Problem with Studio .22

[kakemonikossa]

Gents,

I'm having little trouble with this Studio .22 amp. Problem is this weird effect I get during long single notes. It sounds like very fast tremolo and some amount of hum which both seems to be dependant on the frequency of the electricity (50Hz). It appears when the amp is properly warmed, seems to be fine just after I switch it on and it still running rather cool.

I bet I'm not the first one to have this kind of issue so I'm hoping someone would help me out and get this amp sorted. Any help will be much appreciated!

 

[plumptone]

When was the last time you did a complete re-tube? I had one of these back in the 80's and whenever it did that it meant it was time. Do the whole thing - you'll be amazed what a difference it makes. In my experience these things will burn through output tubes pretty quickly if you run it hard and often. Good luck.

 

[kakemonikossa]

When was the last time you did a complete re-tube? I had one of these back in the 80's and whenever it did that it meant it was time. Do the whole thing - you'll be amazed what a difference it makes. In my experience these things will burn through output tubes pretty quickly if you run it hard and often. Good luck.

Thanks for the tip! I retubed the amp but unfortunately it didn't help. Still this subtle tremolo-like effect..

:?

 

[Boogiebabies]

Tremolo in effect is an oscillation. You may have a bad coupling or power supply filter cap and what you are hearing is a ripple.

I would send it to Mesa, or at least give them a call.

 

[stomper]

Tremolo in effect is an oscillation. You may have a bad coupling or power supply filter cap and what you are hearing is a ripple.

A good assessment of the issue. A local tech could take care of this. Unfortunately, this amp is a "pita" to work on. Power section capacitors are best changed out every 10 years. Yours are probably 20+ in the .22 caliber. Many amps run about this long without problems. The 10 year recommendation is a safe window 98% of the time. Fix them before they fail. Check here.

http://geofex.com/ampdbug/ampdebug.htm

 

[kakemonikossa]

Tremolo in effect is an oscillation. You may have a bad coupling or power supply filter cap and what you are hearing is a ripple.

A good assessment of the issue. A local tech could take care of this. Unfortunately, this amp is a "pita" to work on. Power section capacitors are best changed out every 10 years. Yours are probably 20+ in the .22 caliber. Many amps run about this long without problems. The 10 year recommendation is a safe window 98% of the time. Fix them before they fail. Check here.

http://geofex.com/ampdbug/ampdebug.htm

Thanks! I opened the amp and judging from the solder joints those caps are original, the amp is dated 08/87 so your estimate was pretty accurate

Thanks for everyone! Much appreciated! Gotta call to local tech. Like said looks like PITA to work on so I'd rather not do it by my self. These are the moments when one really starts to appreciate ptp :?

 

[stomper]

Glad to help. Let us know how you make out.