Mark 4 effects loop

[brianf]

When I kick in the loop on my Mark 4 I get an amp volume drop. This is while using my Boss Chorus or Boss Flanger.

I have the level on full on the effect.

This does not happen on my Road King which has level adjustments on the amp.


Any ideas how to fix this???

Thanks in advance.

brianf

 

[paleamberglow]

i never noticed this problem with my mark IV head, and i am using a boss CE-5 chorus and boss RV-3 reverb/delay in the loop . then again i usually leave the loop on all the time. i bet it has something to do with how your pedals are hooked up, maybe the cables are bad? or maybe the volume drop is occuring inside one of your pedals? try disconnecting everything but one effect in the loop, for each effect you have, and see if you can isolate the problem that way. you might try just running a cable from the fx send output to the return and see if you get the level drop by turning the loop on and off, that could rule out the amp as the culprit (never tried this , but should work theoretically)

 

[Russ]

Check your V2 also. That 12ax7 is responsible for fx return. It may be going bad. Sometimes a 12ax7 will be bad on one side but fine on the other. The V2 is the closest to the shielded one (V1). See if that helps...

 

[paleamberglow]

this just happened to me tonight with my mark iv, i am pretty sure it is the tubes, i haven't changed them in over 2 years.
any suggestions on new tubes for the mark iv ?

 

[zebpedersen]

My EH gear in the loop of my MKIV boosts the volume, if anything. Does this happen on all the channels?

 

[Russ]

Paleamberglow-

In that position just about any good 12ax7 would be fine. I would try to use something that is naturally brighter though so maybe an EH instead of a JJ. I don't think much tone comes into play there but just in case you don't want your tone to go south with your loop. As far as gain, I am thinking that less gain will diminish the effect of the effects. Also the other side of the tube handles the 3rd gain stage from rhythym modes and the 5th lead gain stage. Thus, a good 12ax7 would be best there. Long v. short plate.... microphonics would not necessarily come into play with the loop but why chance it with gain stages possibly at risk, go short because long plates tend to go microphonic more often and sooner.


Zebpedersen-

What EH gear are you running in the loop?

 

[paleamberglow]

i ordered some EH 12ax7's... i think they will get the job done. i'll keep in mind what you said about the plates. I dont think JJ's would be my cup of tea, as I am more about clarity in my sound than having loads of extra gain

zeb --
as far as EH pedals go, I know that my big muff has its own volume control, and it can be louder than what i have set on the amp. i dont run the big muff through the effects loop though. maybe your EH pedals have their own volume controls too and could be rolled back a little...

 

[zebpedersen]

My loop goes as follows:

SEND>> EH Poly Chorus > EH Electric Mistress > EH Wiggler > BOSS DD6 <<RETURN

The Wiggler has a volume control but it's pretty easy to match the volume, but the Poly Chorus doesn't and that's the one that boosts the signal. It's not a huge problem (unless it's damaging something, but it's not a massive volume boost) but if anyone knows anything more about it....

 

[brianf]

OK. It's not the effect or effects. I tried a couple of different cables going straight from the effects send to return and there is the identical volume drop.

I also tried a couple of new 12 AX7's in V2 and that is not it either????

I guess I have a much bigger problem.

Thanks for the ideas though guys.


brianf

 

[paleamberglow]

keep us updated on what's going on with it, i'm curious since I could have the same problem myself.. if not now than somewhere down the road

 

[brianf]

keep us updated on what's going on with it, i'm curious since I could have the same problem myself.. if not now than somewhere down the road

I'll call my dealer and Mesa on Monday. I'll report back.

brianf

 

[brianf]

Well it's fixed. I had been using 2 low quality 3 foot cables in the loop. I was just noodling around and did not want long cables lying all over.

When I tried plugging the cable straight from the send to the return to see if it was the effect causing the problem I had the volume drop. Tried the other low quality one and same thing. So I did not think it was a cable issue.

I asked my son (who uses my gear a lot) if he had noticed the problem and he said no.

Hmmm. I asked him to show me and with 2 Planet Waves cables he hooked up my delay.

NO VOLUME DROP!!!!!

brianf

 

[Russ]

I am glad to hear that you found your fix.

I had been assuming that you were using good cables already. I never skimp on those things. In fact, I am mostly Monster cable in my setup but I do have some Mogami stuff.

 

[paleamberglow]

cool, glad to hear it wasn't something more serious. hopefully my issue will be resolved with new tubes, as i highly doubt it is the cables

 

[zebpedersen]

Cool, it's always good to invest in 'proper' cables. I really like the PW ones.

When my rig is in 'big' mode (i.e. pretty much everything) the signal travels through 41 foot of cable in front of the MKIV and another 24 foot from the loop and back. Before I got my PW, I was getting a similar problem to the one you were having, but it all dissappeared when I switched everything for Planet Waves leads.

 

[paleamberglow]

the volume drop i'm getting is pretty substantial... i have to turn the output level up to about 7 or 8 to get even close to the level when the loop is turned off, where the output level is set at about 2. is it still safe to play the amp if i'm getting this problem, until the new tubes get here?

 

[paleamberglow]

i got my tubes today, put them in, and problem solved! turns out i really needed a tube change, the tone is 100% better than before

 

[Russ]

I am glad to hear that your tube change fixed the effects loop volume issue. In a way though I was hoping to hear something different so I would have yet more info in my arsenal for troubleshooting should I ever experience that.