Amp Help - 84' Carvin X100b - 2 Issues Connected?

[thedudebro]

So Czech this out comrades, I've got a couple questions that have been riddling me for a couple days now, and I'm considering shelling out the money to get them fixed.

Now first off, I love this amp, I will never sell it. In fact it's going to be in my family for generations to come.

However, I picked it up off Craigslist for $240 (purchased a cab later for 180.. [180 + 240 = 420] lol )

It came packed with all new tubes, but it also came with a special, "mod." Which later became apparent as a big problem with the unit.

So this brings me to problem #1:

 

The guy said it was "modded" to have a "neutral effects loop," which I later found out was more of a "neutered effects loop."

I've put a cheap BBE Sonic Maximizer through it and it was hardly noticeable, though in any other amp it is VERY noticeable.. as all of you are probably aware.

Not only that, but when I engage the effects 2 button on the amp's foot-switch, it actually acts as a kill-switch.

Though it should be noted that hard attacks with a pick will come through just barely as little farts, like as if you slapped the strings just as you flipped the standby switch.

And so just last week I started having problem #2, I'm thinking that the two are symbiotically connected, and so now I will describe said problem:

 

On the Clean Channel with the "lead switch" engaged (which in Carvin terms is pretty much "the quiet switch")

The signal starts out ok, but not really pristine like when the Rhythm switch is engaged.

It starts to distort, and then breaks up and crackles (at all volume levels, but especially at higher levels)

 

These two problems are preventing me from playing quietly at home, and prevent me from using my other gear effectively;

Like for instance, to go from distortion to clean I have to hit the channel button on the footswitch and then flip the Lead/Rythm switch..

Pain In The Ass!

 

So any of you have enough experience to diagnose what might be wrong here?

I am proficient enough to learn from the schematic and perform minor surgery, but I also know the risk..

(The amp exploding and my very life)

Also note: I have a friend that has not only moved/bumped the amp while on, but also flipped the off switch without turning it on standby at all... 5 TIMES!!!

 

[Mr.Grumpy]

Turning the amp off without putting it on standby is no big deal. Tons of tube amps don't even have standby switches, and they work fine. It might slightly shorten the life of your power tubes, but even that is debatable. In any case, this is not the cause of your problem.

 

A quick glance at the blurry schematic I found on-line does reveal a couple of things:

1) This is a complex guitar amp.

2) The channel switching, reverb and effects loop switching are controlled by JFETs, similar to the electronic bypass in modern effects pedals.

 

With stuff like this, I like to check the 'moving parts' first. Switches and jacks can fail or act flaky from dirt, oxidation and wear. The problem could be the footswitch, the cable between the footswitch and the amp, or the footswitch jack. Exercise the effects loop switch by flipping it up and down several times. Try jumpering the effects loop with a guitar cable.

 

I have no idea what a "neutral" effects loop means. There's a couple of small capacitors in the effects loops input and output buffers, but I doubt they have any effect on tone.

 

There's a Carvin forum out there, you'll probably get a more informed response there.

[AJ6stringsting]

I've had mine since 1986, back in the day we called the Carvin X-100 B , the "JCM 800 Marshall Killer".

I had mine serviced in 1989, and the idiots at the factory redone my EQ switch back to only assignable to one channel ..... I was mad !!!

It's a great amp, just take it in to get serviced. Speaking of which, I gotta take mine in soon for some service maintenance.

[thedudebro]

I've had mine since 1986, back in the day we called the Carvin X-100 B , the "JCM 800 Marshall Killer".

I had mine serviced in 1989, and the idiots at the factory redone my EQ switch back to only assignable to one channel ..... I was mad !!!

It's a great amp, just take it in to get serviced. Speaking of which, I gotta take mine in soon for some service maintenance.

 

 

Dang dude, hope they fixed it back without charging you the second time.

 

UPDATE: I have yet to get it serviced, probably will with regard to the low-output mode on clean. (Rhythm)

The effects loop however was completely because I didn't have the footswitch engaged! Hitting my head on that one.

 

Also, I've been playing an eleven rack through it, and it sounds AWESOME. Even got the voodoo labs ground control pro for a couple of bills.

The amp is so complimentary and tweakable, in a way transparent, but yet giving all the digital stuff BALLS!

I'm forever satisfied with this, it is my dream rig come true!

Cheers folks!

[AJ6stringsting]

 

 

Dang dude, hope they fixed it back without charging you the second time.

 

UPDATE: I have yet to get it serviced, probably will with regard to the low-output mode on clean. (Rhythm)

The effects loop however was completely because I didn't have the footswitch engaged! Hitting my head on that one.

 

Also, I've been playing an eleven rack through it, and it sounds AWESOME. Even got the voodoo labs ground control pro for a couple of bills.

The amp is so complimentary and tweakable, in a way transparent, but yet giving all the digital stuff BALLS!

I'm forever satisfied with this, it is my dream rig come true!

Cheers folks!

 

 

I retired my amp heads and using my old Digitech 2112 GSP with Carvin and Crown power amps.

One day, I'll install a three way switch for my X-100 B. That amp is still awesome, but my 2112 does great simulations of my Carvin X-1100 B, V3, various VHT, Mesa-Boogie, Soldano Egnater, Peavey, Marshall and others .... now the ampheads can stay home, where it is safe

 

[thedudebro]

Dang dude, nice to hear Digitech got a little better at their stuff haha. The only thing I could stand from them was the whammy. .png.197c47f720636f02390cc2b0a33804da.png' alt='smiley-veryhappy'>

[AJ6stringsting]

I have the older gear ; the 2112 GSP, the Rp-1 and RP-12.

This old gear gets better sounds out of the new toys by Digitech or the others ..... hands down !!!!