that low a dollar amount).

Let me advise you to talk this over with your tech, and come to an agreement on the price of his/her labor. If you trust his/her quality of workmanship, then the overall upgraded quality of the repair will pay off for you in the long run, of that I have no doubt whatsoever.

HTH





sumgai

[butterblum]

So I am finally about to buy the switchcraft jack. Here is the link to the part. I am planing on doing the repair myself. www.alliedelec.com/search/productdetail.aspx?sku=70214524
What wire should I buy to connect the jack to the circuit board? Anything from the same site? Thanks.

[sumgai]

'blum,

That's the correct part, go for it!

You can use any wire you wish, it doesn't need to be big, thick, strong, heat-resistant, or any other special character.... plain ol' hook-up wire will be fine. I usually use some 20-gauge solid wire, but only because I have a few miles of it stashed around the place. Certainly stranded core will also work, any size betwen 18 and 24 gauge will be OK.


Also, given that this unit is inside of a metal chassis, you don't need to worry about adding hum into your signal - hence, you don't need expensive (by comparison) shielded cable, either.

HTH





sumgai