Thinking about installing a ACG EQ01 in my L2K

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Re: Thinking about installing a ACG EQ01 in my L2K

Postby dade8283 » Mon Jul 23, 2018 8:12 am

double post
Last edited by dade8283 on Mon Jul 23, 2018 8:34 am, edited 2 times in total.
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Re: Thinking about installing a ACG EQ01 in my L2K

Postby dade8283 » Mon Jul 23, 2018 8:29 am

Ken Baker wrote:
dade8283 wrote:I’m really thinking about installing an ACG EQ01 filter preamp in my tribute L2000 bass. I’m a huge TOOL fan and love the Wal bass sound but don’t have 4K euros to spare, so this might be my best bet! I’ve read of several people online installing that preamp in a G&L L2000 with good success but I have a few questions.

First of, my plan is to (if possible) remove the entire stock preamp and switches so that it easily can be replaced later on if I would sell the bass or just charge my mind.


Clip the leads to the pickups, jack, and bridge ground. Clip as close as possible to the switch, jack, and the lug where the bridge lead connects. Remove the switch and pot jam nuts and the whole assembly should lift out.

I would just install the volyme/blend and LP filter pots so no drilling for a fourth hole! Secondly, I would like to be able to switch from parallel to series mode, preferably for each pickup seperately.


I'm not at all familiar with the ACG preamps, so will only talk about the passive circuit you can use to feed the thing.

1.) is it possible to install two mini switches for series/parallell switching for each pickup or would this just complicate things? How would one go about doing this?


Yes, though our circuits also provide single coil on the outer coils. Here's a passive circuit that does just that. This is an entire working circuit, so you'll need to pare out the bass, treble, and (maybe) the volume controls. Possibly even replace the pickup select switch with a smart blend. Click the image for a PDF.

Image

There is also some info here that you might want to read.

2.) what to do about the holes left from the switches? I would like to plugg them with something that’s not permanent and looks good with the transparent natural finish of the bass. Maybe som type of plastic pluggs exist?


Check online electronics suppliers for panel caps. They're little pop-in pieces that are usually available in black or chrome, maybe other colors, and in various diameters.

Ken...

Sorry for the very late reply!

I finally ended up ordering the ACG EQ01 preamp but I´ve ran into some issues. I have emailed and asked John East (very nice and helpful guy), but thought I take my time and ask the pros here aswell. First of, I decided to keep the series/parallel switch and just 2 unconnected dummy-switches.

John was nice to help me with the wiring and drew this for me:
Namnlös.gif
Namnlös.gif (205.01 KiB) Viewed 220 times


I then realized that my pickups had 5 wires(???) instead of 4 (tribute L2000 from 2012). The extra wire from each pickup (black wire) was soldered together with the green ground wire on the back of the stock volume pot. I asumed that the extra black wire was also a ground wire and connected it together with the pickups green ground wire in the preamps "cold/GND" connection for each pickup respectively. Was this the right way to do it or should it be grounded elsewhere? I also took the time and sheilded the cavity with copper tape where my bridge- and output jack-ground are soldered.

Wire number 4 (from the switch) is also connected to ground ond the ACG preamps main board. The green wire from the jack (nr 5) is also connected to ground ond the main board (not the same as wire 4).

I get sound from the new preamp and all the controls seem to work fine but I get a huge bass loss when blending the to pickups with the active blend control. Each pickups soloed works just fine so I suspect that I have some phasing issue?
Last edited by dade8283 on Mon Jul 23, 2018 1:34 pm, edited 1 time in total.
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Re: Thinking about installing a ACG EQ01 in my L2K

Postby dade8283 » Mon Jul 23, 2018 1:32 pm

http://www.east-uk.com/pdf/ACG_EQ01.pdf

Here´s the ACG manual (page 5) if it´s any help :)
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Re: Thinking about installing a ACG EQ01 in my L2K

Postby Ken Baker » Mon Jul 23, 2018 7:46 pm

dade8283 wrote:John was nice to help me with the wiring and drew this for me:

I then realized that my pickups had 5 wires(???) instead of 4 (tribute L2000 from 2012). The extra wire from each pickup (black wire) was soldered together with the green ground wire on the back of the stock volume pot. I asumed that the extra black wire was also a ground wire and connected it together with the pickups green ground wire in the preamps "cold/GND" connection for each pickup respectively. Was this the right way to do it or should it be grounded elsewhere? I also took the time and sheilded the cavity with copper tape where my bridge- and output jack-ground are soldered.


This all sounds good.

I get sound from the new preamp and all the controls seem to work fine but I get a huge bass loss when blending the to pickups with the active blend control. Each pickups soloed works just fine so I suspect that I have some phasing issue?


Perceptions... Did you hear a huge bass loss or an overall volume loss? It's a bass guitar, so it might be a little hard to distinguish between loss of bass and loss of volume. Also, what happens with the blend at the center detent? If the blend is a smart one, or active, you should hear full volume. A normal blend would take the hot output leads (2) from the series/parallel switch and output a single (1) hot lead to the preamp.

I'm betting that there's an issue somewhere in the blend circuitry, either the interconnects or the preamp (if active blend).

Ken...
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Re: Thinking about installing a ACG EQ01 in my L2K

Postby dade8283 » Tue Jul 24, 2018 12:34 am

Ken Baker wrote:
dade8283 wrote:John was nice to help me with the wiring and drew this for me:

I then realized that my pickups had 5 wires(???) instead of 4 (tribute L2000 from 2012). The extra wire from each pickup (black wire) was soldered together with the green ground wire on the back of the stock volume pot. I asumed that the extra black wire was also a ground wire and connected it together with the pickups green ground wire in the preamps "cold/GND" connection for each pickup respectively. Was this the right way to do it or should it be grounded elsewhere? I also took the time and sheilded the cavity with copper tape where my bridge- and output jack-ground are soldered.


This all sounds good.

I get sound from the new preamp and all the controls seem to work fine but I get a huge bass loss when blending the to pickups with the active blend control. Each pickups soloed works just fine so I suspect that I have some phasing issue?


Perceptions... Did you hear a huge bass loss or an overall volume loss? It's a bass guitar, so it might be a little hard to distinguish between loss of bass and loss of volume. Also, what happens with the blend at the center detent? If the blend is a smart one, or active, you should hear full volume. A normal blend would take the hot output leads (2) from the series/parallel switch and output a single (1) hot lead to the preamp.

I'm betting that there's an issue somewhere in the blend circuitry, either the interconnects or the preamp (if active blend).

Ken...

Thanks. I think it´s just the bass that drops. The blend is active and part of the main PCB. There´s a PCB for each pickup with a filter. When having both filters on full (letting all treble freq through) the sound is really bright and using the active blend to mix between the 2 pickups doesn´t change the volume. However, when dailing in one pickup´s filter to be bass heavy soloed, all that bass drops when you mix it with the other pickup making a much thinner sound. This led me to beleive there was a phasing issue. I never lost bass when having both pickups on with the stock wiring.
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Re: Thinking about installing a ACG EQ01 in my L2K

Postby Ken Baker » Tue Jul 24, 2018 7:39 am

Reminder of the standard disclaimer: Your bass isn't on my bench.

dade8283 wrote:Thanks. I think it´s just the bass that drops. The blend is active and part of the main PCB. There´s a PCB for each pickup with a filter. When having both filters on full (letting all treble freq through) the sound is really bright and using the active blend to mix between the 2 pickups doesn´t change the volume. However, when dailing in one pickup´s filter to be bass heavy soloed, all that bass drops when you mix it with the other pickup making a much thinner sound. This led me to beleive there was a phasing issue. I never lost bass when having both pickups on with the stock wiring.


So long as you made no changes to the series/parallel switch, it's unlikely to be a phasing problem. Anything downstream of that, such as a feed to a pickup select switch or blend, is just a pair of hot leads from the pickups (one from each pickup), so no chance of a phase problem.

Ken...
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Re: Thinking about installing a ACG EQ01 in my L2K

Postby dade8283 » Tue Jul 24, 2018 9:51 am

Ken Baker wrote:Reminder of the standard disclaimer: Your bass isn't on my bench.

dade8283 wrote:Thanks. I think it´s just the bass that drops. The blend is active and part of the main PCB. There´s a PCB for each pickup with a filter. When having both filters on full (letting all treble freq through) the sound is really bright and using the active blend to mix between the 2 pickups doesn´t change the volume. However, when dailing in one pickup´s filter to be bass heavy soloed, all that bass drops when you mix it with the other pickup making a much thinner sound. This led me to beleive there was a phasing issue. I never lost bass when having both pickups on with the stock wiring.


So long as you made no changes to the series/parallel switch, it's unlikely to be a phasing problem. Anything downstream of that, such as a feed to a pickup select switch or blend, is just a pair of hot leads from the pickups (one from each pickup), so no chance of a phase problem.

Ken...

I think I figured it out!

The controls work really defferent compared to normal bass preamps. There´s a filter and resonance peak for each pickup that you can set individually. For some reason the center detent on the filter resonance peak controll is not at cero but 50% boosted (+6db at filter cut off point), so when leaving one pickup with the filter fully open, and with what I thought was a flat resonance peak, I was actually boosting really high freq on one pickup, making the overall tone sound really thin until I soloed the other pickup with the filter turned down a bit. Totally a user error from my part :roll: Having the filters actually set flat and setting the blend at center detent gives you that usuall slight dip in the upper mids/highs while maintaining the lows, so no phasing issues.

I think it will take some time and practice getting used to the controls, but really cool to play around with. Boosting the resonance peak and turning the filter up and down makes it sound like a fat wah pedal! It reminds me of a Wal bass.
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Re: Thinking about installing a ACG EQ01 in my L2K

Postby Ken Baker » Tue Jul 24, 2018 4:39 pm

dade8283 wrote:I think I figured it out!


Very good. Thanks for letting us know.

Ken...
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