Stiletto Ace 50w head issue! HELP!

[dualrec26]

Okay, so, I love the way my stiletto sounds BUT for quite sometime the sound keeps cutting in and out. I will be playing at a decently low volume and the amp just cuts out and I can only hear faintly through the cab THEN it cuts back in up to the volume I have it at. I have had the amp looked at and the guy said the preamp valves are find and the power tubes are fine.

When I turn up the volume on the fluid drive/tite gain channel, it doesn't cut out. On the clean channel, it cuts out at any volume.

My guesses:
1. Could it be my speaker cable?
2. Could it be my cabinets/speakers? (Marshall 1960bx 4x12)
3. Could it be a fried output transformer?

 

[MrMarkIII]

Here's the info from a Mesa Memo...


SOUND “DROP-OUTS” / INTERMITTENT SIGNAL

One Possible Cause



Most (but not all) Mesa/Boogie amplifiers have one or two “cathode follower” tube
stages in their preamps. Tube selection is CRITICAL in these stages.



Specifically, in a 12AX7 tube used as a “cathode follower”, the voltage difference
between that present at the cathode, as compared with the heater voltage, can be
withstood or tolerated by certain types of tubes, whereas other tubes will fail. The
failure of a “cathode follower“ tube will cause sound dropouts or signal loss.



For the past few years, Mesa has been using two types of 12AX7 tubes: ones
originating in Russia (Sovtek EH), and ones originating in China. The Russian (Sovtek)
tube is NOT reliable as a cathode follower. Of the tubes we are using today (March
2008), ONLY THE CHINESE 12AX7 IS RELIABLE AS A CATHODE FOLLOWER.



In conclusion, if you are troubleshooting for signal dropout in a Mesa/Boogie amp,
suspect a cathode follower tube, and try replacing it with a Mesa 12AX7 that is marked
as “CHINESE” (silk-screened on the tube itself).



Below is a partial list of Mesa amps and cathode follower tube locations:

GUITAR AMPS BASS AMPS

Lone Star & LS Special: V3
M-Pulse: V2
Stiletto: V3 & V4
Venture: V2
Road King I: V3 & V4
Big Block 750: V4
Road King II: V3 & V5
Titan: V4
Roadster: V3 & V5
M2000: V2
Dual & Triple (2ch or 3ch): V3 & V4
Bass 400+: V2
Tremoverb: V3 & V4

ANOTHER POSSIBLE SCENARIO may occur in the “SPONGY” (or on some models,
“TWEED”) power setting: the reduced filament voltage may cause very low output from
a RUSSIAN preamp tube. Again, the recommended fix is to replace the “sagging” tube
with the CHINESE type of Mesa 12AX7 - which are more immune to this type of failure.

 

[dualrec26]

Well, I just talked to a guy from mesa and he said it maybe the fact that on the back I had a button set on loop in instead of hard bypass. I switched it to hard bypass and had no issues.

He also brought up the chinese vs russian 12ax7's. Does anyone know where I can get the chinese 12x7's that they make?

What I am now curious about is how I would go about running the fx loop. On loop in? or hard bypass? I haven't started using the fx loop but I am going to start pretty soon because I just got a flanger and a delay pedal.

 

[Stonge]

That sounds like it might be a dirty effects loop jacks. Maybe? It's worth a shot. It is always nice when an amp requires on an easy fix such as spraying a little contact cleaner in there!

 

[Old BF Shred]

That sounds like it might be a dirty effects loop jacks. Maybe? It's worth a shot. It is always nice when an amp requires on an easy fix such as spraying a little contact cleaner in there!

+1000!!
My Ace had this problem because the "unplugged state" contacts barely touched when nothing was used in the loop. I simply opened the amp and "reformed" the contact so it would seat more tightly when unplugged.

Now, please understand that I don't recommend trying this unless you are comfortable working on amps, but it was a quick easy fix that avoided a trip to the service center. And yes it did cause occasional drop outs. :roll:

Also be careful what you spray into the amp....what gets past the jack itself lands on other parts of the amp that may not respond too well to it! 8)
If you need to use contact cleaner I like to use the small squeeze bottles of "Deoxit" (or =)....much easier to control where it goes.

Good luck!

 

[dualrec26]

How I would go about running the fx loop? On loop in? or hard bypass? I haven't started using the fx loop but I am going to start pretty soon because I just got a flanger and a delay pedal.

 

[Old BF Shred]

The manual explains this pretty well...better than I could in this thread, but be aware that the problem I describe will only happen when the FX loop jacks have nothing plugged in them and the loop is engaged (NOT hard bypassed). :wink:

 

[Stonge]

With the loop on, you have the ability to use the solo function. I personally do not use the loop on this amp. Although, I used to, and I must say that the loop on this amp is pretty sweet. You want to start everything at about 50% (output knob on front and send knob on back) then go from there. If you blend those 2 nice you will get an extra pair of balls out of this thing. Then just set your solo knob to an acceptable level depending what you are using it (solo) for.
Hope this helps out.

 

[cradlefish]

Okay, so, I love the way my stiletto sounds BUT for quite sometime the sound keeps cutting in and out. I will be playing at a decently low volume and the amp just cuts out and I can only hear faintly through the cab THEN it cuts back in up to the volume I have it at. I have had the amp looked at and the guy said the preamp valves are find and the power tubes are fine.

When I turn up the volume on the fluid drive/tite gain channel, it doesn't cut out. On the clean channel, it cuts out at any volume.

My guesses:
1. Could it be my speaker cable?
2. Could it be my cabinets/speakers? (Marshall 1960bx 4x12)
3. Could it be a fried output transformer?

This reply may be too late.

Replace your preamp tubes. That's the first thing I would do if it's it not cable related as well as input jack.

 

[Jak0lantern01]

I had somewhat similar symptoms, turned out the V2 pre-amp tube was shot.

 

[crosty81]

Okay, so, I love the way my stiletto sounds BUT for quite sometime the sound keeps cutting in and out. I will be playing at a decently low volume and the amp just cuts out and I can only hear faintly through the cab THEN it cuts back in up to the volume I have it at. I have had the amp looked at and the guy said the preamp valves are find and the power tubes are fine.

When I turn up the volume on the fluid drive/tite gain channel, it doesn't cut out. On the clean channel, it cuts out at any volume.

My guesses:
1. Could it be my speaker cable?
2. Could it be my cabinets/speakers? (Marshall 1960bx 4x12)
3. Could it be a fried output transformer?

I have the same problem
Did you fixed it?

 

[rarebitusa]

I have the same problem
Did you fixed it?

Look at the following post from

MrMarkIII​