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jwkelley
Junior
Username: jwkelley

Post Number: 15
Registered: 5-2010
Posted on Thursday, May 10, 2012 - 6:00 pm:   Edit Post

I would like to have some way to bypass the tone controls on a Series II bass without bypassing the entire preamp. Has anyone tried this?
adriaan
Moderator
Username: adriaan

Post Number: 2928
Registered: 6-2002
Posted on Thursday, May 10, 2012 - 11:27 pm:   Edit Post

Keep the filter wide open, and the Qs fully closed. That should give you a fairly unadulterated signal, with a minor boost around 6.5 kHz.
jwkelley
Junior
Username: jwkelley

Post Number: 16
Registered: 5-2010
Posted on Friday, May 11, 2012 - 10:22 am:   Edit Post

Thanks, Adrian. It sounds to me that, in the case of my bass at least, that setting may have a bit more than a minor boost. Having a bypass switch is certainly the way to know for sure. I've spent hours trying to get natural sounding tones from this bass. I have this luxury when I'm at home, but not so much while I'm standing on stage. The EQ is extremely versatile and I'm sure there is a setting that comes close to a natural sound.

With the amp systems I have, I can plug in any of my other basses (including the Series I) set flat and get a nice sound. In my experience, an Alembic bass doesn't need a lot of EQ in order to sound amazing. The fact is, in the case of this '89 Series II, it really needs a lot less.

So I would like to leave all of the electronics in place and in tact, and simply bypass the state variable filters with a switch. Aren't some of the newer basses offered with an EQ bypass switch? I need to be able to do it on this bass.
serialnumber12
Senior Member
Username: serialnumber12

Post Number: 966
Registered: 12-2004
Posted on Sunday, May 13, 2012 - 5:23 am:   Edit Post

i dont think series basses can go passive, however alembic did make a bass with no control knobs on the bass it just had the 5 pin jack.does this sound like what you're after?
terryc
Senior Member
Username: terryc

Post Number: 1845
Registered: 11-2004
Posted on Sunday, May 13, 2012 - 9:29 am:   Edit Post

Correct me if I am wrong(I am sure someone will LOL) but the sound you get is already the natural sound, the filters enhance the frequencies coming from the strings at each fret.
jwkelley
Junior
Username: jwkelley

Post Number: 17
Registered: 5-2010
Posted on Sunday, May 13, 2012 - 11:48 am:   Edit Post

All good points. And yes, the low impedance pickups probably must have a preamp in order to have sufficient level to drive the front end of the amplifier. However what I was after is a means for bypassing the equalization portion of the preamplifier. Granted, this may not be a realistic goal since the EQ section is integrated into the preamp as a whole. A glance at a schematic diagram would reveal the extent to which it might be possible.

Perhaps the idea of 'natural sound' is too subjective. What I had intended by using the term was something like 'a fair reproduction of the acoustic qualities of the instrument'. To my way of thinking the meticulous layering of woods, crafting of shapes and resonant cavities, and all of the many other aspects that contribute to the creation of a properly vibrating instrument is the difficult part - the part which Alembic does without equal in the world. But in my opinion, introducing electronic resonances tends to adulterate the response of the instrument and its pickups. Don't get me wrong. Like everyone else, there are times when I really like doing that. But I don't necessarily want to be forced into it. :-)

This particular instrument, it seems to me, may have spent too much of its 23 year life in the case. It's 'natural' tone still seems to be evolving slowly as I play it, and it continues to get better as it seemingly becomes more accustomed to the vibrations. Or it could be that I'm imagining all that. ;-)
edwin
Senior Member
Username: edwin

Post Number: 1176
Registered: 5-2002
Posted on Sunday, May 13, 2012 - 11:06 pm:   Edit Post

Well, I have been able to compare SII pickups with and without the tone controls and with the Q backed off all the way and the filters wide open, it's very very similar. Without being able to switch back and forth, I don't know that it would be possible to hear a difference.

There is a way to do this, but it's not trivial and in my view, not really worth it. YMMV.
elwoodblue
Senior Member
Username: elwoodblue

Post Number: 1392
Registered: 6-2002
Posted on Monday, May 14, 2012 - 12:01 am:   Edit Post

One thing I might be tempted to try is to
adjust the gain trimpots to a low setting,
(and maybe lowering the pickups a tad?).

Just make a note of where they are( or take a pic)
if/when you want to backtrack.
You might be able to quell a couple electronic resonances .
serialnumber12
Senior Member
Username: serialnumber12

Post Number: 967
Registered: 12-2004
Posted on Monday, May 14, 2012 - 6:17 am:   Edit Post

sounds like he needs a stethoscope type of mic/pickup installed into or onto the alembic to experience the true acoustic nature of those exotic woods with out the bass being turned on ???

(Message edited by serialnumber12 on May 14, 2012)
elwoodblue
Senior Member
Username: elwoodblue

Post Number: 1393
Registered: 6-2002
Posted on Monday, May 14, 2012 - 11:55 am:   Edit Post

I think Zappa had a piezo installed in his SG neck to catch those woody tones.
I call your stethoscopes and raise you a DeArmond 900 :
(apologies for the tangent jwkelly)
mica
Moderator
Username: mica

Post Number: 7724
Registered: 6-2000
Posted on Monday, May 14, 2012 - 7:14 pm:   Edit Post

I sent you the schematic, you should be able to take the output off the preamps, and I know you are clever!
jwkelley
Junior
Username: jwkelley

Post Number: 18
Registered: 5-2010
Posted on Thursday, May 31, 2012 - 11:16 pm:   Edit Post

I managed to successfully bypass the EQ, and now it really does give the natural sound I have been hoping to hear from this bass. It sounds best without any bumps or dips in the response - in my humble opinion.

Thanks for the invaluable help, Mica. The pickups made a world of difference. You were right that the hum coil isn't perfectly matched to them. But I think I'll be able to find a reasonable balance using the gain controls.

Is there such a thing as a break in period for a bass? Do you think that playing an instrument has an effect on it?
edwin
Senior Member
Username: edwin

Post Number: 1187
Registered: 5-2002
Posted on Friday, June 01, 2012 - 9:40 am:   Edit Post

Do you have it set up with a bypass switch or are the filters just out of the circuit? I've thought about doing a bypass, but I find that I use the filters constantly, at least on my SII equipped Starfire.
jwkelley
Junior
Username: jwkelley

Post Number: 19
Registered: 5-2010
Posted on Wednesday, June 13, 2012 - 4:11 pm:   Edit Post

Hello Edwin -

At the moment I just have it bypassed. It would probably require a 4-pole double throw switch to make it switchable. I think all it really needs are a couple of old fashioned tone controls. It's a bit of a dilema.
adriaan
Moderator
Username: adriaan

Post Number: 2941
Registered: 6-2002
Posted on Wednesday, June 13, 2012 - 11:33 pm:   Edit Post

According to this thread, #16 and #17 had passive tone pots, so it's not unheard of. There is another thread where Michael talks about the differences in sound, but I haven't found it yet.
jwkelley
Junior
Username: jwkelley

Post Number: 20
Registered: 5-2010
Posted on Thursday, June 14, 2012 - 9:48 pm:   Edit Post

Hi Adriaan -

Thanks for that. It is interesting - and a beautiful bass, too. It occurs to me that I've never had any issues with the Series I electronics in either of my '77 basses. Always kept them stock and been perfectly happy with them. I really don't want to get too weird with anything on this bass, so here's a thought. Would it be weird to put Series I electronics in it instead? Probably be a job best for the factory, but if the CVQ pots were changed out for switches it might still be cool. What do you think?
edwin
Senior Member
Username: edwin

Post Number: 1211
Registered: 5-2002
Posted on Saturday, June 23, 2012 - 2:11 am:   Edit Post

This thread is rekindling desires to install my SF2 into my Starfire again. I know, it's crazy talk, but it would be soooo fun!

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