weird pot behaviour !?...

[nuno1959]

[color=#000000][font=verdana, geneva, lucida,]Hi guys[/font][/color]

[color=#000000][font=verdana, geneva, lucida,]just dropping by to ask a couple of things about my Squier Vintage Modified Fretless Jazz Bass, recently acquired 2nd hand for 200€..[/font][/color]

[color=#000000][font=verdana, geneva, lucida,]the pickups are definitely NOT Duncan Designed - since they bear no markings whatsoever, i'll pull them out one of these days to check out if there are any clues under them...[/font][/color]

[color=#000000][font=verdana, geneva, lucida,]they sound quite nice & are on the quiet side of things as far as hum & other ''afflictions''...[/font][/color]

[color=#000000][font=verdana, geneva, lucida,]however it's the pot's behaviour that baffle me a bit :[/font][/color]

[color=#000000][font=verdana, geneva, lucida,]1 - i have 1 Volume pot per PU & 1 tone pot for both PU. when i set BOTH vol. pots to their max, the sound kind of ''ducks'' a little !? [/font][/color]
[color=#000000][font=verdana, geneva, lucida,]2 - if i back one or the other a tiny bit the overall level actually goes up[/font][/color]
[color=#000000][font=verdana, geneva, lucida,]3 - if turn all the way down either of them & the remaining one to it's max i get a full sound as well, w/ good volume, punch, etc...[/font][/color]

[color=#000000][font=verdana, geneva, lucida,]looking at the control plate & without having pulled it out, i can see the knobs are a bit further away from the plate than usual in these basses - could they have been replaced - ''upgraded'' !?.. - w/ what seems to be longer shaft ones & maybe even the wrong type ?[/font][/color]

[color=#000000][font=verdana, geneva, lucida,]what would the original spec be ? perhaps even an original wiring diagram so i can compare what was & what's there ?[/font][/color]

[color=#000000][font=verdana, geneva, lucida,]it's not like the bass DOESN'T sound good - it does & it's tone is actually quite nice but i never had anything such as this volume ducking happen to me before so i'm a bit baffled[/font][/color]

[color=#000000][font=verdana, geneva, lucida,]last but not least : i think i'd like to make it active - what would be ''the right way to do it'' if there's such a thing...[/font][/color]

[color=#000000][font=verdana, geneva, lucida,]now i can't but tomorrow i'll post some photos - any suggestions about what could be off would be most welcome[/font][/color]

[color=#000000][font=verdana, geneva, lucida,]many thanks to all[/font][/color]

[color=#000000][font=verdana, geneva, lucida,]Nuno[/font][/color]

[xgsjx]

Seymour Duncan website has diagrams...

http://www.seymourduncan.com/support/wiring-diagrams/schematics.php?schematic=std_jazz_bass

Could be a pot wired incorrectly.

[nuno1959]

thank you for your input ! i had a look at the Seymour Duncan site but thought maybe the Squier had a wiring of it's own

i definitely have to take it apart & get some photos happening otherwise .....

[Mr. Foxen]

Both volumes on full drops the output compared to favouring one pickup because the pickups are out of phase in the mids, its pretty standard with jazz basses, treat it as three tone knobs.

[RAY AGAINST THE MACHINE]

Thought this was gonna be a cheech & chong type thread

[nuno1959]

i just took the whole thing apart to take some photos, would appreciate if you could take a look sometime later/tomorrow - as far as i can tell it all looks kosher, the pots are CTS but the PU's have NOTHING on them that could shed some light but a friend in a musicstore played it & told me they are definitely quieter than Duncan Designed original PU's !?....

[nuno1959]

[quote name='RAY AGAINST THE MACHINE' timestamp='1373160193' post='2134288']
Thought this was gonna be a cheech & chong type thread
[/quote] if only !!....LOL....

[nuno1959]

ok, did the photos - if curious you can check them here :

http://www.flickr.com/photos/13706825@N03/sets/72157634522800076/

all seems pretty good, i compared the wiring to the link you sent me & as far as i can tell, it's all there

the pots are CTS, ref nº 013446 250K A 0626 CTS
then there's this green thing, printed on it's side : K 42Y - 2, 160V, 0,0047uF +/- 10%

[color=#000000][font=verdana, geneva, lucida,]any ideas what the PU's on this bass could be ? besides having absolutely no identifying marks the only thing is that blue tape - typical of any manufacturer you guys might know ? not that it matters since as i said, it DOES sound quite GOOD - i'm just curious what they might be..[/font][/color]
[color=#000000][font=verdana, geneva, lucida,]Mr.Foxen : i understand what you're saying, not knowing this just shows how ignorant i am !! :-b[/font][/color]

[color=#000000][font=verdana, geneva, lucida,]anyway,[/font][/color][left] all your input[/left][color=#000000][font=verdana, geneva, lucida,] is [/font][/color][left]MUCH APPRECIATED, this forum rocks...many thanks[/left]

[left]Nuno[/left]

[nuno1959]

[color=#000000][font=verdana, geneva, lucida,]well, not wanting to take advantage of you guys but since we're all here & considering you are a lot more knowledgeable than me in these matters...[/font][/color]
[color=#000000][font=verdana, geneva, lucida,]even when i was only thinking about buying it, i've been toying with the idea of getting a preamp for it...[/font][/color]
[color=#000000][font=verdana, geneva, lucida,]now on my Cort GB35 i got a Delano Sonar2 preamp & it sounds AWESOME but[/font][/color]
[color=#000000][font=verdana, geneva, lucida,]1 - wouldn't it make this bass sound a bit like the Cort[/font][/color]
[color=#000000][font=verdana, geneva, lucida,]2 - in your experience what would be a preamp that would bring the ''sonic signature'' of this instrument forth but still preserving it ?[/font][/color]

[color=#000000][font=verdana, geneva, lucida,]if it brought a bit extra ooomph to the table i wouldn't mind either....[/font][/color]

[Prime_BASS]

I don't know the city bass, but sticking any preamp in any bass retains its characteristics, but you lose the original tonal options.

Personally I prefer two separate volume knobs per pickup, adding a preamp means using a pan pot in a lot of cases.

Although if you want a easy drop in preamp that has passive options still available, look at John East preamps.

In regards to the pickups. No idea what they are, definitely not Duncan designed but the circuit looks similar to the the original, same wires etc( had one and took it to bits before)
Solve the volume issue though, it's true that you get a mid scoop with both pickups on full, but in my past experience balancing them even outs the volume differences.
Raising the pickups will make it louder, and lowering, quieter. I have my bridge pickup 3mm from the strings the low side and just under on the high side, and a milimetre further on the other pickup.

[Green Alsatian]

Looks like the pickups/electronics have been modded/changed by the original owner. I've owned a couple of Squier VM basses and none of them have:

- have used CTS pots.
- used 'vintage' cloth-covered wiring.
- that type of tone capacitor (the green thing).
- been shielded with foil.
- 'vintage' cloth-covered wiring on the - they're not the original DD pickups.

Looks like good-quality parts have been used anyway. When you say that the volume drops when both pickups are on, does it cut out most of the bass frequencies? If this is the case, the two pickups could have been wired out-of-phase.

If you can trace the wires, here's a diagram from the Seymour Duncan website:

[url="http://cdn.seymourduncan.com/pdfs/support/schematics/std_jazz_bass.pdf"]http://cdn.seymourduncan.com/pdfs/support/schematics/std_jazz_bass.pdf[/url]

[KiOgon]

The pots & wiring look OK - but; "then there's this green thing, printed on it's side : K 42Y - 2, 160V, 0,0047uF +/- 10%"

you've either got an extra zero in there or it's the wrong value cap, typical Jazz bass cap should be .047uF. Does the tone control seem to work, or not much difference?

Someone has definitely upgraded the pots to good quality & right value/type CTS, 250K A = Audio Log, 0626 = made in 2006 week 26.
The Russian cap was probably sold as an expensive 'upgrade' from ebay or similar, so could well be the wrong value.

Cheerz, John

Edited July 7, 2013 by KiOgon

[nuno1959]

hi guys

i agree w/ you guys - the bass has definitely been redone using nicer parts : a friend of mine who works in this music store were i get my strings, etc...tried it & he told me that it was definitely quieter than originally, he also liked it's tone a lot

the volume issue is very much so as Mr.Foxen states above & now that i know it's ''normal'' for Jazz Basses i have no issues with that - it's just that in every other bass i've had this was never the case since they were of the 1 vol.pot/blend pot variety
not knowing any better i was left wondering if it had been tinkered w/ by someone w/ good intentions but lacking some expertise

as for the wiring diagram, i got that exact same one & yes everything is fine

i think all i need to do for now is to try out raising/lowering the PU's & get used to setting one volume pot to slightly less than all the way up

one more problem solved - thanks guys !!

[nuno1959]

[quote name='KiOgon' timestamp='1373190011' post='2134423']
The pots & wiring look OK - but; "then there's this green thing, printed on it's side : K 42Y - 2, 160V, 0,0047uF +/- 10%"

you've either got an extra zero in there or it's the wrong value cap, typical Jazz bass cap should be .047uF. Does the tone control seem to work, or not much difference?

Someone has definitely upgraded the pots to good quality & right value/type CTS, 250K A = Audio Log, 0626 = made in 2006 week 26.
The Russian cap was probably sold as an expensive 'upgrade' from ebay or similar, so could well be the wrong value.

Cheerz, John
[/quote]

hi John

no the zeros are as printed in the cap ( capacitor ?.. ) & although the tone control does work now that you mention this it does strike me as having a somewhat limited range & flat feels treblier ( for lack of a better word..) than i think it should - all the way for more bass adds not too much bass, all the way to the treble side adds quite a bit of treble
could this be caused by the cap value you mention or is it part of this type of PU's ? my other basses are either P/J ( Cort Action 4 A w/ standard electronics..) or in my Cort GB35's case : Delano J/MM + Delano Sonar2 preamp, both use a blend pot...

cheers

[Woodinblack]

I have a [color=#000000][font=helvetica, arial, sans-serif]Squier Vintage Modified Fretless Jazz Bass which I bought new last month. I get exactly the same 'ducking' and general sound levels as you describe in your post, ie, it is louder with one of the pots backed off a little.[/font][/color]
[color=#000000][font=helvetica, arial, sans-serif]However, my pickups are different from yours (as they say duncan designed), Do you want me to photograph the inside of mine so you can see if there is a difference?[/font][/color]

[nuno1959]

Hi W

well if you have them out of your bass, sure why not...but if not, i thank you for the offer but since everyone agrees these are NOT the original Duncan Designed PU's, please don't

finally i was just curious to determine what they could be but ultimately what matters is that they DO sound real nice ! ;-)

are you happy w/ your new toy ? isn't this an amazing bass for the price & a GREAT way to try out a fretless without spending a small fortune ? i AM thrilled i got this...
man, when i was a kid EVERY bass that cost this little, it's fretwork would shred one's hands to pieces & they'd sound like s***e !!....LOL....

although there are plenty of high-end basses i WOULD get in a heart beat if i had enough funds to blow, fact is i'm having a ball pursuing this ''very cheap/well built/upgrade electronics later'' approach - there REALLY are some little gems out there costing next to nothing
sure, one doesn't get any of those amazingly good looking exotic woods/top of the range hand finishes BUT....sound wise ? WOW !!

Edited July 7, 2013 by nuno1959

[Woodinblack]

Oh I didn't mean taking the pickups out, didn't want to do that, I meant the control cavity with the pots, that is just a few screws, and I already took it apart to see if there was room for a preamp.

I love this bass. I went to the bass part of wunjo in london to try different basses as I had determined I was going to get something as a late birthday present. I tried loads of stuff (and they had a large range) but I just kept going back to the fretless squier (even more so than the fretless fender whose balance I didn't like). There was nothing else in the same price range that I was really that bothered about (there was an older jazz at £1000 that was nice!), except maybe the fender jag which I hated the look of it.

I certainly didn't go in for a fretless but it was just so much fun to play, now I have been playing it to death - I already have marks on the fingerboard!

The sound is great. The only thing I would change is having a preamp, I have to remember if I go from the squier to the ibanez I need to turn it down or I lose the speakers as it is much quieter (although the ibanez is active, it isn't louder than my guitars)

[nuno1959]

for now i must confess i'm tempted by the preamp thing too & i might look into some PU's later, not that these don't sound nice but i'm used to quieter PU's without any hum/buzzes & so on...

[KiOgon]

Nuno, the upgrades have certainly been done - as you said - by someone with limited experience, for example I don't know why anybody would stick cheap aluminium foil shielding to the underside of a perfectly good chrome plated piece of solid steel no benefit to be had there

Also you mention the knobs are high up from the bell plate, that is because the CTS pots have a mounting thread 10mm overall length & if you don't have a extra backing nut between the pot & the plate, which is probably only 1.75 or 2mm thick, too much excess thread sticks through, leaving a unsightly gap.

I just checked Airmail to Portugal, it's not much, I could happily send you some bits to help you - can you do soldering? At least enough to change the cap (capacitor)? A normal poly drop 0.047uF cap is less than 5mm thick & a few nuts & washers for the pots don't amount to much. BTW the Jack socket fitted is a cheap Alpha type or similar, maybe the original, not the top quality Switchcraft, so in the long term that could prove to be a weak point.

At least if you change the cap to the correct value you will get an improved range on the tone control. With that & careful adjustment of the pick up height, I think you'll have a perfectly workable passive bass . If you want to go to an active system like a John East you will egt a much wider range of control/tones, but do you need that?

Cheerz, John

[Woodinblack]

I like the sound of the pickups and don't have any noise through them at all. Well, maybe I do depending on ones views of my playing!.
I have the original pickups though - presumably you have something better as I assume yours were upgraded.

[nuno1959]

Hi John

wow !! thank you VERY much for the offer but while i really appreciate it, i'd be more than happy & satisfied if you just gave me the right specs/brand for the cap - with that in hand i can hit up my friend at the music store & he'll get those easily for me for next to nothing, you know what i mean ?

yes, the foil over the metal control plate struck me as odd but since it was sloppy & will all be redone w/ graphite paint anyway, i didn't pay too much attention to it. same for the knobs, at first i thought it was just part of the ''cheapness'' of the bass's manufacture but as you say nothing an extra nut won't solve

as for the jack socket you are absolutely right, it IS a VERY crappy little number : when i played the bass the first few times i accidentally touched the chord/jack & it did cut out the signal momentarily & i'm pretty sure it had nothing to do with my chords - i make them myself, only use Klotz cables & Neutrik jacks & they've NEVER let me down before...
thing is, among the several things that have been crossing my mind to do to this bass ( i'm a hopeless tinkerer & a new bass to me is just one more list of endless, fun possibilities ;-) .. ) one i think i will most definitely do is to remove the jack from the control plate & drill a hole on the side of it's body to mount a new, high quality jack/jack plate as on my other basses

this, together w/ my angled Neutrik plug, my Schaller Strap Locks AND the way i ''wrap'' a loop on the cable to reinforce it were it goes over the StrapLock works VERY nicely not only to keep the cable out of the way but to prevent it getting sheared over the StrapLock if accidentally pulled, stepped on, etc..

you mentioned Switchcraft, how do they compare to Neutrik stuff ? as good ? better ? although Neutrik has always been my ''safety blanket brand'', i'm always open to new stuff & could try that...

but it DOES work + it would leave me an extra hole in the control plate to maybe rewire the whole thing differently ? at this point it's all in the realm of possibilities & i still have to go through my usual process of learning about it, selection & elimination before i decide what i'll actually do

isn't this all a bit convoluted ? slightly paranoid ? yup that's me alright !!....LOL.... when in doubt, over-engineer it to death & you'll be OK !!

& this is one more reason why nice, cheap basses can be so much fun for me !! ;-)

[Woodinblack]

The odd thing is, when I looked in mine, it is already coated in graphite paint and connected to the earth of the electronics.

[nuno1959]

a different production run hence different finishing touches perhaps ? i have NO CLUE what year is mine...

[iconic]

VMJ fretted versions come with cloth looking wiring out the bag...strange but true!

[nuno1959]

hi guys

just to say that after fitting a new set of strings ( D'Addario half-rounds.. ) & fooling around setting the pickup's heights, the bass does sound better. next i'll look into a cap of the correct value/type & a better quality output jack

i REALLY like this bass & having had the chance of ''digging in'' quite a bit these last few days, now i find the others too rough !...LOL...their strings hurt my fingers ! yup, i'm a p***y alright !!...LMAO...

thanks to all for chipping in