Thumb 5-string White noise!

[72jazz]

Hey all! Hopefully Florin may be able to see this, or if possible some of the other estimable forum members here may be able to field this question! I just acquired a 97 Thumb last week, via Ebay, and when I received it, I took it for a test drive and noticed some type of white noise which came from the volume control! Upon lifting the volume knob up, (which I believe puts the bass in a passive-mode, correct?) the noise completely stopped! Pop it back down, and it was there again! What is happening? Batteries? or.......what?
Any help would be appreciated, and we thank you, Henry!

Also I'd like to know what woods we're used in the making of this particular bass! The serial # is C-036333 97! Thanks you one and all!

[itsalljustaride]

My thumb picks up a Christian Inspirational radio station if you point it the right way. I think I just happen to be in the right spot, because when I took it in to be worked on a while ago they couldn't reproduce it. It also might be my amp, I'm not positive. Something about the active pickups going through my older Peavey TKO might be causing some funky "features" to manifest themselves. My outlets aren't grounded either (it's an old house) so who knows where the problem is coming from ultimately.

[72jazz]

Well, that would be ideal for me, but again all I'm getting is the white/hiss type of noise and I know it's coming from the volume stack for some reason...but thanks for your input!

[itsalljustaride]

I mention it because when I pull the knob on mine to cut to passive, as you do, it greatly reduces the interference as well (turning the tone knob down also reduces it further). So the active electronics may simply be amplifying a problem that exists elsewhere in the chain.

And yeah, I like to think my bass has it's own personal preferences in music. I'm not into Christian music at all, but my bass seems to prefer it exclusively

We're the odd couple. Haha.

[Shoewreck]

How loud is the hiss? Could you compare it with signal level? Does it change when you turn EQ knobs?

[72jazz]

Boy! This is a truly great site! I've been a member for a day, and I'm getting some quick help/response from around the world!

Per shoewreck and itsalljustaride; the hiss starts when I turn my GK amp on, and when the volume is in the lower position (active) and totally off. When I lift it up, (In passive) it stops totally and is quiet. Even if I increase the volume, the noise does not increase, it just stays at the same level, but is very noticeable!!

I've put all my other Warwicks and other basses thru this rig with no issues, so I know it's this bass, and something to do with the active/passive volume setting/control!

[nizzrooster]

Does the hiss change when you turn the treble knob??

[Callum]

I'd go with the preamp being the issue...the exact issue I don't know. Unless you have good experience with electronics i'd advise having it looked over by someone.

[Gerry]

Could be a few things. Some people turn up the internal gain (on the bass preamp) to increase output while active and get this problem too. I believe the volume should be the same active and passive, just fuller in active mode. If it's way louder active, turn down the gain.

[72jazz]

Hello again folks! Well, per nizzrooster, the hiss only deviates in sound with the treble knob being turned either way; obviously it will vary pending on which way the treble knob is turned!

Per Gerry and Callums comments, I've a local luthier whom I trust, and I'll be taking it to him to diagnose, with your comments!

Also the bridge set-up is at issue with me. As the base of the bridge on the B string side is adjusted so it's coming out of the body in order to allow for playability. I just haven't seen a bass set up quite like this yet, so it will need a good looking over!

Thank you all for your help! If anyone else has any further diagnosis it would still be appreciated, Henry!

[Florin]

Hi Henry,

Is it a thumb BO, or NT? 2 way EQ or 3 Wat?
If it is a BO, you have an ovankol body, wenge neck, wenge fingerboard. If it is a NT, then you have bubinga body, wenge neck with bubinga stripes, and wenge fingerboard.

It seems the preamp has an issue, or it is amplifying something that already is in the house, some interferences.
The bass is not new, and maybe the shielding is not working good anymore. Try to redo the shielding with a graphite spray.

The body of your bass is arched, so it is not an uncommon thing for the bridge to be out of the body on the bass side for a good setup. It is kind of sexy too if you ask me :-)

I hope it helps, welcome to the forum buddy!

[72jazz]

Hey all! Good Day! Thanks for the continued help/comments on my Thumb!
This bass, by the way, is an Thumb NT, if that helps my query any further.

And a special thanks to Florin for his help with this issue, and from about the first hour that I became a member, he just happened to be there and was an assist from the get go! A great place to be for the novice member. Don't know why I didn't join sooner; probably just wasn't aware of the forum! Henry!

[72jazz]

A note for Florin! Henry here! On the B side of the bridge, both adjustment screws for the bridge are almost at the end of their travel for adjustment (just about at the base/bottom of the bridge) And I'd like to acquire longer set screws for the B side! Can you tell me what mm they are, so that I may acquire 2 more please? Thank you!

[Florin]

Hello Henry.

I am pretty sure you don't need other screws...
Please check the neck relief, is it straight enough?
Please check the saddles, are they completely down? You shoud raise them untill the string is not touching the back part of the saddle.

[72jazz]

Morning Florin! The neck relief is good, to me the saddles are kind of high but I'm awaiting a call back from my luthier to bring it over and have him check it out for both the hiss and the set up as it came from the previous owner. As for the screws, I'm just compulsive, and possibly prefer a slightly longer screw on the B side for better adjustment possibilities. But Mr. Luthier will be the final determination! Thanks, Henry!

[Angrychair]

well with my corvette, when i moved to a new house, there was a grounding issue that caused my bass to have bad 'white-noise' in active mode, and barely noticeable in passive. but it was a grounding issue nothing guitar/gear related. just wanted to throw that out there.

[Florin]

here in the house I am living the noiseis crazy... Passive basses are almost unplayable.

Henry, please let me know how it works.

[72jazz]

I'm on my way to the Luthier's house right now! Hopefully in the next hour I'll have some answers, Henry!

[72jazz]

Well here's the scoop so far! Nothing conclusive, and we've ruled out the ground of this house as, the same white noise is indeed occuring at my luthiers house, and if it's a sheilding issue, (he's not sure at this time,) he normally shields the compartment with 5mm copper tape,conductive on both sides, though he wonders about the amount of "headroom" that the 18v system is having on this bass' output! He's asked me to take this bass to a Guitar Center and find another 18v Warwick to A/B, to see if there is any difference!

Again, when we put the bass into "passive" mode, it by-passes the tone controls and the pronounced hiss stops. With the active "on", and turning the treble control clockwise, the hiss becomes even more pronounced. The pickup pan, the mid-control, or the bass control does not effect any changes, only the treble control going all the way clockwise makes it very pronounced. Backing it off to the center, or fully counter-clockwise only eliminates it to a small degree. In active-mode it brings out the high frequency white-noise to a great degree! Even tried to back-off the internal pot on the pre-amp and that only made a minimal difference!

So what the heck am I to do? He agreed that it's not something that he'd put up with, and would have to have it fixed! So help is definitely needed, and my last two Wicks we're very quiet; it's what I've come to expect from these basses! So, thanks one and all for any help, Henry!

[Greg]

Can you change over the treble pot?I think it's a 100K.

[72jazz]

Thanks for the heads up Greg; I'll mention it to my mechanic and we'll see if that's a possibility! This is an easy fix, yes?

[Greg]

Very easy.All you need is a replacement pot & soldering iron.

[72jazz]

Hey Gang! Ok! Today I went to my local Guitar Center in Southeastern Ct. And also plugged The Hissy Thumb into an SVT, a Mark Bass 2-10 combo and four different GK heads, and the result was the same; we still hissed. This was per my luthier to try this out. And the tech there, had not heard of this happening either!

My luthier will not have the time to look at it until at least mid-Jan. so I may try another luthier to check into this. So in the meanwhile, I'll check into the Thumb club to see what responses I get: if anyone else has had this problem. I hope to try the replacement of the treble pot soon! Good day!

[donnyrockaholic]

Hey Gang! Ok! Today I went to my local Guitar Center in Southeastern Ct. And also plugged The Hissy Thumb into an SVT, a Mark Bass 2-10 combo and four different GK heads, and the result was the same; we still hissed. This was per my luthier to try this out. And the tech there, had not heard of this happening either!

My luthier will not have the time to look at it until at least mid-Jan. so I may try another luthier to check into this. So in the mesnwhile, I'll check into the Thumb club to see what responses I get: if anyone else has had this problem. I hope to try the replacement of the treble pot soon! Good day!

Hi there Heny! I went home at lunch today because I'd noticed a bit of a treble-pot hiss in my 2007 Thumb too. But it's nowhere near as bad as what you describe, just barely noticeable when my volume's down, going away when switched to passive. Sounds like you're on the right trail to getting it fixed, it's a shame the seller didn't warn you of that pre-purchase.
I just had a completely different eBay experience, got a great Dolphin from a real good guy up CT way ;-)
Thanks again, and good luck with your Thumb!

[72jazz]

Hey Donny! Please take good care of her, (I'm sure you will) and if you ever...
let me know first, thanks and a Merry Christmas to you!

P.S. after I let her go, I was going to still try to find a less expensive 5-stringer, and lo and behold for the price I was going to invest in a lesser brand bass, this opportunity popped up, and I had to acquire it! I couldn't go without the Warwick-sound! When I asked the seller about my concern, he'd said that he never played it! So I'm stuck, but I guess, for the price.......And thanks for the kudo's....Henry!

[projectapollo]

Hi -- I also just purchased a used 1997 Thumb NT, 4-string. As a matter of fact, I came to this forum today to post my question about the loud hiss I get when in active mode. Quiets down when switched to EQ-bypass. Interesting..... Same exact year of bass, same problem. I'm having to do all my EQ at the amp.

[72jazz]

Well now! That makes at least two of us; and the same year? Florin, was there possibly an issue with the treble pot in that year, the preamp? Mr. Projectapollo; is yours also an 18v system? (two 9 v. batteries?) I won't know for sure till maybe mid-late Jan. at the earliest. So when I get any info, I'll pass it along, and we thank you....Have a Merry Christmas All!!!!!

[projectapollo]

Follow-up to my previous post -- I'm having this same white noise problem with a 1997 Thumb NT. Fiddling today I noticed that the noise is steady regardless of the volume setting!! Yes, with the volume all the way off, the hiss comes pouring out. Pop her up to passive and it quits. Hmmm...

[projectapollo]

... is yours also an 18v system? (two 9 v. batteries?)

Yes, 18v, mine has two brand new 9v batteries in it.

[Florin]

Interesting... I will ask for more informations, bunt untill now it doesn't seemed to be a known issue.
But... Please remember, 1997 is 12 - 13 ago. You don't expect a 13 years old TV to be as new, you shouldn't expect for the electronics to work perfect forever...

On the other hand I have a Thumb from 87 and it is OK.

I will ask :-)

[projectapollo]

You don't expect a 13 years old TV to be as new, you shouldn't expect for the electronics to work perfect forever...I will ask :-)

Florin -- Completely understood. Yes, older electronics will have their issues. But knowing a cause and solution would sure help the troubleshooting process. Two very interesting facts for the tech guys -- 1) the hiss is produced independent of the volume knob position; 2) my parametric does a fine job of filtering most of it from 1K to 3K. Seems to be centered right in that range. Thx...

[72jazz]

Morning Florin/Projectapollo! Henry here! Florin; thanks for chasing an answer for us.....we're both, and possibly more than the two of us are curious as to what the deal might be with our Thumbs! Hope an answer may be coming our way forthwith, and hope you had a good Christmas, Henry!

[Leif Bas]

My Thumb is a -98 NT5 that I bought used. When I received it there was this little plastic bag with 2 op-amps inside the case. The seller told me that the bass had been very noisy when he bought it new. The service center had replaced the two op-amps on the cicuit board when he complained (very easy to do as they are mounted in sockets):
TL064CN is now TL074CN
TL062CP is TL072CN.
I can´t guess if the originals just were "rotten apples", or if the new ones are of the more expensive "noiseless" type. My Thumb is very quiet anyway - as long as I don´t play it...

[projectapollo]

Reading some old posts on this forum and others have commented on the hiss from the 18v electronics from the late 90's era Thumbs. Maybe its just time for us to replace the MEC preamp? Is there a current MEC equivelant preamp we can purchase -- and preserve the bass's original tone? How to order? (I noted that there is no 18v preamp diagram posted on this website -- only the 9v. Is the 18v now obsolete?)

[projectapollo]

My Thumb is a -98 NT5 that I bought used. The seller told me that the bass had been very noisy when he bought it new. The service center had replaced the two op-amps on the cicuit board when he complained (very easy to do as they are mounted in sockets):
TL064CN is now TL074CN
TL062CP is TL072CN. My Thumb is very quiet anyway ...

Great intell. Anyone have any idea how to get these replacement parts?

[Florin]

Hey man, we are not using 18v anymore. Well I am using - 9V for Piezo, 9V for LEDs.

If you want my real honest opinion... I was always using the 2Way EQ switched off, for an obvious better sound...
I like the MEC 3 Way though. So an upgrade to 9V BEC 3, is a good option.

[Leif Bas]

Great intell. Anyone have any idea how to get these replacement parts?

Please check via Google - there are many sellers out there, who is in your country? I googled for one of the amps and found many links, and a proof that I was a fool believing that the low-noise amplifiers are expensive.

If anyone is interested in these amplifiers perhaps Florin can ask the preamp gurus after the holidays if any voltage adjustments should be done b4 the new IC:s are installed - or is it straightforward plug and pray?

[72jazz]

Henry here! Yup that's what I hope to do after my Thumb has been looked at, plug and pray!!! (I know it was a typo, but a humorous one!)

Florin, I want to keep the bass' controls original, so per Leif Bas, are the op-amps described still available?

Can you tell me what is the 9v BEC 3 that your referring to?

[Genral Specific]

This might be kind of silly and I am sure you have already thought of this, but have you changed the battery? My Thumb gets very noisy when the battery in the preamp is dying. Cheers!

[Florin]

Hi Henry,

It is the MEC 3 way EQ. And I think this is a cool upgrade for your bass, really :-) The mids are very sweet!
The 2 way preamps look different now...

You can contact info@mec-pickups.de
, ad MR Vlado Hansal will reply to you directly.