Musicians Roadhouse

I spoke with several other men and they all seem to have a slight hum when the effects loop is engaged. I was very surprised at how well the effects loop actually works in this amplifier especially with most of the distortion coming from the power stage. The hum does bother me though. The hum is there even with taking the short patch cable from the send to the return and enabling the effects loop without any effect involved in the equation. It was suggested to try and break the ground on the return side of the cable but that didn't have any affect, just wondering if other men are using the effects loop.

I get it as well. It would be nice if the designer could chime in and say why it
exists. It doesn't bother me though.

I noticed it too. I presumed it was the generic power supply I was using, but it doesnt do it with my Engl Blackmore.

I must admit, I wasnt too happy with the fx loop, mainly cos I like the sound with masters maxed and it made the fx sound messy, which was to be expected when so much of the sound comes from the cranked output valves. I have recently got into using a yamaha magicstomp (Holdsworth inspired...!!!) which sounds amazing with the Engl but a waste of time with this amp. I need to check out my analog pedals in the fx loop yet. I expect them to be more suited. Wish there was more hours in the day!!!!

I had a hum through my JVM that I could not tack down so I ended up bringing my pedal board and JVM into the shop to see if the tech could get things figured out. The hum went away once he removed the batteries from the pedals on the board which still had batteries in them. I always figured that the batteries were being bypassed since my pedals were being powered by my Modtone power supply. The tech said that the batteries were still interfering with the circuit and causing the hum I was getting through my effects loop. Is there any chance that some of you guys could be having the same issue?

I am planning on selling my JVM to help fund a YJM100.

John 14:6 wrote:I had a hum through my JVM that I could not tack down so I ended up bringing my pedal board and JVM into the shop to see if the tech could get things figured out. The hum went away once he removed the batteries from the pedals on the board which still had batteries in them. I always figured that the batteries were being bypassed since my pedals were being powered by my Modtone power supply. The tech said that the batteries were still interfering with the circuit and causing the hum I was getting through my effects loop. Is there any chance that some of you guys could be having the same issue?

The hum still occurs even if you place a patch cord from the send to the return, no pedal or rack unit in the chain.

This Solved my issue: http://www.ebtechaudio.com/llsdes.html

But I am connecting to rack effects...

snark wrote:This Solved my issue: http://www.ebtechaudio.com/llsdes.html

But I am connecting to rack effects...

so this product solved the hum issue with your YJM100? If so, which model of the Ebtech did the trick?

donbarzini wrote:

snark wrote:This Solved my issue: http://www.ebtechaudio.com/llsdes.html

But I am connecting to rack effects...

so this product solved the hum issue with your YJM100? If so, which model of the Ebtech did the trick?

Sent you a pm on this...

I just found out that one side of V1 controls the effects loop. I turned on my amp and there was nothing but silence whenever I turned on the effects loop. I tried trouble shooting every cord and I switched out all the preamp tubes in V2 through V4. I did not think the V1 first gain stage tube would do anything to help, but I thought it was at least worth a shot before I took the amp in the repair shop. I switched out V1 and everything worked properly after that. THANK GOD! I think the slight effects loop hum may be caused by the effects loop running off the same preamp tube driving the first gain stage.

When I linked a long cable between send and return I noticed more ground noise when the cable come near the power transformer.. so I think that send and return sockets have been placed too close to the power transformer....