Genz-Benz Streamliner Part 5

[KJung]

IMO, Eublet choose a reasonable scale, given what he intended to show. I don't think his plots are misleading, nor do I think that a smaller vertical scale which shows more "bumps" would be misleading, at least if the reader understands what they are reading (i.e. they look at the size of the units used in the plot). I agree with Tom that if you choose a large enough vertical scale, all amps look flatter than they are in reality, and that this would provide some sort of aesthetic advantage for those who think that flat response is good... but low resolution of actual visual data for comparison.

Are such plots an accurate representation of the sound of a given amp? Somewhat.... as they show static frequency response, yet fail to show other factors like various distortions, phase, and dynamic response. So, while useful, such information is still incomplete. Still, I'd rather have amplifier response plots for comparison, even if they aren't perfect.

+1 all the way. My comments were more 'in general' versus having to do with Eublet's nice little plots which address a specific issue and are nicely presented within that context.

 

[wateroftyne]

First gig using my P last night!

Like my J, it also has old flats on it. I rolled the lows back to 9:30, pushed the low mids a bit, and left the treble at 12.

Totally, totally wonderful.. punchy, tight mids... rich, smooth highs.. it drove the band along better than any amp I've owned.

Our bandleader, who's also a live & studio engineer of many years standing, commented how much he liked it. Much more clarity, punchier, etc. He also commented that it sounded more dynamic than the TC.

I completely adore this amp...

 

[wateroftyne]

I should also mention I experimented with the gain in and out. I like both, and couldn't choose between them...

 

[agedhorse]

NOISY BUZZ & 60 hz HUM UPDATE!

It came back! For some reason my Sterling HH is VERY sensitive to the laptop I use to play my music with. Now I've been doing this for months with my PHA-1 with no noise but with the Genz its loud as hell.

I got up & walked away from the laptop & amp, turned the bass away & the noise disappeared. I come back & it returns. I also noticed if I cut the bass to 9 & put my treble at noon I have less noise.
So YES there is a lot of noise with the SL but its dependent on the electronics around. Get your cell & laptop away, try to distance from the amp a bit.

The noise level from an EMI (electromagnetic radiation) source such as many laptops and switchmode power supplies that power laptops can be incredibly high, and some basses were never designed with the proper shielding against this noise, which takes some different techniques than the traditional shielding for more common (read as "old school") lower frequency noise. I suggest that you hook up with an instrument tech that supports the touring side of the industry as this is much more common and the pro's have come up with pretty good solutions for updating such instruments. Many (but not all) of the newer instruments have addressed this much better as the industry has become aware of the problem.

The more articulate the amp, and the higher the gain and number of conventional class A gain stages (limited PSSR in the circuit design of a traditional class A voltage amp), the more likely it is that this noise will be audible.

Also, double-check that you are using a shielded cable, and that it's not a simple ground loop between the laptop and the amp/bass. If the noise goes away when using battery power (not using the laptop's off-line power supply) then it's likely that the problem is a high frequency groundloop that's being picked up by the bass's electronics (like transformer coupling) rather than direct radiated EMI.

If you would like additional help troubleshooting this, PM me.

 

[hasbeen]

First gig using my P last night!

Like my J, it also has old flats on it. I rolled the lows back to 9:30, pushed the low mids a bit, and left the treble at 12.

Totally, totally wonderful.. punchy, tight mids... rich, smooth highs.. it drove the band along better than any amp I've owned.

Our bandleader, who's also a live & studio engineer of many years standing, commented how much he liked it. Much more clarity, punchier, etc. He also commented that it sounded more dynamic than the TC.

I completely adore this amp...

that's my setting with any cab, with my J bass and my Lakland. I'm pushing the 220 mids up to 2 o'clock.

 

[svtb15]

Agree.. I was getting noise from the motorized overhead Vari-Lites at times with my passive J bass.. When you have 50 above you, and they all move at the same time, i would get a hi freq motor noise.. It wasn't loud. but it was noticeable...I have no idea what they did but one day it just stopped..
And computers give off a weird digital glitching RF noise.. I have played basses with EMGs, and P basses which Never get noise for me ,also Bartolini PU basses and if you get to close to a laptop or computer that noise is present.. That RF, or whatever the Tech term for it is , does not remedied with normal shielding as you stated.

..

The noise level from an EMI (electromagnetic radiation) source such as many laptops and switchmode power supplies that power laptops can be incredibly high, and some basses were never designed with the proper shielding against this noise, which takes some different techniques than the traditional shielding for more common (read as "old school") lower frequency noise. I suggest that you hook up with an instrument tech that supports the touring side of the industry as this is much more common and the pro's have come up with pretty good solutions for updating such instruments. Many (but not all) of the newer instruments have addressed this much better as the industry has become aware of the problem.

The more articulate the amp, and the higher the gain and number of conventional class A gain stages (limited PSSR in the circuit design of a traditional class A voltage amp), the more likely it is that this noise will be audible.

Also, double-check that you are using a shielded cable, and that it's not a simple ground loop between the laptop and the amp/bass. If the noise goes away when using battery power (not using the laptop's off-line power supply) then it's likely that the problem is a high frequency groundloop that's being picked up by the bass's electronics (like transformer coupling) rather than direct radiated EMI.

If you would like additional help troubleshooting this, PM me.

 

[wateroftyne]

I have noticed that mine is a little noisy when my laptop right next to it. It's OK with headphones though, and it hasn't made a squeak at a gig...

 

[Tunaman]

The noise level from an EMI (electromagnetic radiation) source such as many laptops and switchmode power supplies that power laptops can be incredibly high, and some basses were never designed with the proper shielding against this noise, which takes some different techniques than the traditional shielding for more common (read as "old school") lower frequency noise. I suggest that you hook up with an instrument tech that supports the touring side of the industry as this is much more common and the pro's have come up with pretty good solutions for updating such instruments. Many (but not all) of the newer instruments have addressed this much better as the industry has become aware of the problem.

The more articulate the amp, and the higher the gain and number of conventional class A gain stages (limited PSSR in the circuit design of a traditional class A voltage amp), the more likely it is that this noise will be audible.

Also, double-check that you are using a shielded cable, and that it's not a simple ground loop between the laptop and the amp/bass. If the noise goes away when using battery power (not using the laptop's off-line power supply) then it's likely that the problem is a high frequency groundloop that's being picked up by the bass's electronics (like transformer coupling) rather than direct radiated EMI.

If you would like additional help troubleshooting this, PM me.

Appreciate the comments. Now that I know the sources of the noise I'm fine with it. I'm going to have to practice near the laptop but with a few EQ tricks & some moving of the power block, cellphones etc it can be minimized for sure & its not an issue.
Thanks!

 

[Red Planet]

When I need to work on or learn a tune, I use my Zune into the Aux in on my Genz Benz and play away.

 

[faulknersj]

Definetely a cool feature!!

 

[Eublet]

Okay, I said my graphs where amateurish, and here's the proof. I believe I had a ground loop when I made those first graphs. The result was a low-frequency hum that caused those bass curves to be so high. I think I've got this fixed. It didn't seem right to me that the bass would be bumped so high at 30-50hz on any head, much less one made by Genz Benz. Such a high boost at that depth would cause speakers to jump out of the cabs! I feel stupid for not realizing this when I looked at them, but apparently no one else did either so maybe we're all idiots!

Anyway, the scopes I'm doing now that I've figured this out have a MUCH better appearance, with a nice taper in those sub-lows. There's still a boost in the lows, but it's a very gradual knee that is probably centered around 85 hz or when flat, and that starts dropping significantly under 60 hz give or take. Adjustments of the bass knob also show some interesting stuff. I'm going to hold off a bit before I post anything else, but when I feel comfortable with what I have, I'll release it.

I'm also deleting those previous posts. Sorry, but they're just too far off to stay up at this point. Misinformation does no one any good. I'll open a new thread with the graphs for anyone who wants to participate, and we can go from there.

I'm not afraid to admit when I'm wrong...badly in this case.

 

[Vic]

I'll open a new thread with the graphs for anyone who wants to participate, and we can go from there.

Please PM me the link to that thread if you don't post it here. I do want to watch that.

 

[Eublet]

I will post the link here.

 

[agedhorse]

I just want to comment that analyzing circuit response, while seemingly simple from the casual observer's perspective, is extremely difficult to do accurately and repeatably since there are so many potential areas where errors can creep in, and these errors may also compound.

I think that anybody who has spent time trying to do this sort of thing for "real" has a much greater appreciation for the complexity of the process than the average or casual observer. Eublet's excercise is a great example, smart guys like Eublet have just as much trouble getting good results as the rest of the world. I have posted in the forums (especially the live audio forums) that it's critical to have high confidence that the data you are getting is good. Verification is very, very important to insure confidence that the data collected and the plots generated match the real world conditions.

 

[Eublet]

You know, the funny thing is I thought that I was making sure I was doing everything I could to get accurate results. Testing my Lexicon device by looping the sine wave back through it worked great. It never occurred to me that connecting the Streamliner would introduce the potential for a ground loop. Simply unplugging my laptop removed a lot of the errors I think I got in the first test, but there's still some things I want to make sure of before I think about posting any results again.

 

[12bass]

Looking forward to your revised results, Eublet.

 

[kesslari]

FWIW, all the discussion of how much you can mess with the EQ on this amp (and the results you can get) have got me enjoying it a lot more. With my previous GB amps, everything sounded great set pretty flat, with just a mild boost around 4-500K (I play mostly fretless).
Cutting the lows on the Streamliner has really helped. Or maybe I'm just learning to appreciate the sound.

 

[smeet]

I really like my Streamliner, but I was wondering about something. Why would GB voice an amp in such a way that 99% of users would need to cut the lows? I can't believe that any of the testers ran the eq flat during testing, so why not voice it closer to what almost everybody would use? I'm sure they knew almost everyone would cut lows, so doesn't it seem strange?

 

[ElMon]

I really like my Streamliner, but I was wondering about something. Why would GB voice an amp in such a way that 99% of users would need to cut the lows? I can't believe that any of the testers ran the eq flat during testing, so why not voice it closer to what almost everybody would use? I'm sure they knew almost everyone would cut lows, so doesn't it seem strange?

My guess and experience tells me that it's much easier and better sounding to cut back something that is there than it is to add in what isn't there in the first place. I set the amp with all knobs at noon when I first got it, and the only difference I made was that I ran my Sadowsky's pre completely flat for once and had PLENTY of thick lows. Definitely a useable sound that was balanced and would cut thru. YMMV of course, and I'm sure the Genz team will chime in on this.

 

[nemo]

I really like my Streamliner, but I was wondering about something. Why would GB voice an amp in such a way that 99% of users would need to cut the lows? I can't believe that any of the testers ran the eq flat during testing, so why not voice it closer to what almost everybody would use? I'm sure they knew almost everyone would cut lows, so doesn't it seem strange?

FYI, it is called "whomp".