Cab clone blowing the main fuse on my Mark V - anyone else?

[AllanCWilliams]

I've used my cab clone twice and both times within about 20 minutes, its blown the main power fuse on my Mark V. I've never had a fuse blow on me ever on an amp, or on this amp, till the cab clone.
I have the correct output and using the same one as the combo speaker connection lead. Its an 8 ohm unit, same as the speaker.
Since purchase I have had to run it with the knob completely at lowest possible level.
I'm about to see if I can get it repaired or exchanged. Checking posts though I cant see that anyone else has had this problem which seems curious.
Any others had this experience with it?

 

[dbagchee]

Yeah sounds like there is something wrong with yours. I've plugged mine into several amps for longer periods of time and no blown fuses yet.

 

[Authorized Boogie]

I've used my cab clone twice and both times within about 20 minutes, its blown the main power fuse on my Mark V. I've never had a fuse blow on me ever on an amp, or on this amp, till the cab clone.
I have the correct output and using the same one as the combo speaker connection lead. Its an 8 ohm unit, same as the speaker.
Since purchase I have had to run it with the knob completely at lowest possible level.
I'm about to see if I can get it repaired or exchanged. Checking posts though I cant see that anyone else has had this problem which seems curious.
Any others had this experience with it?

Are you using a speaker cable from the amp to the Cab Clone? Are you using it as a load or with speaker thru?

Where are your Gain, Master, and Output controls on the amp set?

Thanks

 

[midifail]

Hi!
Instead of opening a new thread, i decided to use this one, since my problem is very close to the one mentioned here.
I got a new CabClone, which i used today to play my Express 5:50+ through headphones.
After a very short time (1 minute), the volume of the amp massively dropped down and didn´t come up anymore.

The CabClone was connected to the matching speaker output (8 ?) via Speaker Cable witch no speaker attached.
D.I Level set to minimum, Phase in, Ground, and Open Back Cab Sim.

The Express+ was in 5 Watt Mode on Clean, with Gain and Master @ 2 o´clock, EQ nearly flat (Bass @ 10 o´clock).

Since then, the amp won´t come up to a usable Volume, even in 25 Watt and 50 Watt mode, regardless of a Speaker or the CabClone is used.

What I did:
Swap Tubes in V2 and V4 to new ones.
Changed V6 to V7 and V7 to V6, since I have no new 6L6 to swap.
(At least this should help in 5 Watt mode, if one 6L6 is blown, since 5 Watt only uses one Tube, right?)

What happened?
How can I fix this?

Or does my Amp (or the CabClone) need Service?

Thanks!

 

[Authorized Boogie]

Hi!
Instead of opening a new thread, i decided to use this one, since my problem is very close to the one mentioned here.
I got a new CabClone, which i used today to play my Express 5:50+ through headphones.
After a very short time (1 minute), the volume of the amp massively dropped down and didn´t come up anymore.

The CabClone was connected to the matching speaker output (8 ?) via Speaker Cable witch no speaker attached.
D.I Level set to minimum, Phase in, Ground, and Open Back Cab Sim.

The Express+ was in 5 Watt Mode on Clean, with Gain and Master @ 2 o´clock, EQ nearly flat (Bass @ 10 o´clock).

Since then, the amp won´t come up to a usable Volume, even in 25 Watt and 50 Watt mode, regardless of a Speaker or the CabClone is used.

What I did:
Swap Tubes in V2 and V4 to new ones.
Changed V6 to V7 and V7 to V6, since I have no new 6L6 to swap.
(At least this should help in 5 Watt mode, if one 6L6 is blown, since 5 Watt only uses one Tube, right?)

What happened?
How can I fix this?

Or does my Amp (or the CabClone) need Service?

Thanks!

Hi,

First - the 5 watt setting is not going to give you enough output for headphone use. (also, DI level is only controlling the DI out)

Now - The CabClone's internal load will not effect the amp or tubes in an way that any other type of load will (i.e. speaker). Turning the Master/Output control up to "dime" the amp while keeping the levels low *WILL* harm your tubes, just as it would if a speaker were attached.

That said - in your case - you need to do a thorough preamp tube troubleshooting. Take 1 new 12AX7 and swap it into each position, one position at a time - testing the amp in between each swap. Your power tube method is good, but better to swap a new pair when troubleshooting.

Since your description is somewhat vague - I would recommend giving us a call in customer service to go over things in more detail. Thanks!

 

[midifail]

Thank you for your fast answer!

First - the 5 watt setting is not going to give you enough output for headphone use.

OK, this is good advice.

That said - in your case - you need to do a thorough preamp tube troubleshooting. Take 1 new 12AX7 and swap it into each position, one position at a time - testing the amp in between each swap.

That did the trick for me!
It was V3!
Put a new one in there and my problem is solved.
Thank you very much!!!


Is there a technical Reason for this Tube to fail in my scenario or is this a remarkable coincidence?

Since your description is somewhat vague - I would recommend giving us a call in customer service to go over things in more detail. Thanks!

Sorry for that!
Since i am not a native speaker, i may not be as precise as i want to.

 

[Authorized Boogie]

Thank you for your fast answer!

First - the 5 watt setting is not going to give you enough output for headphone use.

OK, this is good advice.

That said - in your case - you need to do a thorough preamp tube troubleshooting. Take 1 new 12AX7 and swap it into each position, one position at a time - testing the amp in between each swap.

That did the trick for me!
It was V3!
Put a new one in there and my problem is solved.
Thank you very much!!!


Is there a technical Reason for this Tube to fail in my scenario or is this a remarkable coincidence?

Since your description is somewhat vague - I would recommend giving us a call in customer service to go over things in more detail. Thanks!

Sorry for that!
Since i am not a native speaker, i may not be as precise as i want to.

In this case, it was simply a coincidence that a preamp tube failed. There is simply no way to predict or guarantee the life of a vacuum tube!! Thanks!!

 

[AllanCWilliams]

Hi Authorized Boogie
I've been using it for playing a silent stage so unplugging the fly lead from the combo speaker and plugging in the CC to that same output. No speaker plugged into the CC. Just the XLR out to the PA.
As for settings, Main Output volume never more than 12 o'clock. Gain varies on channel. Channel Master out at max about 1 o'clock. And was using 45W mode on all 3 channels.

Hope that helps.

Can you give me some guidance on which tubes I need to be looking at for the 45W mode not working?

Thanks kindly
Allan

 

[Authorized Boogie]

Hi Authorized Boogie
I've been using it for playing a silent stage so unplugging the fly lead from the combo speaker and plugging in the CC to that same output. No speaker plugged into the CC. Just the XLR out to the PA.
As for settings, Main Output volume never more than 12 o'clock. Gain varies on channel. Channel Master out at max about 1 o'clock. And was using 45W mode on all 3 channels.

Hope that helps.

Can you give me some guidance on which tubes I need to be looking at for the 45W mode not working?

Thanks kindly
Allan

Hi Allan,

Are you using a speaker cable between the amp and CabClone?

In 45W the amp uses the center pair of power tubes.

Thanks!

 

[Authorized Boogie]

Hi Allan,

Have you solved the issue? If not, give me a call in Customer Service and we can discuss further! Thanks!

Garey

 

[AllanCWilliams]

Hi Garey.
Thanks for following up - thats good of you. At the moment I'm just trying to get the amp back up and running correctly again first. Put in the new 6L6 pair yesterday into the 45W position and just checking they, and the amp overall, are stable and ok for a night or two before going any further. (getting stuff to here is 10 days or so each time). Just added back in tonight the 90W pair hoping they are unaffected by the failed 45W pair.
Before I try the CC again, I'll make up a new fly lead for it given that you've mentioned it twice now.
Any other recommendations before I try again?

Allan

 

[Authorized Boogie]

Hi Allen,

As long as you are using a correct speaker cable to the CabClone, and using settings you would use normally with a speaker attached - everything should be good. Through all of our pre-production testing we were unable to make one amp/tube fail - and since your message we have been pounding a Mark V with the CabClone connected using your settings with no issue. Out of the thousands of CabClones that have gone out, we've seen no failures related to the CabClone, so your issue has piqued our interest. Keep in mind, tubes can fail - whether a speaker load or the Cab Clones resistive load is connected to the amp! Thanks again!

 

[2 Boogie]

Hello Allan!

Do the main fuse blows if you have a speaker cabinet connected? or will it blow only when the cab clone is connected?
One reason why main fuse blows, is that the power tubes or the output transformer overheats, caused by wrong impedance connected to the output of the amp.
Is it a 8ohm cab clone you have? or the cab clone could have one or more bad components inside.

Dr B

 

[AllanCWilliams]

Hi Authorised Boogie.
Wanted to give you an update. The new 6L6 pair into the 45W position took care of that problem. Just ran the speaker only for a few gigs to ensure the amp in standard config was all good again. No issue there.

Last week decided to give the CabClone another try. Based on your previous comments I made up a new much heavier weight lead (650W capacity cable). Plugged in my headphones - nothing. Wanting to eliminate every conceivable thing in my control, tried another pair of headphones - nothing. Last thought of anything else that could be causing a problem, I quickly tried a standard patch cable from the speaker output, and it worked. (I only ran for a short time so i didn't induce any problems). Other heavy duty lead back in, which has very clean clear joints, and with some wiggling, it started working. Perhaps a dry joint on the socket connection or some problem with the CC input socket? The plugs I used were very reasonable quality ones.
Because you guys sound to have been going to extensive effort with this, I am wanting to make sure I've covered all bases thoroughly as well. I've ordered a new mogami speaker cable to try. Just waiting for that to arrive. I'll let you know how it behaves after that.

Hi Dr B - yes - at the start of this I'm pretty sure i mentioned that i am using an 8 ohm output into an 8 ohm cab clone. All good there.

Regards
Allan

 

[AllanCWilliams]

Hi Authorised Boogie.
If you want this thing back, or can perhaps organise an exchange, I'd be very happy to send it to you.
A new high quality speaker cable to make sure everything about everything is all top notch.
Output sound through headphones was slightly distorted even through the clean sound. Not enamoured with it, and then after about 10 minutes I got a high pitch squeeling coming through. I'm guessing a/some valves going microphonic. I shut the amp off quickly, let it cool for about half hour played again through the speaker and crisp clean sound through the clean channel. Hopefully it hasnt cooked another pair of valves and another hundo to replace them.
I do not trust this unit at all and its not going back on my amp at all. I love my MV and I dont want to risk damage to it.
I trust that generally these units are fine. But this one is not going back on my amp.
If its helpful for it to come back to you guys for you to check (and preferably exchange/replace), I'd be very happy to do whatever is needed for that to happen.
Regards,
Allan

 

[Authorized Boogie]

Hi Allen,

Please call Mesa Customer Service at 707-778-6565

Thanks!