1999 Chevrolet Blazer - Stereo Integrity, Ground Zero, Soundstream

[gckless]

Zed issues v.2:

http://youtu.be/lVYU42yfaXI

I have no idea what it is. Anyone know about Zed?

[gckless]

So apparently that light is an indicator for when the high voltage rails are turning on, or something to that effect. Which is cool, nothing wrong with that, actually a nice feature. But what is wrong is the fact that the amp kinda resets, or output at least flickers, when those rails switch off.

Of course, I don't fully understand how all that works, so this might not be accurate.

[treylittlefield]

So apparently that light is an indicator for when the high voltage rails are turning on, or something to that effect. Which is cool, nothing wrong with that, actually a nice feature. But what is wrong is the fact that the amp kinda resets, or output at least flickers, when those rails switch off.

Of course, I don't fully understand how all that works, so this might not be accurate.

damn beat me to it. thats exaclty what it does, didnt know what the hell mine was doing, and i asked mantz, lol kinda weird its cutting out, or is it the video? that frontstage sounds soooo damn good man.

[gckless]

So apparently that light is an indicator for when the high voltage rails are turning on, or something to that effect. Which is cool, nothing wrong with that, actually a nice feature. But what is wrong is the fact that the amp kinda resets, or output at least flickers, when those rails switch off.

Of course, I don't fully understand how all that works, so this might not be accurate.

damn beat me to it. thats exaclty what it does, didnt know what the hell mine was doing, and i asked mantz, lol kinda weird its cutting out, or is it the video? that frontstage sounds soooo damn good man.

It was cutting out whenever it switched off the high voltage rails, for some reason is was shutting the MOSFETs off or something like that. I still have to talk to Stephen and find out exactly what it was. He said when I called him initially he had never heard of this problem since the Levi existed. The amp was sent to Stephen a week ago, got there Monday, and apparently shipped out Wednesday. Was hoping to have it back today but no sign of it yet

But yeah man, it sounded awesome. Tons of power on that amp, actually smelled coils of the Anarchy's once (and I turned the amp down after that lol), and that is pure clean power, nothing clipped. But it sounded sweet as hell and got loud, can't wait to get this thing back.

[gckless]

Got the Levi back tonight. No pics, but it looks the same. This was written on the contact info page I sent with the amp:

Installed it, functionally it seems fine so far. Got my fingers crossed, because if I have to take this out again, it's getting replaced with a Zapco.

Got it tuned up a bit, had to run the auto-EQ twice because the first time was complete booger. Here's what I am getting on the RTA (and again, pay attention to the blue lines):

This was my first full-range sweep after the auto-EQ:

Sub was too high, and there's a bunch of things to fix.

Then I did a 20-1500Hz sweep. Sub was too high, but ignore that for now. This first sweep was at 80Hz crossover point:

Compare that to the same sweep, same volume, only crossed at 63Hz this time:

Much smoother transition between the drivers. Looks like my sub falls off quick after around 65Hz or so. Gonna confirm this tomorrow and run a sweep with the sub running without a LPF. Either way, I like crossing at 63Hz right now. Smoother transition, my mids can handle it, and I can get a little more punch out of the subs before localization kicks in.

After about an hour of tuning and playing around, I am left with this today:

Pretty sure I'm just gonna bump up the level on the tweeters one notch and see how that does.

One thing I did notice when setting gain with a 0dB track is that it started to clip around 36V on a bridged channel, which is around 160W at 8ohms, which is much less than what I should be getting. It's possible I was screwing something up, so I'm not blaming the amp, and it's really not even an issue right now as my mids are really moving set at around 110W, but it's something I want to test.

[gckless]

Played with T/A tonight! Kinda embarrassed to admit, was my first time actually adjusting T/A. And I think I got it adjusted pretty damn well actually. The auto-T/A on the HU really screwed it up, my driver mid was set at 75" for example. So, I just played around a little, used the distance it set for my driver tweeter as a distance, and just kinda measured the rest with my arm. Played with the distance around where I thought it should be, and eventually nailed it down pretty decent IMO. I really wished I had a dude into SQ here so I could bounce ideas off of him and get feedback.

Then I moved to my EQ. Used pink noise this time. I played around for a few minutes, and found a lul at around 100Hz. So, turned off my subs, and here's the graph I have:

Turned my subs back up to SQ level (which is a twat hair above 1/4 on my PAC LC-1), and here is my graph as it stands:

I see three problems:

- There is a lull at 100Hz

- Spike at 150Hz

- Spike at 1kHz

I'm pretty sure this is all due to installation. There's not a whole lot I can do right now (that I know of). I should be getting my door panels back soon, so hopefully that will solve one or both of the lower frequency anomalies.

All in all I'm very happy with it after tonight.

[gckless]

Looks pretty good at night

It's kinda bright though. Might hit the LEDs with some dark blue nail polish and dim them a bit.

[gckless]

So, figured out my problem with staging: windows. Must be getting nasty reflections, because when the windows are up the stage is a little confusing, not immediately localizable (is that a word?), and scattered. With the windows down, the stage immediately moves to about 4" to the right of directly in front of me, and past the dash. It's magical.

Guess I'm just keeping my windows open from now on

[gckless]

Scope time!

So, went out and scoped my Levi. I was only getting around 160W @ 8ohms on a bridged channel (which is rated at 380W @ 8ohms) where the clipping lights came on, so I needed to investigate. What I found was that I was getting much more power capability after the clipping lights came on, with on caveat: I am seeing harmonic distortion.

So here are two videos I shot. Sorry about the poor lighting. Keep in mind that the clipping lights came on the amp around 36V. This was tested with a 1k 0dB tone, an on a pair of channels bridged.

http://www.youtube.com/watch?v=DW0VFXOGP6E&feature=youtu.be

http://www.youtube.com/watch?v=l24HcfUwDM4&feature=youtu.be

Now I know it's the amp inducing the harmonic distortion. Verified by putting HU on volume 20/62, where there was no distortion at all, and then turning the level up on the amp. I also then turned the HU up to volume 50/62, and turned the amp level down to where distortion went away. Both times distortion started at ~16VAC.

On the plus side the amp has much more power than I thought (based on the clipping indicators), if I don't mind that distortion. I honestly can't hear it, so.....

Couple questions:

- What would make an amp do this? Is it truly a bum amp altogether?

- Why would the clipping indicators be lighting up that early?

- Is this distortion bad? Should I even mind it?

- What are your recommendations?

I'm seriously considering going with a Zapco Z-150.6, and will more than likely swap out shortly.

[kryptonite]

Lookin good! Awesome how you take the time to figure all of that out.