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Carvin BX500: Pt. 3
- Thread starter Chef
- Start date
So, I've been using my Bx500 for a while now, and have just encountered some issues. I was using it as a DI box for practice, and it started (was originally clean) to distort intermittently. As time progressed, the distortion became more constant and louder. Ground lift and a tube removal (physical removal) provided no relief. I brought it home and tried it with one of my cabs. I get an intermittent radio static sound and the same distorted sound, which is getting more and more severe.
I bought used from the classifieds here, and this is not one of the bad serial number units, but I don't have a warranty for this piece and as I understand it due to the method of construction most independent repair guys won't touch it. Should I start shopping for a replacement? I'm not wild about spending 2/3rds of what i paid to have it repaired, but I really like this head.
Thoughts?
I bought used from the classifieds here, and this is not one of the bad serial number units, but I don't have a warranty for this piece and as I understand it due to the method of construction most independent repair guys won't touch it. Should I start shopping for a replacement? I'm not wild about spending 2/3rds of what i paid to have it repaired, but I really like this head.
Thoughts?
I don't know if it is still active, but Carvin used to have a place to post questions and "talk" to techs on their site, but it is now blocked at my office so I haven't been there in a long while. If it still exists, explain your issue there and a Carvin Tech as well as other Carvin owners may have some excellent advice for you.
Sounds like a good idea, otherwise, I think the only option is to call support and see what options they may be able to offer.
This may sound like a shot in the dark, but if what they quote you displeases you, ask them if they'd want to buy the thing as a "core" (think water pumps and alternators). There's got to be residual value in the case and preamp section and power supply, assuming it's the power amp section that's gone 'round the bend.
Also, if the preamp's output is clean, your BX may be a candidate for use with a separate power amp. Might be able to find a used power amp for what it'd cost you to fix the BX. Lots of sleds out there these days for cheap 'cause everyone's got the fever for switchers, and more and more sleds are finding themselves lost and alone.
Also, if the preamp's output is clean, your BX may be a candidate for use with a separate power amp. Might be able to find a used power amp for what it'd cost you to fix the BX. Lots of sleds out there these days for cheap 'cause everyone's got the fever for switchers, and more and more sleds are finding themselves lost and alone.
True, but in this case, he was talking about using it as a DI box, so I think the issue is actually in the preamp.
LOL! If that's what you consider to be a big major f-up, you're doing one helluva lot better than I am!LOL, well, that's my Big Major Effup for the day! Let's see if I can keep it to just one.
Moose, have you tried bridging the effects loop?
Also, as long as this isn't eligible for warranty work, try going back in and disconnecting and then reconnecting every plug on the PC boards you can find. Also check every internal screw, in case one of those screws is responsible for holding a PCB ground plane firmly against a metal standoff, or part of a wired ground connection to the metal case. Actually you could loosen and re-tighten each one just to make sure.
Also, as long as this isn't eligible for warranty work, try going back in and disconnecting and then reconnecting every plug on the PC boards you can find. Also check every internal screw, in case one of those screws is responsible for holding a PCB ground plane firmly against a metal standoff, or part of a wired ground connection to the metal case. Actually you could loosen and re-tighten each one just to make sure.
Passinwind
I know nothing.
- Dec 3, 2003
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- Designer/Toaster Tech @ Passinwind Electronics
Quick update on Craig p's thoughts, It does not seem to act like a grounding issue due to the fact that it's more prevalent in the di than through the power amp. In fact, inserting at the effects loop input eliminated the loud bursts of static through the speaker, but this eliminates the DI capabilities. To me, it sounds like a bad cap in the DI circuit. I've seen worse reasons to drop a Jensen transformer DI into a bass head.
However, the graphic eq comes after the effects loop return, so this unit still has eq ability if you bypass the preamp. This will likely be my live workaround for now.
However, the graphic eq comes after the effects loop return, so this unit still has eq ability if you bypass the preamp. This will likely be my live workaround for now.
When you mentioned DI before, I thought you were taking a feed off the XLR. This would be the only way I know of to "bypass the preamp." Now it looks like you're actually taking a signal from the effects send jack. Also I'm not sure how inserting at the "effects loop input" (effects return?) would be an option if you're looking to get a line-level signal from the amp. Scratching my head over this one.
Backing away a bit, if it were my amp and I wanted to use it to throw a line level at a mixer or power amp, I'd take the feed off the effects send, but I'd also insert a shorted phone plug into the effects return jack.
Backing away a bit, if it were my amp and I wanted to use it to throw a line level at a mixer or power amp, I'd take the feed off the effects send, but I'd also insert a shorted phone plug into the effects return jack.
Sorry, I did not mean to confuse.
Craig, I was taking a feed from the xLR DI output. Instead of bypassing the preamp, it's a pre-eq feed, at least, for the most part... the Graphic still seems to work on the DI as well. It's not supposed to, but it does on my unit.
And I was mistaken when I said that the effects send bypasses the preamp... I'm on drugs or something. I only input at the effects return to try and bypass the preamp signal and see if the poweramp was the culprit when it came to the noise and such. It provides me a workaround solution, and more information to any of the amp geniuses who might be able to tell me what's going wrong with my unit.
Craig, I was taking a feed from the xLR DI output. Instead of bypassing the preamp, it's a pre-eq feed, at least, for the most part... the Graphic still seems to work on the DI as well. It's not supposed to, but it does on my unit.
And I was mistaken when I said that the effects send bypasses the preamp... I'm on drugs or something. I only input at the effects return to try and bypass the preamp signal and see if the poweramp was the culprit when it came to the noise and such. It provides me a workaround solution, and more information to any of the amp geniuses who might be able to tell me what's going wrong with my unit.
No problem. I've had days like that.
Except now I'm really confused regarding the signal path inside that amp. Wish they supplied a block diagram the way GK does. Or is there one and I just missed it somewhere? I might pop over to the Carvin boards and see if there's an answer.
But anyway, glad you found a workaround.
Except now I'm really confused regarding the signal path inside that amp. Wish they supplied a block diagram the way GK does. Or is there one and I just missed it somewhere? I might pop over to the Carvin boards and see if there's an answer.
But anyway, glad you found a workaround.
I was also having distortion problems. I emailed tech support and was advised to clean the ribbon cable connections. It worked---so far so good.
Here's the reply:
Hi my name is Emeric. I'm guessing a bad or dirty ribbon cable. If you can open it up and move each black ribbon cables around and test it and see if it goes back to normal. If it does. I suggest cleaning cables with electronic contact spray.
Emeric Cornel
Service Department
1.800.854.2235 x193
Carvin Corp.
12340 World Trade Dr.
San Diego, CA 92128
Mooselumps,
Did you try patching a cord from the effects send to the effects return?
It sounds like you may have a problem jack which has been a common problem on the Mesa Walkabout (why they added the switch for the effects loop) and some older GK amps.
Buzz
Did you try patching a cord from the effects send to the effects return?
It sounds like you may have a problem jack which has been a common problem on the Mesa Walkabout (why they added the switch for the effects loop) and some older GK amps.
Buzz
Hey folks...
I ran across a Carvin BX500 here locally and I had some questions about it.
The owner says he bought it a couple months ago new off ebay without a tube. I checked there and carvin has a listing for them that way so I'm figuring that's legit. He says everything is working fine, but he just doesn't care for the sound he's getting.
What I'm wondering is can I put a tube in it? Is it just a PNP situation or is there more to it when a tube is installed/replaced?
Second, I can't find a spec beyond 12ax7 for the tube, but when I search 12ax7 there are apparently a bunch of different versions of the basic tube. Are they all the same with the P/N suffix denoting maker or something, or are they different enough I could screw up buying the wrong one? I've got a NIB Electro Harmonix 12ax7 I picked up many years ago as a spare for my SWR basic 350 and I'm wondering if I could use it in the carvin or would I be better off to buy a tube and keep the EH in case I need it for my SWR?
I've skimmed the 3 threads dedicated to the bx500 and the general impression I got was it's a nice amp. did I get the right impression or did I bias myself because I can get it for a really good price if I decide I want it?
I'm going over to try it out one night this week, anything in particular I should look for?
Thanks in advance for any and all help/info/opinions.
I ran across a Carvin BX500 here locally and I had some questions about it.
The owner says he bought it a couple months ago new off ebay without a tube. I checked there and carvin has a listing for them that way so I'm figuring that's legit. He says everything is working fine, but he just doesn't care for the sound he's getting.
What I'm wondering is can I put a tube in it? Is it just a PNP situation or is there more to it when a tube is installed/replaced?
Second, I can't find a spec beyond 12ax7 for the tube, but when I search 12ax7 there are apparently a bunch of different versions of the basic tube. Are they all the same with the P/N suffix denoting maker or something, or are they different enough I could screw up buying the wrong one? I've got a NIB Electro Harmonix 12ax7 I picked up many years ago as a spare for my SWR basic 350 and I'm wondering if I could use it in the carvin or would I be better off to buy a tube and keep the EH in case I need it for my SWR?
I've skimmed the 3 threads dedicated to the bx500 and the general impression I got was it's a nice amp. did I get the right impression or did I bias myself because I can get it for a really good price if I decide I want it?
I'm going over to try it out one night this week, anything in particular I should look for?
Thanks in advance for any and all help/info/opinions.
I did. I still get the same dirty DI and Shots of static through the power amp.
I bought mine from ebay without a tube. I've got a couple of 12AX7 tubes that I've tried in mine. A generic Chinese made tube and a JJ brand tube. Both work just fine, and the difference in sound between the two is barely noticeable. I prefer the JJ, but there's not enough voltage on it to really make much of a difference. With the tube engaged is definitely a little warmer sounding than bypassed though, so I recommend at least experimenting with a tube. All you do is press it into the socket and put the lid back on the amp. Couldn't be easier.
