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Post by guitarhead on Mar 13, 2006 7:20:36 GMT -7
Last night I was playing my Maz 18 jr. and I noticed when doing double stops and double bends that there was a strange ring modulator sound happening behind the notes. If I bend up the overtone pitch goes down. Anyone else experience this?
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Post by Lefty on Mar 13, 2006 9:11:35 GMT -7
Tubes. Sounds like you have one that's microphonic.
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Post by guitargeorge on Mar 13, 2006 9:12:48 GMT -7
yes, numerous people have experienced this, I've posted here about it before, my amp is quiet as a mouse untill I play certain notes which produce like a hum in the background and at higher gain settings it becomes more like a note (ghost note) rather than a hum. One guy said he isolated the problem down to one of his power tubes was doing it,and stopped when he pressed on the tube with the eraser end of a pencil. I also had a lot of glass like vibration in the background that was'nt coming through the amp. Just this weekend I bought a tube of high temp. silicone sealant from an auto parts store and ran 3 rings around each of my power tubes, one on top, one in the middle and one on the bottom, so there are 3 rings or dampening rings on both my power tubes. This seemed to eliminate the glass ringig sound and seemed to tighten up the bass on the amp but I still have the overtone on certain notes (notably C# on the 14th fret, 2ND string or a bend from the 12th fret, same note) but it seems now it's a little less intense as it was.
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Post by Strato on Mar 13, 2006 18:45:02 GMT -7
Yeah i have the same problem. I dont know what to do, other than try to avoid playing in the problem spots.
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Post by Strato on Mar 13, 2006 18:50:31 GMT -7
And no, its not tubes. Me and guitar george replaced every tube there is. Same problem. Its also not the speakers. I have a Zbest. I tried it on a friends marshall... with the same results. However, the it was more evident with the zbest... probably due to it's ported design. I sorda wish we could get some answers on this issue. I'm glad someone else is having the problem(I was beginning to think i was crazy.)
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Post by guitarhead on Mar 13, 2006 20:42:14 GMT -7
I played the amp again today and noticed some chords sounded out of tune because of the overtone.......this does not happen with single notes......only with two or more notes....I tried the amp with different guitars and different cabs with the same result.
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Post by foxx on Mar 13, 2006 22:29:14 GMT -7
guitarhead, you should ask Myles about this on the Ask Myles forum. He's the man!!
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Post by guitargeorge on Mar 14, 2006 5:13:30 GMT -7
I did an experiment last night, I started replacing the power tubes with different brands, different pairs, I have a big box of tubes and I found that different tubes shifted the problem note, some the 12th fret bend to C# produced the overtone and some tubes it was'nt so evident on the 12th fret bend to C# (second string) but showed up on lower notes, one set of Groove Tubes produced the least ammount of overtones but the problem was still there, I did a cap check with a cap checker a while back and I may have a bad cap. I'll have to borrow the cap checker again and see. I thought it may be the tubes but I am really not thinking this now. My neighbor who had an electronics buisness said that certain frequencys will cause the inner elements of the 6BQ5/EL84 tube to rattle inside the tube and causes this thing to happen, my question is, where can I get a good hearty set of EL84's that don't do this?
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Post by zane on Mar 14, 2006 15:12:04 GMT -7
I quess you've already tightened the chassis screws & such...
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Post by guitarhead on Mar 14, 2006 19:04:34 GMT -7
Hey zane......when you say chassis screws are you referring to the 4 screws on the bottom of the head?
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Post by zane on Mar 14, 2006 22:28:55 GMT -7
yeah I imagine they're on the bottom of a Maz Jr head...the Dr said his chassis are aluminium, & they will heat up & the retainer screws will need to be "tightened" ever so often... worth checking out ;^)
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Post by guitargeorge on Mar 15, 2006 6:10:15 GMT -7
Why can't I get an answer here, although I apreciate all the help, I've done everything that was suggested as a possible cause for this. I am not alone with this problem, I don't think it's tubes, it's not my speakers, it's not loose bolts. The answer I got from Dr Z was this is "normal" then explain why some people have MAZ 18's that don't exhibit this behavior. Why are there pictures of MAZ 18 chassis posted on the internet that have 2 large can filter caps when mine has one, why is a schematic not available? Are there different MAZ 18's ? What can I do if I have the noisy, ring modulator sound makin version of this amp to minimize or eliminate this problem, I'd like some concrete answers, Not "it's normal" or "tighten the pots, bolts, trannies" I've done all this and it is still not functioning to my satisfaction. It seems like this problem seems to get swept under the rug at Dr Z , is this a cover-up or something? I just want to know if my MAZ is malfunctioning or an explanation as to why some amps make weird sounds along with the note being played.
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Post by zdogma on Mar 15, 2006 7:08:39 GMT -7
I would have a tech check your amp. If no schematics are available, you may need to send it back to dr.z. Regarding your conspiracy theory, I have never had any problems of this type with the 3 or 4 maz 18's that I have played. All were recent (since 2004). None of my other amps do it, either (z or otherwise). Could be a certain build version or part choice that has changed or something. The schematics are not widely available for modern amps due to problems with knockoffs. The matchless lightning is a good example, every amp kit manufacturer now makes one. Dumble goes so far as to pour black silicone over the innerds of his amps to prevent copies (but he's a little crazy...) My two cents worth - check the filter caps. You can sometimes have a defective cap in the power supply filtering chain, which can lead to ghost notes. I've seen it with old fenders and marshalls quite often. They usually last 10 years of so , but maybe there was a bad batch of filter caps or something. Unfortunately, not all problems can be solved by amateurs over the internet
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Post by guitargeorge on Mar 15, 2006 9:18:09 GMT -7
I'm not trying to start conspiracy rumors here but it seems like when I brought this topic up to Dr Z his response was "its normal" and I've heard of others that were kind of blown off with the "thats normal" response. If his newer MAZ 18 design has better power supply filtering than his older ones then I would like an explanation or at least a "send it back in and we'll upgrade it" It seems that issues such as this don't get adressed, I bought the amp used but I paid a good ammount of money for it and overall I think the build quality is superior, the sound of the amp is stellar, but this little problem is annoying, I don't know if it's a simple fix or if I just have to live with it, or if my amp needs help, I'll be out gigging in about a month and I'd like to get this resolved.
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Post by guitargeorge on Mar 15, 2006 13:59:07 GMT -7
Question, which caps are the power supply caps? I know the big one that hangs off the bottom of the amp chassis probably is annd the big blue one inside is probably one. Is the one that is wired up with the large resistor next to the big cap also one. This cap is the one I suspect may be the bad one. I checked all the caps with a capacitor checker one day and this particular cap was giving me an erratic reading. My MAZ was made in the 90's so it's possible that one of the caps could have gone bad.
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Post by guitarhead on Mar 16, 2006 6:37:53 GMT -7
I tried tightening the chassis screws.Unfortunately the problem still exists.
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Post by guitargeorge on Mar 16, 2006 8:36:09 GMT -7
So far I've replaced all the tubes with brand new JJ's all around (JJ's from Bob @eurotubes) I tightened all the pots, tranny mounts, chassis bolts,etc. I cleaned the pots, retensioned the tube sockets, checked for cracked solder joints, did a capacitor check with a cap checker, checked the reverb cables, put dampening rings (automotive high temp silicone) on all the power tubes and rectifier, and armor-alled the cabinet, still makes ring mod sounding overtones. I had one suspect cap tat I may change this weekend, I'll let yu know if this helps.
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Post by guitargeorge on Mar 16, 2006 11:06:12 GMT -7
The plot thickens, I pulled up chassis pics for a MAZ 18 JR and of the 2, both are different. Looking at the right side of the turret board from the front of the amp, I see a large blue cap, then 2 resistors that are wired together near side and "y" off on the far side, and then a 150 ohm resistor in parallel with a 25uf cap. this is from right to left. In another picture I see the large blue cap but this has a smaller (but large) cap gong from the near side of it to the right side of the "y" on the resistors and then the 150 ohm resistor with no cap in parallel. Obviously all MAZ 18's are not created equal, The cap in parallel with the 150 ohm resistor is the one I suspect may be bad, my amp is like the the 1st mentioned above, the second mentioned must be the upgraded version.
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Post by Strato on Mar 16, 2006 15:58:08 GMT -7
Well not to burst your bubble, but my maz is about 2 months olds. It does the same thing. If the filter cap is the big blue thing that sticks out of the chassis, then mine has 2.
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Post by guitargeorge on Mar 17, 2006 5:22:47 GMT -7
Well, there goes my theory about older MAZ 18's vs newer Maz 18's, It looks like there are examples of this behavior in older and newer ones so this leads me to start thinking that it may be a bad component in the amp. I'm going to borrow that cap tester from my TV repairing drummer and check the cap again to see if I get any leakage readings and then I'll head up to the electronics store and get a replacement and swap them out, this may work, I'll keep you posted.
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Post by zdogma on Mar 17, 2006 6:19:06 GMT -7
You asked about the filter caps, yes they are the big blue caps maybe sprague atoms? And the big one on the outside is a filter can cap, so you were quite right.
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Post by guitargeorge on Mar 17, 2006 7:33:18 GMT -7
Zdogma, thanks for your assistance, I am a guitar player, I'm not an electronics tech but I maintain all my equipment to the best of my knowledge and ability, I don't have the money to have a tech bench check a piece of gear everytime something is not right and my name is not "Brad Paisley". I am very determined to find out what is causing this problem on an otherwise perfect amp and I will, I don't accept the 2 word response that "it's normal" and if I find a fix for this I'll be sure to post it here so everybody else with this problem can have a great amp and not a great amp with a problem.
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Post by guitarhead on Mar 18, 2006 18:42:15 GMT -7
Today I bought new Groove Tubes el84s and installed in Maz 18 Jr. and nasty overtones are still there.It still sounds like ring modulator. This is really frustrating. I don't think I have the same problem others have. My problem occurs with 2 or more notes. Single notes sound great. The overtones make chords sound out of tune especially altered chords I guess I will have to call Doc.
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Post by guitargeorge on Mar 20, 2006 6:05:12 GMT -7
I talked to my friend whom I bought my MAZ from, He got it brand new, I asked him about the ring mod overtone thing and he told me it did this since day 1. Maybe the Doc saying this is normal is right, but why would some have this and some not? He told me he asked an amp tech about this and the guy had him plug into a brand new AC30 in the store and guess what, The AC30 did this more than the MAZ. If anybody finds out a way to stop this please post as I will do likewise, in the mean time I'm going to practice my guitar.
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Post by oldgoat on Mar 27, 2006 7:51:06 GMT -7
I need some clarification on this sound. I'm getting a buzzing sound only when I play an 'a' note; low e string 5th fret, open a string, d string 7th fret. Sounds like that sympathetic vibration when a snare drum is on, a sizzling sound. And only with reasonably high gain. Is this what people are calling the "ring tone" or is something maybe loose in my Maz? Thanks everyone.
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Post by guitargeorge on Mar 27, 2006 8:31:09 GMT -7
Your problem sounds like you have something loose, I havent had an amp yet that did'nt have something in the amp rattling, especially on the low notes. You may want to check the transformer mount bolts, Dr Z puts big washers on these, and I thought this was odd, but he does this so when the bolts come loose the washers rattle like little cymbals and let you know the bolt is loose. I actually found one of mine stuck to a speaker magnet. Don't overtighten your speaker mounting screws, overtightening can cause the frame to twist and may cause rubbing. Check your reverb tank, especially the two posts that are pressed into the housing to keep the insides lined up. These were the culprit in two VOX AC15's that I had. The ring mod tone is an electrical thing and I was told is a natural thing with EL84 tubes, it sounds lke a faint note or hum in the background only there when the note is being played and usually notes around the 12Th fret on the higher strings will do this.
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Post by Greg G. on Mar 27, 2006 13:50:22 GMT -7
My Maz Jr. does the same exact thing (its an '05 model). I thought for a while that it was cone cry when the speakers are being pushed hard or overdriven, but I noticed it last night with the amp set very clean and master volume at about 10 o'clock, double stops and chording at and above the 12th fret, high strings. You seem a little more set on figuring this thing out than I do, so please let me know if you find a fix for this annoying little problem. I'm going to change out the G12H's this week with a Tonker/Swamp Thang speaker combo I ordered, so I'll let you know if that reduces it at all.
-Greg
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Post by crackpot on Mar 27, 2006 19:03:38 GMT -7
My 1-12 combo has done it ever since I brought it home 4 years ago -- a weird, low (and pretty loud) moan only when I bend double stops around the 12th fret. The moan bends too -- a kind of boingy sound.
Does it with the stock G12H30. Does it with a Blue. Does it with the speaker in the combo cabinet or in an outboard cabinet. Does it with brand new (several sets of) JJ and NOS Phillips and Sylvania power tubes and whatever odd new and NOS preamp tubes I've tried.
I've learned to live with it because it's the only sound the amp makes that's not perfect. If anyone has made it go away, though, I'd be happy to hear how.
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Post by Ryan (shorty) on Mar 27, 2006 19:59:22 GMT -7
Are people with reverb and NR models having this problem or is it NR only or reverb only?
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Post by Strato on Mar 27, 2006 21:05:07 GMT -7
I have an NR... and tonezealot, that is the EXACT problem me and others are having.
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