SC Brown Wireing and trim pots ?

[rnolan]

So far I can't find any information (diagram would be good) of the electronics in my new SC Brown.  Also what the batteries do (3 in the rear battery cavity, I'm assuming for the LEDs ??) and 1 in the electronics cavity (I assume for the active circuit ?).  It seems to have 3 (possibly 4) trim pots, 2 are located on the filters (so I assume related to their operation ), one in the centre and another on its side which is hard to see.  I'd like to know what they all do as it seems I'll need to play with them (advice from another post (Jerry re fretless mwah)) to balance the PUs in both PU selected mode.  Currently both PUs selected is much louder than either PU, not what I'm used to on guitar.

Cheers Richard

[rv_bass]

Hi rnolan,
Welcome.  You should explore the FAQ section, there's some good info there...

http://club.alembic.com/index.php?board=6.0

Also, look through the Must Read section for more info.

http://club.alembic.com/index.php?board=29.0

Here's the Brown Bass link to start...

http://club.alembic.com/index.php?topic=282.0

Not sure what the trim pots look like inside a Brown Bass, but this might be a place to start...

http://club.alembic.com/index.php?topic=222.0

[keith_h]

Richard - I replied in your other thread. The gain trim pots are on the filter PC boards. If you only have three trim pots then I suspect the 3rd one is to adjust the neck LED brightness. If it is four I still suspect one is for the LED's but the other? No idea. 

[rnolan]

Thanks keith_h, I think you are on the money there.  Posted a cavity pic on the other post but I'll put it here to in case someone trips over it.

Hey Rob, many thanks, yeah checked those links first  , when you see the cavity pic you'll see its a bit different.  I'd still like to know what the 4 9v batteries do, I'm thinking 3 for the leds (the ones in the battery cavity) and one for the electronics (in the control cavity).

[hammer]

Richard

You've got the battery function correct.  Just make sure that you date the battery in the control cavity so you'll know when it needs to get changed out.  I've had my Custom and SC go down on me (during practices only so far) because I did not monitor how long I had been using the battery.  It's one thing if the LEDS go out, quite another when you started getting the dying battery distortion in the middle of a song.

[keith_h]

Yep the third switch is for dimming the LEDs. Depending upon the color some of them can be quite bright. In the past I think most of us just added a resistor inline to dim them but I think the pot is now installed as a standard feature. To sum up. The gain pots are on the filter boards and the LED dimmer is attached to the LED on/off switch.

As Brian mentions it is good to keep track of the battery. Unlike any other active bass I have dealt with there is no warning with my Alembics for when the battery is starting to go. One minute they are clear as a bell, next is total distortion and a dead battery.

One last thing. In case you're not aware of it the BB is the only non-Series instrument that comes standard with a thicker body capable of accepting Series electronics. This means if you want to upgrade at some point in the future you will have enough thickness and space to stuff all of the electronics and hum canceller into your instrument.

[rnolan]

Good advice re the battery, thanks.  So this bass hasn't been played (as far as I'm aware) but it was built March 2015 so the batteries are nearly 1.5 years old (at least). However, if it hasn't been used, then they should still be fresh.

Also good to know about the space for the series electronics.  I see in other posts there's a bit of upgrading going on within the community here.

So far I've been using the middle position (N + B), which sounds just gorgeous.  And all the pots full and Q switches off.  I'll start to tweak from there.  Also the MB1 has soo much to fiddle with as well. Lots to keep me occupied for quite a while I suspect.  I'm just waiting on an optocoupler for one of the MB1s (part of the MIDI circuit) which should come in a day or so, then I'll try the stereo option.  Also need to get some new sensor Mullard re-issue long plate 12AX7s for both MB1s, these are very 3D tubes and should go very well with the Alembic (being such a sensitive, responsive and articulate bass)

[hankster]

I love the dying battery distortion on my SJ. It is often unfortunately unsuitable for the moment. But a lovely smooth sound.

[hieronymous]

I believe that the Anniversary electronics have been said to be "as close as you can get to Series without being Series" (can't find an actual thread for proof) - it's basically the same setup, but without the Series single coils & humcanceler. I had my SC Signature 5-string upgraded to the Anniversary electronics - I prefer separate volumes for the two pickups as opposed to a blend knob. I will admit I have also been finding the volume to drop when both are selected - I think the approach is different than guitar where one is constantly switching between pickups - with an Alembic bass I personally have been looking for a single consistent sound that I may vary slightly either with the filter knob or with effects.

[rnolan]

Hey hieronymous, I quite like the electronics so far, I like individual vols as well.  So I get a marked (~3db?) increase in vol with both PUs selected, not that it's being an issue as it seems to be my goto setting for now (and vary the PU vols to taste..). Very early days for me though as I find my way around the vast array of sounds/tones you can get.  So if you get a drop in vol with both PUs in.. could be trim pot adjust (like in Joey's post, he talks about this and trim pot settings) or a PU is too far from the strings (which is a trick I use with 3 PU strat style guitars). I wind the middle PU as low as it will go and it tends to suck output when combined with neck or bridge (good for clean sounds) ?

So from what I've read so far (lots to learn): the FAT Boys in the brown have their hum cancel coil under the PU coil (stacked?).  So due to it's proximity to the magnet it will pick up some string (and cancel RF noise).  Allegedly the Fat Boys have a bit more thump than other Alembic PUs, so this stacked setup is most likely adding that (my guess).  In the Series set up the coil is in between the PUs so not affected by the magnets so doesn't pick up the strings.  Also only one coil shared between the PUs ("tuneable" to optimise noise reduction for each PU with the 2 assigned trim pots).  The FBs have a coil each which is a compromise approach.

[hieronymous]

As far as I know, all non-Series pickups are stacked humcancellers, as seen here: http://club.alembic.com/index.php?topic=293.0


Actually this thread I've linked to has a wealth of info. And then there's this one: http://club.alembic.com/index.php?topic=2269 which directly addresses pan vs. 2 volumes