Big Boy Hogg
2 posts
May 27, 2016
1:35 PM
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Ok... Return to blues and guitar after 23yr going well so decide time for harp to come back out too. I have a piezo Japan bm-3 crystal mic... Plug into pignose and feedback city as soon as volume beyond 1/3 about talking level at best (regardless of distance and direction). So try a Marshall 12w practise amp as well. It's a little better but still goes into feedback far too early on volume regardless of whether being used or not. Am I doing something wrong?
Any idea? Any things I can try? Got a zoom 507 reverb and a Joyo American sound pedal so will try through them see if any difference.
Could it be mic is one of the seriously high impendence ones which is maybe causing a really strange eq curve/spike or something?
Any help really appreciated :)
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indigo
256 posts
May 27, 2016
4:15 PM
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I have one,it is a great mike and dirties up nicely but yeah it is very feedback prone.I wouldn't use it without a volume control especially at a gig or jam where i might not know what the set up will be.
A pedal that works really well with it is the L/W harp break you can tame it down a bit and make the tone a bit warmer.
The joyo should be able to cut the gain to suit as well.
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Barley Nectar
1218 posts
May 27, 2016
4:37 PM
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well, we could give you all kinds of advice about feedback but it's best to do a forum search. It's all been said before. Mouse over the blue "Blues harp forum" bar on the left of this page and hit forum search. Happy reading...BN
Last Edited by Barley Nectar on May 27, 2016 4:38 PM
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ME.HarpDoc
154 posts
May 27, 2016
7:20 PM
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Research the Mojo Pad from Lone Wolf Blues
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Big Boy Hogg
4 posts
May 28, 2016
12:31 AM
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Done loads of searching and most advice here and elsewhere is for on stage or amp positioning etc. Haven't seen much about epic low volume feedback I'm getting even in a quiet room without playing:)
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didjcripey
1038 posts
May 28, 2016
2:12 AM
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I've got a few mics and amps and I find the same thing. I've done valve swaps and other things but still find it hard to get drive and volume up anywhere near what you could get with a guitar amp. My main rig is a super reverb ad CM mic. Going well to get it past 3 on the volume before feedback. Mind you, that's pretty loud; you wouldn't really want it any louder. Guitar amps are made for guitars.... using hi Z mics is a perfect setup for feedback.
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Lucky Lester
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Big Boy Hogg
5 posts
May 28, 2016
2:49 AM
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With me we are talking medium talking volume at most and feedback there even if not playing. If the gain thing is the issue I assume a wee test with my Joyo American sound turning drive and volume down to reduce gain before going into amp would test theory... See if I can get more volume....
Do think something is causing an eq spike as tapping mic gives a almost chirpy metallic sound as if a freq about that level is spiked very high.... Wonder if filling mic up with something to damp the metal tube and some foam between grill and piezo crystal unit would help. But also wonder if very high impedance can cause weird eq spikes too. Maybe an old 1/4" mic preamp designed for high impedance would be an idea but would love to test things out before I spend cash :). Not got that much as wee lad is autistic and I look after him full time :)
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Big Boy Hogg
6 posts
May 28, 2016
2:51 AM
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Maybe just need to go for a more std mic for now and re-look at this when got proper harp amp
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Ofir Levi
50 posts
May 28, 2016
3:49 AM
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MOJO pad won't work with small amps. You will have to turn them all the way up and still not hear the amp.
Pignose feeds back at 1/3 with any mic, it's just a cool room volume amp.
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dougharps
1236 posts
May 28, 2016
4:36 AM
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Tube Pignose or original? Settings on Marshalls and Pignoses for guitar may be too gainy for a harp mic. For best volume use the cleanest settings possible.
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Doug S.
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Big Boy Hogg
7 posts
May 28, 2016
6:34 AM
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Original pignose... And seen lots of vids with harmonica players using pignose 7100 at full volume :)
Other thought I have is have some very old celestion 12" drivers (old fashioned semi full range)... I could make a 1x12 or 2x12 up and you can get some old public address amps for pennies. Ones designed for hi-z mics. Eg can get a TOA 60w one that has a selection of inputs up to 50k ohm and a selection of sensitivities as well allowing me to pick a good matched input with lower gain. It also has some tape/aux outs so can go into mixing desk fine.
One I have seen even comes with a nice looking desk mic that looks like it unscrews from stand at mic making a nice size mic for hand, so have two mics (one which was used with pa amp).
Any issues using an old hi-z pa amp or is that a reasonable idea for low cost option?
Last Edited by Big Boy Hogg on May 28, 2016 6:35 AM
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Big Boy Hogg
8 posts
May 28, 2016
6:37 AM
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Tried the Marshall clean channel with gain lower and master up higher but didn't seem much different...
If mic was meg ohm type would that cause strange eq issues on guitar amp?
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jbone
2179 posts
May 28, 2016
11:39 AM
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The 7-100 Pig was never intended for a mic. It's a guitar amp like most that are made. High gain very early. Save some dough and get a vintage tube amp, 5 to 12 watts. Maybe experiment with a gain cutter tube. Try a Shure 585 mic, I have had good success at small club volumes with that kind of setup.
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arnenym
391 posts
May 28, 2016
12:25 PM
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Try a song mic and see what happends.
Its the combination of hi gain amps and a very hot mic. Piezo microphones are well known as feedback prone and start with another mic seems to be the best alternative to get some volume out of the Marshall.
If you got a good sound out from it you could try with a Mojo Pad. It works on some small hi gain amps, but not on all small amps.
The pignose is a bedroom amp with a great tone, and is good for recordings, but you never get a useable volume out from it.
Last Edited by arnenym on May 28, 2016 12:27 PM
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nowmon
86 posts
May 28, 2016
12:41 PM
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I have and use silvertone,champ, 68` twin and 2x10 music man and since 68` whenever I blow harp through any of them I set amp with treble down to I or 2 and never had a problem with feedback...I have used the twin on a big stage ,ware I could get 20 ft. away from the amp and turned it up to 9...I was as loud as the guitar and was getting controllable feedback...using a 57 or 545 .
Last Edited by nowmon on May 28, 2016 12:42 PM
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dougharps
1237 posts
May 28, 2016
1:02 PM
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I have had good luck with old tube PA heads.
Also, the 585 is the most feedback resistant mic I have used.
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Doug S.
Last Edited by dougharps on May 28, 2016 1:02 PM
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Greg Heumann
3236 posts
May 28, 2016
6:00 PM
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Look. When you have "terrible" feedback problems - the mic is hardly ever the root cause. Mics do vary in output - but not that much.
It is my job to deal help people with this. Every day I help customers. And I've certainly been around the block with it myself, and I've played more mics than anyone else in the world - I'm sure of it. I have played THOUSANDS of mics.
So let me tell you a few things:
The single most common reason for feedback is needing your amp to be louder than it can be (which is usually because you were blown away at how loud it was in your living room and then couldn't hear it on stage at a jam.) The solution to this? You need a MUCH bigger amp. 10x the power to increase the sound level 10dB, or twice as loud.
The next most common problem with feedback comes from amps that have too much gain. For a given amount of power, some amps make it possible to use MOST of that power because they have “gentle” easily controlled onset of feedback. But most amps are setup for guitar, and have way too much gain for a microphone. Gain is not the same as volume. Imagine you have a Mazda Miata with a 500hp V8 motor - and the gas pedal only moves 1/2”. THAT is what trying to “drive” an amp with too much gain is like. Reducing the gain considerably is like adding 5” of throttle pedal travel. Note that idle is still idle, and full throttle is still full throttle. But you can much more easily control the car in the corners, and you can much more easily control the amp - which allows you to use more of its useful power. That gets you A LITTLE louder but sure helps you manage feedback while playing.
You can reduce the gain of some amps via tube substitution and that to me is the best and mot economic solution when possible. However devices like the Mojo Pad, Squeal Killer and Kinder AFB+ can accomplish the same thing.
Once you've got the amplification under control, THEN you can worry about which mic feds back a little more or a little less, but you will no longer care and will simply choose a mic for its tone and its ergonomics, because the different between a "hot" mic and a "soft" mic will only be a number or two on your amp's volume control.
Every once in a while I come upon a mic that IS more feedbacky then its peers. Often this is due to the placement of a dynamic element in a shell made for a crystal, like an Astatic T3, where all of a sudden the space to the rear of the element becomes involved. Crystal/ceramic elements don't "care" what's behind them. In the case of the T3, lots of sound can enter the already thin shell through the large hole where the swivel stalk enters the shell. That causes feedback. A leaky gasket or a hole in the shell to the rear of the element can do the same thing.
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***************************************************
/Greg
BlowsMeAway Productions
See my Customer Mics album on Facebook
Bluestate on iTunes
Last Edited by Greg Heumann on May 28, 2016 6:04 PM
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Barley Nectar
1220 posts
May 28, 2016
11:02 PM
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Sweet!
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Big Boy Hogg
9 posts
May 29, 2016
1:06 AM
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How would I tell if it has a dynamic element fitted?
To me if I tap mic there is a pingy metallic sound. That to me makes me think a really odd massive eq spike at that freq or like you say tube interacting with mic more than should which kinda makes me wonder about your thing about a dynamic being fitted???
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didjcripey
1039 posts
May 29, 2016
2:48 AM
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I reckon you'd do well to focus on Greg Heumann's advice... he knows his stuff.
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Lucky Lester
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Big Boy Hogg
10 posts
May 29, 2016
4:17 AM
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Yep hence why I asked about element in mic being changed... My ears tell me something else may be at play :)
Last Edited by Big Boy Hogg on May 29, 2016 4:17 AM
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dougharps
1238 posts
May 29, 2016
8:04 AM
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Greg is exactly right about addressing the amp issues before worrying about mic issues. Greg's first and next most common reasons for feedback should be quoted each time this comes up.
The mic can be a problem, and some are better than others for varying reasons, but the amp issues he notes are of much greater significance and should be dealt with first.
After you have a good amp setup, also consider your mic handling, cupping, and where you stand relative to the amp.
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Doug S.
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Big Boy Hogg
11 posts
May 29, 2016
8:50 AM
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Think your getting me wrong... I am starting to think the mic isn't right... Faulty or As per Greg's txt a dynamic element in a crystal mic case (which he lists as an issue) something do with what's behind the element effects sound with dynamic in a crystal case ... The sound the mic makes tapped with my fingers makes me thing there is a huge freq spike or something amiss as it's pingy and metallic. And if you heard the crazy low volume it goes into constant feedback at you'd be like me looking for something amiss and not believing it was normal behaviour.
Also I have asked would popping it through a Joyo American sound pedal (which has a volume control) allowing me to turn gain down. Would that work for me to test if gain is an issue.
I'm not doubting advice and have read it all I am trying to find was to actually test the setup and narrow down what is or isn't the issue.
I will try lowering gain later though do think I did that on Marshall with gain very low and using master. I have tried moving as far away as I can from amp, behind amp, to side of amp, pretty much all the same regardless feedback kicks in at same point on volume consistently (again something that makes me suspect all not as it should be as would expect moving would allow a little more volume)
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Greg Heumann
3237 posts
May 29, 2016
9:42 AM
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@Big Boy - yes, it sounds like something might be wrong with your mic. If you send me a photo of the rear of the element I can probably tell you if it is dynamic or crystal. If you send me the mic, I'm happy to check it out for you.
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***************************************************
/Greg
BlowsMeAway Productions
See my Customer Mics album on Facebook
Bluestate on iTunes
Last Edited by Greg Heumann on May 29, 2016 9:43 AM
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Big Boy Hogg
12 posts
May 29, 2016
11:08 AM
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Will grab some photos later... Dundee, Scotland I guess me be a little far to post...
Once you unscrew top and lump of metal with holes in is is fixable, does that lump of metal come apart further or is it not easy/possible?
Will probably try and grab another mic to make do in mean time :)
Cheers
John
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Big Boy Hogg
13 posts
May 29, 2016
2:11 PM
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Photos here https://onedrive.live.com/redir?resid=DE8F1F3159E407D1!499870&authkey=!ANW1rJiS9HSQgR8&ithint=folder%2cjpg
My suspicion is the bit of metal that did hold crystal has been opened and something else has been put inside...
John
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Barley Nectar
1221 posts
May 29, 2016
5:17 PM
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Whatever is in that mic is original. No, it does not come any further apart. Looks like a crystal element to me. You tried the mic in two amps. This tells me the mic is screwy. Find a different mic and try that..BN
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Big Boy Hogg
14 posts
May 30, 2016
12:37 AM
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I think they split it in half. Look at the marks around one half of the metal case for element... Looks like something has gripped it vice or pliers I'd guess. And although I can't take a photo what I can see through wee holes doesn't look from 1960's to me, looks brand new (whoever is beyond centre hole is old but what I see behind that from other holes looks brand new)
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Greg Heumann
3238 posts
May 30, 2016
8:03 AM
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I concur with BN- the looks like a crystal that began life as a telephone handset mic or earpiece. Crystal elements are not serviceable. Best bet is to replace the element or the entire mic.
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***************************************************
/Greg
BlowsMeAway Productions
See my Customer Mics album on Facebook
Bluestate on iTunes
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Big Boy Hogg
15 posts
May 30, 2016
8:21 AM
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Thanks Greg, think bn thought it was original. where as due to size, the good fit diameter and length + the tool marks I though it was original metal from element but guts removed and something cheap and modern put in place (so to outside looks original).
You reckon out a phone or something similar.... Cool. Will maybe ask seller and see what he has to say cos he has 100% on near 500 feedback advertised as harp package and said he tested before sending which I kinda doubt.
Oh well save some pennies and see what else can find :(
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Big Boy Hogg
16 posts
May 30, 2016
8:22 AM
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Oh, if looking for an element doing just need something same size and diameter? Or specific to mic?
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Greg Heumann
3239 posts
May 30, 2016
9:10 AM
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Elements need to be fit to shells with gaskets. I am in the business of making gaskets to fit all of the common elements to all of the common shells. I'm afraid I can't help you with either in this case. However there are lots of ways to make decent gaskets when you're only making one. For crystals, all that is needed is to hold the element securely while providing shock absorption in the event of a drop. For dynamic elements, it is also important to provide an acoustic seal between the front and rear of the element. Some people use putty; some people cut out disks of rubber and glue them together, etc.
As for elements, any high impedance element that fits will work. You can use a low impedance element plus an impedance matching transformer if you like as well. I offer a range of elements for sale. Feel free to contact me privately.
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***************************************************
/Greg
BlowsMeAway Productions
See my Customer Mics album on Facebook
Bluestate on iTunes
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Big Boy Hogg
17 posts
May 30, 2016
9:57 AM
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Thanks for everything...
I have a rubber gasket that was fitted between screw on grill and element. Should there be one between tube and element as well? Or does it not matter on crystal? Would gasket being dodgy cause issue? Think mine is so old it has compressed and doesn't quite fill gap as well as it should.
I notice honkin harmonicas in UK has same mic for sale so out of interest asked what original looks like (in case I spot original).
May just try and get a reasonable value s/h compact length dynamic mic for now and try and repair crystal as a project. Will drop you a PM at some point to discuss.
Really appreciate all the input from everyone :)
Thanks a million ;)
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Big Boy Hogg
18 posts
May 30, 2016
1:28 PM
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Added photo to same gallery from another auction person took for me. Looks like case for element is standard for mic.
I am thinking something horrible and cheap has been put inside element case. Defo plier/vice marks on mine.
Friend may have something I can get going with so will keep you updated with what I find inside :)
Last Edited by Big Boy Hogg on May 30, 2016 1:29 PM
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JustFuya
917 posts
Jun 12, 2016
12:52 PM
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You really need to trust the professionals who are taking the time to share their knowledge with you.
I am not among that group but I have dismantled just about everything that ever broke on me. The "defo plier/vice marks" look like wear from friction (in and out movement). If you can't move beyond the disassembly theory, grab a magnifier and compare the colors on the 'element' and its seating. Look for wear marks on the seat surface where they would rub. The locations may even match.
Frankly, if it was mine, see above. I would take it apart and note the tool marks most people would create even if they did so carefully.
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