Filter Preamps - anyone compared ACG, Lusithand, Passinwind, Underhill?

[ctmullins]

I agree - my EQ-01 behaves perfectly.

Further, as I'm pretty sure both the volume and the blend are buffered, it would be wildly inappropriate to use 500KOhm pots. I'm quite sure Mr. East is smart enough to understand this.

 

[4848277]

I own/owned an EQ-01 and had neither of those problems - my volume would mute and my balance would perfectly cut off each pickup on either end.

Thanks. I guess I'll be contacting John East about this.

 

[sunbeast]

I can only comment on the ACG EQ01 that I installed in one of my basses. A major thing I dislike about it is that the value of the volume/balance pots that come with this preamp are too low in my opinion. The volume won't go down low enough to completely mute the instrument, and it's the same situation with the balance control. I'm still getting signal from the neck pickup when the control is adjusted to full for the bridge pickup, and vice versa.

I haven't read all of the related posts yet, but I see that some of you have recently said that the low values are required for this sort of preamp, but I find it a major problem.

I'd like to go back to 500K pots for these controls if I could find a part that'll fit the board. Will the filtering still function correctly though? (I don't see why not.) Has anyone here tried it with the EQ01, or is there a workaround to remedy the problem with the circuit as is?

Yeah that isn’t normal at all. I have an EQ-01 and the Balance/Blend work exactly as expected. The active blend East uses in this preamp and some of his others is my favorite Blend control ever in fact (does the incremental blending across the whole taper that is so rare in blend controls)

 

[4848277]

Yeah that isn’t normal at all. I have an EQ-01 and the Balance/Blend work exactly as expected. The active blend East uses in this preamp and some of his others is my favorite Blend control ever in fact (does the incremental blending across the whole taper that is so rare in blend controls)

I can turn the volume pot all the way down and still hear the bass quite clearly (but less volume of course) through my amp that wasn't turned up loud. Also, I can tap on my bridge pickup (with a little screwdriver or whatever) with the balance fader turned fully to the neck pickup and still here that tapping clearly.

I've contacted Alan, and John about this. So far Alan says...

"Regarding the blend.

Because there are 3 channels in the preamp one for each pickup and one for the treble feed there will be signal present. The treble feed is supplied by both pickups this is independent of the main blend So there is always some signal from both pickups or one of the pickups. The internal trim pot which controls the signal from the pickups going to the treble feed is set up as an equal blend of both pickups as the default."

... which may be true, but I replied to this saying that I've been speaking to people here on this forum who claim that their's work flawlessly. I also said that it sounded like he's saying that the treble filter is the culprit, and reading between the lines, (I think) for the circuit to work correctly, it should be disconnected. Alan hasn't replied to that email yet. UK is 5 hours ahead of my time zone, so I may not hear back from him until tomorrow.

John says...

"It seems as if there is a ground missing, or some incorrect wiring somewhere, very unusual symptoms.

+ Is this the first time of installing this unit?

+ Are the filters working?

+ Can you send some pics of the installation?

Thanks, John"

... which is fine, and I told him the preamp has only been in the one bass, the filters are working, and sent him a couple of pics of the installation. He hasn't sent further replies as of yet. Again, he's in the UK, so I probably won't hear anything further until tomorrow.

I thought I did a fairly decent job installing it. It's fairly straight forward anyway, and I'm certainly not incompetent with changing parts in my basses.

Are you guys sure your EQ-01 volume/balance control functions as expected?

The EQ-01 is an expensive piece of rig in my opinion, and for this kind of thing to happen after laying out the dough in good faith is a complete 5h!t show for me.

P.S.: Sorry about posting my question to this thread. I didn't intend to hijack it.

 

[sunbeast]

I can turn the volume pot all the way down and still hear the bass quite clearly (but less volume of course) through my amp that wasn't turned up loud. Also, I can tap on my bridge pickup (with a little screwdriver or whatever) with the balance fader turned fully to the neck pickup and still here that tapping clearly.

I've contacted Alan, and John about this. So far Alan says...

"Regarding the blend.

Because there are 3 channels in the preamp one for each pickup and one for the treble feed there will be signal present. The treble feed is supplied by both pickups this is independent of the main blend So there is always some signal from both pickups or one of the pickups. The internal trim pot which controls the signal from the pickups going to the treble feed is set up as an equal blend of both pickups as the default."

... which may be true, but I replied to this saying that I've been speaking to people here on this forum who claim that their's work flawlessly. I also said that it sounded like he's saying that the treble filter is the culprit, and reading between the lines, (I think) for the circuit to work correctly, it should be disconnected. Alan hasn't replied to that email yet. UK is 5 hours ahead of my time zone, so I may not hear back from him until tomorrow.

John says...

"It seems as if there is a ground missing, or some incorrect wiring somewhere, very unusual symptoms.

+ Is this the first time of installing this unit?

+ Are the filters working?

+ Can you send some pics of the installation?

Thanks, John"

... which is fine, and I told him the preamp has only been in the one bass, the filters are working, and sent him a couple of pics of the installation. He hasn't sent further replies as of yet. Again, he's in the UK, so I probably won't hear anything further until tomorrow.

I thought I did a fairly decent job installing it. It's fairly straight forward anyway, and I'm certainly not incompetent with changing parts in my basses.

Are you guys sure your EQ-01 volume/balance control functions as expected?

The EQ-01 is an expensive piece of rig in my opinion, and for this kind of thing to happen after laying out the dough in good faith is a complete 5h!t show for me.

P.S.: Sorry about posting my question to this thread. I didn't intend to hijack it.

What you are saying is not the way my EQ-01 works RE: the Volume control, and I just checked right now to verify. I can turn the High-pass Filter level up all the way and the Volume control still mutes the entire signal when turned all the way down.

However Alan is correct about the way the High-pass Filter works in the sense that it receives signal independent of the Blend control (using the trim pot internally to decide where its signal comes from), so if you have it set for the high-pass to receive signal from the bridge pickup only, then roll the Blend to Neck only you will still be getting high-passed signal from the bridge pickup (unless you turn the high-pass level all the way down)- though to reiterate, if you turn the Volume all the way down it should still mute the entire signal (at least mine does) regardless of high-pass level settings. The High-pass Filter in the ACG is basically a much more tweakable version of the Attack switch in a Wal bass, and it works the same in a Wal (except I believe the Attack is hard-wired to receive signal from the neck pickup in a Wal IIRC, regardless of whether the neck pickup is turned up). I don't see an issue with this function (as far as the preamp "working correctly"- it does as intended/designed and is only letting a small section of the signal through as an attack boost). If you turn the High-pass Filter down all the way it should be equivalent to removing it if it is working correctly- the top knob of the HPF is the level control in case that wasn't obvious (not sure why it has a center detent, but turn it all the way down to turn it off)

I assume you carefully wired all the connections as shown in the manual on ACG's site? lots of potential for miswiring here!

 

[4848277]

Further to my last post, and probably as you were composing your's, I disconnected the treble filter, and everything worked perfect. So I unplugged the bass and carefully reinstalled the ribbon cable for the treble filter, and everything still works!

Looking at it as it was, you'd never see that there was a problem. The ribbon cable looked perfectly connected, but it obviously wasn't. It was the only thing I changed, so it must've been it. I just hope it's not intermittant.

Sorry for disrupting this thread with this fiasco. I feel like my bass was trolling me. :|

Cheers!

 

[ctmullins]

Yay! Nice work!

(I’m not really a fan of those ribbon cables…)

 

[4848277]

Yay! Nice work!

(I’m not really a fan of those ribbon cables…)

Thanks! I'm not a fan of those ribbon cables either now.

Thank you to everybody else too.

At least this part of the thread can still be a benefit to those in the market for these kinds of preamps. Just gotta watch out for those #@[|<in' ribbon cables and make sure they're actually connected even if they look solid.

 

[bassvirtuoso]

No one who worked on my bass when I had the ACG installed liked those ribbons.

 

[kesslari]

I can only comment on the ACG EQ01 that I installed in one of my basses. A major thing I dislike about it is that the value of the volume/balance pots that come with this preamp are too low in my opinion. The volume won't go down low enough to completely mute the instrument, and it's the same situation with the balance control. I'm still getting signal from the neck pickup when the control is adjusted to full for the bridge pickup, and vice versa.

I haven't read all of the related posts yet, but I see that some of you have recently said that the low values are required for this sort of preamp, but I find it a major problem.

I'd like to go back to 500K pots for these controls if I could find a part that'll fit the board. Will the filtering still function correctly though? (I don't see why not.) Has anyone here tried it with the EQ01, or is there a workaround to remedy the problem with the circuit as is?

Count me as another EQ01 owner who does not experience those problems at all. Glad you got it sorted out.

 

[OJ Dorson]

I've had experience with the JTex Distillers and can second the enthusiastic feelings for them. They're beautifully designed and do *exactly* what they should - which is emulate the Alembic filter+q switch. The quality of the pieces Jerry makes are all top notch. I've bought at least half a dozen filters over the last couple years for different project and I've got his headphone amp and a few battery Indicators. I'm planning to use two in the solid rosewood fretless I'm restoring and I'm still looking for the right way to blend them. They are a bargain for what they do and Jerry is awesome to work with!

I've had experience with the Lusithand Double NFP and it is not what I'm looking for. It's aggressive and I'm not happy with the quality of it, but based on pictures of the current parts I think I have an early example and the stuff they're putting out now looks better. (this preamp will be for sale soon)

Most recently, I took delivery of an [This invalid link has been removed] with multi-coils and the DFM preamp. I am blown away by the DFM and can hardly put this bass down. It seems to me that every tone you could ever want is hiding in this preamp... To me this bass can even cop a pretty close Smith tone if you pull the knob on the neck stack to activate the mid-boost, something I've never gotten on any other bass. There's adjustments for the mid-boost frequency and gain (pull on neck stack), and the upper-mid/attack boost (pull on bridge stack) with similar adjustments in the cavity. It is so incredibly flexible and it's pretty quick and intuitive. This is far and away the best preamp I've ever used. I've put in a custom build order (still multi-coils and DFM) and am looking to find this bass a new home asap.

 

[Jim C]

Passinwind Filter Pre-amp / Pedal Format
I've worked with Charlie on a few different versions and I'm here to say that the latest is unlike any EQ device you have ever used. Super quiet, plenty of gain, and tone controls unlike anything I've ever used.
This would include years of big studio engineering with graphic and parametric EQ's like Orban, Klark Technique, Urei, API, Neve, etc. If anything it's closest to a Pultec and I've used both the SS and tube versions.
The resonance and freq. controls (as well as 3 position mid, HPF, and bass control) allow for unique tone shaping unlike any other pedal or onboard bass EQ I've tried.
Here's the thread:
The Passinwind Open Source Preamp

Here is my current pedal:

 

[sunbeast]

Passinwind Filter Pre-amp / Pedal Format
I've worked with Charlie on a few different versions and I'm here to say that the latest is unlike any EQ device you have ever used. Super quiet, plenty of gain, and tone controls unlike anything I've ever used.
This would include years of big studio engineering with graphic and parametric EQ's like Orban, Klark Technique, Urei, API, Neve, etc. If anything it's closest to a Pultec and I've used both the SS and tube versions.
The resonance and freq. controls (as well as 3 position mid, HPF, and bass control) allow for unique tone shaping unlike any other pedal or onboard bass EQ I've tried.
Here's the thread:
The Passinwind Open Source Preamp

Here is my current pedal:
View attachment 5058228

This looks awesome! What are the specs for your added HPF control? I want to build one of these yesterday!

 

[Jim C]

I'm not sure the exact setting on this one as it is the third in a chain of test units.
The link in the post above is pretty up to date spec wise though and those guys have it all figured out.
Pre made PC boards, parts lists, and powder coated, labeled boxes for something like $20 each in small quantities.
The last revision for me is awaiting Charlie as he has other work to finish as well as some crazy idea for a home made 100 Watt tube bass amp!

 

[Inkadibass]

Sorry I'm a little late to this discussion, but I'd highly recommend not forgetting about JTEX Distillers! They're my favorite and I have a set of them in both my 1970 Guild Starfire and my 1962 Gibson EB0.
JTEX is a one-man shop in Canada and you can get his preamps via Ebay. He's also a friendly/accessible/helpful guy, so don't hesitate to reach out to him if you have questions specific to your project idea. I have had basses with ACG EQ-01 and EQ-02 preamps, I own an Alembic, and I've played around with trying Alembic filters in other basses. The JTEX Distiller, in my experience is essentially identical in function to an Alembic filter with the 3 position resonance/Q switch, plus the battery life is better and it's compatible with just about any kind of pickup (as far as I know).

My filter fleet:

View attachment 4902542

have you compared the J-TEX with the Underhill ?

 

[mellowgerman]

have you compared the J-TEX with the Underhill ?

Sorry to say that I do not have any experience with the Underhill preamp.

 

[Mister_GothFrak]

I was going to get all of them and compare but, the more I think about it, the more I feel like I should just build the OSH copyleft Passingwind one!

 

[Passinwind]

I was going to get all of them and compare but, the more I think about it, the more I feel like I should just build the OSH copyleft Passingwind one!

I'm currently testing a new PCB and some very promising lower current opamps for onboard builds, FWIW.

 

[Jared Lash]

Bump to an old thread, but if anyone is interested I have three basses arriving soon with different filter preamps.

Two four strings (one fretted, one fretless) with Turner Multicoils. One has the Lusithand NFP Special Mk II and one with the Underhill "The Full English".

The third bass has Nordstrand PolyVox pickups and the Underhill "Cali Dub" with a push/pull treble boost added.

I also owned a fretless for years that had the ACG EQ02. It was the first commercially available ACG/East preamp with a single filter.

And I owned two ACGs with the EQ03 preamps, one with Multicoils and one with the FB pickups.

I've played a few Wals, including recording an album with one owned by the studio, but that was over 20 years ago now.

If anyone is interested I can give my thoughts on any or all of these preamps.

 

[LowWay]

Considering my current exploration of these kinds of preamps, I’d love your thoughts.