• TalkBass has been independent since 1998. Add your voice.
    Create a free account to reply to discussions, view embedded media, and browse with fewer display ads.
    Join free Log in
    Want zero display ads or expanded classifieds tools? Compare plans.

Do all MEC Electronic (Warwick basses) preamps hiss?

M

MusicBear

Jan 22, 2010
188
30
East coast, USA
#1
I've worked on a fair number of Warwick active basses fitted with MEC Electronics' preamplifiers, some which include MEC active pickups as well, and it seems that they all have a very noticeable amount of white noise hiss in the background. Much of this hiss will disappear when the active EQ is bypassed (volume knob pulled up).

Is this a characteristic of MEC preamps? Do they all hiss, or am I just finding ones that have problems?

I have worked with active systems from Fender, G&L, Ibanez, Bartolini, EMG, Alembic, Fishman, LR Baggs, Shadow, and many more, and I do not recall such consistent background hiss or noise from any except the MEC Electronics-equipped instruments.
 
#6
I think it depends on the room, your rig and so on as much as its about the electronics. With warwick I had more issues with ground noise than anything. In one studio I went to I a actually took a wire and connected one end to the bridge and the other I tucked in side my pants waistline to cut out some noise. I have had issues especially with the thumb bass of some how picking up radio signals but that was a while back.

As far as hiss are you boosting the highs a lot? I generally played the 2 band pre warwicks (for example the thumb bolt on) with the 3 band (thumb nt and fna I did all kinds of stuff. Boosted mids, lows, but for more attack i rolled back the volume a hair to get a little more "string noise" because rolling up the highs was pretty harsh sounding. If you have a cab with a horn and your boosting the highs it is going to have a hiss
 
#7
Nephilymbass said:
I think it depends on the room, your rig and so on as much as its about the electronics. With warwick I had more issues with ground noise than anything. In one studio I went to I a actually took a wire and connected one end to the bridge and the other I tucked in side my pants waistline to cut out some noise. I have had issues especially with the thumb bass of some how picking up radio signals but that was a while back.

As far as hiss are you boosting the highs a lot? I generally played the 2 band pre warwicks (for example the thumb bolt on) with the 3 band (thumb nt and fna I did all kinds of stuff. Boosted mids, lows, but for more attack i rolled back the volume a hair to get a little more "string noise" because rolling up the highs was pretty harsh sounding. If you have a cab with a horn and your boosting the highs it is going to have a hiss
Click to expand...
I have not noticed any unusual amount of ground noise or hum from the Warwick basses - no more so that from the other basses I mentioned in my original post. High-frequency "white noise" hiss has been the kicker!

I am using a G-K 200MB amp - single 12" speaker and no HF driver. Amp controls set "flat." Also, controls on the Warwick basses "flat" (at the center detent position).

It is possible that I am seeing older Warwick basses with earlier revision electronics. I've heard that some of their preamps are now up to Rev. 3 or even Rev. 4. I found a recommendation that changing the TL062 and TL064 op-amps to TL072 and TL074 will quiet the hiss, but an increased current draw will shorten battery life.
 
#10
it is quite possible that "flat" on your GK is not, in fact, flat.

Not sure if this has anything to do with the effects you are seeing, but GK (like many others) has on a number of its amps a tonal response curve that is not flat with controls at default.. an extra 6dB at 3-5kHz would certainly enhance any amp hiss.

I have plotted my two amps..BG250 and GB Streamliner and they are very different, so perhaps i would suggest posting in the amp sub forum to see in anyone has plotted for your amp a) the default response and b) the controls for a flat response

MusicBear said:
I have not noticed any unusual amount of ground noise or hum from the Warwick basses - no more so that from the other basses I mentioned in my original post. High-frequency "white noise" hiss has been the kicker!

I am using a G-K 200MB amp - single 12" speaker and no HF driver. Amp controls set "flat." Also, controls on the Warwick basses "flat" (at the center detent position).

It is possible that I am seeing older Warwick basses with earlier revision electronics. I've heard that some of their preamps are now up to Rev. 3 or even Rev. 4. I found a recommendation that changing the TL062 and TL064 op-amps to TL072 and TL074 will quiet the hiss, but an increased current draw will shorten battery life.
Click to expand...
 
#12
mystic38 said:
it is quite possible that "flat" on your GK is not, in fact, flat.

Not sure if this has anything to do with the effects you are seeing, but GK (like many others) has on a number of its amps a tonal response curve that is not flat with controls at default.. an extra 6dB at 3-5kHz would certainly enhance any amp hiss.

I have plotted my two amps..BG250 and GB Streamliner and they are very different, so perhaps i would suggest posting in the amp sub forum to see in anyone has plotted for your amp a) the default response and b) the controls for a flat response
Click to expand...
My comment about the controls on both the amp and the bass was to address questions about whether or not I might be boosting higher frequencies in ways that might emphasize any hiss in an undesirable fashion.

I am aware that when all the controls are centered on my G-K the response is not "flat" in the engineering sense. Musical instrument amplifiers, whether they are for electric guitar, bass, or acoustic guitar have tone circuits that are optimized for their expected instrument. Switches such as "Shape" and "Contour" alter the frequency response further away from "flat."

Amplifiers that are intended to reproduce source material without any coloration can be truly "flat." This includes stereos and PA systems.
 
#13
fair enough regarding the hiss..but a reader of your post would assume (my italics) that since all bass amps are for a bass then their responses would be similar...and that is as far from reality as is possible, ..... some are flat, some are mid scooped, some are prescence and treble enhanced..

MusicBear said:
My comment about the controls on both the amp and the bass was to address questions about whether or not I might be boosting higher frequencies in ways that might emphasize any hiss in an undesirable fashion.

I am aware that when all the controls are centered on my G-K the response is not "flat" in the engineering sense. Musical instrument amplifiers, whether they are for electric guitar, bass, or acoustic guitar have tone circuits that are optimized for their expected instrument. Switches such as "Shape" and "Contour" alter the frequency response further away from "flat."

Amplifiers that are intended to reproduce source material without any coloration can be truly "flat." This includes stereos and PA systems.
Click to expand...
 
#15
(Reviving an old thread to summarize what I learned.)

I recently bought a 2000 Thumb NT4 with the 18V pre-amp and the TL062/TL064 ICs. It hisses badly when the active EQ is engaged (when the top knob of the push/pull Volume/Balance control is down).

I've read threads that recommend replacing the two TL062 and TL064 pre-amp ICs with a TL072 and TL074. That reduces noise at the expense of shorter battery life.

You can reduce the noise further by swapping the TL062 for an AD822. I did that long ago with my Music Man StingRay. Again, it trades lower noise for shorter battery life.

I actually did these mods and the reduction in hiss was a lot!
 
Last edited:
#18
replacing the ICs with TL072 and TL074
Click to expand...

FWIW, there's more to noise in a preamp than just the opamps. The design itself, plus the quality and materials that make up the resistors and caps. But yeah using a higher spec opamp will certainly help. The old yamaha TRBs were full of tl062s back in the day. A very nice bass with an underwhelming pre. Back in the 90's, I knew a busy tech in Sydney that had a draw full of replaced TRB preamps.

These days there are opamps with as good or better noise specs than the tl072, that also have very low current draw. Every designer has his/her favourites. You have to trawl through all the manufacturer's listings. In general, you can't have low current, low noise, and high slew rate in one device. So for battery operated stuff at audio frequencies, obviously you compromise with slew rate. They are bringing out new ones every day. The option of 8-pin dip are disappearing, but with a steady hand and a magnifying glass, you can use an smt adapter.
 
  • Like
Reactions: LenMinNJ
#20
RobbieK said:
...So for battery operated stuff at audio frequencies, obviously you compromise with slew rate. They are bringing out new ones every day. The option of 8-pin dip are disappearing, but with a steady hand and a magnifying glass, you can use an smt adapter.
Click to expand...

If you have recommendations, they'd be appreciated.
 

Latest posts

Top Bottom
Back