Bass Guitar Electronics Question: passive to active conversion.

Mike Sorr

Mike Sorr

Supporting Member
Oct 24, 2012
3,009
3,157
4,926
Manchester, NJ
www.graceandpeace.org
#1
I have a passive Carvin B50 with two volumes and a tone control. It has their quieter H50A pickups. I would like to add a preamp to boost the signal a bit. What I need are suggestions about which preamp to consider that won't require major surgery to the bass. I like the EMG BTC but have been told that it can only be used with EMG pickups. Sounds like marketing to me, is there any truth to it? My plan is to keep the three control knobs with two volumes, but add a stacked bass/treble boost. Guidance would be appreciated. Thanks.
 
#2
People always say active pickups. It's wrong in a lot of cases. To be active, the pickups themselves are energized by the batteries and don't work unless energized. Most other active systems are passive pickups that run through an active pre. Those particular EMG pickups are truly ACTIVE PICKUPS. They don't work unless energized.

Audere makes a highly regarded onboard preamp.
 
  • Like
Reactions: Leo Smith and Mike Sorr
#4
One of the things that is causing me to consider going with an active pre is the idea that a 100% passive 5 string bass is probably not going to sound all that great and that the B string would benefit from a boost in signal. As I thought about that it occurred to me that you really don't see many passive 5s and that there must be a reason for that. I've owned active Carvin 5s in the past and all had B string that were pretty good for 34" scale basses. I just bought this one used at a great price, so I don't mind putting a few bucks into it, but I want to make sure I know what to buy before making dumb mistakes. I admit that I know nothing about the various inner workings of my basses. I just play them.
 
#6
wcriley said:
From the EMG website:


However, EMG preamps don't boost the signal much, if any, with the EQ knobs set at the detents.
Click to expand...

Not at detent, But that's what the 'Boost' is for- on bass, treble (BTC), and mids (BQC), including 'cut' also for the tonal balance desired, and the only difference is using the correct pots (bal and vol) for passive or active pickups.

18db of boost should be enough for most pickups.
 
#7
Mike Sorr said:
I have a passive Carvin B50 with two volumes and a tone control. It has their quieter H50A pickups. I would like to add a preamp to boost the signal a bit. What I need are suggestions about which preamp to consider that won't require major surgery to the bass. I like the EMG BTC but have been told that it can only be used with EMG pickups. Sounds like marketing to me, is there any truth to it? My plan is to keep the three control knobs with two volumes, but add a stacked bass/treble boost. Guidance would be appreciated. Thanks.
Click to expand...

The BTC's I've run across have been dirt cheap...relatively speaking. Keep an eye open on E-bay. I have BTC's in my Schack 5, G&L 1505, and some variation in my NS Design CR5 headless. They can be used with just about any pickup and are classified as "Controls" in the EMG catalog. "Systems" can only be used with EMG pickups.

EMG Pickups / Electric Guitar Pickups, Bass Guitar Pickups, Acoustic Guitar Pickups

They won't boost your signal at detent position but they are very nice for tone-shaping. I'm still trying to get a handle on which treble DIP switch setting sounds best!

Riis
 

Attachments

  • BTC_Control_0230-0206rB.pdf
    593.3 KB · Views: 202
  • Like
Reactions: Mike Sorr
#8
JustForSport said:
Not at detent, But that's what the 'Boost' is for- on bass, treble (BTC), and mids (BQC), including 'cut' also for the tonal balance desired, and the only difference is using the correct pots (bal and vol) for passive or active pickups.

18db of boost should be enough for most pickups.
Click to expand...
Don't get me wrong, I'm a big fan of EMG preamps. Mainly because they're pretty much transparent at the detents.

I just didn't want the OP to find out after installing it that there wouldn't be an overall boost.
 
#9
wcriley said:
I just didn't want the OP to find out after installing it that there wouldn't be an overall boost.
Click to expand...

Gotcha- yeah, at center/detent, there's no boost/gain to be noticed, but if the bass, treble, and mids (if BQC) are boosted, that's a lot of boost, and it's pretty clean, too. Some have too much treble with it boosted much, and some pickups (like EMG DCs) if bass-boosted much, can clip the amp input, so there's a lot of boost avail.
The Bart preamps have a gain trim-pot to boost the overall output, but I think with each BTC/BQC pot boosted just a little, it's sort of the same thing.
 
#10
Zooberwerx said:
The BTC's I've run across have been dirt cheap...relatively speaking. Keep an eye open on E-bay. I have BTC's in my Schack 5, G&L 1505, and some variation in my NS Design CR5 headless. They can be used with just about any pickup and are classified as "Controls" in the EMG catalog. "Systems" can only be used with EMG pickups.

EMG Pickups / Electric Guitar Pickups, Bass Guitar Pickups, Acoustic Guitar Pickups

They won't boost your signal at detent position but they are very nice for tone-shaping. I'm still trying to get a handle on which treble DIP switch setting sounds best!

Riis
Click to expand...

Thank you! I noticed that in the PDF file EMG recommends two 9 volt batteries "if you play very hard" and one 9 volt "if you play mildly or use a minimum of boost". Can someone explain the reason for this? What is the benefit of an 18 volt system over a 9 volt? I hear the term "added headroom" used as an explanation, but I'm not exactly sure what that means.
 
  • Like
Reactions: rufus.K
#13
Mike Sorr said:
Thank you! I noticed that in the PDF file EMG recommends two 9 volt batteries "if you play very hard" and one 9 volt "if you play mildly or use a minimum of boost". Can someone explain the reason for this? What is the benefit of an 18 volt system over a 9 volt? I hear the term "added headroom" used as an explanation, but I'm not exactly sure what that means.
Click to expand...

In lay terms, it means you have enough power in reserve to cleanly accommodate the peaks without clipping or distorting. If you have the room, go with the 18 v configuration. We were able to stick two 9 volts in the control cavity of my Schack, the G&L has only one, and the CR5 has two but we're also having to contend with a piezo system.

Riis
 
#15
mmbongo said:
Bartolini 3.3 A/P
Bartolini NTBT Preamps - Best Bass Gear

I love Bart pre's because they have adjustable gain controls where most other pre's do not. Very handy if you need more or less output, or need to match output with other basses.
Click to expand...

Any idea if this can be wired to run 18 volt? I assume most systems can, but since I have no idea about such things I had better ask. I know the BTC can be wired 9v or 18v.
 
#17
mmbongo said:
Yes, 18v is fine with Bart pre's.
Click to expand...

Cool, I think I'm going to go with this. Two more things: are you aware of any reviews or sound files for this? And, I'll be using this on a Carvin with knurled metal knobs, any reason I can't use the existing knobs? I know I'll have to call Carvin and get a stacked knob for the bass/treble control.

I lied, one more question. Just to save me the time of scouring the internet, where else do they sell this other than at the Best Bass Gear site?
 
#18
Mike Sorr said:
Cool, I think I'm going to go with this. Two more things: are you aware of any reviews or sound files for this? And, I'll be using this on a Carvin with knurled metal knobs, any reason I can't use the existing knobs? I know I'll have to call Carvin and get a stacked knob for the bass/treble control.

I lied, one more question. Just to save me the time of scouring the internet, where else do they sell this other than at the Best Bass Gear site?
Click to expand...

Planet Bass has them.
Bartolini HR 3.3AP/918 , High End Bass Guitars, Amps & Bass Strings

All of the Bart NTMB pre's are the same, so if you hear sound clips of a Bart preamp, you're hearing the 3.3. The difference is in how the pots are configured. No reason your knobs shouldn't work.
 
#19
Mike Sorr said:
One of the things that is causing me to consider going with an active pre is the idea that a 100% passive 5 string bass is probably not going to sound all that great and that the B string would benefit from a boost in signal.....
Click to expand...

I have two passive 5's right now, had a third, and there's nothing inherently wrong with a passive 5. I suspect many 5's are active merely because 5 strings are somewhat "trendy" and active preamps are somewhat trendy as well. It's not a signal strength issue (typically).

Don't get me wrong, I wish you success with your active conversion, but there's typically not a problem with the low B's signal strength (granted there might be instances of setup issues, or pickup height issues, or perhaps some pickups may not be wound to optimize the B string). The reality is that the speakers are typically the weak link in a system with a 5 string, and boosting the lows are going to be counterproductive.

A hot pickup can give a 2 or 3 volt peak-to-peak signal, maybe even 4, without a preamp. That's more than ample to drive a typical input tube into saturation, no preamp required. An onboard preamp does act nicely as an impedance buffer, should one be desired.

Again, I'm not trying to dissuade you from your efforts, but rather let's clarify exact what the goals are and what could/should be obtained from adding an onboard preamp.
 
#20
It would be going into a Carvin B50 with two of their H50A stacked humbuckers. From what I read the H50A pickups have a lower output than their J99A pickups which are supposed to be very hot and sound great, but are crazy noisy when soloed. I was thinking about adding the preamp to give the H50A pickups a boost.
 
You must log in or register to reply here.
Top Bottom
Back