Electric Guitars/Engl Screamer 50
About 2 years ago, I purchased a used Engl Screamer 50 head and a Marshall 1960A cabinet. It is the second tube amp that I have ever owned, so I don't know a whole lot about tube amp maintenance. I'm having a few problems with the amp, so I'm hoping that you can help me. First of all, the reverb on the amp doesn't work. It uses a tank, and I was wondering if the reverb tank is a simple circuit that I would be able to take apart and investigate. The amp also buzzes really, really badly. I replaced the power tubes in the amp, but it didn't seem to help. When I turn off the fx loop, the amp has a very treble-y sizzle, and when I activate the fx loop, the amp has a very fuzzy, low-pitched sounding buzz. The buzzing is louder when the fx loop is on. I've never had any maintenance done to the amp besides just replacing the tubes. What are some things that I can do to fix the buzzing and the occasional loss in gain and eq?
Also, the amp isn't necessarily a very "high-gain" amp, which is fine because I use a pedal to drive the preamp. I would, however, like the distortion to sound more saturated, even though it is a lower gain amp. I've tried attenuating the amp to drive the power tubes, but I only seem to lose gain when I do that. The preamp is driven by a quartet of 12ax7's, and the power amp is driven by 2 6l6's.
This amp is used, so I'm sure there are some things that I should have done to it, I just haven't gotten around to it.
Hi Matthew, I spent so time with an amp like your Engl to get a better understanding of the trouble you ran in to. You have several things going on. I will try to cover them all, if I do not address a point complete please send it back as a new question. The age is about five years? There is no handbook on maintenance for valve amp, just good care. Clean is very important, dirt and the like can be the death of the amp. Inspections for cracked solder joints and dirty pins.
The tank reverb runs off the pre amp, it is not made by Engl. These tanks can fail because the springs are not free or no output or input. The RCA jacks can be checked with a Volt Ohm meter set on 200 ohms range. Input should be 10 ohms, output 2575. Mega ohms open. The thin copper wires break easy. The tanks are made by Accutronics and are replaced not repaired. The part number is 9AB2A1B. I found them on Amazon.com for $19.99 not a bad price. This can cause corrupt behavior of other components connected to the pre amp like the effects loop. I found many fixes for the noise from your FX loop. Tube effects buffers are a good way to keep the pre amp tubes from interference. A hi temp foam enclose to shield the tube. Moving the head off and away from the Cabinet. General, many with an effects loop noise problem install a microphonic power tube. NOS from Siemens power is a last effort for many people with similar problem. I played thru an Engl Screamer 50 with a Les Paul and a Fender Telecaster trying to recreate the noise you describe. With some settings on the Gibson Les Paul I was close to it. I think a crack in the solder is the problem that is the fix. The solder points should be inspected any way. I do have some other thing that may be of help. Write back if you can and tell me the guitar you use. The age of the amp. I want to fix this with out going to a tech, leaving things of this quality in strange hands was never to my liking. Get back if you can and need to.