Struggling with ACG pre

[lowlandtrees]

Bought a 2007 ACG Recurve with a retro fitted John East designed 02 pre. I think it had the 01 pre earlier, all the work done by John Cringean. I have had it a couple of months but I am struggling with it and am on the fence about punting it. I don’t want to tbh, it’s such a lovely player. Very comfortable, lightweight and best neck I’ve ever played. I am of course used to big standard bass controls and I realise this pre is different. I have followed the set up instructions but still not happy. So much tweaking to get a sound! It is so sensitive, the slightest dial movement totally changes the sound. 

[Geek99]

Why don’t you message John east himself ? He is on here, and when I called the number on his website he himself answered and was very helpful 

[ped]

My advice - if it doesn’t sound great with everything flat, it won’t sound greater with a pre. Sweeping statement I know but you have to start off with a great core tone. 

[MoonBassAlpha]

I wouldn't punt it based on the preamp. East does a bunch of other more conventional preamps you would find easier to work with,  and easy to change, as they are  solderless connectors. This preamp would probably fly out of the classified ads if the price was right. 

[lowlandtrees]

28 minutes ago, Geek99 said:

Why don’t you message John east himself ? He is on here, and when I called the number on his website he himself answered and was very helpful 

He designs them for Alan Cringean. Don’t think it’s built by JE?

[lowlandtrees]

I have messaged ACG . He reckons it’s perseverance. It’s possibly a skill in itself 

[Geek99]

13 minutes ago, lowlandtrees said:

He designs them for Alan Cringean. Don’t think it’s built by JE?

Probably is.
You don’t clarify exactly how you’re struggling with it 

Edited March 28, 2021 by Geek99

[ezbass]

3 minutes ago, lowlandtrees said:

I have messaged ACG . He reckons it’s perseverance. It’s possibly a skill in itself 

It shouldn’t be hard. As @ped says, if you can’t get a tone you like from a flat eq, you’re probably on a hiding to nothing. Is there a passive option? If there is, how do the pickups sound to you unprocessed (or for a value of unprocessed)? If you don’t like the core tone of the pickups, they may not be for you.

[BassBunny]

The ACG pre-amp is not a conventional cut/boost pre. There is no "flat" . It's a filter based pre-amp like Wal use.

It needs a completely different thought process to setting it up and once you dial in the tone you want from each pickup, that's it. I've got 2 ACG's with Alan's pre-amps and it's worth percevering.

One of the members on here, Pete @GreeneKing wrote a very comprehensive "how it works" guide which explains it very well. I should still have a copy so I'll send it to you.

If you still don't get on with it, swap the pre-amp out for an East Uni-pre and sell the ACG. They normally sell very quickly as are in demand.

[Elfrasho]

I must say, I struggled abut with my acg pre for the first wee while too. Not ensure what I have but it's bass mid(sweepable) high with a pull pot for ultra high. In fact, I found its output was actually clipping the input of my b3n. 

 

But persevering with it is the best advice I can give. You'll get used to it, and you'll find the little settings you like. 

I find I tend to roll off a tiny bit if bass and push low mids. Or sometimes I go the complete opposite.. Push bass and treble and remove the mids! Very powerful! 

 

[BassBunny]

1 minute ago, Elfrasho said:

I must say, I struggled abut with my acg pre for the first wee while too. Not ensure what I have but it's bass mid(sweepable) high with a pull pot for ultra high. In fact, I found its output was actually clipping the input of my b3n. 

 

But persevering with it is the best advice I can give. You'll get used to it, and you'll find the little settings you like. 

I find I tend to roll off a tiny bit if bass and push low mids. Or sometimes I go the complete opposite.. Push bass and treble and remove the mids! Very powerful! 

 

That sounds like an East Uni-pre, which Alan also fits. The ACG pre-amp doesn't have treble/bass/mid controls.

It's a filter stack for each pick-up.

[Elfrasho]

12 minutes ago, BassBunny said:

That sounds like an East Uni-pre, which Alan also fits. The ACG pre-amp doesn't have treble/bass/mid controls.

It's a filter stack for each pick-up.

Good to know man, cheers. 

[lowlandtrees]

41 minutes ago, Geek99 said:

Probably is.
You don’t clarify exactly how you’re struggling with it 

It’s very bright. Great for funky pop stuff etc. I was hoping to get warmer and rockier tone out of it as well. To be fair my amp / speaker combo is also quite bright..quilter bass block /Greenboy but tried it through my EA micro as well. Maybe asking too much or have to spend more time on it. Just put new Newtone strings on which I love. Maybe they need playing in a bit more.

[Hellzero]

With filter based preamps, you have more to think like what's missing in my sound or what's prominent in my sound and start from that to tailor your sound, but it's quite difficult to use if you can't figure yourself how it's working.

If you already have troubles dialing in a decent sound with a semi-parametric mids control (frequency + cut/boost), forget the filter based preamp and swap it for a conventional preamp.

I would suggest the John East BTB-02 preamp (2 or 3 bands without any semi-parametric mids) which is the easiest to use and excellent sounding.

Just ask John who is the kindest man on earth to help you solve this "issue".

That said, I sincerely think that conventional filter based preamps are a total heresy as 80% of the people will NEVER get a decent sound out of it, because it's much harder to understand than a conventional 2, 3 or 4 bands preamp.

People want to pick up their bass and start playing and when hearing their sound, they want to be able to immediately correct it without figuring for 10 minutes which knob is doing what and thinking about sweep, curve, Q factor, frequency response, inductance, capacitance, sensitivity, impedance, matching impedance, etc of their pickup(s) and preamp.

If you're a tech nerd, these filter based preamps are definitely for you, if you're not forget them.

[Hellzero]

@lowlandtrees you can ask @mhoss32 to help you as he builds his own filter based preamps (and pickups) and fully understand them.

[chris_b]

I had Pete Stevens explain the Wal controls to me, twice, and I still never got it!! when I got home I had to sit down with the bass and fiddle until I got the sound I wanted. I never knew what I'd done, but it sounded pretty good.

[TheGreek]

I had one in my SC Harlot and, yes, they can be a nightmare to master (not saying that I did).

I fiddled with it till I found a tone that I liked then left it alone.

You're absolutely right about "best neck" - love the asymmetric design Alan uses...

Definitely persist with it... 

[mhoss32]

@lowlandtrees the ACG preamps are very sensitive indeed, i agree. the EQ01, EQ02 and EQ03 are all a very wide frequency sweep.

as @BassBunny says, there isn't really a "flat" response, because the idea is that the preamp is mimicking different frequency responses as you manipulate the pots.

all pickups have a natural frequency response of broadly the same shape, here is a plot that shows a bunch of different guitar pickups plotted next to one another:

you can see that they are all broadly flat until 2000(ish) hz, and then they have a peak and then the frequency drops away. when we say a preamp is giving a "flat" response, we really just mean it is letting the pickup's natural sound through unobstructed.

with a traditional boost/cut preamp, you're then applying boost or cut of different amounts at different frequencies. lots of different preamp makers allow for different levels of cut/boost, and at different frequencies, and this is generally what sets these preamps apart from one another.

with filter control preamps like ACG, Wal or Alembic, its better to think of them as mimicking the sounds of a lot of different passive setups in one instrument.

in a passive bass tone control, you have a pot that slowly pulls down that resonant peak, and then starts to roll off more and more high frequencies. here is a (exagerrated) plot of a normal tone control from the tone at 10, down to the tone at 0:

(with the tone at 0 you get a low mid "hump" which is the blue line, ignore that for now )

you can see more and more of the high frequencies being wicked away as the tone control is turned.

and different cap values change where the resonant peak and dropoff are:

what the filter preamps do is allow you to mimick these different tone controls with a smooth sweep. on the EQ02, the frequency knob sweeps from high frequency to low, and the resonance knob changes the height of the resonant peak.

here is a sweep from 500hz (red line) up to 5000hz (blue line)

and here is a resonant sweep from 0 (green line) up to 13db ( blue line)

the reason the ACG pre feels so sensitive, is that the frequency sweep on the bass filter stack is sweeping over a VERY wide range. all the way up to 6.3KHz, and down to below 100Hz i believe.

Alan then also has a treble stack, that allows the treble frequencies to be attenuated sperately.

I have an ACG EQ02 in one of my basses as well, and i know exactly what you mean. with the resosnance control all the way up (10db peak), even the tiniest movement of the frequency knob can make an enourmous difference to the sound. in reality with a resonant peak like that the frequency knob is acting like a wah wah pedal.

my advice on getting the best out of it would be this: try sweeping the low stack frequency up and down a few times with the resonance knob in different positions. when you can sweep it without the change feeling extremely unnatural leave the resonance control there. then treat the frequency knob as a "set and forget" control as well, find a spot where it gives you the right balance of low end and midrange growl.

then use the treble stack as you would a normal tone control. the lower knob chooses the actual sound of the high frequencies, and the upper knob decides how loud you want them to be. it really does take some getting used to, and i admit its certainly not for everyone, but you can get some really great sounds out of it if you give it a little time.

i hope all that hasn't just made it more confusing. if you want to learn more about low pass filtering the first page of my latest build log has some details about the different examples out there (wal, alembic, ACG etc)

(also, if you want to persevere with filter preamps but find the ACG too sensitive / complicated, im working on some at the moment that are based around Wal's current control setup, but that will let you choose how wide you want the sweep to be.)

id also second the general advice that you shouldnt give up on a great bass because of the preamp. swapping out electronics is a great way to change the sounds you get out of a bass without major surgery

 

 

 

[Hellzero]

Told you that @mhoss32 knew what he was doing. 😉

[skelf]

There is no flat as such with a filter preamp the filters are engaged all the time. (Unless you have the ACG DFM which has an active/passive option) This is a common misunderstanding made by people who don't really understand how they work. There is however a close to flat as you can get setting.

Stack 1 is the volume/blend.

Stack 2 Upper ring fully of. Lower ring full on. This is the filter fully open so the full range allowable by the filter is allowed through.

Stack 3 as stack 1

Stack 4. Upper ring fully of. This is a gain so with it fully off the highness filter does nothing so the lower rings position does not matter.

 

Both pickups are now useable with the blend and both filters are open the highpass disengaged.

The way I would go from there is to move the blend on to the bridge pickup. Then adjust the lower ring of stack 3 until you get something you like. I generally close the filter to a degree to cut the top end so I have a more mid heavy sound. 

Now move the blend to the neck pickup and do the same. I would normally generate the bottom end from there which again means closing the filter to remove the top end and some of the mids. 

So you have reduced the preamp to a Volume/Blend/Tone/Tone and that is basically all it is. 

Now use the blend to go between the two pickups to change the overall sound.

 

The upper ring on stack 2 and 3 just boost the effect of the filter cut off so you get more filter effect if you turn them up. I like them in the centre detent.

The preamp only appears complicated if you try to adjust every thing at the same time if you take it one thing at a time it is not that complicated but it does not work the way a 3 band does and most people approach it that way and generally can't get what they want. This is a common problem and it is why filter pre-amps are not that common people as a rule don't really get them. For those that get their head round it you will get sounds you will struggle to get with any other on board pre-amp. But there is a learning curve and some people just don't get on with them which is why I have always offered an alternative to the filter preamps. 

 

If you don't get on with the pre-amp and like the bass just replace the pre-amp would be my advice. Sell an 01 will not be difficult and the East Uni-Pre will fit the cavity it is what I use for builds that don't need the filters.

 

 

 

 

 

Edited March 29, 2021 by skelf

[ezbass]

There’s some customer service, right there. Thanks for clarifying the ‘flat’ question @skelf, every day’s a school day.

[skelf]

I think I should also point out that the pre-amp has evolved and is now on the MK4. Original 01/02/03 had a very wide range covered by the lowpass filter. The original thinking behind this was to covert ranges of the Wal and the Alembic filter systems. The Wal  goes down lower than the Alembic the Alembic goes higher than the Wal. The DFM was a complete redesign on the filter pre-amp where I decided I want it to be a more focused pre-amp to cover more of what I liked rather than be all things to all men. The DFM reduced the top end of the lowpass filter down to 3.5kHz and removed the highpass filter. The highpass filter is a useful tool but so many people could not get how it worked it is counter intuitive. It was replaced with a sweepable mid/treble. The other feature added was an active/passive option. I am very happy with the DFM and don't see us doing anything else with its development.

 

 

 

 

 

PS. The 01 lowpass filter range was changed to match the DFM at the same time. 

Edited March 28, 2021 by skelf

[skelf]

34 minutes ago, ezbass said:

There’s some customer service, right there. Thanks for clarifying the ‘flat’ question @skelf, every day’s a school day.

No problem at all. 

 

Some times I wish I had never gone down the filter route it has made my life more difficult in that I spend a great deal of time explaining how it works. As I said some people it just clicks with I was one of them. The first time I picked up a Wal I fell in love with the pre-amp could not understand why everyone was not using filter pre-amps. But I very quickly realised I was in a minority but I still to this day think it is a great system for bass. Hence spending a lot of money to develop the system with John but some times at shows when I hear myself saying the same thing all day just some times I think passive is the way to go.

Edited March 28, 2021 by skelf

[binky_bass]

2 hours ago, skelf said:

some times at shows when I hear myself saying the same thing all day just some times I think passive is the way to go.

The new 'simplified' ACG prototype...

[lowlandtrees]

14 hours ago, skelf said:

No problem at all. 

 

Some times I wish I had never gone down the filter route it has made my life more difficult in that I spend a great deal of time explaining how it works. As I said some people it just clicks with I was one of them. The first time I picked up a Wal I fell in love with the pre-amp could not understand why everyone was not using filter pre-amps. But I very quickly realised I was in a minority but I still to this day think it is a great system for bass. Hence spending a lot of money to develop the system with John but some times at shows when I hear myself saying the same thing all day just some times I think passive is the way to go.

I think sound is very high on the agenda for most bassists and I certainly am always looking for ways to improve it. It was one of my lockdown goals in fact, to move my sound forward. That’s the reason I went for this particular bass/pre combination. I first saw it on the Maruszczyk range. 
When you see the demo of someone who knows how to use the pre it’s very impressive and looks intuitive! I will persist and get to know it better...as I said, it’s a hidden art in itself. Thanks for all the feedback....now back to the bedroom noodling and tweaking.