Fix my broke Carvin BX1500

[scottfeldstein]

I really loved my Carvin BX1500. (Whoa, that post says I paid "about $600" for it. I actually paid 3 in April of 2017. I think I was confusing it with the purchase of my Warwick 5-string.) But, love or not, it developed a problem a couple of years ago. One of the two amps just...lost low end. For a time I thought I was experiencing a speaker problem. I even replaced a perfectly good GK 15 at one point, only to later realize that it was the amp.

I think someone in these forums once suggested that I needed to open it up and blow out the ribbon connections with deoxit or something. Any other opinions? I don't have anyone local I can take it to. Besides, if it's a no-solder, no-parts repair, I should just do it myself.

 

[byacey]

I read this as " The honeymoon is over!"

If the audio quality is good, but the low end is lost, it sounds like an issue in the preamp or EQ stages. It's possible reseating any ribbon connectors may solve the problem if it's just an intermittent contact; I wouldn't be spraying de-oxit into those connectors. Deoxit leaves an oily residue behind that can potentially cause more problems down the road. If anything, use a zero residue contact cleaner.
Anything beyond that, you should get it to a qualified tech, one who has real credentials displayed on the wall.

 

[arbiterusa]

I'm sure there's a perfectly good trash can somewhere near you. Such has always been the destination of all Carvin electronics.

 

[jeff7bass]

I'm sure there's a perfectly good trash can somewhere near you. Such has always been the destination of all Carvin electronics.

Nonsense but everybody has an as... I mean an opinion.

 

[byacey]

I'm sure there's a perfectly good trash can somewhere near you. Such has always been the destination of all Carvin electronics.

That sounds a little harsh. It sounds like Carvin was trying to offer a feature-rich product, but to maintain profitability on the market, cuts have to be made somewhere in the manufacturing process. Perhaps the connectors are problematic, but usually there is a way to increase reliability, if this indeed the problem.

Getting a proper evaluation done by a qualified technician is the only way to know for sure.

 

[scottfeldstein]

I read this as " The honeymoon is over!"

If the audio quality is good, but the low end is lost, it sounds like an issue in the preamp or EQ stages. It's possible reseating any ribbon connectors may solve the problem if it's just an intermittent contact; I wouldn't be spraying de-oxit into those connectors. Deoxit leaves an oily residue behind that can potentially cause more problems down the road. If anything, use a zero residue contact cleaner.
Anything beyond that, you should get it to a qualified tech, one who has real credentials displayed on the wall.

Interesting idea, about the preamp/EQ stages. But the two amps share those, so it would be affecting both of them, not just one. Right? About "zero residue" contact cleaner...like MG Chemicals' Electrosolve? $15 on Amazon.

 

[scottfeldstein]

It sounds like Carvin was trying to offer a feature-rich product, but to maintain profitability on the market, cuts have to be made somewhere ...

This has always been my suspicion, both pre- and post-brokenness. How could they be offering so many features and so many watts at such a great price? It's got to be paid for in component quality or manufacturing process compromises.

 

[byacey]

Interesting idea, about the preamp/EQ stages. But the two amps share those, so it would be affecting both of them, not just one. Right? About "zero residue" contact cleaner...like MG Chemicals' Electrosolve? $15 on Amazon.

That MG product should be fine for that purpose. Does that amp have a switchable crossover between full range and biamp function between the two outputs?

 

[scottfeldstein]

That MG product should be fine for that purpose. Does that amp have a switchable crossover between full range and biamp function between the two outputs?

It does have a frequency-adjustable crossover that you can switch on and off, making one amp bass and the other amp treble. I have never used it. But of course it was one of my first troubleshooting ideas, that perhaps I had accidentally turned it on. Not so.

 

[byacey]

From the symptoms you described, that's where I would be looking first.

Before you replaced your cabinet, you didn't think to plug it into the other output, or test it with altogether another amplifier first?

 

[scottfeldstein]

From the symptoms you described, that's where I would be looking first.

Before you replaced your cabinet, you didn't think to plug it into the other output, or test it with altogether another amplifier first?

I didn't replace a cabinet, I bought a replacement speaker for it. It was years ago now, but yes I did switch the amp outputs to two cabs to compare. Doing so didn't reveal much at the time. Perhaps I had them stacked and their positions masked the difference. Not sure anymore. But it wasn't just me. My guitar player/producer at the time also concluded that it was probably the speaker. Our opinions may have been shaped by the fact that we had recently returned from a very loud gig in Minneapolis and it seemed a likely scenario that I had damaged one.

 

[Drummerboy2]

I read this as " The honeymoon is over!"

If the audio quality is good, but the low end is lost, it sounds like an issue in the preamp or EQ stages. It's possible reseating any ribbon connectors may solve the problem if it's just an intermittent contact; I wouldn't be spraying de-oxit into those connectors. Deoxit leaves an oily residue behind that can potentially cause more problems down the road. If anything, use a zero residue contact cleaner.
Anything beyond that, you should get it to a qualified tech, one who has real credentials displayed on the wall.

There was a wipe back in the 90's called Gold Wipes, This was for cleaning the gold plated edge connectors on PCB's, Test fixture contact points, and Ribbon cable edge contact point. Good stuff no residue left behind. I don't know if it's still around. You would actually see the contaminants come off onto the wipe, the cleaned surface was nice and clean.

 

[byacey]

I remember an MG product similar to this, but it was in a small bottle, application by Q tip or syringe. If I recall correctly, it was not recommended for anything other than gold contacts.

 

[coy garcia]

I had a carvin bx500 that I bought when my boogie 400+ went bad (needed something quick) . I used it for years and loved how easy it was to transport and that it powered my boogie stack with good tone.. until one day it stopped working. Was quoted by carvin 300 bucks to fix it (almost what I paid new). Took my boogie into the shop instead and when I got it back I was blown away by how good it sounded. Those amps seem good until they don't work and then they are not worth it to fix IMHO.

 

[braud357]

Carvin's repair policy only applied to units still in warranty. If your amp was out of warranty, they offered an "Exchange" program" - basically selling you a new amp at a discounted price. I had a BX-500 that went bad after the warranty expired - I had NEVER played a gig with it ! They offered me another for a bit under $300 (if I am remembering correctly ). I asked if I could upgrade, and they said "certainly" ! I paid another $100 and got a BX-1500. I did find it sad that they did not offer repairs on their own products !!

 

[dbsfgyd1]

I’m not qualified to offer an opinion on a repair, but I’m sure a qualified technician could. I do have some experience with two Carvin amps, the ones that had red knobs, and covered in rat fur. They sounded great, but tended to fail when bridged. I had a tech tell me (what do I know if this is the truth or not?) said that the balance knob needed to be dead evenly balanced when they were bridged or they would fry. Best wished with yours. Hope it doesn’t cost too much to fix.

 

[coy garcia]

Carvin's repair policy only applied to units still in warranty. If your amp was out of warranty, they offered an "Exchange" program" - basically selling you a new amp at a discounted price. I had a BX-500 that went bad after the warranty expired - I had NEVER played a gig with it ! They offered me another for a bit under $300 (if I am remembering correctly ). I asked if I could upgrade, and they said "certainly" ! I paid another $100 and got a BX-1500. I did find it sad that they did not offer repairs on their own products !!

Somehow I don't think these amps will ever be collectable like a old ampeg or boogie.

 

[Funkinthetrunk]

I had a carvin bx500 that I bought when my boogie 400+ went bad (needed something quick) . I used it for years and loved how easy it was to transport and that it powered my boogie stack with good tone.. until one day it stopped working. Was quoted by carvin 300 bucks to fix it (almost what I paid new). Took my boogie into the shop instead and when I got it back I was blown away by how good it sounded. Those amps seem good until they don't work and then they are not worth it to fix IMHO.

In my 40+ years of playing, all amps seems good until they don't work. I've had my share.

 

[agedhorse]

I had a tech tell me (what do I know if this is the truth or not?) said that the balance knob needed to be dead evenly balanced when they were bridged or they would fry.

Urban myth and old wive’s tale, but it is true that bridged linear amps tend to be less reliable for a variety of other reasons however.

 

[mrjim123]

My Carvin BX500 failed (totally, didn't just drop the low end) and I was able to restore it by removing the ribbon connectors, cleaning them with Deoxit, then of course replacing them. At some point I also had to disable the tube via a switch in the back, which was OK because I never noticed any difference with the tube engaged. It wouldn't hurt to Deoxit the ribbon connectors. YMMV.