Fitting a q switch to an Aria Pro SB LTD

[andy3hal]

Dear Alembic folks,


Looking for some advice on fitting a three way Q switch to the Alembic electronics fitted to my Aria Pro SB LTD.


So, first attaching a photo of my two Alembics on the sofa, yes I am an Alembic fan and nerd of all things Alembic !


Saw an advert on ebay for the Aria and thought just had to have it, because of the Alembic connection.


This model Aria comes factory fitted with Alembic pick ups and electronics, two volumes and a filter.


The sound and playability is great.


The filter control sound definately has the Alembic sweep/wah sound, but it is not as pronounced as the filter modules on my Scorpion fitted with the anniversary electronics.


The filter modules from the photos look very very similar between that in the Aria and that in the Scorpion, with some box capacitor and op amp differences.


The Aria op amp is the 4558, whilst the Scorpion is the TLE 2022.


So the advice I am requesting is:
Can I change the box capacitors and op amp on the Aria filter board to the same on the Scorpion filter board to achieve the more pronounced range of sweep/wah.
The original Aria electronics is supplied via a single 9v battery, can I fit two in series to provide 18v, same as my Scorpion.
To fit a three Q switch is covered in previous Alembic postings - but looks like I would have to remove one off box capacitor to install the switch and possibly change the other two as mentioned.


Attaching some photos, Alembics on the couch, Aria & Scorpion filter boards and the Aria catalogues for the LTD bass.


Any advice much appreciated, thanks, Andy.

[edwardofhuncote]

Welcome to our hangout, Andrew... cool Aria Pro you have there.

I know of one other Club Member who has/or used to have one, and he may chime in. 

I am guessing, based on what I know about other activator sets, that in the absence of a Q-switch, the "Q" is attenuated on. Adding a switch gives you the ability to toggle it off, or to vary its boost in the case of a 3-position switch. (they come in different values... 0-3-6dB or 0-6-9dB. I think the default on was 8dB for Persuader models with 2-volume electronics that work like yours) Even with the Q toggled off, you still experience that little hump in the frequency, just not as boosted. Adding a switch is a great mod to do if you have that capability.


(if I'm wrong on this, somebody straighten it out please)

[gtrguy]

Neat bass. I love interesting hard to find instruments like this. The 4558 chip doesn't draw that much power, especially if you remember to keep it unplugged as much as possible.

I recently added a home built 6 position 'multi-Q' switch to a bass with Alembic electronics and love it. Very worthwhile mod. For yours you de-solder a yellow box cap and then put in a switch that can kick it in or out of the circuit (2 way) or kick it in or out and also go through another cap as well (3-way).


https://club.alembic.com/index.php?topic=26763.0

[andy3hal]

Hi there, and many thanks,


What a great idea fitting a vari tone switch, I am definately going to look into that and see what components I have readily available.


If you don't mind could you please share the capacitor values.


I also have an interest in the more hard to find basses, I also came across and bought a Kawaii F2B, its sort of in the style of an Alembic, the build quality and sound is great, I have attached some photos, there is a lot going on in the electronics cavity.


What a great source of info the club is.


All the best


Andy

[mica]

The 4558 op amps were at the low noise end of things when we used them, but they are high drain compared to the the newer 2022 which are quiet and lower drain. Generally people need to chargeout the battery with the 4558 about once a month, where the 2022 is once or twice a year. Filter modules we sold to Japan had a variety of different ranges, but generally more limited than the regular ones - it's what the distributor ordered and tailored to their market.

So yeah, you can change the opamp for battery life, but the capacitors are what will change the tone range.

Anniversary electronics only have one 9V battery, so if you have 2 that's something custom and it may not be the only custom thing you have.

You might want to compare the tone of the basses unplugged to get an idea about how the construction materials influence the sound - it's not all electronics.

[gtrguy]

When I made my 'varitone' Q switch I just hooked up some wire in the circuit with clips on the ends and tried out many old vintage caps from my collection until I found some I liked. Some squealed loudly and some were just not good sounding though.