|
Post by slideman on Jan 17, 2008 15:04:54 GMT -7
Hey Guys, I have a Z Maz 18jr w/reverb. Dr Z installed an effects loop in it for me, and it's been working great up until a few days ago.
The ONLY thing that runs in the loop, is a Boss DD3 Delay Pedal.
When I hit the delay, it's giving me a *distorted* signal, but it's in the repeats. The harder you hit the strings, the more ''distorted'' the repeats are, and if your playing a line, then it progressively gets more and more distorted, until you hear more distortion, than delay repeats. Kind of a grinding sound...
Now, I've changed cables, I've cleaned the jacks , and the tube sockets. I've even used another DD3, same thing. I can put the delay into 2 other amps, and it's quiet. And, I can put the DD3 in the front of the Z, and it's quiet there also. It just happens in the loop.
Any ideas on how to fix this. The only thing that i haven't tried, and will do this tomorrow (i just thought of this). I use a 2 amp rig, and I have a ground lift on the Z's power cord, to keep the ''hum'' quiet between the amps, since they are both on all the time.
Could this be the ground loop, or is it more than likely in the effects loop itself?
Any Ideas? The Z is my main amp in my rig, and I need it worse than any of the other amps I have..
Thanks!
Slideman
|
|
|
Post by benttop (Steve) on Jan 17, 2008 15:44:26 GMT -7
With the information supplied, I don't see how it can do this. Your dry signal and your wet signal are mixed back together before exiting the delay, so the amp has no way to react differently to one vs. the other. There is a detail or fact that you're missing somewhere...
|
|
|
Post by slideman on Jan 17, 2008 16:06:02 GMT -7
What detail could I be missing? I guess tomorrow I can record it, and host it so it can be heard. It's VERY noticeable. But, it's funny, i changed everything, used deoxit on all the tube sockets and jacks, changed cables, changed delay pedals, even changed amps, and the only time that it does it, is in the Z's effects loop. Not even in the front end of the amp.
It's more of a distorted, growing sound, the more you play, the harder you play, it's more noticeable. If you play clean, roll back the volume on the guitar, it's STILL there. Not as prevelent, but there none the less. If your playing very melodically, where you can play with big holes, it's not as noticeable. But, if your ripping on some Eric Johnson style stuff, it gets to be just more and more than the notes themselves.
But, it does not do it on any other amp i have with the same kind of loop. I also have a amp with the loop series/parallel, and it doesn't do it on it either.
It's weird. And trust me. After playing this amp for nearly 200 dates a year, for the last couple of years, i can tell when something just isn't right..
The DD3, is only in the effects loop. It is completely isolated from any other effects, except what is coming in from the front end. The DD3 is not in line with any other effects..
I also tried it on several speaker combinations. It does it on Celestions, it does it on DrZ 10's, it does it on EVM12L's. And this is a very low volumes also. The louder you play,,, well, you know.. the louder it is...
|
|
|
Post by benttop (Steve) on Jan 17, 2008 18:30:35 GMT -7
Does it do it if you turn your delay's regeneration feature completely off? In other words, limit the delay to one echo?
|
|
|
Post by slideman on Jan 18, 2008 8:02:26 GMT -7
If you turn the feedback off, where there is only one echo, it still has that ''distortion'' in the signal..... weird eh?
|
|
|
Post by benttop (Steve) on Jan 18, 2008 8:25:45 GMT -7
Well I'm stumped. I don't see how it can do that. Here's what I would do if I had this stuff sitting in front of me. If the delay has the ability to output separate wet and dry signals, I'd split them to two amps and see what that sounds like. I'd try playing harder and softer and see if there is any difference. I'd try every variation on how to connect things and follow my nose depending on what happened. Because really, since the two signals are recombined before the power amp sees them, that says that the distortion must be there before it gets to the power amp, OR, the power amp is distorting lower level signals (I'm assuming the delays are lower level - if they're not, throw that out). Since the distortion must be there when it arrives at the power amp, you should focus on what's driving the delay, the input levels to the delay, etc. I'm thinking that the delay's dry signal certainly uses a different signal path from its wet signal - your amp's loop send might be overdriving one but not the other. Does the delay have an input level control? What happens when you vary that? If not, could you stick a volume pedal between the loop send and the delay to see if lowering the signal level affects the distortion? Try that. Another thing that could be causing problems in that area is impedance matching. If you have a buffer of some kind, try sticking that in front of the delay to see if it affects the tone. It wouldn't have to be any great buffer to understand if this is an issue - an RC Booster turned very clean would suffice to accept or reject this theory. Hope one of those helps...
|
|
|
Post by slideman on Jan 18, 2008 8:35:33 GMT -7
Thanks Benttop,, I'll try all these things. It's weird, that it's just all of a sudden started this. I'll report back in a little while after I try out all these options, and i'll keep a note of what i'm doing, so that i can be more detailed in what i'm doing when troubleshooting..
|
|
|
Post by kruzty on Jan 18, 2008 8:39:09 GMT -7
Did anything change "a few days ago?" Amps settings, a new effect in front of the amp, new cable, pedal board, moved to a new house, got sick... anything?
I've noticed some not-so-plesant repeats from a delay before, but it is usually if I'm running the amp at pretty low volume and if I have an overdrive pedal in front.
|
|
|
Post by Phil (aka Phil) on Jan 18, 2008 9:23:09 GMT -7
This is just a thought, but I haven't had my second cup of Starbucks yet, so...
I don't own a Z reverb amp with an effects loop, so I don't have one to look at for reference. I do know that on a lot of "other" tube amps (i.e. non-Z), you see the "tube driven" type of effects loop that are buffered with a tube, usually a 12AX7. This will help with the impedance matching issues. On some amps, you get buffering plus a level control- that way you can deal with both the impedance issues and level matching issues.
I remember reading somewhere that Doc said his amp's effects loops were "nothing special", basically inserts in the circuit. However, I believe he was addressing the MAZ NR's and the Stingray. I don't know what he does on the reverb models that have an effects loop, like yours. I wonder if it's possible that on the reverb versions that it is driven by a tube? If that's the case, it could be a bad tube.
I hope the Doc chimes in here.
Phil
|
|
|
Post by benttop (Steve) on Jan 18, 2008 9:55:59 GMT -7
Well I'm having a hard time imagining a bad tube that could pass the dry signal unaffected but distort the delayed signal.. what the heck? This is definitely one of the weirder problems I've seen lately...
|
|
|
Post by slideman on Jan 18, 2008 11:32:46 GMT -7
Ok, here's the latest. Nothing except guitar straight in to the amp. High jack. DD3 in the loop. Still does it.
But, it's only doing it ''the worst", when the volume (preamp) is WFO like i usually run it. I can back off the volume and ''clean'' up the amp, and it's not as bad, but, still there. Could it be a possible bad preamp tube, or a noisy preamp tube to the volume. Does'nt matter about the master.. Low or high, it still is there. It's something to do with the preamp gain on the ''volume'' control. What tube would affect that.. If your looking left to right, at the back of the amp, is it the first tube on the left, or the 2nd? Tried the low jack and it's still the same...
The first tube is a Telefunken 12ax7. The 2nd tube is a JJ 12ax7.
|
|
|
Post by billyguitar on Jan 18, 2008 14:38:34 GMT -7
It sounds to me like you're overloading the input of the delay itself. Try the delay in front of the amp instead of in the loop.
|
|
|
Post by Phil (aka Phil) on Jan 18, 2008 16:49:50 GMT -7
It sounds to me like you're overloading the input of the delay itself. Try the delay in front of the amp instead of in the loop. Except for the part where he said "it was working great up until a few days ago". What's up with that? It wasn't overloading before.
|
|
|
Post by dixiechicken on Jan 19, 2008 4:27:53 GMT -7
Yes but.... If the above is indeed true - you have basically whipped your BOSS pedal too hard for a long time. It was designed to handle an input from your guitar foremost ( or was it??? ) - not the amplified signal from a "driver-tube" or whatever. It may be that you have finally broken some component in the pedal that no longer handles the amplified signal from the loop-out. Just a theory try another pedal in the same loop to check - preferably another Boos pedal just like it. Cheers: Dixiechicken!
|
|
|
Post by Phil (aka Phil) on Jan 19, 2008 6:48:46 GMT -7
It may be that you have finally broken some component in the pedal that no longer handles the amplified signal from the loop-out. Except for the part where he says "I've even used another DD3, same problem". I find it hard to believe two pedals were damaged the exact same way . Phil
|
|
|
Post by bluzman on Jan 19, 2008 9:31:35 GMT -7
If you're diming the volume, then I would think there would be distortion with the way the loop is. I know when I dime my volume on my Maz Jrs I'm doing it for the pre-amp to do it's thang at low volume.
|
|
|
Post by dixiechicken on Jan 20, 2008 8:23:31 GMT -7
Yep - that's unlikely. Then perhaps try another pedal - another brand? Just to see if the problem remains?
Cheers: Dixiechicken!
|
|
|
Post by jammergreg on Jan 20, 2008 21:43:28 GMT -7
How hot is the mix on the delay pedal ? Whenever I use a Delay now days I have the mix very low.. more when I'm not using the loop. hope you figure it out..
|
|