[Date Prev][Date Next]   [Thread Prev][Thread Next]   [Date Index][Thread Index][Author Index]

Re: echoplex or jamman?

The circuit is so noisy that you really have to set the gain too close to
the headroom limit, even with the input gain mod.
-Chuck Zwicky

At 01:11 PM 10/29/98 -0800, you wrote:
>At 11:34 AM 10/29/98 -0600, Chuck Zwicky vitriolically wrote:
>>I have used both. The jamman sounds so much better it's shocking. The EDP
>>is very noisy. The EDP uses pre-emphasis/de-emphasis in their converter
>>topology, this means that any signals with a lot of high end, like from a
>>fuzzbox, will overload or alias like crazy. The EDP sounds subjectively
>>dull or cloudy compared to the jamman.
>If you have this problem, it means you have the input level set too high,
>and you are clipping the digital input. If you turn the input down a bit,
>the problem goes away. Every person I've every dealt with who had this
>complaint was happy after they knew how to set the input level right.
>Personally, I use the echoplex with drum loops containing lots of cymbals,
>and have no trouble with high end response at all. 
>On older units, the problem was compounded by too much gain in the input, 
>it was a little difficult to set properly. Most of the range of the input
>volume knob was way too loud, and people tended to have it way too high.
>That gain range was reset some time ago, so it's much easier to work with
>This has been covered here numerous times, and is also in the echoplex FAQ
>on the website. If you have an older unit and want to change how the input
>gain works, that mod is also in the FAQ.
>>I really wish that they had done a better job with the EDP circuit board
>>layout, so that the fidelity was higher. The seem to use a decent 
>>in the EDP, but Lexicon has such a great design team when it comes to
>>digital audio....
>I measured the Echoplex's audio characteristics on an Audio Precision 
>>From memory (sorry, I don't have the details with me...they all get ~):
>Signal-to-Noise Ratio (A-weighted): ~88dB
>Signal-to-Noise Ratio (unweighted): ~80dB
>Freq Response (+0/-3dB): 18Hz - 19.5KHz
>If you have the input signal too high, you definitely see the frequency
>response roll off in the high end. That's why it is important to set the
>input level correctly. I typically use the loudest signal with the most 
>end I expect to use (typically a crash cymbal, or a loud/clean skank 
>thing) in a loop to set the level to where it does not clip.
>Kim Flint, MTS                408-752-9284
>Chromatic Research            kflint@chromatic.com